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1/*
2 * linux/mm/page_alloc.c
3 *
4 * Manages the free list, the system allocates free pages here.
5 * Note that kmalloc() lives in slab.c
6 *
7 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
8 * Swap reorganised 29.12.95, Stephen Tweedie
9 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
10 * Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
11 * Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
12 * Zone balancing, Kanoj Sarcar, SGI, Jan 2000
13 * Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
14 * (lots of bits borrowed from Ingo Molnar & Andrew Morton)
15 */
16
17#include <linux/stddef.h>
18#include <linux/mm.h>
19#include <linux/swap.h>
20#include <linux/interrupt.h>
21#include <linux/pagemap.h>
22#include <linux/jiffies.h>
23#include <linux/bootmem.h>
24#include <linux/memblock.h>
25#include <linux/compiler.h>
26#include <linux/kernel.h>
27#include <linux/kmemcheck.h>
28#include <linux/module.h>
29#include <linux/suspend.h>
30#include <linux/pagevec.h>
31#include <linux/blkdev.h>
32#include <linux/slab.h>
33#include <linux/ratelimit.h>
34#include <linux/oom.h>
35#include <linux/notifier.h>
36#include <linux/topology.h>
37#include <linux/sysctl.h>
38#include <linux/cpu.h>
39#include <linux/cpuset.h>
40#include <linux/memory_hotplug.h>
41#include <linux/nodemask.h>
42#include <linux/vmalloc.h>
43#include <linux/vmstat.h>
44#include <linux/mempolicy.h>
45#include <linux/stop_machine.h>
46#include <linux/sort.h>
47#include <linux/pfn.h>
48#include <linux/backing-dev.h>
49#include <linux/fault-inject.h>
50#include <linux/page-isolation.h>
51#include <linux/page_cgroup.h>
52#include <linux/debugobjects.h>
53#include <linux/kmemleak.h>
54#include <linux/compaction.h>
55#include <trace/events/kmem.h>
56#include <linux/ftrace_event.h>
57#include <linux/memcontrol.h>
58#include <linux/prefetch.h>
59#include <linux/mm_inline.h>
60#include <linux/migrate.h>
61#include <linux/page-debug-flags.h>
62#include <linux/hugetlb.h>
63#include <linux/sched/rt.h>
64
65#include <asm/sections.h>
66#include <asm/tlbflush.h>
67#include <asm/div64.h>
68#include "internal.h"
69
70/* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
71static DEFINE_MUTEX(pcp_batch_high_lock);
72
73#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
74DEFINE_PER_CPU(int, numa_node);
75EXPORT_PER_CPU_SYMBOL(numa_node);
76#endif
77
78#ifdef CONFIG_HAVE_MEMORYLESS_NODES
79/*
80 * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
81 * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
82 * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
83 * defined in <linux/topology.h>.
84 */
85DEFINE_PER_CPU(int, _numa_mem_); /* Kernel "local memory" node */
86EXPORT_PER_CPU_SYMBOL(_numa_mem_);
87#endif
88
89/*
90 * Array of node states.
91 */
92nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
93 [N_POSSIBLE] = NODE_MASK_ALL,
94 [N_ONLINE] = { { [0] = 1UL } },
95#ifndef CONFIG_NUMA
96 [N_NORMAL_MEMORY] = { { [0] = 1UL } },
97#ifdef CONFIG_HIGHMEM
98 [N_HIGH_MEMORY] = { { [0] = 1UL } },
99#endif
100#ifdef CONFIG_MOVABLE_NODE
101 [N_MEMORY] = { { [0] = 1UL } },
102#endif
103 [N_CPU] = { { [0] = 1UL } },
104#endif /* NUMA */
105};
106EXPORT_SYMBOL(node_states);
107
108/* Protect totalram_pages and zone->managed_pages */
109static DEFINE_SPINLOCK(managed_page_count_lock);
110
111unsigned long totalram_pages __read_mostly;
112unsigned long totalreserve_pages __read_mostly;
113/*
114 * When calculating the number of globally allowed dirty pages, there
115 * is a certain number of per-zone reserves that should not be
116 * considered dirtyable memory. This is the sum of those reserves
117 * over all existing zones that contribute dirtyable memory.
118 */
119unsigned long dirty_balance_reserve __read_mostly;
120
121int percpu_pagelist_fraction;
122gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
123
124#ifdef CONFIG_PM_SLEEP
125/*
126 * The following functions are used by the suspend/hibernate code to temporarily
127 * change gfp_allowed_mask in order to avoid using I/O during memory allocations
128 * while devices are suspended. To avoid races with the suspend/hibernate code,
129 * they should always be called with pm_mutex held (gfp_allowed_mask also should
130 * only be modified with pm_mutex held, unless the suspend/hibernate code is
131 * guaranteed not to run in parallel with that modification).
132 */
133
134static gfp_t saved_gfp_mask;
135
136void pm_restore_gfp_mask(void)
137{
138 WARN_ON(!mutex_is_locked(&pm_mutex));
139 if (saved_gfp_mask) {
140 gfp_allowed_mask = saved_gfp_mask;
141 saved_gfp_mask = 0;
142 }
143}
144
145void pm_restrict_gfp_mask(void)
146{
147 WARN_ON(!mutex_is_locked(&pm_mutex));
148 WARN_ON(saved_gfp_mask);
149 saved_gfp_mask = gfp_allowed_mask;
150 gfp_allowed_mask &= ~GFP_IOFS;
151}
152
153bool pm_suspended_storage(void)
154{
155 if ((gfp_allowed_mask & GFP_IOFS) == GFP_IOFS)
156 return false;
157 return true;
158}
159#endif /* CONFIG_PM_SLEEP */
160
161#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
162int pageblock_order __read_mostly;
163#endif
164
165static void __free_pages_ok(struct page *page, unsigned int order);
166
167/*
168 * results with 256, 32 in the lowmem_reserve sysctl:
169 * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
170 * 1G machine -> (16M dma, 784M normal, 224M high)
171 * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
172 * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
173 * HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
174 *
175 * TBD: should special case ZONE_DMA32 machines here - in those we normally
176 * don't need any ZONE_NORMAL reservation
177 */
178int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
179#ifdef CONFIG_ZONE_DMA
180 256,
181#endif
182#ifdef CONFIG_ZONE_DMA32
183 256,
184#endif
185#ifdef CONFIG_HIGHMEM
186 32,
187#endif
188 32,
189};
190
191EXPORT_SYMBOL(totalram_pages);
192
193static char * const zone_names[MAX_NR_ZONES] = {
194#ifdef CONFIG_ZONE_DMA
195 "DMA",
196#endif
197#ifdef CONFIG_ZONE_DMA32
198 "DMA32",
199#endif
200 "Normal",
201#ifdef CONFIG_HIGHMEM
202 "HighMem",
203#endif
204 "Movable",
205};
206
207int min_free_kbytes = 1024;
208int user_min_free_kbytes = -1;
209
210static unsigned long __meminitdata nr_kernel_pages;
211static unsigned long __meminitdata nr_all_pages;
212static unsigned long __meminitdata dma_reserve;
213
214#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
215static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
216static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
217static unsigned long __initdata required_kernelcore;
218static unsigned long __initdata required_movablecore;
219static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
220
221/* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
222int movable_zone;
223EXPORT_SYMBOL(movable_zone);
224#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
225
226#if MAX_NUMNODES > 1
227int nr_node_ids __read_mostly = MAX_NUMNODES;
228int nr_online_nodes __read_mostly = 1;
229EXPORT_SYMBOL(nr_node_ids);
230EXPORT_SYMBOL(nr_online_nodes);
231#endif
232
233int page_group_by_mobility_disabled __read_mostly;
234
235void set_pageblock_migratetype(struct page *page, int migratetype)
236{
237 if (unlikely(page_group_by_mobility_disabled &&
238 migratetype < MIGRATE_PCPTYPES))
239 migratetype = MIGRATE_UNMOVABLE;
240
241 set_pageblock_flags_group(page, (unsigned long)migratetype,
242 PB_migrate, PB_migrate_end);
243}
244
245bool oom_killer_disabled __read_mostly;
246
247#ifdef CONFIG_DEBUG_VM
248static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
249{
250 int ret = 0;
251 unsigned seq;
252 unsigned long pfn = page_to_pfn(page);
253 unsigned long sp, start_pfn;
254
255 do {
256 seq = zone_span_seqbegin(zone);
257 start_pfn = zone->zone_start_pfn;
258 sp = zone->spanned_pages;
259 if (!zone_spans_pfn(zone, pfn))
260 ret = 1;
261 } while (zone_span_seqretry(zone, seq));
262
263 if (ret)
264 pr_err("page %lu outside zone [ %lu - %lu ]\n",
265 pfn, start_pfn, start_pfn + sp);
266
267 return ret;
268}
269
270static int page_is_consistent(struct zone *zone, struct page *page)
271{
272 if (!pfn_valid_within(page_to_pfn(page)))
273 return 0;
274 if (zone != page_zone(page))
275 return 0;
276
277 return 1;
278}
279/*
280 * Temporary debugging check for pages not lying within a given zone.
281 */
282static int bad_range(struct zone *zone, struct page *page)
283{
284 if (page_outside_zone_boundaries(zone, page))
285 return 1;
286 if (!page_is_consistent(zone, page))
287 return 1;
288
289 return 0;
290}
291#else
292static inline int bad_range(struct zone *zone, struct page *page)
293{
294 return 0;
295}
296#endif
297
298static void bad_page(struct page *page, const char *reason,
299 unsigned long bad_flags)
300{
301 static unsigned long resume;
302 static unsigned long nr_shown;
303 static unsigned long nr_unshown;
304
305 /* Don't complain about poisoned pages */
306 if (PageHWPoison(page)) {
307 page_mapcount_reset(page); /* remove PageBuddy */
308 return;
309 }
310
311 /*
312 * Allow a burst of 60 reports, then keep quiet for that minute;
313 * or allow a steady drip of one report per second.
314 */
315 if (nr_shown == 60) {
316 if (time_before(jiffies, resume)) {
317 nr_unshown++;
318 goto out;
319 }
320 if (nr_unshown) {
321 printk(KERN_ALERT
322 "BUG: Bad page state: %lu messages suppressed\n",
323 nr_unshown);
324 nr_unshown = 0;
325 }
326 nr_shown = 0;
327 }
328 if (nr_shown++ == 0)
329 resume = jiffies + 60 * HZ;
330
331 printk(KERN_ALERT "BUG: Bad page state in process %s pfn:%05lx\n",
332 current->comm, page_to_pfn(page));
333 dump_page_badflags(page, reason, bad_flags);
334
335 print_modules();
336 dump_stack();
337out:
338 /* Leave bad fields for debug, except PageBuddy could make trouble */
339 page_mapcount_reset(page); /* remove PageBuddy */
340 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
341}
342
343/*
344 * Higher-order pages are called "compound pages". They are structured thusly:
345 *
346 * The first PAGE_SIZE page is called the "head page".
347 *
348 * The remaining PAGE_SIZE pages are called "tail pages".
349 *
350 * All pages have PG_compound set. All tail pages have their ->first_page
351 * pointing at the head page.
352 *
353 * The first tail page's ->lru.next holds the address of the compound page's
354 * put_page() function. Its ->lru.prev holds the order of allocation.
355 * This usage means that zero-order pages may not be compound.
356 */
357
358static void free_compound_page(struct page *page)
359{
360 __free_pages_ok(page, compound_order(page));
361}
362
363void prep_compound_page(struct page *page, unsigned long order)
364{
365 int i;
366 int nr_pages = 1 << order;
367
368 set_compound_page_dtor(page, free_compound_page);
369 set_compound_order(page, order);
370 __SetPageHead(page);
371 for (i = 1; i < nr_pages; i++) {
372 struct page *p = page + i;
373 set_page_count(p, 0);
374 p->first_page = page;
375 /* Make sure p->first_page is always valid for PageTail() */
376 smp_wmb();
377 __SetPageTail(p);
378 }
379}
380
381/* update __split_huge_page_refcount if you change this function */
382static int destroy_compound_page(struct page *page, unsigned long order)
383{
384 int i;
385 int nr_pages = 1 << order;
386 int bad = 0;
387
388 if (unlikely(compound_order(page) != order)) {
389 bad_page(page, "wrong compound order", 0);
390 bad++;
391 }
392
393 __ClearPageHead(page);
394
395 for (i = 1; i < nr_pages; i++) {
396 struct page *p = page + i;
397
398 if (unlikely(!PageTail(p))) {
399 bad_page(page, "PageTail not set", 0);
400 bad++;
401 } else if (unlikely(p->first_page != page)) {
402 bad_page(page, "first_page not consistent", 0);
403 bad++;
404 }
405 __ClearPageTail(p);
406 }
407
408 return bad;
409}
410
411static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
412{
413 int i;
414
415 /*
416 * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
417 * and __GFP_HIGHMEM from hard or soft interrupt context.
418 */
419 VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
420 for (i = 0; i < (1 << order); i++)
421 clear_highpage(page + i);
422}
423
424#ifdef CONFIG_DEBUG_PAGEALLOC
425unsigned int _debug_guardpage_minorder;
426
427static int __init debug_guardpage_minorder_setup(char *buf)
428{
429 unsigned long res;
430
431 if (kstrtoul(buf, 10, &res) < 0 || res > MAX_ORDER / 2) {
432 printk(KERN_ERR "Bad debug_guardpage_minorder value\n");
433 return 0;
434 }
435 _debug_guardpage_minorder = res;
436 printk(KERN_INFO "Setting debug_guardpage_minorder to %lu\n", res);
437 return 0;
438}
439__setup("debug_guardpage_minorder=", debug_guardpage_minorder_setup);
440
441static inline void set_page_guard_flag(struct page *page)
442{
443 __set_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
444}
445
446static inline void clear_page_guard_flag(struct page *page)
447{
448 __clear_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
449}
450#else
451static inline void set_page_guard_flag(struct page *page) { }
452static inline void clear_page_guard_flag(struct page *page) { }
453#endif
454
455static inline void set_page_order(struct page *page, int order)
456{
457 set_page_private(page, order);
458 __SetPageBuddy(page);
459}
460
461static inline void rmv_page_order(struct page *page)
462{
463 __ClearPageBuddy(page);
464 set_page_private(page, 0);
465}
466
467/*
468 * Locate the struct page for both the matching buddy in our
469 * pair (buddy1) and the combined O(n+1) page they form (page).
470 *
471 * 1) Any buddy B1 will have an order O twin B2 which satisfies
472 * the following equation:
473 * B2 = B1 ^ (1 << O)
474 * For example, if the starting buddy (buddy2) is #8 its order
475 * 1 buddy is #10:
476 * B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
477 *
478 * 2) Any buddy B will have an order O+1 parent P which
479 * satisfies the following equation:
480 * P = B & ~(1 << O)
481 *
482 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
483 */
484static inline unsigned long
485__find_buddy_index(unsigned long page_idx, unsigned int order)
486{
487 return page_idx ^ (1 << order);
488}
489
490/*
491 * This function checks whether a page is free && is the buddy
492 * we can do coalesce a page and its buddy if
493 * (a) the buddy is not in a hole &&
494 * (b) the buddy is in the buddy system &&
495 * (c) a page and its buddy have the same order &&
496 * (d) a page and its buddy are in the same zone.
497 *
498 * For recording whether a page is in the buddy system, we set ->_mapcount
499 * PAGE_BUDDY_MAPCOUNT_VALUE.
500 * Setting, clearing, and testing _mapcount PAGE_BUDDY_MAPCOUNT_VALUE is
501 * serialized by zone->lock.
502 *
503 * For recording page's order, we use page_private(page).
504 */
505static inline int page_is_buddy(struct page *page, struct page *buddy,
506 int order)
507{
508 if (!pfn_valid_within(page_to_pfn(buddy)))
509 return 0;
510
511 if (page_zone_id(page) != page_zone_id(buddy))
512 return 0;
513
514 if (page_is_guard(buddy) && page_order(buddy) == order) {
515 VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
516 return 1;
517 }
518
519 if (PageBuddy(buddy) && page_order(buddy) == order) {
520 VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
521 return 1;
522 }
523 return 0;
524}
525
526/*
527 * Freeing function for a buddy system allocator.
528 *
529 * The concept of a buddy system is to maintain direct-mapped table
530 * (containing bit values) for memory blocks of various "orders".
531 * The bottom level table contains the map for the smallest allocatable
532 * units of memory (here, pages), and each level above it describes
533 * pairs of units from the levels below, hence, "buddies".
534 * At a high level, all that happens here is marking the table entry
535 * at the bottom level available, and propagating the changes upward
536 * as necessary, plus some accounting needed to play nicely with other
537 * parts of the VM system.
538 * At each level, we keep a list of pages, which are heads of continuous
539 * free pages of length of (1 << order) and marked with _mapcount
540 * PAGE_BUDDY_MAPCOUNT_VALUE. Page's order is recorded in page_private(page)
541 * field.
542 * So when we are allocating or freeing one, we can derive the state of the
543 * other. That is, if we allocate a small block, and both were
544 * free, the remainder of the region must be split into blocks.
545 * If a block is freed, and its buddy is also free, then this
546 * triggers coalescing into a block of larger size.
547 *
548 * -- nyc
549 */
550
551static inline void __free_one_page(struct page *page,
552 struct zone *zone, unsigned int order,
553 int migratetype)
554{
555 unsigned long page_idx;
556 unsigned long combined_idx;
557 unsigned long uninitialized_var(buddy_idx);
558 struct page *buddy;
559
560 VM_BUG_ON(!zone_is_initialized(zone));
561
562 if (unlikely(PageCompound(page)))
563 if (unlikely(destroy_compound_page(page, order)))
564 return;
565
566 VM_BUG_ON(migratetype == -1);
567
568 page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
569
570 VM_BUG_ON_PAGE(page_idx & ((1 << order) - 1), page);
571 VM_BUG_ON_PAGE(bad_range(zone, page), page);
572
573 while (order < MAX_ORDER-1) {
574 buddy_idx = __find_buddy_index(page_idx, order);
575 buddy = page + (buddy_idx - page_idx);
576 if (!page_is_buddy(page, buddy, order))
577 break;
578 /*
579 * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
580 * merge with it and move up one order.
581 */
582 if (page_is_guard(buddy)) {
583 clear_page_guard_flag(buddy);
584 set_page_private(page, 0);
585 __mod_zone_freepage_state(zone, 1 << order,
586 migratetype);
587 } else {
588 list_del(&buddy->lru);
589 zone->free_area[order].nr_free--;
590 rmv_page_order(buddy);
591 }
592 combined_idx = buddy_idx & page_idx;
593 page = page + (combined_idx - page_idx);
594 page_idx = combined_idx;
595 order++;
596 }
597 set_page_order(page, order);
598
599 /*
600 * If this is not the largest possible page, check if the buddy
601 * of the next-highest order is free. If it is, it's possible
602 * that pages are being freed that will coalesce soon. In case,
603 * that is happening, add the free page to the tail of the list
604 * so it's less likely to be used soon and more likely to be merged
605 * as a higher order page
606 */
607 if ((order < MAX_ORDER-2) && pfn_valid_within(page_to_pfn(buddy))) {
608 struct page *higher_page, *higher_buddy;
609 combined_idx = buddy_idx & page_idx;
610 higher_page = page + (combined_idx - page_idx);
611 buddy_idx = __find_buddy_index(combined_idx, order + 1);
612 higher_buddy = higher_page + (buddy_idx - combined_idx);
613 if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
614 list_add_tail(&page->lru,
615 &zone->free_area[order].free_list[migratetype]);
616 goto out;
617 }
618 }
619
620 list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
621out:
622 zone->free_area[order].nr_free++;
623}
624
625static inline int free_pages_check(struct page *page)
626{
627 const char *bad_reason = NULL;
628 unsigned long bad_flags = 0;
629
630 if (unlikely(page_mapcount(page)))
631 bad_reason = "nonzero mapcount";
632 if (unlikely(page->mapping != NULL))
633 bad_reason = "non-NULL mapping";
634 if (unlikely(atomic_read(&page->_count) != 0))
635 bad_reason = "nonzero _count";
636 if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_FREE)) {
637 bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
638 bad_flags = PAGE_FLAGS_CHECK_AT_FREE;
639 }
640 if (unlikely(mem_cgroup_bad_page_check(page)))
641 bad_reason = "cgroup check failed";
642 if (unlikely(bad_reason)) {
643 bad_page(page, bad_reason, bad_flags);
644 return 1;
645 }
646 page_cpupid_reset_last(page);
647 if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
648 page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
649 return 0;
650}
651
652/*
653 * Frees a number of pages from the PCP lists
654 * Assumes all pages on list are in same zone, and of same order.
655 * count is the number of pages to free.
656 *
657 * If the zone was previously in an "all pages pinned" state then look to
658 * see if this freeing clears that state.
659 *
660 * And clear the zone's pages_scanned counter, to hold off the "all pages are
661 * pinned" detection logic.
662 */
663static void free_pcppages_bulk(struct zone *zone, int count,
664 struct per_cpu_pages *pcp)
665{
666 int migratetype = 0;
667 int batch_free = 0;
668 int to_free = count;
669
670 spin_lock(&zone->lock);
671 zone->pages_scanned = 0;
672
673 while (to_free) {
674 struct page *page;
675 struct list_head *list;
676
677 /*
678 * Remove pages from lists in a round-robin fashion. A
679 * batch_free count is maintained that is incremented when an
680 * empty list is encountered. This is so more pages are freed
681 * off fuller lists instead of spinning excessively around empty
682 * lists
683 */
684 do {
685 batch_free++;
686 if (++migratetype == MIGRATE_PCPTYPES)
687 migratetype = 0;
688 list = &pcp->lists[migratetype];
689 } while (list_empty(list));
690
691 /* This is the only non-empty list. Free them all. */
692 if (batch_free == MIGRATE_PCPTYPES)
693 batch_free = to_free;
694
695 do {
696 int mt; /* migratetype of the to-be-freed page */
697
698 page = list_entry(list->prev, struct page, lru);
699 /* must delete as __free_one_page list manipulates */
700 list_del(&page->lru);
701 mt = get_freepage_migratetype(page);
702 /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
703 __free_one_page(page, zone, 0, mt);
704 trace_mm_page_pcpu_drain(page, 0, mt);
705 if (likely(!is_migrate_isolate_page(page))) {
706 __mod_zone_page_state(zone, NR_FREE_PAGES, 1);
707 if (is_migrate_cma(mt))
708 __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, 1);
709 }
710 } while (--to_free && --batch_free && !list_empty(list));
711 }
712 spin_unlock(&zone->lock);
713}
714
715static void free_one_page(struct zone *zone, struct page *page, int order,
716 int migratetype)
717{
718 spin_lock(&zone->lock);
719 zone->pages_scanned = 0;
720
721 __free_one_page(page, zone, order, migratetype);
722 if (unlikely(!is_migrate_isolate(migratetype)))
723 __mod_zone_freepage_state(zone, 1 << order, migratetype);
724 spin_unlock(&zone->lock);
725}
726
727static bool free_pages_prepare(struct page *page, unsigned int order)
728{
729 int i;
730 int bad = 0;
731
732 trace_mm_page_free(page, order);
733 kmemcheck_free_shadow(page, order);
734
735 if (PageAnon(page))
736 page->mapping = NULL;
737 for (i = 0; i < (1 << order); i++)
738 bad += free_pages_check(page + i);
739 if (bad)
740 return false;
741
742 if (!PageHighMem(page)) {
743 debug_check_no_locks_freed(page_address(page),
744 PAGE_SIZE << order);
745 debug_check_no_obj_freed(page_address(page),
746 PAGE_SIZE << order);
747 }
748 arch_free_page(page, order);
749 kernel_map_pages(page, 1 << order, 0);
750
751 return true;
752}
753
754static void __free_pages_ok(struct page *page, unsigned int order)
755{
756 unsigned long flags;
757 int migratetype;
758
759 if (!free_pages_prepare(page, order))
760 return;
761
762 local_irq_save(flags);
763 __count_vm_events(PGFREE, 1 << order);
764 migratetype = get_pageblock_migratetype(page);
765 set_freepage_migratetype(page, migratetype);
766 free_one_page(page_zone(page), page, order, migratetype);
767 local_irq_restore(flags);
768}
769
770void __init __free_pages_bootmem(struct page *page, unsigned int order)
771{
772 unsigned int nr_pages = 1 << order;
773 struct page *p = page;
774 unsigned int loop;
775
776 prefetchw(p);
777 for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
778 prefetchw(p + 1);
779 __ClearPageReserved(p);
780 set_page_count(p, 0);
781 }
782 __ClearPageReserved(p);
783 set_page_count(p, 0);
784
785 page_zone(page)->managed_pages += nr_pages;
786 set_page_refcounted(page);
787 __free_pages(page, order);
788}
789
790#ifdef CONFIG_CMA
791/* Free whole pageblock and set its migration type to MIGRATE_CMA. */
792void __init init_cma_reserved_pageblock(struct page *page)
793{
794 unsigned i = pageblock_nr_pages;
795 struct page *p = page;
796
797 do {
798 __ClearPageReserved(p);
799 set_page_count(p, 0);
800 } while (++p, --i);
801
802 set_page_refcounted(page);
803 set_pageblock_migratetype(page, MIGRATE_CMA);
804 __free_pages(page, pageblock_order);
805 adjust_managed_page_count(page, pageblock_nr_pages);
806}
807#endif
808
809/*
810 * The order of subdivision here is critical for the IO subsystem.
811 * Please do not alter this order without good reasons and regression
812 * testing. Specifically, as large blocks of memory are subdivided,
813 * the order in which smaller blocks are delivered depends on the order
814 * they're subdivided in this function. This is the primary factor
815 * influencing the order in which pages are delivered to the IO
816 * subsystem according to empirical testing, and this is also justified
817 * by considering the behavior of a buddy system containing a single
818 * large block of memory acted on by a series of small allocations.
819 * This behavior is a critical factor in sglist merging's success.
820 *
821 * -- nyc
822 */
823static inline void expand(struct zone *zone, struct page *page,
824 int low, int high, struct free_area *area,
825 int migratetype)
826{
827 unsigned long size = 1 << high;
828
829 while (high > low) {
830 area--;
831 high--;
832 size >>= 1;
833 VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]);
834
835#ifdef CONFIG_DEBUG_PAGEALLOC
836 if (high < debug_guardpage_minorder()) {
837 /*
838 * Mark as guard pages (or page), that will allow to
839 * merge back to allocator when buddy will be freed.
840 * Corresponding page table entries will not be touched,
841 * pages will stay not present in virtual address space
842 */
843 INIT_LIST_HEAD(&page[size].lru);
844 set_page_guard_flag(&page[size]);
845 set_page_private(&page[size], high);
846 /* Guard pages are not available for any usage */
847 __mod_zone_freepage_state(zone, -(1 << high),
848 migratetype);
849 continue;
850 }
851#endif
852 list_add(&page[size].lru, &area->free_list[migratetype]);
853 area->nr_free++;
854 set_page_order(&page[size], high);
855 }
856}
857
858/*
859 * This page is about to be returned from the page allocator
860 */
861static inline int check_new_page(struct page *page)
862{
863 const char *bad_reason = NULL;
864 unsigned long bad_flags = 0;
865
866 if (unlikely(page_mapcount(page)))
867 bad_reason = "nonzero mapcount";
868 if (unlikely(page->mapping != NULL))
869 bad_reason = "non-NULL mapping";
870 if (unlikely(atomic_read(&page->_count) != 0))
871 bad_reason = "nonzero _count";
872 if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP)) {
873 bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set";
874 bad_flags = PAGE_FLAGS_CHECK_AT_PREP;
875 }
876 if (unlikely(mem_cgroup_bad_page_check(page)))
877 bad_reason = "cgroup check failed";
878 if (unlikely(bad_reason)) {
879 bad_page(page, bad_reason, bad_flags);
880 return 1;
881 }
882 return 0;
883}
884
885static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
886{
887 int i;
888
889 for (i = 0; i < (1 << order); i++) {
890 struct page *p = page + i;
891 if (unlikely(check_new_page(p)))
892 return 1;
893 }
894
895 set_page_private(page, 0);
896 set_page_refcounted(page);
897
898 arch_alloc_page(page, order);
899 kernel_map_pages(page, 1 << order, 1);
900
901 if (gfp_flags & __GFP_ZERO)
902 prep_zero_page(page, order, gfp_flags);
903
904 if (order && (gfp_flags & __GFP_COMP))
905 prep_compound_page(page, order);
906
907 return 0;
908}
909
910/*
911 * Go through the free lists for the given migratetype and remove
912 * the smallest available page from the freelists
913 */
914static inline
915struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
916 int migratetype)
917{
918 unsigned int current_order;
919 struct free_area *area;
920 struct page *page;
921
922 /* Find a page of the appropriate size in the preferred list */
923 for (current_order = order; current_order < MAX_ORDER; ++current_order) {
924 area = &(zone->free_area[current_order]);
925 if (list_empty(&area->free_list[migratetype]))
926 continue;
927
928 page = list_entry(area->free_list[migratetype].next,
929 struct page, lru);
930 list_del(&page->lru);
931 rmv_page_order(page);
932 area->nr_free--;
933 expand(zone, page, order, current_order, area, migratetype);
934 return page;
935 }
936
937 return NULL;
938}
939
940
941/*
942 * This array describes the order lists are fallen back to when
943 * the free lists for the desirable migrate type are depleted
944 */
945static int fallbacks[MIGRATE_TYPES][4] = {
946 [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE },
947 [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE },
948#ifdef CONFIG_CMA
949 [MIGRATE_MOVABLE] = { MIGRATE_CMA, MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
950 [MIGRATE_CMA] = { MIGRATE_RESERVE }, /* Never used */
951#else
952 [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
953#endif
954 [MIGRATE_RESERVE] = { MIGRATE_RESERVE }, /* Never used */
955#ifdef CONFIG_MEMORY_ISOLATION
956 [MIGRATE_ISOLATE] = { MIGRATE_RESERVE }, /* Never used */
957#endif
958};
959
960/*
961 * Move the free pages in a range to the free lists of the requested type.
962 * Note that start_page and end_pages are not aligned on a pageblock
963 * boundary. If alignment is required, use move_freepages_block()
964 */
965int move_freepages(struct zone *zone,
966 struct page *start_page, struct page *end_page,
967 int migratetype)
968{
969 struct page *page;
970 unsigned long order;
971 int pages_moved = 0;
972
973#ifndef CONFIG_HOLES_IN_ZONE
974 /*
975 * page_zone is not safe to call in this context when
976 * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
977 * anyway as we check zone boundaries in move_freepages_block().
978 * Remove at a later date when no bug reports exist related to
979 * grouping pages by mobility
980 */
981 BUG_ON(page_zone(start_page) != page_zone(end_page));
982#endif
983
984 for (page = start_page; page <= end_page;) {
985 /* Make sure we are not inadvertently changing nodes */
986 VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
987
988 if (!pfn_valid_within(page_to_pfn(page))) {
989 page++;
990 continue;
991 }
992
993 if (!PageBuddy(page)) {
994 page++;
995 continue;
996 }
997
998 order = page_order(page);
999 list_move(&page->lru,
1000 &zone->free_area[order].free_list[migratetype]);
1001 set_freepage_migratetype(page, migratetype);
1002 page += 1 << order;
1003 pages_moved += 1 << order;
1004 }
1005
1006 return pages_moved;
1007}
1008
1009int move_freepages_block(struct zone *zone, struct page *page,
1010 int migratetype)
1011{
1012 unsigned long start_pfn, end_pfn;
1013 struct page *start_page, *end_page;
1014
1015 start_pfn = page_to_pfn(page);
1016 start_pfn = start_pfn & ~(pageblock_nr_pages-1);
1017 start_page = pfn_to_page(start_pfn);
1018 end_page = start_page + pageblock_nr_pages - 1;
1019 end_pfn = start_pfn + pageblock_nr_pages - 1;
1020
1021 /* Do not cross zone boundaries */
1022 if (!zone_spans_pfn(zone, start_pfn))
1023 start_page = page;
1024 if (!zone_spans_pfn(zone, end_pfn))
1025 return 0;
1026
1027 return move_freepages(zone, start_page, end_page, migratetype);
1028}
1029
1030static void change_pageblock_range(struct page *pageblock_page,
1031 int start_order, int migratetype)
1032{
1033 int nr_pageblocks = 1 << (start_order - pageblock_order);
1034
1035 while (nr_pageblocks--) {
1036 set_pageblock_migratetype(pageblock_page, migratetype);
1037 pageblock_page += pageblock_nr_pages;
1038 }
1039}
1040
1041/*
1042 * If breaking a large block of pages, move all free pages to the preferred
1043 * allocation list. If falling back for a reclaimable kernel allocation, be
1044 * more aggressive about taking ownership of free pages.
1045 *
1046 * On the other hand, never change migration type of MIGRATE_CMA pageblocks
1047 * nor move CMA pages to different free lists. We don't want unmovable pages
1048 * to be allocated from MIGRATE_CMA areas.
1049 *
1050 * Returns the new migratetype of the pageblock (or the same old migratetype
1051 * if it was unchanged).
1052 */
1053static int try_to_steal_freepages(struct zone *zone, struct page *page,
1054 int start_type, int fallback_type)
1055{
1056 int current_order = page_order(page);
1057
1058 /*
1059 * When borrowing from MIGRATE_CMA, we need to release the excess
1060 * buddy pages to CMA itself.
1061 */
1062 if (is_migrate_cma(fallback_type))
1063 return fallback_type;
1064
1065 /* Take ownership for orders >= pageblock_order */
1066 if (current_order >= pageblock_order) {
1067 change_pageblock_range(page, current_order, start_type);
1068 return start_type;
1069 }
1070
1071 if (current_order >= pageblock_order / 2 ||
1072 start_type == MIGRATE_RECLAIMABLE ||
1073 page_group_by_mobility_disabled) {
1074 int pages;
1075
1076 pages = move_freepages_block(zone, page, start_type);
1077
1078 /* Claim the whole block if over half of it is free */
1079 if (pages >= (1 << (pageblock_order-1)) ||
1080 page_group_by_mobility_disabled) {
1081
1082 set_pageblock_migratetype(page, start_type);
1083 return start_type;
1084 }
1085
1086 }
1087
1088 return fallback_type;
1089}
1090
1091/* Remove an element from the buddy allocator from the fallback list */
1092static inline struct page *
1093__rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
1094{
1095 struct free_area *area;
1096 int current_order;
1097 struct page *page;
1098 int migratetype, new_type, i;
1099
1100 /* Find the largest possible block of pages in the other list */
1101 for (current_order = MAX_ORDER-1; current_order >= order;
1102 --current_order) {
1103 for (i = 0;; i++) {
1104 migratetype = fallbacks[start_migratetype][i];
1105
1106 /* MIGRATE_RESERVE handled later if necessary */
1107 if (migratetype == MIGRATE_RESERVE)
1108 break;
1109
1110 area = &(zone->free_area[current_order]);
1111 if (list_empty(&area->free_list[migratetype]))
1112 continue;
1113
1114 page = list_entry(area->free_list[migratetype].next,
1115 struct page, lru);
1116 area->nr_free--;
1117
1118 new_type = try_to_steal_freepages(zone, page,
1119 start_migratetype,
1120 migratetype);
1121
1122 /* Remove the page from the freelists */
1123 list_del(&page->lru);
1124 rmv_page_order(page);
1125
1126 expand(zone, page, order, current_order, area,
1127 new_type);
1128
1129 trace_mm_page_alloc_extfrag(page, order, current_order,
1130 start_migratetype, migratetype, new_type);
1131
1132 return page;
1133 }
1134 }
1135
1136 return NULL;
1137}
1138
1139/*
1140 * Do the hard work of removing an element from the buddy allocator.
1141 * Call me with the zone->lock already held.
1142 */
1143static struct page *__rmqueue(struct zone *zone, unsigned int order,
1144 int migratetype)
1145{
1146 struct page *page;
1147
1148retry_reserve:
1149 page = __rmqueue_smallest(zone, order, migratetype);
1150
1151 if (unlikely(!page) && migratetype != MIGRATE_RESERVE) {
1152 page = __rmqueue_fallback(zone, order, migratetype);
1153
1154 /*
1155 * Use MIGRATE_RESERVE rather than fail an allocation. goto
1156 * is used because __rmqueue_smallest is an inline function
1157 * and we want just one call site
1158 */
1159 if (!page) {
1160 migratetype = MIGRATE_RESERVE;
1161 goto retry_reserve;
1162 }
1163 }
1164
1165 trace_mm_page_alloc_zone_locked(page, order, migratetype);
1166 return page;
1167}
1168
1169/*
1170 * Obtain a specified number of elements from the buddy allocator, all under
1171 * a single hold of the lock, for efficiency. Add them to the supplied list.
1172 * Returns the number of new pages which were placed at *list.
1173 */
1174static int rmqueue_bulk(struct zone *zone, unsigned int order,
1175 unsigned long count, struct list_head *list,
1176 int migratetype, int cold)
1177{
1178 int mt = migratetype, i;
1179
1180 spin_lock(&zone->lock);
1181 for (i = 0; i < count; ++i) {
1182 struct page *page = __rmqueue(zone, order, migratetype);
1183 if (unlikely(page == NULL))
1184 break;
1185
1186 /*
1187 * Split buddy pages returned by expand() are received here
1188 * in physical page order. The page is added to the callers and
1189 * list and the list head then moves forward. From the callers
1190 * perspective, the linked list is ordered by page number in
1191 * some conditions. This is useful for IO devices that can
1192 * merge IO requests if the physical pages are ordered
1193 * properly.
1194 */
1195 if (likely(cold == 0))
1196 list_add(&page->lru, list);
1197 else
1198 list_add_tail(&page->lru, list);
1199 if (IS_ENABLED(CONFIG_CMA)) {
1200 mt = get_pageblock_migratetype(page);
1201 if (!is_migrate_cma(mt) && !is_migrate_isolate(mt))
1202 mt = migratetype;
1203 }
1204 set_freepage_migratetype(page, mt);
1205 list = &page->lru;
1206 if (is_migrate_cma(mt))
1207 __mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
1208 -(1 << order));
1209 }
1210 __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
1211 spin_unlock(&zone->lock);
1212 return i;
1213}
1214
1215#ifdef CONFIG_NUMA
1216/*
1217 * Called from the vmstat counter updater to drain pagesets of this
1218 * currently executing processor on remote nodes after they have
1219 * expired.
1220 *
1221 * Note that this function must be called with the thread pinned to
1222 * a single processor.
1223 */
1224void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
1225{
1226 unsigned long flags;
1227 int to_drain;
1228 unsigned long batch;
1229
1230 local_irq_save(flags);
1231 batch = ACCESS_ONCE(pcp->batch);
1232 if (pcp->count >= batch)
1233 to_drain = batch;
1234 else
1235 to_drain = pcp->count;
1236 if (to_drain > 0) {
1237 free_pcppages_bulk(zone, to_drain, pcp);
1238 pcp->count -= to_drain;
1239 }
1240 local_irq_restore(flags);
1241}
1242#endif
1243
1244/*
1245 * Drain pages of the indicated processor.
1246 *
1247 * The processor must either be the current processor and the
1248 * thread pinned to the current processor or a processor that
1249 * is not online.
1250 */
1251static void drain_pages(unsigned int cpu)
1252{
1253 unsigned long flags;
1254 struct zone *zone;
1255
1256 for_each_populated_zone(zone) {
1257 struct per_cpu_pageset *pset;
1258 struct per_cpu_pages *pcp;
1259
1260 local_irq_save(flags);
1261 pset = per_cpu_ptr(zone->pageset, cpu);
1262
1263 pcp = &pset->pcp;
1264 if (pcp->count) {
1265 free_pcppages_bulk(zone, pcp->count, pcp);
1266 pcp->count = 0;
1267 }
1268 local_irq_restore(flags);
1269 }
1270}
1271
1272/*
1273 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
1274 */
1275void drain_local_pages(void *arg)
1276{
1277 drain_pages(smp_processor_id());
1278}
1279
1280/*
1281 * Spill all the per-cpu pages from all CPUs back into the buddy allocator.
1282 *
1283 * Note that this code is protected against sending an IPI to an offline
1284 * CPU but does not guarantee sending an IPI to newly hotplugged CPUs:
1285 * on_each_cpu_mask() blocks hotplug and won't talk to offlined CPUs but
1286 * nothing keeps CPUs from showing up after we populated the cpumask and
1287 * before the call to on_each_cpu_mask().
1288 */
1289void drain_all_pages(void)
1290{
1291 int cpu;
1292 struct per_cpu_pageset *pcp;
1293 struct zone *zone;
1294
1295 /*
1296 * Allocate in the BSS so we wont require allocation in
1297 * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
1298 */
1299 static cpumask_t cpus_with_pcps;
1300
1301 /*
1302 * We don't care about racing with CPU hotplug event
1303 * as offline notification will cause the notified
1304 * cpu to drain that CPU pcps and on_each_cpu_mask
1305 * disables preemption as part of its processing
1306 */
1307 for_each_online_cpu(cpu) {
1308 bool has_pcps = false;
1309 for_each_populated_zone(zone) {
1310 pcp = per_cpu_ptr(zone->pageset, cpu);
1311 if (pcp->pcp.count) {
1312 has_pcps = true;
1313 break;
1314 }
1315 }
1316 if (has_pcps)
1317 cpumask_set_cpu(cpu, &cpus_with_pcps);
1318 else
1319 cpumask_clear_cpu(cpu, &cpus_with_pcps);
1320 }
1321 on_each_cpu_mask(&cpus_with_pcps, drain_local_pages, NULL, 1);
1322}
1323
1324#ifdef CONFIG_HIBERNATION
1325
1326void mark_free_pages(struct zone *zone)
1327{
1328 unsigned long pfn, max_zone_pfn;
1329 unsigned long flags;
1330 int order, t;
1331 struct list_head *curr;
1332
1333 if (zone_is_empty(zone))
1334 return;
1335
1336 spin_lock_irqsave(&zone->lock, flags);
1337
1338 max_zone_pfn = zone_end_pfn(zone);
1339 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1340 if (pfn_valid(pfn)) {
1341 struct page *page = pfn_to_page(pfn);
1342
1343 if (!swsusp_page_is_forbidden(page))
1344 swsusp_unset_page_free(page);
1345 }
1346
1347 for_each_migratetype_order(order, t) {
1348 list_for_each(curr, &zone->free_area[order].free_list[t]) {
1349 unsigned long i;
1350
1351 pfn = page_to_pfn(list_entry(curr, struct page, lru));
1352 for (i = 0; i < (1UL << order); i++)
1353 swsusp_set_page_free(pfn_to_page(pfn + i));
1354 }
1355 }
1356 spin_unlock_irqrestore(&zone->lock, flags);
1357}
1358#endif /* CONFIG_PM */
1359
1360/*
1361 * Free a 0-order page
1362 * cold == 1 ? free a cold page : free a hot page
1363 */
1364void free_hot_cold_page(struct page *page, int cold)
1365{
1366 struct zone *zone = page_zone(page);
1367 struct per_cpu_pages *pcp;
1368 unsigned long flags;
1369 int migratetype;
1370
1371 if (!free_pages_prepare(page, 0))
1372 return;
1373
1374 migratetype = get_pageblock_migratetype(page);
1375 set_freepage_migratetype(page, migratetype);
1376 local_irq_save(flags);
1377 __count_vm_event(PGFREE);
1378
1379 /*
1380 * We only track unmovable, reclaimable and movable on pcp lists.
1381 * Free ISOLATE pages back to the allocator because they are being
1382 * offlined but treat RESERVE as movable pages so we can get those
1383 * areas back if necessary. Otherwise, we may have to free
1384 * excessively into the page allocator
1385 */
1386 if (migratetype >= MIGRATE_PCPTYPES) {
1387 if (unlikely(is_migrate_isolate(migratetype))) {
1388 free_one_page(zone, page, 0, migratetype);
1389 goto out;
1390 }
1391 migratetype = MIGRATE_MOVABLE;
1392 }
1393
1394 pcp = &this_cpu_ptr(zone->pageset)->pcp;
1395 if (cold)
1396 list_add_tail(&page->lru, &pcp->lists[migratetype]);
1397 else
1398 list_add(&page->lru, &pcp->lists[migratetype]);
1399 pcp->count++;
1400 if (pcp->count >= pcp->high) {
1401 unsigned long batch = ACCESS_ONCE(pcp->batch);
1402 free_pcppages_bulk(zone, batch, pcp);
1403 pcp->count -= batch;
1404 }
1405
1406out:
1407 local_irq_restore(flags);
1408}
1409
1410/*
1411 * Free a list of 0-order pages
1412 */
1413void free_hot_cold_page_list(struct list_head *list, int cold)
1414{
1415 struct page *page, *next;
1416
1417 list_for_each_entry_safe(page, next, list, lru) {
1418 trace_mm_page_free_batched(page, cold);
1419 free_hot_cold_page(page, cold);
1420 }
1421}
1422
1423/*
1424 * split_page takes a non-compound higher-order page, and splits it into
1425 * n (1<<order) sub-pages: page[0..n]
1426 * Each sub-page must be freed individually.
1427 *
1428 * Note: this is probably too low level an operation for use in drivers.
1429 * Please consult with lkml before using this in your driver.
1430 */
1431void split_page(struct page *page, unsigned int order)
1432{
1433 int i;
1434
1435 VM_BUG_ON_PAGE(PageCompound(page), page);
1436 VM_BUG_ON_PAGE(!page_count(page), page);
1437
1438#ifdef CONFIG_KMEMCHECK
1439 /*
1440 * Split shadow pages too, because free(page[0]) would
1441 * otherwise free the whole shadow.
1442 */
1443 if (kmemcheck_page_is_tracked(page))
1444 split_page(virt_to_page(page[0].shadow), order);
1445#endif
1446
1447 for (i = 1; i < (1 << order); i++)
1448 set_page_refcounted(page + i);
1449}
1450EXPORT_SYMBOL_GPL(split_page);
1451
1452static int __isolate_free_page(struct page *page, unsigned int order)
1453{
1454 unsigned long watermark;
1455 struct zone *zone;
1456 int mt;
1457
1458 BUG_ON(!PageBuddy(page));
1459
1460 zone = page_zone(page);
1461 mt = get_pageblock_migratetype(page);
1462
1463 if (!is_migrate_isolate(mt)) {
1464 /* Obey watermarks as if the page was being allocated */
1465 watermark = low_wmark_pages(zone) + (1 << order);
1466 if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
1467 return 0;
1468
1469 __mod_zone_freepage_state(zone, -(1UL << order), mt);
1470 }
1471
1472 /* Remove page from free list */
1473 list_del(&page->lru);
1474 zone->free_area[order].nr_free--;
1475 rmv_page_order(page);
1476
1477 /* Set the pageblock if the isolated page is at least a pageblock */
1478 if (order >= pageblock_order - 1) {
1479 struct page *endpage = page + (1 << order) - 1;
1480 for (; page < endpage; page += pageblock_nr_pages) {
1481 int mt = get_pageblock_migratetype(page);
1482 if (!is_migrate_isolate(mt) && !is_migrate_cma(mt))
1483 set_pageblock_migratetype(page,
1484 MIGRATE_MOVABLE);
1485 }
1486 }
1487
1488 return 1UL << order;
1489}
1490
1491/*
1492 * Similar to split_page except the page is already free. As this is only
1493 * being used for migration, the migratetype of the block also changes.
1494 * As this is called with interrupts disabled, the caller is responsible
1495 * for calling arch_alloc_page() and kernel_map_page() after interrupts
1496 * are enabled.
1497 *
1498 * Note: this is probably too low level an operation for use in drivers.
1499 * Please consult with lkml before using this in your driver.
1500 */
1501int split_free_page(struct page *page)
1502{
1503 unsigned int order;
1504 int nr_pages;
1505
1506 order = page_order(page);
1507
1508 nr_pages = __isolate_free_page(page, order);
1509 if (!nr_pages)
1510 return 0;
1511
1512 /* Split into individual pages */
1513 set_page_refcounted(page);
1514 split_page(page, order);
1515 return nr_pages;
1516}
1517
1518/*
1519 * Really, prep_compound_page() should be called from __rmqueue_bulk(). But
1520 * we cheat by calling it from here, in the order > 0 path. Saves a branch
1521 * or two.
1522 */
1523static inline
1524struct page *buffered_rmqueue(struct zone *preferred_zone,
1525 struct zone *zone, int order, gfp_t gfp_flags,
1526 int migratetype)
1527{
1528 unsigned long flags;
1529 struct page *page;
1530 int cold = !!(gfp_flags & __GFP_COLD);
1531
1532again:
1533 if (likely(order == 0)) {
1534 struct per_cpu_pages *pcp;
1535 struct list_head *list;
1536
1537 local_irq_save(flags);
1538 pcp = &this_cpu_ptr(zone->pageset)->pcp;
1539 list = &pcp->lists[migratetype];
1540 if (list_empty(list)) {
1541 pcp->count += rmqueue_bulk(zone, 0,
1542 pcp->batch, list,
1543 migratetype, cold);
1544 if (unlikely(list_empty(list)))
1545 goto failed;
1546 }
1547
1548 if (cold)
1549 page = list_entry(list->prev, struct page, lru);
1550 else
1551 page = list_entry(list->next, struct page, lru);
1552
1553 list_del(&page->lru);
1554 pcp->count--;
1555 } else {
1556 if (unlikely(gfp_flags & __GFP_NOFAIL)) {
1557 /*
1558 * __GFP_NOFAIL is not to be used in new code.
1559 *
1560 * All __GFP_NOFAIL callers should be fixed so that they
1561 * properly detect and handle allocation failures.
1562 *
1563 * We most definitely don't want callers attempting to
1564 * allocate greater than order-1 page units with
1565 * __GFP_NOFAIL.
1566 */
1567 WARN_ON_ONCE(order > 1);
1568 }
1569 spin_lock_irqsave(&zone->lock, flags);
1570 page = __rmqueue(zone, order, migratetype);
1571 spin_unlock(&zone->lock);
1572 if (!page)
1573 goto failed;
1574 __mod_zone_freepage_state(zone, -(1 << order),
1575 get_pageblock_migratetype(page));
1576 }
1577
1578 __mod_zone_page_state(zone, NR_ALLOC_BATCH, -(1 << order));
1579
1580 __count_zone_vm_events(PGALLOC, zone, 1 << order);
1581 zone_statistics(preferred_zone, zone, gfp_flags);
1582 local_irq_restore(flags);
1583
1584 VM_BUG_ON_PAGE(bad_range(zone, page), page);
1585 if (prep_new_page(page, order, gfp_flags))
1586 goto again;
1587 return page;
1588
1589failed:
1590 local_irq_restore(flags);
1591 return NULL;
1592}
1593
1594#ifdef CONFIG_FAIL_PAGE_ALLOC
1595
1596static struct {
1597 struct fault_attr attr;
1598
1599 u32 ignore_gfp_highmem;
1600 u32 ignore_gfp_wait;
1601 u32 min_order;
1602} fail_page_alloc = {
1603 .attr = FAULT_ATTR_INITIALIZER,
1604 .ignore_gfp_wait = 1,
1605 .ignore_gfp_highmem = 1,
1606 .min_order = 1,
1607};
1608
1609static int __init setup_fail_page_alloc(char *str)
1610{
1611 return setup_fault_attr(&fail_page_alloc.attr, str);
1612}
1613__setup("fail_page_alloc=", setup_fail_page_alloc);
1614
1615static bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1616{
1617 if (order < fail_page_alloc.min_order)
1618 return false;
1619 if (gfp_mask & __GFP_NOFAIL)
1620 return false;
1621 if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
1622 return false;
1623 if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
1624 return false;
1625
1626 return should_fail(&fail_page_alloc.attr, 1 << order);
1627}
1628
1629#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1630
1631static int __init fail_page_alloc_debugfs(void)
1632{
1633 umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
1634 struct dentry *dir;
1635
1636 dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
1637 &fail_page_alloc.attr);
1638 if (IS_ERR(dir))
1639 return PTR_ERR(dir);
1640
1641 if (!debugfs_create_bool("ignore-gfp-wait", mode, dir,
1642 &fail_page_alloc.ignore_gfp_wait))
1643 goto fail;
1644 if (!debugfs_create_bool("ignore-gfp-highmem", mode, dir,
1645 &fail_page_alloc.ignore_gfp_highmem))
1646 goto fail;
1647 if (!debugfs_create_u32("min-order", mode, dir,
1648 &fail_page_alloc.min_order))
1649 goto fail;
1650
1651 return 0;
1652fail:
1653 debugfs_remove_recursive(dir);
1654
1655 return -ENOMEM;
1656}
1657
1658late_initcall(fail_page_alloc_debugfs);
1659
1660#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1661
1662#else /* CONFIG_FAIL_PAGE_ALLOC */
1663
1664static inline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1665{
1666 return false;
1667}
1668
1669#endif /* CONFIG_FAIL_PAGE_ALLOC */
1670
1671/*
1672 * Return true if free pages are above 'mark'. This takes into account the order
1673 * of the allocation.
1674 */
1675static bool __zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1676 int classzone_idx, int alloc_flags, long free_pages)
1677{
1678 /* free_pages my go negative - that's OK */
1679 long min = mark;
1680 long lowmem_reserve = z->lowmem_reserve[classzone_idx];
1681 int o;
1682 long free_cma = 0;
1683
1684 free_pages -= (1 << order) - 1;
1685 if (alloc_flags & ALLOC_HIGH)
1686 min -= min / 2;
1687 if (alloc_flags & ALLOC_HARDER)
1688 min -= min / 4;
1689#ifdef CONFIG_CMA
1690 /* If allocation can't use CMA areas don't use free CMA pages */
1691 if (!(alloc_flags & ALLOC_CMA))
1692 free_cma = zone_page_state(z, NR_FREE_CMA_PAGES);
1693#endif
1694
1695 if (free_pages - free_cma <= min + lowmem_reserve)
1696 return false;
1697 for (o = 0; o < order; o++) {
1698 /* At the next order, this order's pages become unavailable */
1699 free_pages -= z->free_area[o].nr_free << o;
1700
1701 /* Require fewer higher order pages to be free */
1702 min >>= 1;
1703
1704 if (free_pages <= min)
1705 return false;
1706 }
1707 return true;
1708}
1709
1710bool zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1711 int classzone_idx, int alloc_flags)
1712{
1713 return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1714 zone_page_state(z, NR_FREE_PAGES));
1715}
1716
1717bool zone_watermark_ok_safe(struct zone *z, int order, unsigned long mark,
1718 int classzone_idx, int alloc_flags)
1719{
1720 long free_pages = zone_page_state(z, NR_FREE_PAGES);
1721
1722 if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
1723 free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
1724
1725 return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1726 free_pages);
1727}
1728
1729#ifdef CONFIG_NUMA
1730/*
1731 * zlc_setup - Setup for "zonelist cache". Uses cached zone data to
1732 * skip over zones that are not allowed by the cpuset, or that have
1733 * been recently (in last second) found to be nearly full. See further
1734 * comments in mmzone.h. Reduces cache footprint of zonelist scans
1735 * that have to skip over a lot of full or unallowed zones.
1736 *
1737 * If the zonelist cache is present in the passed zonelist, then
1738 * returns a pointer to the allowed node mask (either the current
1739 * tasks mems_allowed, or node_states[N_MEMORY].)
1740 *
1741 * If the zonelist cache is not available for this zonelist, does
1742 * nothing and returns NULL.
1743 *
1744 * If the fullzones BITMAP in the zonelist cache is stale (more than
1745 * a second since last zap'd) then we zap it out (clear its bits.)
1746 *
1747 * We hold off even calling zlc_setup, until after we've checked the
1748 * first zone in the zonelist, on the theory that most allocations will
1749 * be satisfied from that first zone, so best to examine that zone as
1750 * quickly as we can.
1751 */
1752static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1753{
1754 struct zonelist_cache *zlc; /* cached zonelist speedup info */
1755 nodemask_t *allowednodes; /* zonelist_cache approximation */
1756
1757 zlc = zonelist->zlcache_ptr;
1758 if (!zlc)
1759 return NULL;
1760
1761 if (time_after(jiffies, zlc->last_full_zap + HZ)) {
1762 bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1763 zlc->last_full_zap = jiffies;
1764 }
1765
1766 allowednodes = !in_interrupt() && (alloc_flags & ALLOC_CPUSET) ?
1767 &cpuset_current_mems_allowed :
1768 &node_states[N_MEMORY];
1769 return allowednodes;
1770}
1771
1772/*
1773 * Given 'z' scanning a zonelist, run a couple of quick checks to see
1774 * if it is worth looking at further for free memory:
1775 * 1) Check that the zone isn't thought to be full (doesn't have its
1776 * bit set in the zonelist_cache fullzones BITMAP).
1777 * 2) Check that the zones node (obtained from the zonelist_cache
1778 * z_to_n[] mapping) is allowed in the passed in allowednodes mask.
1779 * Return true (non-zero) if zone is worth looking at further, or
1780 * else return false (zero) if it is not.
1781 *
1782 * This check -ignores- the distinction between various watermarks,
1783 * such as GFP_HIGH, GFP_ATOMIC, PF_MEMALLOC, ... If a zone is
1784 * found to be full for any variation of these watermarks, it will
1785 * be considered full for up to one second by all requests, unless
1786 * we are so low on memory on all allowed nodes that we are forced
1787 * into the second scan of the zonelist.
1788 *
1789 * In the second scan we ignore this zonelist cache and exactly
1790 * apply the watermarks to all zones, even it is slower to do so.
1791 * We are low on memory in the second scan, and should leave no stone
1792 * unturned looking for a free page.
1793 */
1794static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1795 nodemask_t *allowednodes)
1796{
1797 struct zonelist_cache *zlc; /* cached zonelist speedup info */
1798 int i; /* index of *z in zonelist zones */
1799 int n; /* node that zone *z is on */
1800
1801 zlc = zonelist->zlcache_ptr;
1802 if (!zlc)
1803 return 1;
1804
1805 i = z - zonelist->_zonerefs;
1806 n = zlc->z_to_n[i];
1807
1808 /* This zone is worth trying if it is allowed but not full */
1809 return node_isset(n, *allowednodes) && !test_bit(i, zlc->fullzones);
1810}
1811
1812/*
1813 * Given 'z' scanning a zonelist, set the corresponding bit in
1814 * zlc->fullzones, so that subsequent attempts to allocate a page
1815 * from that zone don't waste time re-examining it.
1816 */
1817static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1818{
1819 struct zonelist_cache *zlc; /* cached zonelist speedup info */
1820 int i; /* index of *z in zonelist zones */
1821
1822 zlc = zonelist->zlcache_ptr;
1823 if (!zlc)
1824 return;
1825
1826 i = z - zonelist->_zonerefs;
1827
1828 set_bit(i, zlc->fullzones);
1829}
1830
1831/*
1832 * clear all zones full, called after direct reclaim makes progress so that
1833 * a zone that was recently full is not skipped over for up to a second
1834 */
1835static void zlc_clear_zones_full(struct zonelist *zonelist)
1836{
1837 struct zonelist_cache *zlc; /* cached zonelist speedup info */
1838
1839 zlc = zonelist->zlcache_ptr;
1840 if (!zlc)
1841 return;
1842
1843 bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1844}
1845
1846static bool zone_local(struct zone *local_zone, struct zone *zone)
1847{
1848 return local_zone->node == zone->node;
1849}
1850
1851static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
1852{
1853 return node_isset(local_zone->node, zone->zone_pgdat->reclaim_nodes);
1854}
1855
1856static void __paginginit init_zone_allows_reclaim(int nid)
1857{
1858 int i;
1859
1860 for_each_node_state(i, N_MEMORY)
1861 if (node_distance(nid, i) <= RECLAIM_DISTANCE)
1862 node_set(i, NODE_DATA(nid)->reclaim_nodes);
1863 else
1864 zone_reclaim_mode = 1;
1865}
1866
1867#else /* CONFIG_NUMA */
1868
1869static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1870{
1871 return NULL;
1872}
1873
1874static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1875 nodemask_t *allowednodes)
1876{
1877 return 1;
1878}
1879
1880static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1881{
1882}
1883
1884static void zlc_clear_zones_full(struct zonelist *zonelist)
1885{
1886}
1887
1888static bool zone_local(struct zone *local_zone, struct zone *zone)
1889{
1890 return true;
1891}
1892
1893static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
1894{
1895 return true;
1896}
1897
1898static inline void init_zone_allows_reclaim(int nid)
1899{
1900}
1901#endif /* CONFIG_NUMA */
1902
1903/*
1904 * get_page_from_freelist goes through the zonelist trying to allocate
1905 * a page.
1906 */
1907static struct page *
1908get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
1909 struct zonelist *zonelist, int high_zoneidx, int alloc_flags,
1910 struct zone *preferred_zone, int migratetype)
1911{
1912 struct zoneref *z;
1913 struct page *page = NULL;
1914 int classzone_idx;
1915 struct zone *zone;
1916 nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
1917 int zlc_active = 0; /* set if using zonelist_cache */
1918 int did_zlc_setup = 0; /* just call zlc_setup() one time */
1919
1920 classzone_idx = zone_idx(preferred_zone);
1921zonelist_scan:
1922 /*
1923 * Scan zonelist, looking for a zone with enough free.
1924 * See also __cpuset_node_allowed_softwall() comment in kernel/cpuset.c.
1925 */
1926 for_each_zone_zonelist_nodemask(zone, z, zonelist,
1927 high_zoneidx, nodemask) {
1928 unsigned long mark;
1929
1930 if (IS_ENABLED(CONFIG_NUMA) && zlc_active &&
1931 !zlc_zone_worth_trying(zonelist, z, allowednodes))
1932 continue;
1933 if ((alloc_flags & ALLOC_CPUSET) &&
1934 !cpuset_zone_allowed_softwall(zone, gfp_mask))
1935 continue;
1936 BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
1937 if (unlikely(alloc_flags & ALLOC_NO_WATERMARKS))
1938 goto try_this_zone;
1939 /*
1940 * Distribute pages in proportion to the individual
1941 * zone size to ensure fair page aging. The zone a
1942 * page was allocated in should have no effect on the
1943 * time the page has in memory before being reclaimed.
1944 */
1945 if (alloc_flags & ALLOC_FAIR) {
1946 if (!zone_local(preferred_zone, zone))
1947 continue;
1948 if (zone_page_state(zone, NR_ALLOC_BATCH) <= 0)
1949 continue;
1950 }
1951 /*
1952 * When allocating a page cache page for writing, we
1953 * want to get it from a zone that is within its dirty
1954 * limit, such that no single zone holds more than its
1955 * proportional share of globally allowed dirty pages.
1956 * The dirty limits take into account the zone's
1957 * lowmem reserves and high watermark so that kswapd
1958 * should be able to balance it without having to
1959 * write pages from its LRU list.
1960 *
1961 * This may look like it could increase pressure on
1962 * lower zones by failing allocations in higher zones
1963 * before they are full. But the pages that do spill
1964 * over are limited as the lower zones are protected
1965 * by this very same mechanism. It should not become
1966 * a practical burden to them.
1967 *
1968 * XXX: For now, allow allocations to potentially
1969 * exceed the per-zone dirty limit in the slowpath
1970 * (ALLOC_WMARK_LOW unset) before going into reclaim,
1971 * which is important when on a NUMA setup the allowed
1972 * zones are together not big enough to reach the
1973 * global limit. The proper fix for these situations
1974 * will require awareness of zones in the
1975 * dirty-throttling and the flusher threads.
1976 */
1977 if ((alloc_flags & ALLOC_WMARK_LOW) &&
1978 (gfp_mask & __GFP_WRITE) && !zone_dirty_ok(zone))
1979 goto this_zone_full;
1980
1981 mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
1982 if (!zone_watermark_ok(zone, order, mark,
1983 classzone_idx, alloc_flags)) {
1984 int ret;
1985
1986 if (IS_ENABLED(CONFIG_NUMA) &&
1987 !did_zlc_setup && nr_online_nodes > 1) {
1988 /*
1989 * we do zlc_setup if there are multiple nodes
1990 * and before considering the first zone allowed
1991 * by the cpuset.
1992 */
1993 allowednodes = zlc_setup(zonelist, alloc_flags);
1994 zlc_active = 1;
1995 did_zlc_setup = 1;
1996 }
1997
1998 if (zone_reclaim_mode == 0 ||
1999 !zone_allows_reclaim(preferred_zone, zone))
2000 goto this_zone_full;
2001
2002 /*
2003 * As we may have just activated ZLC, check if the first
2004 * eligible zone has failed zone_reclaim recently.
2005 */
2006 if (IS_ENABLED(CONFIG_NUMA) && zlc_active &&
2007 !zlc_zone_worth_trying(zonelist, z, allowednodes))
2008 continue;
2009
2010 ret = zone_reclaim(zone, gfp_mask, order);
2011 switch (ret) {
2012 case ZONE_RECLAIM_NOSCAN:
2013 /* did not scan */
2014 continue;
2015 case ZONE_RECLAIM_FULL:
2016 /* scanned but unreclaimable */
2017 continue;
2018 default:
2019 /* did we reclaim enough */
2020 if (zone_watermark_ok(zone, order, mark,
2021 classzone_idx, alloc_flags))
2022 goto try_this_zone;
2023
2024 /*
2025 * Failed to reclaim enough to meet watermark.
2026 * Only mark the zone full if checking the min
2027 * watermark or if we failed to reclaim just
2028 * 1<<order pages or else the page allocator
2029 * fastpath will prematurely mark zones full
2030 * when the watermark is between the low and
2031 * min watermarks.
2032 */
2033 if (((alloc_flags & ALLOC_WMARK_MASK) == ALLOC_WMARK_MIN) ||
2034 ret == ZONE_RECLAIM_SOME)
2035 goto this_zone_full;
2036
2037 continue;
2038 }
2039 }
2040
2041try_this_zone:
2042 page = buffered_rmqueue(preferred_zone, zone, order,
2043 gfp_mask, migratetype);
2044 if (page)
2045 break;
2046this_zone_full:
2047 if (IS_ENABLED(CONFIG_NUMA))
2048 zlc_mark_zone_full(zonelist, z);
2049 }
2050
2051 if (unlikely(IS_ENABLED(CONFIG_NUMA) && page == NULL && zlc_active)) {
2052 /* Disable zlc cache for second zonelist scan */
2053 zlc_active = 0;
2054 goto zonelist_scan;
2055 }
2056
2057 if (page)
2058 /*
2059 * page->pfmemalloc is set when ALLOC_NO_WATERMARKS was
2060 * necessary to allocate the page. The expectation is
2061 * that the caller is taking steps that will free more
2062 * memory. The caller should avoid the page being used
2063 * for !PFMEMALLOC purposes.
2064 */
2065 page->pfmemalloc = !!(alloc_flags & ALLOC_NO_WATERMARKS);
2066
2067 return page;
2068}
2069
2070/*
2071 * Large machines with many possible nodes should not always dump per-node
2072 * meminfo in irq context.
2073 */
2074static inline bool should_suppress_show_mem(void)
2075{
2076 bool ret = false;
2077
2078#if NODES_SHIFT > 8
2079 ret = in_interrupt();
2080#endif
2081 return ret;
2082}
2083
2084static DEFINE_RATELIMIT_STATE(nopage_rs,
2085 DEFAULT_RATELIMIT_INTERVAL,
2086 DEFAULT_RATELIMIT_BURST);
2087
2088void warn_alloc_failed(gfp_t gfp_mask, int order, const char *fmt, ...)
2089{
2090 unsigned int filter = SHOW_MEM_FILTER_NODES;
2091
2092 if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs) ||
2093 debug_guardpage_minorder() > 0)
2094 return;
2095
2096 /*
2097 * This documents exceptions given to allocations in certain
2098 * contexts that are allowed to allocate outside current's set
2099 * of allowed nodes.
2100 */
2101 if (!(gfp_mask & __GFP_NOMEMALLOC))
2102 if (test_thread_flag(TIF_MEMDIE) ||
2103 (current->flags & (PF_MEMALLOC | PF_EXITING)))
2104 filter &= ~SHOW_MEM_FILTER_NODES;
2105 if (in_interrupt() || !(gfp_mask & __GFP_WAIT))
2106 filter &= ~SHOW_MEM_FILTER_NODES;
2107
2108 if (fmt) {
2109 struct va_format vaf;
2110 va_list args;
2111
2112 va_start(args, fmt);
2113
2114 vaf.fmt = fmt;
2115 vaf.va = &args;
2116
2117 pr_warn("%pV", &vaf);
2118
2119 va_end(args);
2120 }
2121
2122 pr_warn("%s: page allocation failure: order:%d, mode:0x%x\n",
2123 current->comm, order, gfp_mask);
2124
2125 dump_stack();
2126 if (!should_suppress_show_mem())
2127 show_mem(filter);
2128}
2129
2130static inline int
2131should_alloc_retry(gfp_t gfp_mask, unsigned int order,
2132 unsigned long did_some_progress,
2133 unsigned long pages_reclaimed)
2134{
2135 /* Do not loop if specifically requested */
2136 if (gfp_mask & __GFP_NORETRY)
2137 return 0;
2138
2139 /* Always retry if specifically requested */
2140 if (gfp_mask & __GFP_NOFAIL)
2141 return 1;
2142
2143 /*
2144 * Suspend converts GFP_KERNEL to __GFP_WAIT which can prevent reclaim
2145 * making forward progress without invoking OOM. Suspend also disables
2146 * storage devices so kswapd will not help. Bail if we are suspending.
2147 */
2148 if (!did_some_progress && pm_suspended_storage())
2149 return 0;
2150
2151 /*
2152 * In this implementation, order <= PAGE_ALLOC_COSTLY_ORDER
2153 * means __GFP_NOFAIL, but that may not be true in other
2154 * implementations.
2155 */
2156 if (order <= PAGE_ALLOC_COSTLY_ORDER)
2157 return 1;
2158
2159 /*
2160 * For order > PAGE_ALLOC_COSTLY_ORDER, if __GFP_REPEAT is
2161 * specified, then we retry until we no longer reclaim any pages
2162 * (above), or we've reclaimed an order of pages at least as
2163 * large as the allocation's order. In both cases, if the
2164 * allocation still fails, we stop retrying.
2165 */
2166 if (gfp_mask & __GFP_REPEAT && pages_reclaimed < (1 << order))
2167 return 1;
2168
2169 return 0;
2170}
2171
2172static inline struct page *
2173__alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
2174 struct zonelist *zonelist, enum zone_type high_zoneidx,
2175 nodemask_t *nodemask, struct zone *preferred_zone,
2176 int migratetype)
2177{
2178 struct page *page;
2179
2180 /* Acquire the OOM killer lock for the zones in zonelist */
2181 if (!try_set_zonelist_oom(zonelist, gfp_mask)) {
2182 schedule_timeout_uninterruptible(1);
2183 return NULL;
2184 }
2185
2186 /*
2187 * Go through the zonelist yet one more time, keep very high watermark
2188 * here, this is only to catch a parallel oom killing, we must fail if
2189 * we're still under heavy pressure.
2190 */
2191 page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask,
2192 order, zonelist, high_zoneidx,
2193 ALLOC_WMARK_HIGH|ALLOC_CPUSET,
2194 preferred_zone, migratetype);
2195 if (page)
2196 goto out;
2197
2198 if (!(gfp_mask & __GFP_NOFAIL)) {
2199 /* The OOM killer will not help higher order allocs */
2200 if (order > PAGE_ALLOC_COSTLY_ORDER)
2201 goto out;
2202 /* The OOM killer does not needlessly kill tasks for lowmem */
2203 if (high_zoneidx < ZONE_NORMAL)
2204 goto out;
2205 /*
2206 * GFP_THISNODE contains __GFP_NORETRY and we never hit this.
2207 * Sanity check for bare calls of __GFP_THISNODE, not real OOM.
2208 * The caller should handle page allocation failure by itself if
2209 * it specifies __GFP_THISNODE.
2210 * Note: Hugepage uses it but will hit PAGE_ALLOC_COSTLY_ORDER.
2211 */
2212 if (gfp_mask & __GFP_THISNODE)
2213 goto out;
2214 }
2215 /* Exhausted what can be done so it's blamo time */
2216 out_of_memory(zonelist, gfp_mask, order, nodemask, false);
2217
2218out:
2219 clear_zonelist_oom(zonelist, gfp_mask);
2220 return page;
2221}
2222
2223#ifdef CONFIG_COMPACTION
2224/* Try memory compaction for high-order allocations before reclaim */
2225static struct page *
2226__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
2227 struct zonelist *zonelist, enum zone_type high_zoneidx,
2228 nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2229 int migratetype, bool sync_migration,
2230 bool *contended_compaction, bool *deferred_compaction,
2231 unsigned long *did_some_progress)
2232{
2233 if (!order)
2234 return NULL;
2235
2236 if (compaction_deferred(preferred_zone, order)) {
2237 *deferred_compaction = true;
2238 return NULL;
2239 }
2240
2241 current->flags |= PF_MEMALLOC;
2242 *did_some_progress = try_to_compact_pages(zonelist, order, gfp_mask,
2243 nodemask, sync_migration,
2244 contended_compaction);
2245 current->flags &= ~PF_MEMALLOC;
2246
2247 if (*did_some_progress != COMPACT_SKIPPED) {
2248 struct page *page;
2249
2250 /* Page migration frees to the PCP lists but we want merging */
2251 drain_pages(get_cpu());
2252 put_cpu();
2253
2254 page = get_page_from_freelist(gfp_mask, nodemask,
2255 order, zonelist, high_zoneidx,
2256 alloc_flags & ~ALLOC_NO_WATERMARKS,
2257 preferred_zone, migratetype);
2258 if (page) {
2259 preferred_zone->compact_blockskip_flush = false;
2260 compaction_defer_reset(preferred_zone, order, true);
2261 count_vm_event(COMPACTSUCCESS);
2262 return page;
2263 }
2264
2265 /*
2266 * It's bad if compaction run occurs and fails.
2267 * The most likely reason is that pages exist,
2268 * but not enough to satisfy watermarks.
2269 */
2270 count_vm_event(COMPACTFAIL);
2271
2272 /*
2273 * As async compaction considers a subset of pageblocks, only
2274 * defer if the failure was a sync compaction failure.
2275 */
2276 if (sync_migration)
2277 defer_compaction(preferred_zone, order);
2278
2279 cond_resched();
2280 }
2281
2282 return NULL;
2283}
2284#else
2285static inline struct page *
2286__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
2287 struct zonelist *zonelist, enum zone_type high_zoneidx,
2288 nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2289 int migratetype, bool sync_migration,
2290 bool *contended_compaction, bool *deferred_compaction,
2291 unsigned long *did_some_progress)
2292{
2293 return NULL;
2294}
2295#endif /* CONFIG_COMPACTION */
2296
2297/* Perform direct synchronous page reclaim */
2298static int
2299__perform_reclaim(gfp_t gfp_mask, unsigned int order, struct zonelist *zonelist,
2300 nodemask_t *nodemask)
2301{
2302 struct reclaim_state reclaim_state;
2303 int progress;
2304
2305 cond_resched();
2306
2307 /* We now go into synchronous reclaim */
2308 cpuset_memory_pressure_bump();
2309 current->flags |= PF_MEMALLOC;
2310 lockdep_set_current_reclaim_state(gfp_mask);
2311 reclaim_state.reclaimed_slab = 0;
2312 current->reclaim_state = &reclaim_state;
2313
2314 progress = try_to_free_pages(zonelist, order, gfp_mask, nodemask);
2315
2316 current->reclaim_state = NULL;
2317 lockdep_clear_current_reclaim_state();
2318 current->flags &= ~PF_MEMALLOC;
2319
2320 cond_resched();
2321
2322 return progress;
2323}
2324
2325/* The really slow allocator path where we enter direct reclaim */
2326static inline struct page *
2327__alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
2328 struct zonelist *zonelist, enum zone_type high_zoneidx,
2329 nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2330 int migratetype, unsigned long *did_some_progress)
2331{
2332 struct page *page = NULL;
2333 bool drained = false;
2334
2335 *did_some_progress = __perform_reclaim(gfp_mask, order, zonelist,
2336 nodemask);
2337 if (unlikely(!(*did_some_progress)))
2338 return NULL;
2339
2340 /* After successful reclaim, reconsider all zones for allocation */
2341 if (IS_ENABLED(CONFIG_NUMA))
2342 zlc_clear_zones_full(zonelist);
2343
2344retry:
2345 page = get_page_from_freelist(gfp_mask, nodemask, order,
2346 zonelist, high_zoneidx,
2347 alloc_flags & ~ALLOC_NO_WATERMARKS,
2348 preferred_zone, migratetype);
2349
2350 /*
2351 * If an allocation failed after direct reclaim, it could be because
2352 * pages are pinned on the per-cpu lists. Drain them and try again
2353 */
2354 if (!page && !drained) {
2355 drain_all_pages();
2356 drained = true;
2357 goto retry;
2358 }
2359
2360 return page;
2361}
2362
2363/*
2364 * This is called in the allocator slow-path if the allocation request is of
2365 * sufficient urgency to ignore watermarks and take other desperate measures
2366 */
2367static inline struct page *
2368__alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
2369 struct zonelist *zonelist, enum zone_type high_zoneidx,
2370 nodemask_t *nodemask, struct zone *preferred_zone,
2371 int migratetype)
2372{
2373 struct page *page;
2374
2375 do {
2376 page = get_page_from_freelist(gfp_mask, nodemask, order,
2377 zonelist, high_zoneidx, ALLOC_NO_WATERMARKS,
2378 preferred_zone, migratetype);
2379
2380 if (!page && gfp_mask & __GFP_NOFAIL)
2381 wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
2382 } while (!page && (gfp_mask & __GFP_NOFAIL));
2383
2384 return page;
2385}
2386
2387static void reset_alloc_batches(struct zonelist *zonelist,
2388 enum zone_type high_zoneidx,
2389 struct zone *preferred_zone)
2390{
2391 struct zoneref *z;
2392 struct zone *zone;
2393
2394 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
2395 /*
2396 * Only reset the batches of zones that were actually
2397 * considered in the fairness pass, we don't want to
2398 * trash fairness information for zones that are not
2399 * actually part of this zonelist's round-robin cycle.
2400 */
2401 if (!zone_local(preferred_zone, zone))
2402 continue;
2403 mod_zone_page_state(zone, NR_ALLOC_BATCH,
2404 high_wmark_pages(zone) - low_wmark_pages(zone) -
2405 atomic_long_read(&zone->vm_stat[NR_ALLOC_BATCH]));
2406 }
2407}
2408
2409static void wake_all_kswapds(unsigned int order,
2410 struct zonelist *zonelist,
2411 enum zone_type high_zoneidx,
2412 struct zone *preferred_zone)
2413{
2414 struct zoneref *z;
2415 struct zone *zone;
2416
2417 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx)
2418 wakeup_kswapd(zone, order, zone_idx(preferred_zone));
2419}
2420
2421static inline int
2422gfp_to_alloc_flags(gfp_t gfp_mask)
2423{
2424 int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
2425 const gfp_t wait = gfp_mask & __GFP_WAIT;
2426
2427 /* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
2428 BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
2429
2430 /*
2431 * The caller may dip into page reserves a bit more if the caller
2432 * cannot run direct reclaim, or if the caller has realtime scheduling
2433 * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
2434 * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
2435 */
2436 alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
2437
2438 if (!wait) {
2439 /*
2440 * Not worth trying to allocate harder for
2441 * __GFP_NOMEMALLOC even if it can't schedule.
2442 */
2443 if (!(gfp_mask & __GFP_NOMEMALLOC))
2444 alloc_flags |= ALLOC_HARDER;
2445 /*
2446 * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
2447 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
2448 */
2449 alloc_flags &= ~ALLOC_CPUSET;
2450 } else if (unlikely(rt_task(current)) && !in_interrupt())
2451 alloc_flags |= ALLOC_HARDER;
2452
2453 if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
2454 if (gfp_mask & __GFP_MEMALLOC)
2455 alloc_flags |= ALLOC_NO_WATERMARKS;
2456 else if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
2457 alloc_flags |= ALLOC_NO_WATERMARKS;
2458 else if (!in_interrupt() &&
2459 ((current->flags & PF_MEMALLOC) ||
2460 unlikely(test_thread_flag(TIF_MEMDIE))))
2461 alloc_flags |= ALLOC_NO_WATERMARKS;
2462 }
2463#ifdef CONFIG_CMA
2464 if (allocflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
2465 alloc_flags |= ALLOC_CMA;
2466#endif
2467 return alloc_flags;
2468}
2469
2470bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
2471{
2472 return !!(gfp_to_alloc_flags(gfp_mask) & ALLOC_NO_WATERMARKS);
2473}
2474
2475static inline struct page *
2476__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
2477 struct zonelist *zonelist, enum zone_type high_zoneidx,
2478 nodemask_t *nodemask, struct zone *preferred_zone,
2479 int migratetype)
2480{
2481 const gfp_t wait = gfp_mask & __GFP_WAIT;
2482 struct page *page = NULL;
2483 int alloc_flags;
2484 unsigned long pages_reclaimed = 0;
2485 unsigned long did_some_progress;
2486 bool sync_migration = false;
2487 bool deferred_compaction = false;
2488 bool contended_compaction = false;
2489
2490 /*
2491 * In the slowpath, we sanity check order to avoid ever trying to
2492 * reclaim >= MAX_ORDER areas which will never succeed. Callers may
2493 * be using allocators in order of preference for an area that is
2494 * too large.
2495 */
2496 if (order >= MAX_ORDER) {
2497 WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
2498 return NULL;
2499 }
2500
2501 /*
2502 * GFP_THISNODE (meaning __GFP_THISNODE, __GFP_NORETRY and
2503 * __GFP_NOWARN set) should not cause reclaim since the subsystem
2504 * (f.e. slab) using GFP_THISNODE may choose to trigger reclaim
2505 * using a larger set of nodes after it has established that the
2506 * allowed per node queues are empty and that nodes are
2507 * over allocated.
2508 */
2509 if (IS_ENABLED(CONFIG_NUMA) &&
2510 (gfp_mask & GFP_THISNODE) == GFP_THISNODE)
2511 goto nopage;
2512
2513restart:
2514 if (!(gfp_mask & __GFP_NO_KSWAPD))
2515 wake_all_kswapds(order, zonelist, high_zoneidx, preferred_zone);
2516
2517 /*
2518 * OK, we're below the kswapd watermark and have kicked background
2519 * reclaim. Now things get more complex, so set up alloc_flags according
2520 * to how we want to proceed.
2521 */
2522 alloc_flags = gfp_to_alloc_flags(gfp_mask);
2523
2524 /*
2525 * Find the true preferred zone if the allocation is unconstrained by
2526 * cpusets.
2527 */
2528 if (!(alloc_flags & ALLOC_CPUSET) && !nodemask)
2529 first_zones_zonelist(zonelist, high_zoneidx, NULL,
2530 &preferred_zone);
2531
2532rebalance:
2533 /* This is the last chance, in general, before the goto nopage. */
2534 page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist,
2535 high_zoneidx, alloc_flags & ~ALLOC_NO_WATERMARKS,
2536 preferred_zone, migratetype);
2537 if (page)
2538 goto got_pg;
2539
2540 /* Allocate without watermarks if the context allows */
2541 if (alloc_flags & ALLOC_NO_WATERMARKS) {
2542 /*
2543 * Ignore mempolicies if ALLOC_NO_WATERMARKS on the grounds
2544 * the allocation is high priority and these type of
2545 * allocations are system rather than user orientated
2546 */
2547 zonelist = node_zonelist(numa_node_id(), gfp_mask);
2548
2549 page = __alloc_pages_high_priority(gfp_mask, order,
2550 zonelist, high_zoneidx, nodemask,
2551 preferred_zone, migratetype);
2552 if (page) {
2553 goto got_pg;
2554 }
2555 }
2556
2557 /* Atomic allocations - we can't balance anything */
2558 if (!wait) {
2559 /*
2560 * All existing users of the deprecated __GFP_NOFAIL are
2561 * blockable, so warn of any new users that actually allow this
2562 * type of allocation to fail.
2563 */
2564 WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL);
2565 goto nopage;
2566 }
2567
2568 /* Avoid recursion of direct reclaim */
2569 if (current->flags & PF_MEMALLOC)
2570 goto nopage;
2571
2572 /* Avoid allocations with no watermarks from looping endlessly */
2573 if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL))
2574 goto nopage;
2575
2576 /*
2577 * Try direct compaction. The first pass is asynchronous. Subsequent
2578 * attempts after direct reclaim are synchronous
2579 */
2580 page = __alloc_pages_direct_compact(gfp_mask, order,
2581 zonelist, high_zoneidx,
2582 nodemask,
2583 alloc_flags, preferred_zone,
2584 migratetype, sync_migration,
2585 &contended_compaction,
2586 &deferred_compaction,
2587 &did_some_progress);
2588 if (page)
2589 goto got_pg;
2590 sync_migration = true;
2591
2592 /*
2593 * If compaction is deferred for high-order allocations, it is because
2594 * sync compaction recently failed. In this is the case and the caller
2595 * requested a movable allocation that does not heavily disrupt the
2596 * system then fail the allocation instead of entering direct reclaim.
2597 */
2598 if ((deferred_compaction || contended_compaction) &&
2599 (gfp_mask & __GFP_NO_KSWAPD))
2600 goto nopage;
2601
2602 /* Try direct reclaim and then allocating */
2603 page = __alloc_pages_direct_reclaim(gfp_mask, order,
2604 zonelist, high_zoneidx,
2605 nodemask,
2606 alloc_flags, preferred_zone,
2607 migratetype, &did_some_progress);
2608 if (page)
2609 goto got_pg;
2610
2611 /*
2612 * If we failed to make any progress reclaiming, then we are
2613 * running out of options and have to consider going OOM
2614 */
2615 if (!did_some_progress) {
2616 if (oom_gfp_allowed(gfp_mask)) {
2617 if (oom_killer_disabled)
2618 goto nopage;
2619 /* Coredumps can quickly deplete all memory reserves */
2620 if ((current->flags & PF_DUMPCORE) &&
2621 !(gfp_mask & __GFP_NOFAIL))
2622 goto nopage;
2623 page = __alloc_pages_may_oom(gfp_mask, order,
2624 zonelist, high_zoneidx,
2625 nodemask, preferred_zone,
2626 migratetype);
2627 if (page)
2628 goto got_pg;
2629
2630 if (!(gfp_mask & __GFP_NOFAIL)) {
2631 /*
2632 * The oom killer is not called for high-order
2633 * allocations that may fail, so if no progress
2634 * is being made, there are no other options and
2635 * retrying is unlikely to help.
2636 */
2637 if (order > PAGE_ALLOC_COSTLY_ORDER)
2638 goto nopage;
2639 /*
2640 * The oom killer is not called for lowmem
2641 * allocations to prevent needlessly killing
2642 * innocent tasks.
2643 */
2644 if (high_zoneidx < ZONE_NORMAL)
2645 goto nopage;
2646 }
2647
2648 goto restart;
2649 }
2650 }
2651
2652 /* Check if we should retry the allocation */
2653 pages_reclaimed += did_some_progress;
2654 if (should_alloc_retry(gfp_mask, order, did_some_progress,
2655 pages_reclaimed)) {
2656 /* Wait for some write requests to complete then retry */
2657 wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
2658 goto rebalance;
2659 } else {
2660 /*
2661 * High-order allocations do not necessarily loop after
2662 * direct reclaim and reclaim/compaction depends on compaction
2663 * being called after reclaim so call directly if necessary
2664 */
2665 page = __alloc_pages_direct_compact(gfp_mask, order,
2666 zonelist, high_zoneidx,
2667 nodemask,
2668 alloc_flags, preferred_zone,
2669 migratetype, sync_migration,
2670 &contended_compaction,
2671 &deferred_compaction,
2672 &did_some_progress);
2673 if (page)
2674 goto got_pg;
2675 }
2676
2677nopage:
2678 warn_alloc_failed(gfp_mask, order, NULL);
2679 return page;
2680got_pg:
2681 if (kmemcheck_enabled)
2682 kmemcheck_pagealloc_alloc(page, order, gfp_mask);
2683
2684 return page;
2685}
2686
2687/*
2688 * This is the 'heart' of the zoned buddy allocator.
2689 */
2690struct page *
2691__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
2692 struct zonelist *zonelist, nodemask_t *nodemask)
2693{
2694 enum zone_type high_zoneidx = gfp_zone(gfp_mask);
2695 struct zone *preferred_zone;
2696 struct page *page = NULL;
2697 int migratetype = allocflags_to_migratetype(gfp_mask);
2698 unsigned int cpuset_mems_cookie;
2699 int alloc_flags = ALLOC_WMARK_LOW|ALLOC_CPUSET|ALLOC_FAIR;
2700 struct mem_cgroup *memcg = NULL;
2701
2702 gfp_mask &= gfp_allowed_mask;
2703
2704 lockdep_trace_alloc(gfp_mask);
2705
2706 might_sleep_if(gfp_mask & __GFP_WAIT);
2707
2708 if (should_fail_alloc_page(gfp_mask, order))
2709 return NULL;
2710
2711 /*
2712 * Check the zones suitable for the gfp_mask contain at least one
2713 * valid zone. It's possible to have an empty zonelist as a result
2714 * of GFP_THISNODE and a memoryless node
2715 */
2716 if (unlikely(!zonelist->_zonerefs->zone))
2717 return NULL;
2718
2719 /*
2720 * Will only have any effect when __GFP_KMEMCG is set. This is
2721 * verified in the (always inline) callee
2722 */
2723 if (!memcg_kmem_newpage_charge(gfp_mask, &memcg, order))
2724 return NULL;
2725
2726retry_cpuset:
2727 cpuset_mems_cookie = read_mems_allowed_begin();
2728
2729 /* The preferred zone is used for statistics later */
2730 first_zones_zonelist(zonelist, high_zoneidx,
2731 nodemask ? : &cpuset_current_mems_allowed,
2732 &preferred_zone);
2733 if (!preferred_zone)
2734 goto out;
2735
2736#ifdef CONFIG_CMA
2737 if (allocflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
2738 alloc_flags |= ALLOC_CMA;
2739#endif
2740retry:
2741 /* First allocation attempt */
2742 page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
2743 zonelist, high_zoneidx, alloc_flags,
2744 preferred_zone, migratetype);
2745 if (unlikely(!page)) {
2746 /*
2747 * The first pass makes sure allocations are spread
2748 * fairly within the local node. However, the local
2749 * node might have free pages left after the fairness
2750 * batches are exhausted, and remote zones haven't
2751 * even been considered yet. Try once more without
2752 * fairness, and include remote zones now, before
2753 * entering the slowpath and waking kswapd: prefer
2754 * spilling to a remote zone over swapping locally.
2755 */
2756 if (alloc_flags & ALLOC_FAIR) {
2757 reset_alloc_batches(zonelist, high_zoneidx,
2758 preferred_zone);
2759 alloc_flags &= ~ALLOC_FAIR;
2760 goto retry;
2761 }
2762 /*
2763 * Runtime PM, block IO and its error handling path
2764 * can deadlock because I/O on the device might not
2765 * complete.
2766 */
2767 gfp_mask = memalloc_noio_flags(gfp_mask);
2768 page = __alloc_pages_slowpath(gfp_mask, order,
2769 zonelist, high_zoneidx, nodemask,
2770 preferred_zone, migratetype);
2771 }
2772
2773 trace_mm_page_alloc(page, order, gfp_mask, migratetype);
2774
2775out:
2776 /*
2777 * When updating a task's mems_allowed, it is possible to race with
2778 * parallel threads in such a way that an allocation can fail while
2779 * the mask is being updated. If a page allocation is about to fail,
2780 * check if the cpuset changed during allocation and if so, retry.
2781 */
2782 if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
2783 goto retry_cpuset;
2784
2785 memcg_kmem_commit_charge(page, memcg, order);
2786
2787 return page;
2788}
2789EXPORT_SYMBOL(__alloc_pages_nodemask);
2790
2791/*
2792 * Common helper functions.
2793 */
2794unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
2795{
2796 struct page *page;
2797
2798 /*
2799 * __get_free_pages() returns a 32-bit address, which cannot represent
2800 * a highmem page
2801 */
2802 VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
2803
2804 page = alloc_pages(gfp_mask, order);
2805 if (!page)
2806 return 0;
2807 return (unsigned long) page_address(page);
2808}
2809EXPORT_SYMBOL(__get_free_pages);
2810
2811unsigned long get_zeroed_page(gfp_t gfp_mask)
2812{
2813 return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
2814}
2815EXPORT_SYMBOL(get_zeroed_page);
2816
2817void __free_pages(struct page *page, unsigned int order)
2818{
2819 if (put_page_testzero(page)) {
2820 if (order == 0)
2821 free_hot_cold_page(page, 0);
2822 else
2823 __free_pages_ok(page, order);
2824 }
2825}
2826
2827EXPORT_SYMBOL(__free_pages);
2828
2829void free_pages(unsigned long addr, unsigned int order)
2830{
2831 if (addr != 0) {
2832 VM_BUG_ON(!virt_addr_valid((void *)addr));
2833 __free_pages(virt_to_page((void *)addr), order);
2834 }
2835}
2836
2837EXPORT_SYMBOL(free_pages);
2838
2839/*
2840 * __free_memcg_kmem_pages and free_memcg_kmem_pages will free
2841 * pages allocated with __GFP_KMEMCG.
2842 *
2843 * Those pages are accounted to a particular memcg, embedded in the
2844 * corresponding page_cgroup. To avoid adding a hit in the allocator to search
2845 * for that information only to find out that it is NULL for users who have no
2846 * interest in that whatsoever, we provide these functions.
2847 *
2848 * The caller knows better which flags it relies on.
2849 */
2850void __free_memcg_kmem_pages(struct page *page, unsigned int order)
2851{
2852 memcg_kmem_uncharge_pages(page, order);
2853 __free_pages(page, order);
2854}
2855
2856void free_memcg_kmem_pages(unsigned long addr, unsigned int order)
2857{
2858 if (addr != 0) {
2859 VM_BUG_ON(!virt_addr_valid((void *)addr));
2860 __free_memcg_kmem_pages(virt_to_page((void *)addr), order);
2861 }
2862}
2863
2864static void *make_alloc_exact(unsigned long addr, unsigned order, size_t size)
2865{
2866 if (addr) {
2867 unsigned long alloc_end = addr + (PAGE_SIZE << order);
2868 unsigned long used = addr + PAGE_ALIGN(size);
2869
2870 split_page(virt_to_page((void *)addr), order);
2871 while (used < alloc_end) {
2872 free_page(used);
2873 used += PAGE_SIZE;
2874 }
2875 }
2876 return (void *)addr;
2877}
2878
2879/**
2880 * alloc_pages_exact - allocate an exact number physically-contiguous pages.
2881 * @size: the number of bytes to allocate
2882 * @gfp_mask: GFP flags for the allocation
2883 *
2884 * This function is similar to alloc_pages(), except that it allocates the
2885 * minimum number of pages to satisfy the request. alloc_pages() can only
2886 * allocate memory in power-of-two pages.
2887 *
2888 * This function is also limited by MAX_ORDER.
2889 *
2890 * Memory allocated by this function must be released by free_pages_exact().
2891 */
2892void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
2893{
2894 unsigned int order = get_order(size);
2895 unsigned long addr;
2896
2897 addr = __get_free_pages(gfp_mask, order);
2898 return make_alloc_exact(addr, order, size);
2899}
2900EXPORT_SYMBOL(alloc_pages_exact);
2901
2902/**
2903 * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
2904 * pages on a node.
2905 * @nid: the preferred node ID where memory should be allocated
2906 * @size: the number of bytes to allocate
2907 * @gfp_mask: GFP flags for the allocation
2908 *
2909 * Like alloc_pages_exact(), but try to allocate on node nid first before falling
2910 * back.
2911 * Note this is not alloc_pages_exact_node() which allocates on a specific node,
2912 * but is not exact.
2913 */
2914void *alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
2915{
2916 unsigned order = get_order(size);
2917 struct page *p = alloc_pages_node(nid, gfp_mask, order);
2918 if (!p)
2919 return NULL;
2920 return make_alloc_exact((unsigned long)page_address(p), order, size);
2921}
2922EXPORT_SYMBOL(alloc_pages_exact_nid);
2923
2924/**
2925 * free_pages_exact - release memory allocated via alloc_pages_exact()
2926 * @virt: the value returned by alloc_pages_exact.
2927 * @size: size of allocation, same value as passed to alloc_pages_exact().
2928 *
2929 * Release the memory allocated by a previous call to alloc_pages_exact.
2930 */
2931void free_pages_exact(void *virt, size_t size)
2932{
2933 unsigned long addr = (unsigned long)virt;
2934 unsigned long end = addr + PAGE_ALIGN(size);
2935
2936 while (addr < end) {
2937 free_page(addr);
2938 addr += PAGE_SIZE;
2939 }
2940}
2941EXPORT_SYMBOL(free_pages_exact);
2942
2943/**
2944 * nr_free_zone_pages - count number of pages beyond high watermark
2945 * @offset: The zone index of the highest zone
2946 *
2947 * nr_free_zone_pages() counts the number of counts pages which are beyond the
2948 * high watermark within all zones at or below a given zone index. For each
2949 * zone, the number of pages is calculated as:
2950 * managed_pages - high_pages
2951 */
2952static unsigned long nr_free_zone_pages(int offset)
2953{
2954 struct zoneref *z;
2955 struct zone *zone;
2956
2957 /* Just pick one node, since fallback list is circular */
2958 unsigned long sum = 0;
2959
2960 struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
2961
2962 for_each_zone_zonelist(zone, z, zonelist, offset) {
2963 unsigned long size = zone->managed_pages;
2964 unsigned long high = high_wmark_pages(zone);
2965 if (size > high)
2966 sum += size - high;
2967 }
2968
2969 return sum;
2970}
2971
2972/**
2973 * nr_free_buffer_pages - count number of pages beyond high watermark
2974 *
2975 * nr_free_buffer_pages() counts the number of pages which are beyond the high
2976 * watermark within ZONE_DMA and ZONE_NORMAL.
2977 */
2978unsigned long nr_free_buffer_pages(void)
2979{
2980 return nr_free_zone_pages(gfp_zone(GFP_USER));
2981}
2982EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
2983
2984/**
2985 * nr_free_pagecache_pages - count number of pages beyond high watermark
2986 *
2987 * nr_free_pagecache_pages() counts the number of pages which are beyond the
2988 * high watermark within all zones.
2989 */
2990unsigned long nr_free_pagecache_pages(void)
2991{
2992 return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
2993}
2994
2995static inline void show_node(struct zone *zone)
2996{
2997 if (IS_ENABLED(CONFIG_NUMA))
2998 printk("Node %d ", zone_to_nid(zone));
2999}
3000
3001void si_meminfo(struct sysinfo *val)
3002{
3003 val->totalram = totalram_pages;
3004 val->sharedram = 0;
3005 val->freeram = global_page_state(NR_FREE_PAGES);
3006 val->bufferram = nr_blockdev_pages();
3007 val->totalhigh = totalhigh_pages;
3008 val->freehigh = nr_free_highpages();
3009 val->mem_unit = PAGE_SIZE;
3010}
3011
3012EXPORT_SYMBOL(si_meminfo);
3013
3014#ifdef CONFIG_NUMA
3015void si_meminfo_node(struct sysinfo *val, int nid)
3016{
3017 int zone_type; /* needs to be signed */
3018 unsigned long managed_pages = 0;
3019 pg_data_t *pgdat = NODE_DATA(nid);
3020
3021 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
3022 managed_pages += pgdat->node_zones[zone_type].managed_pages;
3023 val->totalram = managed_pages;
3024 val->freeram = node_page_state(nid, NR_FREE_PAGES);
3025#ifdef CONFIG_HIGHMEM
3026 val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].managed_pages;
3027 val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
3028 NR_FREE_PAGES);
3029#else
3030 val->totalhigh = 0;
3031 val->freehigh = 0;
3032#endif
3033 val->mem_unit = PAGE_SIZE;
3034}
3035#endif
3036
3037/*
3038 * Determine whether the node should be displayed or not, depending on whether
3039 * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
3040 */
3041bool skip_free_areas_node(unsigned int flags, int nid)
3042{
3043 bool ret = false;
3044 unsigned int cpuset_mems_cookie;
3045
3046 if (!(flags & SHOW_MEM_FILTER_NODES))
3047 goto out;
3048
3049 do {
3050 cpuset_mems_cookie = read_mems_allowed_begin();
3051 ret = !node_isset(nid, cpuset_current_mems_allowed);
3052 } while (read_mems_allowed_retry(cpuset_mems_cookie));
3053out:
3054 return ret;
3055}
3056
3057#define K(x) ((x) << (PAGE_SHIFT-10))
3058
3059static void show_migration_types(unsigned char type)
3060{
3061 static const char types[MIGRATE_TYPES] = {
3062 [MIGRATE_UNMOVABLE] = 'U',
3063 [MIGRATE_RECLAIMABLE] = 'E',
3064 [MIGRATE_MOVABLE] = 'M',
3065 [MIGRATE_RESERVE] = 'R',
3066#ifdef CONFIG_CMA
3067 [MIGRATE_CMA] = 'C',
3068#endif
3069#ifdef CONFIG_MEMORY_ISOLATION
3070 [MIGRATE_ISOLATE] = 'I',
3071#endif
3072 };
3073 char tmp[MIGRATE_TYPES + 1];
3074 char *p = tmp;
3075 int i;
3076
3077 for (i = 0; i < MIGRATE_TYPES; i++) {
3078 if (type & (1 << i))
3079 *p++ = types[i];
3080 }
3081
3082 *p = '\0';
3083 printk("(%s) ", tmp);
3084}
3085
3086/*
3087 * Show free area list (used inside shift_scroll-lock stuff)
3088 * We also calculate the percentage fragmentation. We do this by counting the
3089 * memory on each free list with the exception of the first item on the list.
3090 * Suppresses nodes that are not allowed by current's cpuset if
3091 * SHOW_MEM_FILTER_NODES is passed.
3092 */
3093void show_free_areas(unsigned int filter)
3094{
3095 int cpu;
3096 struct zone *zone;
3097
3098 for_each_populated_zone(zone) {
3099 if (skip_free_areas_node(filter, zone_to_nid(zone)))
3100 continue;
3101 show_node(zone);
3102 printk("%s per-cpu:\n", zone->name);
3103
3104 for_each_online_cpu(cpu) {
3105 struct per_cpu_pageset *pageset;
3106
3107 pageset = per_cpu_ptr(zone->pageset, cpu);
3108
3109 printk("CPU %4d: hi:%5d, btch:%4d usd:%4d\n",
3110 cpu, pageset->pcp.high,
3111 pageset->pcp.batch, pageset->pcp.count);
3112 }
3113 }
3114
3115 printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
3116 " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
3117 " unevictable:%lu"
3118 " dirty:%lu writeback:%lu unstable:%lu\n"
3119 " free:%lu slab_reclaimable:%lu slab_unreclaimable:%lu\n"
3120 " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
3121 " free_cma:%lu\n",
3122 global_page_state(NR_ACTIVE_ANON),
3123 global_page_state(NR_INACTIVE_ANON),
3124 global_page_state(NR_ISOLATED_ANON),
3125 global_page_state(NR_ACTIVE_FILE),
3126 global_page_state(NR_INACTIVE_FILE),
3127 global_page_state(NR_ISOLATED_FILE),
3128 global_page_state(NR_UNEVICTABLE),
3129 global_page_state(NR_FILE_DIRTY),
3130 global_page_state(NR_WRITEBACK),
3131 global_page_state(NR_UNSTABLE_NFS),
3132 global_page_state(NR_FREE_PAGES),
3133 global_page_state(NR_SLAB_RECLAIMABLE),
3134 global_page_state(NR_SLAB_UNRECLAIMABLE),
3135 global_page_state(NR_FILE_MAPPED),
3136 global_page_state(NR_SHMEM),
3137 global_page_state(NR_PAGETABLE),
3138 global_page_state(NR_BOUNCE),
3139 global_page_state(NR_FREE_CMA_PAGES));
3140
3141 for_each_populated_zone(zone) {
3142 int i;
3143
3144 if (skip_free_areas_node(filter, zone_to_nid(zone)))
3145 continue;
3146 show_node(zone);
3147 printk("%s"
3148 " free:%lukB"
3149 " min:%lukB"
3150 " low:%lukB"
3151 " high:%lukB"
3152 " active_anon:%lukB"
3153 " inactive_anon:%lukB"
3154 " active_file:%lukB"
3155 " inactive_file:%lukB"
3156 " unevictable:%lukB"
3157 " isolated(anon):%lukB"
3158 " isolated(file):%lukB"
3159 " present:%lukB"
3160 " managed:%lukB"
3161 " mlocked:%lukB"
3162 " dirty:%lukB"
3163 " writeback:%lukB"
3164 " mapped:%lukB"
3165 " shmem:%lukB"
3166 " slab_reclaimable:%lukB"
3167 " slab_unreclaimable:%lukB"
3168 " kernel_stack:%lukB"
3169 " pagetables:%lukB"
3170 " unstable:%lukB"
3171 " bounce:%lukB"
3172 " free_cma:%lukB"
3173 " writeback_tmp:%lukB"
3174 " pages_scanned:%lu"
3175 " all_unreclaimable? %s"
3176 "\n",
3177 zone->name,
3178 K(zone_page_state(zone, NR_FREE_PAGES)),
3179 K(min_wmark_pages(zone)),
3180 K(low_wmark_pages(zone)),
3181 K(high_wmark_pages(zone)),
3182 K(zone_page_state(zone, NR_ACTIVE_ANON)),
3183 K(zone_page_state(zone, NR_INACTIVE_ANON)),
3184 K(zone_page_state(zone, NR_ACTIVE_FILE)),
3185 K(zone_page_state(zone, NR_INACTIVE_FILE)),
3186 K(zone_page_state(zone, NR_UNEVICTABLE)),
3187 K(zone_page_state(zone, NR_ISOLATED_ANON)),
3188 K(zone_page_state(zone, NR_ISOLATED_FILE)),
3189 K(zone->present_pages),
3190 K(zone->managed_pages),
3191 K(zone_page_state(zone, NR_MLOCK)),
3192 K(zone_page_state(zone, NR_FILE_DIRTY)),
3193 K(zone_page_state(zone, NR_WRITEBACK)),
3194 K(zone_page_state(zone, NR_FILE_MAPPED)),
3195 K(zone_page_state(zone, NR_SHMEM)),
3196 K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
3197 K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
3198 zone_page_state(zone, NR_KERNEL_STACK) *
3199 THREAD_SIZE / 1024,
3200 K(zone_page_state(zone, NR_PAGETABLE)),
3201 K(zone_page_state(zone, NR_UNSTABLE_NFS)),
3202 K(zone_page_state(zone, NR_BOUNCE)),
3203 K(zone_page_state(zone, NR_FREE_CMA_PAGES)),
3204 K(zone_page_state(zone, NR_WRITEBACK_TEMP)),
3205 zone->pages_scanned,
3206 (!zone_reclaimable(zone) ? "yes" : "no")
3207 );
3208 printk("lowmem_reserve[]:");
3209 for (i = 0; i < MAX_NR_ZONES; i++)
3210 printk(" %lu", zone->lowmem_reserve[i]);
3211 printk("\n");
3212 }
3213
3214 for_each_populated_zone(zone) {
3215 unsigned long nr[MAX_ORDER], flags, order, total = 0;
3216 unsigned char types[MAX_ORDER];
3217
3218 if (skip_free_areas_node(filter, zone_to_nid(zone)))
3219 continue;
3220 show_node(zone);
3221 printk("%s: ", zone->name);
3222
3223 spin_lock_irqsave(&zone->lock, flags);
3224 for (order = 0; order < MAX_ORDER; order++) {
3225 struct free_area *area = &zone->free_area[order];
3226 int type;
3227
3228 nr[order] = area->nr_free;
3229 total += nr[order] << order;
3230
3231 types[order] = 0;
3232 for (type = 0; type < MIGRATE_TYPES; type++) {
3233 if (!list_empty(&area->free_list[type]))
3234 types[order] |= 1 << type;
3235 }
3236 }
3237 spin_unlock_irqrestore(&zone->lock, flags);
3238 for (order = 0; order < MAX_ORDER; order++) {
3239 printk("%lu*%lukB ", nr[order], K(1UL) << order);
3240 if (nr[order])
3241 show_migration_types(types[order]);
3242 }
3243 printk("= %lukB\n", K(total));
3244 }
3245
3246 hugetlb_show_meminfo();
3247
3248 printk("%ld total pagecache pages\n", global_page_state(NR_FILE_PAGES));
3249
3250 show_swap_cache_info();
3251}
3252
3253static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
3254{
3255 zoneref->zone = zone;
3256 zoneref->zone_idx = zone_idx(zone);
3257}
3258
3259/*
3260 * Builds allocation fallback zone lists.
3261 *
3262 * Add all populated zones of a node to the zonelist.
3263 */
3264static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
3265 int nr_zones)
3266{
3267 struct zone *zone;
3268 enum zone_type zone_type = MAX_NR_ZONES;
3269
3270 do {
3271 zone_type--;
3272 zone = pgdat->node_zones + zone_type;
3273 if (populated_zone(zone)) {
3274 zoneref_set_zone(zone,
3275 &zonelist->_zonerefs[nr_zones++]);
3276 check_highest_zone(zone_type);
3277 }
3278 } while (zone_type);
3279
3280 return nr_zones;
3281}
3282
3283
3284/*
3285 * zonelist_order:
3286 * 0 = automatic detection of better ordering.
3287 * 1 = order by ([node] distance, -zonetype)
3288 * 2 = order by (-zonetype, [node] distance)
3289 *
3290 * If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create
3291 * the same zonelist. So only NUMA can configure this param.
3292 */
3293#define ZONELIST_ORDER_DEFAULT 0
3294#define ZONELIST_ORDER_NODE 1
3295#define ZONELIST_ORDER_ZONE 2
3296
3297/* zonelist order in the kernel.
3298 * set_zonelist_order() will set this to NODE or ZONE.
3299 */
3300static int current_zonelist_order = ZONELIST_ORDER_DEFAULT;
3301static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"};
3302
3303
3304#ifdef CONFIG_NUMA
3305/* The value user specified ....changed by config */
3306static int user_zonelist_order = ZONELIST_ORDER_DEFAULT;
3307/* string for sysctl */
3308#define NUMA_ZONELIST_ORDER_LEN 16
3309char numa_zonelist_order[16] = "default";
3310
3311/*
3312 * interface for configure zonelist ordering.
3313 * command line option "numa_zonelist_order"
3314 * = "[dD]efault - default, automatic configuration.
3315 * = "[nN]ode - order by node locality, then by zone within node
3316 * = "[zZ]one - order by zone, then by locality within zone
3317 */
3318
3319static int __parse_numa_zonelist_order(char *s)
3320{
3321 if (*s == 'd' || *s == 'D') {
3322 user_zonelist_order = ZONELIST_ORDER_DEFAULT;
3323 } else if (*s == 'n' || *s == 'N') {
3324 user_zonelist_order = ZONELIST_ORDER_NODE;
3325 } else if (*s == 'z' || *s == 'Z') {
3326 user_zonelist_order = ZONELIST_ORDER_ZONE;
3327 } else {
3328 printk(KERN_WARNING
3329 "Ignoring invalid numa_zonelist_order value: "
3330 "%s\n", s);
3331 return -EINVAL;
3332 }
3333 return 0;
3334}
3335
3336static __init int setup_numa_zonelist_order(char *s)
3337{
3338 int ret;
3339
3340 if (!s)
3341 return 0;
3342
3343 ret = __parse_numa_zonelist_order(s);
3344 if (ret == 0)
3345 strlcpy(numa_zonelist_order, s, NUMA_ZONELIST_ORDER_LEN);
3346
3347 return ret;
3348}
3349early_param("numa_zonelist_order", setup_numa_zonelist_order);
3350
3351/*
3352 * sysctl handler for numa_zonelist_order
3353 */
3354int numa_zonelist_order_handler(ctl_table *table, int write,
3355 void __user *buffer, size_t *length,
3356 loff_t *ppos)
3357{
3358 char saved_string[NUMA_ZONELIST_ORDER_LEN];
3359 int ret;
3360 static DEFINE_MUTEX(zl_order_mutex);
3361
3362 mutex_lock(&zl_order_mutex);
3363 if (write) {
3364 if (strlen((char *)table->data) >= NUMA_ZONELIST_ORDER_LEN) {
3365 ret = -EINVAL;
3366 goto out;
3367 }
3368 strcpy(saved_string, (char *)table->data);
3369 }
3370 ret = proc_dostring(table, write, buffer, length, ppos);
3371 if (ret)
3372 goto out;
3373 if (write) {
3374 int oldval = user_zonelist_order;
3375
3376 ret = __parse_numa_zonelist_order((char *)table->data);
3377 if (ret) {
3378 /*
3379 * bogus value. restore saved string
3380 */
3381 strncpy((char *)table->data, saved_string,
3382 NUMA_ZONELIST_ORDER_LEN);
3383 user_zonelist_order = oldval;
3384 } else if (oldval != user_zonelist_order) {
3385 mutex_lock(&zonelists_mutex);
3386 build_all_zonelists(NULL, NULL);
3387 mutex_unlock(&zonelists_mutex);
3388 }
3389 }
3390out:
3391 mutex_unlock(&zl_order_mutex);
3392 return ret;
3393}
3394
3395
3396#define MAX_NODE_LOAD (nr_online_nodes)
3397static int node_load[MAX_NUMNODES];
3398
3399/**
3400 * find_next_best_node - find the next node that should appear in a given node's fallback list
3401 * @node: node whose fallback list we're appending
3402 * @used_node_mask: nodemask_t of already used nodes
3403 *
3404 * We use a number of factors to determine which is the next node that should
3405 * appear on a given node's fallback list. The node should not have appeared
3406 * already in @node's fallback list, and it should be the next closest node
3407 * according to the distance array (which contains arbitrary distance values
3408 * from each node to each node in the system), and should also prefer nodes
3409 * with no CPUs, since presumably they'll have very little allocation pressure
3410 * on them otherwise.
3411 * It returns -1 if no node is found.
3412 */
3413static int find_next_best_node(int node, nodemask_t *used_node_mask)
3414{
3415 int n, val;
3416 int min_val = INT_MAX;
3417 int best_node = NUMA_NO_NODE;
3418 const struct cpumask *tmp = cpumask_of_node(0);
3419
3420 /* Use the local node if we haven't already */
3421 if (!node_isset(node, *used_node_mask)) {
3422 node_set(node, *used_node_mask);
3423 return node;
3424 }
3425
3426 for_each_node_state(n, N_MEMORY) {
3427
3428 /* Don't want a node to appear more than once */
3429 if (node_isset(n, *used_node_mask))
3430 continue;
3431
3432 /* Use the distance array to find the distance */
3433 val = node_distance(node, n);
3434
3435 /* Penalize nodes under us ("prefer the next node") */
3436 val += (n < node);
3437
3438 /* Give preference to headless and unused nodes */
3439 tmp = cpumask_of_node(n);
3440 if (!cpumask_empty(tmp))
3441 val += PENALTY_FOR_NODE_WITH_CPUS;
3442
3443 /* Slight preference for less loaded node */
3444 val *= (MAX_NODE_LOAD*MAX_NUMNODES);
3445 val += node_load[n];
3446
3447 if (val < min_val) {
3448 min_val = val;
3449 best_node = n;
3450 }
3451 }
3452
3453 if (best_node >= 0)
3454 node_set(best_node, *used_node_mask);
3455
3456 return best_node;
3457}
3458
3459
3460/*
3461 * Build zonelists ordered by node and zones within node.
3462 * This results in maximum locality--normal zone overflows into local
3463 * DMA zone, if any--but risks exhausting DMA zone.
3464 */
3465static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
3466{
3467 int j;
3468 struct zonelist *zonelist;
3469
3470 zonelist = &pgdat->node_zonelists[0];
3471 for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++)
3472 ;
3473 j = build_zonelists_node(NODE_DATA(node), zonelist, j);
3474 zonelist->_zonerefs[j].zone = NULL;
3475 zonelist->_zonerefs[j].zone_idx = 0;
3476}
3477
3478/*
3479 * Build gfp_thisnode zonelists
3480 */
3481static void build_thisnode_zonelists(pg_data_t *pgdat)
3482{
3483 int j;
3484 struct zonelist *zonelist;
3485
3486 zonelist = &pgdat->node_zonelists[1];
3487 j = build_zonelists_node(pgdat, zonelist, 0);
3488 zonelist->_zonerefs[j].zone = NULL;
3489 zonelist->_zonerefs[j].zone_idx = 0;
3490}
3491
3492/*
3493 * Build zonelists ordered by zone and nodes within zones.
3494 * This results in conserving DMA zone[s] until all Normal memory is
3495 * exhausted, but results in overflowing to remote node while memory
3496 * may still exist in local DMA zone.
3497 */
3498static int node_order[MAX_NUMNODES];
3499
3500static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
3501{
3502 int pos, j, node;
3503 int zone_type; /* needs to be signed */
3504 struct zone *z;
3505 struct zonelist *zonelist;
3506
3507 zonelist = &pgdat->node_zonelists[0];
3508 pos = 0;
3509 for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
3510 for (j = 0; j < nr_nodes; j++) {
3511 node = node_order[j];
3512 z = &NODE_DATA(node)->node_zones[zone_type];
3513 if (populated_zone(z)) {
3514 zoneref_set_zone(z,
3515 &zonelist->_zonerefs[pos++]);
3516 check_highest_zone(zone_type);
3517 }
3518 }
3519 }
3520 zonelist->_zonerefs[pos].zone = NULL;
3521 zonelist->_zonerefs[pos].zone_idx = 0;
3522}
3523
3524static int default_zonelist_order(void)
3525{
3526 int nid, zone_type;
3527 unsigned long low_kmem_size, total_size;
3528 struct zone *z;
3529 int average_size;
3530 /*
3531 * ZONE_DMA and ZONE_DMA32 can be very small area in the system.
3532 * If they are really small and used heavily, the system can fall
3533 * into OOM very easily.
3534 * This function detect ZONE_DMA/DMA32 size and configures zone order.
3535 */
3536 /* Is there ZONE_NORMAL ? (ex. ppc has only DMA zone..) */
3537 low_kmem_size = 0;
3538 total_size = 0;
3539 for_each_online_node(nid) {
3540 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
3541 z = &NODE_DATA(nid)->node_zones[zone_type];
3542 if (populated_zone(z)) {
3543 if (zone_type < ZONE_NORMAL)
3544 low_kmem_size += z->managed_pages;
3545 total_size += z->managed_pages;
3546 } else if (zone_type == ZONE_NORMAL) {
3547 /*
3548 * If any node has only lowmem, then node order
3549 * is preferred to allow kernel allocations
3550 * locally; otherwise, they can easily infringe
3551 * on other nodes when there is an abundance of
3552 * lowmem available to allocate from.
3553 */
3554 return ZONELIST_ORDER_NODE;
3555 }
3556 }
3557 }
3558 if (!low_kmem_size || /* there are no DMA area. */
3559 low_kmem_size > total_size/2) /* DMA/DMA32 is big. */
3560 return ZONELIST_ORDER_NODE;
3561 /*
3562 * look into each node's config.
3563 * If there is a node whose DMA/DMA32 memory is very big area on
3564 * local memory, NODE_ORDER may be suitable.
3565 */
3566 average_size = total_size /
3567 (nodes_weight(node_states[N_MEMORY]) + 1);
3568 for_each_online_node(nid) {
3569 low_kmem_size = 0;
3570 total_size = 0;
3571 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
3572 z = &NODE_DATA(nid)->node_zones[zone_type];
3573 if (populated_zone(z)) {
3574 if (zone_type < ZONE_NORMAL)
3575 low_kmem_size += z->present_pages;
3576 total_size += z->present_pages;
3577 }
3578 }
3579 if (low_kmem_size &&
3580 total_size > average_size && /* ignore small node */
3581 low_kmem_size > total_size * 70/100)
3582 return ZONELIST_ORDER_NODE;
3583 }
3584 return ZONELIST_ORDER_ZONE;
3585}
3586
3587static void set_zonelist_order(void)
3588{
3589 if (user_zonelist_order == ZONELIST_ORDER_DEFAULT)
3590 current_zonelist_order = default_zonelist_order();
3591 else
3592 current_zonelist_order = user_zonelist_order;
3593}
3594
3595static void build_zonelists(pg_data_t *pgdat)
3596{
3597 int j, node, load;
3598 enum zone_type i;
3599 nodemask_t used_mask;
3600 int local_node, prev_node;
3601 struct zonelist *zonelist;
3602 int order = current_zonelist_order;
3603
3604 /* initialize zonelists */
3605 for (i = 0; i < MAX_ZONELISTS; i++) {
3606 zonelist = pgdat->node_zonelists + i;
3607 zonelist->_zonerefs[0].zone = NULL;
3608 zonelist->_zonerefs[0].zone_idx = 0;
3609 }
3610
3611 /* NUMA-aware ordering of nodes */
3612 local_node = pgdat->node_id;
3613 load = nr_online_nodes;
3614 prev_node = local_node;
3615 nodes_clear(used_mask);
3616
3617 memset(node_order, 0, sizeof(node_order));
3618 j = 0;
3619
3620 while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
3621 /*
3622 * We don't want to pressure a particular node.
3623 * So adding penalty to the first node in same
3624 * distance group to make it round-robin.
3625 */
3626 if (node_distance(local_node, node) !=
3627 node_distance(local_node, prev_node))
3628 node_load[node] = load;
3629
3630 prev_node = node;
3631 load--;
3632 if (order == ZONELIST_ORDER_NODE)
3633 build_zonelists_in_node_order(pgdat, node);
3634 else
3635 node_order[j++] = node; /* remember order */
3636 }
3637
3638 if (order == ZONELIST_ORDER_ZONE) {
3639 /* calculate node order -- i.e., DMA last! */
3640 build_zonelists_in_zone_order(pgdat, j);
3641 }
3642
3643 build_thisnode_zonelists(pgdat);
3644}
3645
3646/* Construct the zonelist performance cache - see further mmzone.h */
3647static void build_zonelist_cache(pg_data_t *pgdat)
3648{
3649 struct zonelist *zonelist;
3650 struct zonelist_cache *zlc;
3651 struct zoneref *z;
3652
3653 zonelist = &pgdat->node_zonelists[0];
3654 zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
3655 bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
3656 for (z = zonelist->_zonerefs; z->zone; z++)
3657 zlc->z_to_n[z - zonelist->_zonerefs] = zonelist_node_idx(z);
3658}
3659
3660#ifdef CONFIG_HAVE_MEMORYLESS_NODES
3661/*
3662 * Return node id of node used for "local" allocations.
3663 * I.e., first node id of first zone in arg node's generic zonelist.
3664 * Used for initializing percpu 'numa_mem', which is used primarily
3665 * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
3666 */
3667int local_memory_node(int node)
3668{
3669 struct zone *zone;
3670
3671 (void)first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
3672 gfp_zone(GFP_KERNEL),
3673 NULL,
3674 &zone);
3675 return zone->node;
3676}
3677#endif
3678
3679#else /* CONFIG_NUMA */
3680
3681static void set_zonelist_order(void)
3682{
3683 current_zonelist_order = ZONELIST_ORDER_ZONE;
3684}
3685
3686static void build_zonelists(pg_data_t *pgdat)
3687{
3688 int node, local_node;
3689 enum zone_type j;
3690 struct zonelist *zonelist;
3691
3692 local_node = pgdat->node_id;
3693
3694 zonelist = &pgdat->node_zonelists[0];
3695 j = build_zonelists_node(pgdat, zonelist, 0);
3696
3697 /*
3698 * Now we build the zonelist so that it contains the zones
3699 * of all the other nodes.
3700 * We don't want to pressure a particular node, so when
3701 * building the zones for node N, we make sure that the
3702 * zones coming right after the local ones are those from
3703 * node N+1 (modulo N)
3704 */
3705 for (node = local_node + 1; node < MAX_NUMNODES; node++) {
3706 if (!node_online(node))
3707 continue;
3708 j = build_zonelists_node(NODE_DATA(node), zonelist, j);
3709 }
3710 for (node = 0; node < local_node; node++) {
3711 if (!node_online(node))
3712 continue;
3713 j = build_zonelists_node(NODE_DATA(node), zonelist, j);
3714 }
3715
3716 zonelist->_zonerefs[j].zone = NULL;
3717 zonelist->_zonerefs[j].zone_idx = 0;
3718}
3719
3720/* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */
3721static void build_zonelist_cache(pg_data_t *pgdat)
3722{
3723 pgdat->node_zonelists[0].zlcache_ptr = NULL;
3724}
3725
3726#endif /* CONFIG_NUMA */
3727
3728/*
3729 * Boot pageset table. One per cpu which is going to be used for all
3730 * zones and all nodes. The parameters will be set in such a way
3731 * that an item put on a list will immediately be handed over to
3732 * the buddy list. This is safe since pageset manipulation is done
3733 * with interrupts disabled.
3734 *
3735 * The boot_pagesets must be kept even after bootup is complete for
3736 * unused processors and/or zones. They do play a role for bootstrapping
3737 * hotplugged processors.
3738 *
3739 * zoneinfo_show() and maybe other functions do
3740 * not check if the processor is online before following the pageset pointer.
3741 * Other parts of the kernel may not check if the zone is available.
3742 */
3743static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
3744static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
3745static void setup_zone_pageset(struct zone *zone);
3746
3747/*
3748 * Global mutex to protect against size modification of zonelists
3749 * as well as to serialize pageset setup for the new populated zone.
3750 */
3751DEFINE_MUTEX(zonelists_mutex);
3752
3753/* return values int ....just for stop_machine() */
3754static int __build_all_zonelists(void *data)
3755{
3756 int nid;
3757 int cpu;
3758 pg_data_t *self = data;
3759
3760#ifdef CONFIG_NUMA
3761 memset(node_load, 0, sizeof(node_load));
3762#endif
3763
3764 if (self && !node_online(self->node_id)) {
3765 build_zonelists(self);
3766 build_zonelist_cache(self);
3767 }
3768
3769 for_each_online_node(nid) {
3770 pg_data_t *pgdat = NODE_DATA(nid);
3771
3772 build_zonelists(pgdat);
3773 build_zonelist_cache(pgdat);
3774 }
3775
3776 /*
3777 * Initialize the boot_pagesets that are going to be used
3778 * for bootstrapping processors. The real pagesets for
3779 * each zone will be allocated later when the per cpu
3780 * allocator is available.
3781 *
3782 * boot_pagesets are used also for bootstrapping offline
3783 * cpus if the system is already booted because the pagesets
3784 * are needed to initialize allocators on a specific cpu too.
3785 * F.e. the percpu allocator needs the page allocator which
3786 * needs the percpu allocator in order to allocate its pagesets
3787 * (a chicken-egg dilemma).
3788 */
3789 for_each_possible_cpu(cpu) {
3790 setup_pageset(&per_cpu(boot_pageset, cpu), 0);
3791
3792#ifdef CONFIG_HAVE_MEMORYLESS_NODES
3793 /*
3794 * We now know the "local memory node" for each node--
3795 * i.e., the node of the first zone in the generic zonelist.
3796 * Set up numa_mem percpu variable for on-line cpus. During
3797 * boot, only the boot cpu should be on-line; we'll init the
3798 * secondary cpus' numa_mem as they come on-line. During
3799 * node/memory hotplug, we'll fixup all on-line cpus.
3800 */
3801 if (cpu_online(cpu))
3802 set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
3803#endif
3804 }
3805
3806 return 0;
3807}
3808
3809/*
3810 * Called with zonelists_mutex held always
3811 * unless system_state == SYSTEM_BOOTING.
3812 */
3813void __ref build_all_zonelists(pg_data_t *pgdat, struct zone *zone)
3814{
3815 set_zonelist_order();
3816
3817 if (system_state == SYSTEM_BOOTING) {
3818 __build_all_zonelists(NULL);
3819 mminit_verify_zonelist();
3820 cpuset_init_current_mems_allowed();
3821 } else {
3822#ifdef CONFIG_MEMORY_HOTPLUG
3823 if (zone)
3824 setup_zone_pageset(zone);
3825#endif
3826 /* we have to stop all cpus to guarantee there is no user
3827 of zonelist */
3828 stop_machine(__build_all_zonelists, pgdat, NULL);
3829 /* cpuset refresh routine should be here */
3830 }
3831 vm_total_pages = nr_free_pagecache_pages();
3832 /*
3833 * Disable grouping by mobility if the number of pages in the
3834 * system is too low to allow the mechanism to work. It would be
3835 * more accurate, but expensive to check per-zone. This check is
3836 * made on memory-hotadd so a system can start with mobility
3837 * disabled and enable it later
3838 */
3839 if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
3840 page_group_by_mobility_disabled = 1;
3841 else
3842 page_group_by_mobility_disabled = 0;
3843
3844 printk("Built %i zonelists in %s order, mobility grouping %s. "
3845 "Total pages: %ld\n",
3846 nr_online_nodes,
3847 zonelist_order_name[current_zonelist_order],
3848 page_group_by_mobility_disabled ? "off" : "on",
3849 vm_total_pages);
3850#ifdef CONFIG_NUMA
3851 printk("Policy zone: %s\n", zone_names[policy_zone]);
3852#endif
3853}
3854
3855/*
3856 * Helper functions to size the waitqueue hash table.
3857 * Essentially these want to choose hash table sizes sufficiently
3858 * large so that collisions trying to wait on pages are rare.
3859 * But in fact, the number of active page waitqueues on typical
3860 * systems is ridiculously low, less than 200. So this is even
3861 * conservative, even though it seems large.
3862 *
3863 * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
3864 * waitqueues, i.e. the size of the waitq table given the number of pages.
3865 */
3866#define PAGES_PER_WAITQUEUE 256
3867
3868#ifndef CONFIG_MEMORY_HOTPLUG
3869static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3870{
3871 unsigned long size = 1;
3872
3873 pages /= PAGES_PER_WAITQUEUE;
3874
3875 while (size < pages)
3876 size <<= 1;
3877
3878 /*
3879 * Once we have dozens or even hundreds of threads sleeping
3880 * on IO we've got bigger problems than wait queue collision.
3881 * Limit the size of the wait table to a reasonable size.
3882 */
3883 size = min(size, 4096UL);
3884
3885 return max(size, 4UL);
3886}
3887#else
3888/*
3889 * A zone's size might be changed by hot-add, so it is not possible to determine
3890 * a suitable size for its wait_table. So we use the maximum size now.
3891 *
3892 * The max wait table size = 4096 x sizeof(wait_queue_head_t). ie:
3893 *
3894 * i386 (preemption config) : 4096 x 16 = 64Kbyte.
3895 * ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
3896 * ia64, x86-64 (preemption) : 4096 x 24 = 96Kbyte.
3897 *
3898 * The maximum entries are prepared when a zone's memory is (512K + 256) pages
3899 * or more by the traditional way. (See above). It equals:
3900 *
3901 * i386, x86-64, powerpc(4K page size) : = ( 2G + 1M)byte.
3902 * ia64(16K page size) : = ( 8G + 4M)byte.
3903 * powerpc (64K page size) : = (32G +16M)byte.
3904 */
3905static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3906{
3907 return 4096UL;
3908}
3909#endif
3910
3911/*
3912 * This is an integer logarithm so that shifts can be used later
3913 * to extract the more random high bits from the multiplicative
3914 * hash function before the remainder is taken.
3915 */
3916static inline unsigned long wait_table_bits(unsigned long size)
3917{
3918 return ffz(~size);
3919}
3920
3921/*
3922 * Check if a pageblock contains reserved pages
3923 */
3924static int pageblock_is_reserved(unsigned long start_pfn, unsigned long end_pfn)
3925{
3926 unsigned long pfn;
3927
3928 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
3929 if (!pfn_valid_within(pfn) || PageReserved(pfn_to_page(pfn)))
3930 return 1;
3931 }
3932 return 0;
3933}
3934
3935/*
3936 * Mark a number of pageblocks as MIGRATE_RESERVE. The number
3937 * of blocks reserved is based on min_wmark_pages(zone). The memory within
3938 * the reserve will tend to store contiguous free pages. Setting min_free_kbytes
3939 * higher will lead to a bigger reserve which will get freed as contiguous
3940 * blocks as reclaim kicks in
3941 */
3942static void setup_zone_migrate_reserve(struct zone *zone)
3943{
3944 unsigned long start_pfn, pfn, end_pfn, block_end_pfn;
3945 struct page *page;
3946 unsigned long block_migratetype;
3947 int reserve;
3948 int old_reserve;
3949
3950 /*
3951 * Get the start pfn, end pfn and the number of blocks to reserve
3952 * We have to be careful to be aligned to pageblock_nr_pages to
3953 * make sure that we always check pfn_valid for the first page in
3954 * the block.
3955 */
3956 start_pfn = zone->zone_start_pfn;
3957 end_pfn = zone_end_pfn(zone);
3958 start_pfn = roundup(start_pfn, pageblock_nr_pages);
3959 reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >>
3960 pageblock_order;
3961
3962 /*
3963 * Reserve blocks are generally in place to help high-order atomic
3964 * allocations that are short-lived. A min_free_kbytes value that
3965 * would result in more than 2 reserve blocks for atomic allocations
3966 * is assumed to be in place to help anti-fragmentation for the
3967 * future allocation of hugepages at runtime.
3968 */
3969 reserve = min(2, reserve);
3970 old_reserve = zone->nr_migrate_reserve_block;
3971
3972 /* When memory hot-add, we almost always need to do nothing */
3973 if (reserve == old_reserve)
3974 return;
3975 zone->nr_migrate_reserve_block = reserve;
3976
3977 for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
3978 if (!pfn_valid(pfn))
3979 continue;
3980 page = pfn_to_page(pfn);
3981
3982 /* Watch out for overlapping nodes */
3983 if (page_to_nid(page) != zone_to_nid(zone))
3984 continue;
3985
3986 block_migratetype = get_pageblock_migratetype(page);
3987
3988 /* Only test what is necessary when the reserves are not met */
3989 if (reserve > 0) {
3990 /*
3991 * Blocks with reserved pages will never free, skip
3992 * them.
3993 */
3994 block_end_pfn = min(pfn + pageblock_nr_pages, end_pfn);
3995 if (pageblock_is_reserved(pfn, block_end_pfn))
3996 continue;
3997
3998 /* If this block is reserved, account for it */
3999 if (block_migratetype == MIGRATE_RESERVE) {
4000 reserve--;
4001 continue;
4002 }
4003
4004 /* Suitable for reserving if this block is movable */
4005 if (block_migratetype == MIGRATE_MOVABLE) {
4006 set_pageblock_migratetype(page,
4007 MIGRATE_RESERVE);
4008 move_freepages_block(zone, page,
4009 MIGRATE_RESERVE);
4010 reserve--;
4011 continue;
4012 }
4013 } else if (!old_reserve) {
4014 /*
4015 * At boot time we don't need to scan the whole zone
4016 * for turning off MIGRATE_RESERVE.
4017 */
4018 break;
4019 }
4020
4021 /*
4022 * If the reserve is met and this is a previous reserved block,
4023 * take it back
4024 */
4025 if (block_migratetype == MIGRATE_RESERVE) {
4026 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
4027 move_freepages_block(zone, page, MIGRATE_MOVABLE);
4028 }
4029 }
4030}
4031
4032/*
4033 * Initially all pages are reserved - free ones are freed
4034 * up by free_all_bootmem() once the early boot process is
4035 * done. Non-atomic initialization, single-pass.
4036 */
4037void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
4038 unsigned long start_pfn, enum memmap_context context)
4039{
4040 struct page *page;
4041 unsigned long end_pfn = start_pfn + size;
4042 unsigned long pfn;
4043 struct zone *z;
4044
4045 if (highest_memmap_pfn < end_pfn - 1)
4046 highest_memmap_pfn = end_pfn - 1;
4047
4048 z = &NODE_DATA(nid)->node_zones[zone];
4049 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
4050 /*
4051 * There can be holes in boot-time mem_map[]s
4052 * handed to this function. They do not
4053 * exist on hotplugged memory.
4054 */
4055 if (context == MEMMAP_EARLY) {
4056 if (!early_pfn_valid(pfn))
4057 continue;
4058 if (!early_pfn_in_nid(pfn, nid))
4059 continue;
4060 }
4061 page = pfn_to_page(pfn);
4062 set_page_links(page, zone, nid, pfn);
4063 mminit_verify_page_links(page, zone, nid, pfn);
4064 init_page_count(page);
4065 page_mapcount_reset(page);
4066 page_cpupid_reset_last(page);
4067 SetPageReserved(page);
4068 /*
4069 * Mark the block movable so that blocks are reserved for
4070 * movable at startup. This will force kernel allocations
4071 * to reserve their blocks rather than leaking throughout
4072 * the address space during boot when many long-lived
4073 * kernel allocations are made. Later some blocks near
4074 * the start are marked MIGRATE_RESERVE by
4075 * setup_zone_migrate_reserve()
4076 *
4077 * bitmap is created for zone's valid pfn range. but memmap
4078 * can be created for invalid pages (for alignment)
4079 * check here not to call set_pageblock_migratetype() against
4080 * pfn out of zone.
4081 */
4082 if ((z->zone_start_pfn <= pfn)
4083 && (pfn < zone_end_pfn(z))
4084 && !(pfn & (pageblock_nr_pages - 1)))
4085 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
4086
4087 INIT_LIST_HEAD(&page->lru);
4088#ifdef WANT_PAGE_VIRTUAL
4089 /* The shift won't overflow because ZONE_NORMAL is below 4G. */
4090 if (!is_highmem_idx(zone))
4091 set_page_address(page, __va(pfn << PAGE_SHIFT));
4092#endif
4093 }
4094}
4095
4096static void __meminit zone_init_free_lists(struct zone *zone)
4097{
4098 int order, t;
4099 for_each_migratetype_order(order, t) {
4100 INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
4101 zone->free_area[order].nr_free = 0;
4102 }
4103}
4104
4105#ifndef __HAVE_ARCH_MEMMAP_INIT
4106#define memmap_init(size, nid, zone, start_pfn) \
4107 memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
4108#endif
4109
4110static int __meminit zone_batchsize(struct zone *zone)
4111{
4112#ifdef CONFIG_MMU
4113 int batch;
4114
4115 /*
4116 * The per-cpu-pages pools are set to around 1000th of the
4117 * size of the zone. But no more than 1/2 of a meg.
4118 *
4119 * OK, so we don't know how big the cache is. So guess.
4120 */
4121 batch = zone->managed_pages / 1024;
4122 if (batch * PAGE_SIZE > 512 * 1024)
4123 batch = (512 * 1024) / PAGE_SIZE;
4124 batch /= 4; /* We effectively *= 4 below */
4125 if (batch < 1)
4126 batch = 1;
4127
4128 /*
4129 * Clamp the batch to a 2^n - 1 value. Having a power
4130 * of 2 value was found to be more likely to have
4131 * suboptimal cache aliasing properties in some cases.
4132 *
4133 * For example if 2 tasks are alternately allocating
4134 * batches of pages, one task can end up with a lot
4135 * of pages of one half of the possible page colors
4136 * and the other with pages of the other colors.
4137 */
4138 batch = rounddown_pow_of_two(batch + batch/2) - 1;
4139
4140 return batch;
4141
4142#else
4143 /* The deferral and batching of frees should be suppressed under NOMMU
4144 * conditions.
4145 *
4146 * The problem is that NOMMU needs to be able to allocate large chunks
4147 * of contiguous memory as there's no hardware page translation to
4148 * assemble apparent contiguous memory from discontiguous pages.
4149 *
4150 * Queueing large contiguous runs of pages for batching, however,
4151 * causes the pages to actually be freed in smaller chunks. As there
4152 * can be a significant delay between the individual batches being
4153 * recycled, this leads to the once large chunks of space being
4154 * fragmented and becoming unavailable for high-order allocations.
4155 */
4156 return 0;
4157#endif
4158}
4159
4160/*
4161 * pcp->high and pcp->batch values are related and dependent on one another:
4162 * ->batch must never be higher then ->high.
4163 * The following function updates them in a safe manner without read side
4164 * locking.
4165 *
4166 * Any new users of pcp->batch and pcp->high should ensure they can cope with
4167 * those fields changing asynchronously (acording the the above rule).
4168 *
4169 * mutex_is_locked(&pcp_batch_high_lock) required when calling this function
4170 * outside of boot time (or some other assurance that no concurrent updaters
4171 * exist).
4172 */
4173static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
4174 unsigned long batch)
4175{
4176 /* start with a fail safe value for batch */
4177 pcp->batch = 1;
4178 smp_wmb();
4179
4180 /* Update high, then batch, in order */
4181 pcp->high = high;
4182 smp_wmb();
4183
4184 pcp->batch = batch;
4185}
4186
4187/* a companion to pageset_set_high() */
4188static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch)
4189{
4190 pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch));
4191}
4192
4193static void pageset_init(struct per_cpu_pageset *p)
4194{
4195 struct per_cpu_pages *pcp;
4196 int migratetype;
4197
4198 memset(p, 0, sizeof(*p));
4199
4200 pcp = &p->pcp;
4201 pcp->count = 0;
4202 for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
4203 INIT_LIST_HEAD(&pcp->lists[migratetype]);
4204}
4205
4206static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
4207{
4208 pageset_init(p);
4209 pageset_set_batch(p, batch);
4210}
4211
4212/*
4213 * pageset_set_high() sets the high water mark for hot per_cpu_pagelist
4214 * to the value high for the pageset p.
4215 */
4216static void pageset_set_high(struct per_cpu_pageset *p,
4217 unsigned long high)
4218{
4219 unsigned long batch = max(1UL, high / 4);
4220 if ((high / 4) > (PAGE_SHIFT * 8))
4221 batch = PAGE_SHIFT * 8;
4222
4223 pageset_update(&p->pcp, high, batch);
4224}
4225
4226static void __meminit pageset_set_high_and_batch(struct zone *zone,
4227 struct per_cpu_pageset *pcp)
4228{
4229 if (percpu_pagelist_fraction)
4230 pageset_set_high(pcp,
4231 (zone->managed_pages /
4232 percpu_pagelist_fraction));
4233 else
4234 pageset_set_batch(pcp, zone_batchsize(zone));
4235}
4236
4237static void __meminit zone_pageset_init(struct zone *zone, int cpu)
4238{
4239 struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
4240
4241 pageset_init(pcp);
4242 pageset_set_high_and_batch(zone, pcp);
4243}
4244
4245static void __meminit setup_zone_pageset(struct zone *zone)
4246{
4247 int cpu;
4248 zone->pageset = alloc_percpu(struct per_cpu_pageset);
4249 for_each_possible_cpu(cpu)
4250 zone_pageset_init(zone, cpu);
4251}
4252
4253/*
4254 * Allocate per cpu pagesets and initialize them.
4255 * Before this call only boot pagesets were available.
4256 */
4257void __init setup_per_cpu_pageset(void)
4258{
4259 struct zone *zone;
4260
4261 for_each_populated_zone(zone)
4262 setup_zone_pageset(zone);
4263}
4264
4265static noinline __init_refok
4266int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
4267{
4268 int i;
4269 size_t alloc_size;
4270
4271 /*
4272 * The per-page waitqueue mechanism uses hashed waitqueues
4273 * per zone.
4274 */
4275 zone->wait_table_hash_nr_entries =
4276 wait_table_hash_nr_entries(zone_size_pages);
4277 zone->wait_table_bits =
4278 wait_table_bits(zone->wait_table_hash_nr_entries);
4279 alloc_size = zone->wait_table_hash_nr_entries
4280 * sizeof(wait_queue_head_t);
4281
4282 if (!slab_is_available()) {
4283 zone->wait_table = (wait_queue_head_t *)
4284 memblock_virt_alloc_node_nopanic(
4285 alloc_size, zone->zone_pgdat->node_id);
4286 } else {
4287 /*
4288 * This case means that a zone whose size was 0 gets new memory
4289 * via memory hot-add.
4290 * But it may be the case that a new node was hot-added. In
4291 * this case vmalloc() will not be able to use this new node's
4292 * memory - this wait_table must be initialized to use this new
4293 * node itself as well.
4294 * To use this new node's memory, further consideration will be
4295 * necessary.
4296 */
4297 zone->wait_table = vmalloc(alloc_size);
4298 }
4299 if (!zone->wait_table)
4300 return -ENOMEM;
4301
4302 for (i = 0; i < zone->wait_table_hash_nr_entries; ++i)
4303 init_waitqueue_head(zone->wait_table + i);
4304
4305 return 0;
4306}
4307
4308static __meminit void zone_pcp_init(struct zone *zone)
4309{
4310 /*
4311 * per cpu subsystem is not up at this point. The following code
4312 * relies on the ability of the linker to provide the
4313 * offset of a (static) per cpu variable into the per cpu area.
4314 */
4315 zone->pageset = &boot_pageset;
4316
4317 if (populated_zone(zone))
4318 printk(KERN_DEBUG " %s zone: %lu pages, LIFO batch:%u\n",
4319 zone->name, zone->present_pages,
4320 zone_batchsize(zone));
4321}
4322
4323int __meminit init_currently_empty_zone(struct zone *zone,
4324 unsigned long zone_start_pfn,
4325 unsigned long size,
4326 enum memmap_context context)
4327{
4328 struct pglist_data *pgdat = zone->zone_pgdat;
4329 int ret;
4330 ret = zone_wait_table_init(zone, size);
4331 if (ret)
4332 return ret;
4333 pgdat->nr_zones = zone_idx(zone) + 1;
4334
4335 zone->zone_start_pfn = zone_start_pfn;
4336
4337 mminit_dprintk(MMINIT_TRACE, "memmap_init",
4338 "Initialising map node %d zone %lu pfns %lu -> %lu\n",
4339 pgdat->node_id,
4340 (unsigned long)zone_idx(zone),
4341 zone_start_pfn, (zone_start_pfn + size));
4342
4343 zone_init_free_lists(zone);
4344
4345 return 0;
4346}
4347
4348#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4349#ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
4350/*
4351 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
4352 * Architectures may implement their own version but if add_active_range()
4353 * was used and there are no special requirements, this is a convenient
4354 * alternative
4355 */
4356int __meminit __early_pfn_to_nid(unsigned long pfn)
4357{
4358 unsigned long start_pfn, end_pfn;
4359 int nid;
4360 /*
4361 * NOTE: The following SMP-unsafe globals are only used early in boot
4362 * when the kernel is running single-threaded.
4363 */
4364 static unsigned long __meminitdata last_start_pfn, last_end_pfn;
4365 static int __meminitdata last_nid;
4366
4367 if (last_start_pfn <= pfn && pfn < last_end_pfn)
4368 return last_nid;
4369
4370 nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn);
4371 if (nid != -1) {
4372 last_start_pfn = start_pfn;
4373 last_end_pfn = end_pfn;
4374 last_nid = nid;
4375 }
4376
4377 return nid;
4378}
4379#endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
4380
4381int __meminit early_pfn_to_nid(unsigned long pfn)
4382{
4383 int nid;
4384
4385 nid = __early_pfn_to_nid(pfn);
4386 if (nid >= 0)
4387 return nid;
4388 /* just returns 0 */
4389 return 0;
4390}
4391
4392#ifdef CONFIG_NODES_SPAN_OTHER_NODES
4393bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
4394{
4395 int nid;
4396
4397 nid = __early_pfn_to_nid(pfn);
4398 if (nid >= 0 && nid != node)
4399 return false;
4400 return true;
4401}
4402#endif
4403
4404/**
4405 * free_bootmem_with_active_regions - Call memblock_free_early_nid for each active range
4406 * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
4407 * @max_low_pfn: The highest PFN that will be passed to memblock_free_early_nid
4408 *
4409 * If an architecture guarantees that all ranges registered with
4410 * add_active_ranges() contain no holes and may be freed, this
4411 * this function may be used instead of calling memblock_free_early_nid()
4412 * manually.
4413 */
4414void __init free_bootmem_with_active_regions(int nid, unsigned long max_low_pfn)
4415{
4416 unsigned long start_pfn, end_pfn;
4417 int i, this_nid;
4418
4419 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) {
4420 start_pfn = min(start_pfn, max_low_pfn);
4421 end_pfn = min(end_pfn, max_low_pfn);
4422
4423 if (start_pfn < end_pfn)
4424 memblock_free_early_nid(PFN_PHYS(start_pfn),
4425 (end_pfn - start_pfn) << PAGE_SHIFT,
4426 this_nid);
4427 }
4428}
4429
4430/**
4431 * sparse_memory_present_with_active_regions - Call memory_present for each active range
4432 * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
4433 *
4434 * If an architecture guarantees that all ranges registered with
4435 * add_active_ranges() contain no holes and may be freed, this
4436 * function may be used instead of calling memory_present() manually.
4437 */
4438void __init sparse_memory_present_with_active_regions(int nid)
4439{
4440 unsigned long start_pfn, end_pfn;
4441 int i, this_nid;
4442
4443 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid)
4444 memory_present(this_nid, start_pfn, end_pfn);
4445}
4446
4447/**
4448 * get_pfn_range_for_nid - Return the start and end page frames for a node
4449 * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
4450 * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
4451 * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
4452 *
4453 * It returns the start and end page frame of a node based on information
4454 * provided by an arch calling add_active_range(). If called for a node
4455 * with no available memory, a warning is printed and the start and end
4456 * PFNs will be 0.
4457 */
4458void __meminit get_pfn_range_for_nid(unsigned int nid,
4459 unsigned long *start_pfn, unsigned long *end_pfn)
4460{
4461 unsigned long this_start_pfn, this_end_pfn;
4462 int i;
4463
4464 *start_pfn = -1UL;
4465 *end_pfn = 0;
4466
4467 for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
4468 *start_pfn = min(*start_pfn, this_start_pfn);
4469 *end_pfn = max(*end_pfn, this_end_pfn);
4470 }
4471
4472 if (*start_pfn == -1UL)
4473 *start_pfn = 0;
4474}
4475
4476/*
4477 * This finds a zone that can be used for ZONE_MOVABLE pages. The
4478 * assumption is made that zones within a node are ordered in monotonic
4479 * increasing memory addresses so that the "highest" populated zone is used
4480 */
4481static void __init find_usable_zone_for_movable(void)
4482{
4483 int zone_index;
4484 for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
4485 if (zone_index == ZONE_MOVABLE)
4486 continue;
4487
4488 if (arch_zone_highest_possible_pfn[zone_index] >
4489 arch_zone_lowest_possible_pfn[zone_index])
4490 break;
4491 }
4492
4493 VM_BUG_ON(zone_index == -1);
4494 movable_zone = zone_index;
4495}
4496
4497/*
4498 * The zone ranges provided by the architecture do not include ZONE_MOVABLE
4499 * because it is sized independent of architecture. Unlike the other zones,
4500 * the starting point for ZONE_MOVABLE is not fixed. It may be different
4501 * in each node depending on the size of each node and how evenly kernelcore
4502 * is distributed. This helper function adjusts the zone ranges
4503 * provided by the architecture for a given node by using the end of the
4504 * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
4505 * zones within a node are in order of monotonic increases memory addresses
4506 */
4507static void __meminit adjust_zone_range_for_zone_movable(int nid,
4508 unsigned long zone_type,
4509 unsigned long node_start_pfn,
4510 unsigned long node_end_pfn,
4511 unsigned long *zone_start_pfn,
4512 unsigned long *zone_end_pfn)
4513{
4514 /* Only adjust if ZONE_MOVABLE is on this node */
4515 if (zone_movable_pfn[nid]) {
4516 /* Size ZONE_MOVABLE */
4517 if (zone_type == ZONE_MOVABLE) {
4518 *zone_start_pfn = zone_movable_pfn[nid];
4519 *zone_end_pfn = min(node_end_pfn,
4520 arch_zone_highest_possible_pfn[movable_zone]);
4521
4522 /* Adjust for ZONE_MOVABLE starting within this range */
4523 } else if (*zone_start_pfn < zone_movable_pfn[nid] &&
4524 *zone_end_pfn > zone_movable_pfn[nid]) {
4525 *zone_end_pfn = zone_movable_pfn[nid];
4526
4527 /* Check if this whole range is within ZONE_MOVABLE */
4528 } else if (*zone_start_pfn >= zone_movable_pfn[nid])
4529 *zone_start_pfn = *zone_end_pfn;
4530 }
4531}
4532
4533/*
4534 * Return the number of pages a zone spans in a node, including holes
4535 * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
4536 */
4537static unsigned long __meminit zone_spanned_pages_in_node(int nid,
4538 unsigned long zone_type,
4539 unsigned long node_start_pfn,
4540 unsigned long node_end_pfn,
4541 unsigned long *ignored)
4542{
4543 unsigned long zone_start_pfn, zone_end_pfn;
4544
4545 /* Get the start and end of the zone */
4546 zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
4547 zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
4548 adjust_zone_range_for_zone_movable(nid, zone_type,
4549 node_start_pfn, node_end_pfn,
4550 &zone_start_pfn, &zone_end_pfn);
4551
4552 /* Check that this node has pages within the zone's required range */
4553 if (zone_end_pfn < node_start_pfn || zone_start_pfn > node_end_pfn)
4554 return 0;
4555
4556 /* Move the zone boundaries inside the node if necessary */
4557 zone_end_pfn = min(zone_end_pfn, node_end_pfn);
4558 zone_start_pfn = max(zone_start_pfn, node_start_pfn);
4559
4560 /* Return the spanned pages */
4561 return zone_end_pfn - zone_start_pfn;
4562}
4563
4564/*
4565 * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
4566 * then all holes in the requested range will be accounted for.
4567 */
4568unsigned long __meminit __absent_pages_in_range(int nid,
4569 unsigned long range_start_pfn,
4570 unsigned long range_end_pfn)
4571{
4572 unsigned long nr_absent = range_end_pfn - range_start_pfn;
4573 unsigned long start_pfn, end_pfn;
4574 int i;
4575
4576 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
4577 start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
4578 end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
4579 nr_absent -= end_pfn - start_pfn;
4580 }
4581 return nr_absent;
4582}
4583
4584/**
4585 * absent_pages_in_range - Return number of page frames in holes within a range
4586 * @start_pfn: The start PFN to start searching for holes
4587 * @end_pfn: The end PFN to stop searching for holes
4588 *
4589 * It returns the number of pages frames in memory holes within a range.
4590 */
4591unsigned long __init absent_pages_in_range(unsigned long start_pfn,
4592 unsigned long end_pfn)
4593{
4594 return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
4595}
4596
4597/* Return the number of page frames in holes in a zone on a node */
4598static unsigned long __meminit zone_absent_pages_in_node(int nid,
4599 unsigned long zone_type,
4600 unsigned long node_start_pfn,
4601 unsigned long node_end_pfn,
4602 unsigned long *ignored)
4603{
4604 unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
4605 unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
4606 unsigned long zone_start_pfn, zone_end_pfn;
4607
4608 zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
4609 zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
4610
4611 adjust_zone_range_for_zone_movable(nid, zone_type,
4612 node_start_pfn, node_end_pfn,
4613 &zone_start_pfn, &zone_end_pfn);
4614 return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
4615}
4616
4617#else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4618static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
4619 unsigned long zone_type,
4620 unsigned long node_start_pfn,
4621 unsigned long node_end_pfn,
4622 unsigned long *zones_size)
4623{
4624 return zones_size[zone_type];
4625}
4626
4627static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
4628 unsigned long zone_type,
4629 unsigned long node_start_pfn,
4630 unsigned long node_end_pfn,
4631 unsigned long *zholes_size)
4632{
4633 if (!zholes_size)
4634 return 0;
4635
4636 return zholes_size[zone_type];
4637}
4638
4639#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4640
4641static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
4642 unsigned long node_start_pfn,
4643 unsigned long node_end_pfn,
4644 unsigned long *zones_size,
4645 unsigned long *zholes_size)
4646{
4647 unsigned long realtotalpages, totalpages = 0;
4648 enum zone_type i;
4649
4650 for (i = 0; i < MAX_NR_ZONES; i++)
4651 totalpages += zone_spanned_pages_in_node(pgdat->node_id, i,
4652 node_start_pfn,
4653 node_end_pfn,
4654 zones_size);
4655 pgdat->node_spanned_pages = totalpages;
4656
4657 realtotalpages = totalpages;
4658 for (i = 0; i < MAX_NR_ZONES; i++)
4659 realtotalpages -=
4660 zone_absent_pages_in_node(pgdat->node_id, i,
4661 node_start_pfn, node_end_pfn,
4662 zholes_size);
4663 pgdat->node_present_pages = realtotalpages;
4664 printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
4665 realtotalpages);
4666}
4667
4668#ifndef CONFIG_SPARSEMEM
4669/*
4670 * Calculate the size of the zone->blockflags rounded to an unsigned long
4671 * Start by making sure zonesize is a multiple of pageblock_order by rounding
4672 * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
4673 * round what is now in bits to nearest long in bits, then return it in
4674 * bytes.
4675 */
4676static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize)
4677{
4678 unsigned long usemapsize;
4679
4680 zonesize += zone_start_pfn & (pageblock_nr_pages-1);
4681 usemapsize = roundup(zonesize, pageblock_nr_pages);
4682 usemapsize = usemapsize >> pageblock_order;
4683 usemapsize *= NR_PAGEBLOCK_BITS;
4684 usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
4685
4686 return usemapsize / 8;
4687}
4688
4689static void __init setup_usemap(struct pglist_data *pgdat,
4690 struct zone *zone,
4691 unsigned long zone_start_pfn,
4692 unsigned long zonesize)
4693{
4694 unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
4695 zone->pageblock_flags = NULL;
4696 if (usemapsize)
4697 zone->pageblock_flags =
4698 memblock_virt_alloc_node_nopanic(usemapsize,
4699 pgdat->node_id);
4700}
4701#else
4702static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
4703 unsigned long zone_start_pfn, unsigned long zonesize) {}
4704#endif /* CONFIG_SPARSEMEM */
4705
4706#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
4707
4708/* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
4709void __paginginit set_pageblock_order(void)
4710{
4711 unsigned int order;
4712
4713 /* Check that pageblock_nr_pages has not already been setup */
4714 if (pageblock_order)
4715 return;
4716
4717 if (HPAGE_SHIFT > PAGE_SHIFT)
4718 order = HUGETLB_PAGE_ORDER;
4719 else
4720 order = MAX_ORDER - 1;
4721
4722 /*
4723 * Assume the largest contiguous order of interest is a huge page.
4724 * This value may be variable depending on boot parameters on IA64 and
4725 * powerpc.
4726 */
4727 pageblock_order = order;
4728}
4729#else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4730
4731/*
4732 * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
4733 * is unused as pageblock_order is set at compile-time. See
4734 * include/linux/pageblock-flags.h for the values of pageblock_order based on
4735 * the kernel config
4736 */
4737void __paginginit set_pageblock_order(void)
4738{
4739}
4740
4741#endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4742
4743static unsigned long __paginginit calc_memmap_size(unsigned long spanned_pages,
4744 unsigned long present_pages)
4745{
4746 unsigned long pages = spanned_pages;
4747
4748 /*
4749 * Provide a more accurate estimation if there are holes within
4750 * the zone and SPARSEMEM is in use. If there are holes within the
4751 * zone, each populated memory region may cost us one or two extra
4752 * memmap pages due to alignment because memmap pages for each
4753 * populated regions may not naturally algined on page boundary.
4754 * So the (present_pages >> 4) heuristic is a tradeoff for that.
4755 */
4756 if (spanned_pages > present_pages + (present_pages >> 4) &&
4757 IS_ENABLED(CONFIG_SPARSEMEM))
4758 pages = present_pages;
4759
4760 return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
4761}
4762
4763/*
4764 * Set up the zone data structures:
4765 * - mark all pages reserved
4766 * - mark all memory queues empty
4767 * - clear the memory bitmaps
4768 *
4769 * NOTE: pgdat should get zeroed by caller.
4770 */
4771static void __paginginit free_area_init_core(struct pglist_data *pgdat,
4772 unsigned long node_start_pfn, unsigned long node_end_pfn,
4773 unsigned long *zones_size, unsigned long *zholes_size)
4774{
4775 enum zone_type j;
4776 int nid = pgdat->node_id;
4777 unsigned long zone_start_pfn = pgdat->node_start_pfn;
4778 int ret;
4779
4780 pgdat_resize_init(pgdat);
4781#ifdef CONFIG_NUMA_BALANCING
4782 spin_lock_init(&pgdat->numabalancing_migrate_lock);
4783 pgdat->numabalancing_migrate_nr_pages = 0;
4784 pgdat->numabalancing_migrate_next_window = jiffies;
4785#endif
4786 init_waitqueue_head(&pgdat->kswapd_wait);
4787 init_waitqueue_head(&pgdat->pfmemalloc_wait);
4788 pgdat_page_cgroup_init(pgdat);
4789
4790 for (j = 0; j < MAX_NR_ZONES; j++) {
4791 struct zone *zone = pgdat->node_zones + j;
4792 unsigned long size, realsize, freesize, memmap_pages;
4793
4794 size = zone_spanned_pages_in_node(nid, j, node_start_pfn,
4795 node_end_pfn, zones_size);
4796 realsize = freesize = size - zone_absent_pages_in_node(nid, j,
4797 node_start_pfn,
4798 node_end_pfn,
4799 zholes_size);
4800
4801 /*
4802 * Adjust freesize so that it accounts for how much memory
4803 * is used by this zone for memmap. This affects the watermark
4804 * and per-cpu initialisations
4805 */
4806 memmap_pages = calc_memmap_size(size, realsize);
4807 if (freesize >= memmap_pages) {
4808 freesize -= memmap_pages;
4809 if (memmap_pages)
4810 printk(KERN_DEBUG
4811 " %s zone: %lu pages used for memmap\n",
4812 zone_names[j], memmap_pages);
4813 } else
4814 printk(KERN_WARNING
4815 " %s zone: %lu pages exceeds freesize %lu\n",
4816 zone_names[j], memmap_pages, freesize);
4817
4818 /* Account for reserved pages */
4819 if (j == 0 && freesize > dma_reserve) {
4820 freesize -= dma_reserve;
4821 printk(KERN_DEBUG " %s zone: %lu pages reserved\n",
4822 zone_names[0], dma_reserve);
4823 }
4824
4825 if (!is_highmem_idx(j))
4826 nr_kernel_pages += freesize;
4827 /* Charge for highmem memmap if there are enough kernel pages */
4828 else if (nr_kernel_pages > memmap_pages * 2)
4829 nr_kernel_pages -= memmap_pages;
4830 nr_all_pages += freesize;
4831
4832 zone->spanned_pages = size;
4833 zone->present_pages = realsize;
4834 /*
4835 * Set an approximate value for lowmem here, it will be adjusted
4836 * when the bootmem allocator frees pages into the buddy system.
4837 * And all highmem pages will be managed by the buddy system.
4838 */
4839 zone->managed_pages = is_highmem_idx(j) ? realsize : freesize;
4840#ifdef CONFIG_NUMA
4841 zone->node = nid;
4842 zone->min_unmapped_pages = (freesize*sysctl_min_unmapped_ratio)
4843 / 100;
4844 zone->min_slab_pages = (freesize * sysctl_min_slab_ratio) / 100;
4845#endif
4846 zone->name = zone_names[j];
4847 spin_lock_init(&zone->lock);
4848 spin_lock_init(&zone->lru_lock);
4849 zone_seqlock_init(zone);
4850 zone->zone_pgdat = pgdat;
4851 zone_pcp_init(zone);
4852
4853 /* For bootup, initialized properly in watermark setup */
4854 mod_zone_page_state(zone, NR_ALLOC_BATCH, zone->managed_pages);
4855
4856 lruvec_init(&zone->lruvec);
4857 if (!size)
4858 continue;
4859
4860 set_pageblock_order();
4861 setup_usemap(pgdat, zone, zone_start_pfn, size);
4862 ret = init_currently_empty_zone(zone, zone_start_pfn,
4863 size, MEMMAP_EARLY);
4864 BUG_ON(ret);
4865 memmap_init(size, nid, j, zone_start_pfn);
4866 zone_start_pfn += size;
4867 }
4868}
4869
4870static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat)
4871{
4872 /* Skip empty nodes */
4873 if (!pgdat->node_spanned_pages)
4874 return;
4875
4876#ifdef CONFIG_FLAT_NODE_MEM_MAP
4877 /* ia64 gets its own node_mem_map, before this, without bootmem */
4878 if (!pgdat->node_mem_map) {
4879 unsigned long size, start, end;
4880 struct page *map;
4881
4882 /*
4883 * The zone's endpoints aren't required to be MAX_ORDER
4884 * aligned but the node_mem_map endpoints must be in order
4885 * for the buddy allocator to function correctly.
4886 */
4887 start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
4888 end = pgdat_end_pfn(pgdat);
4889 end = ALIGN(end, MAX_ORDER_NR_PAGES);
4890 size = (end - start) * sizeof(struct page);
4891 map = alloc_remap(pgdat->node_id, size);
4892 if (!map)
4893 map = memblock_virt_alloc_node_nopanic(size,
4894 pgdat->node_id);
4895 pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
4896 }
4897#ifndef CONFIG_NEED_MULTIPLE_NODES
4898 /*
4899 * With no DISCONTIG, the global mem_map is just set as node 0's
4900 */
4901 if (pgdat == NODE_DATA(0)) {
4902 mem_map = NODE_DATA(0)->node_mem_map;
4903#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4904 if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
4905 mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET);
4906#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4907 }
4908#endif
4909#endif /* CONFIG_FLAT_NODE_MEM_MAP */
4910}
4911
4912void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
4913 unsigned long node_start_pfn, unsigned long *zholes_size)
4914{
4915 pg_data_t *pgdat = NODE_DATA(nid);
4916 unsigned long start_pfn = 0;
4917 unsigned long end_pfn = 0;
4918
4919 /* pg_data_t should be reset to zero when it's allocated */
4920 WARN_ON(pgdat->nr_zones || pgdat->classzone_idx);
4921
4922 pgdat->node_id = nid;
4923 pgdat->node_start_pfn = node_start_pfn;
4924 if (node_state(nid, N_MEMORY))
4925 init_zone_allows_reclaim(nid);
4926#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4927 get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
4928#endif
4929 calculate_node_totalpages(pgdat, start_pfn, end_pfn,
4930 zones_size, zholes_size);
4931
4932 alloc_node_mem_map(pgdat);
4933#ifdef CONFIG_FLAT_NODE_MEM_MAP
4934 printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n",
4935 nid, (unsigned long)pgdat,
4936 (unsigned long)pgdat->node_mem_map);
4937#endif
4938
4939 free_area_init_core(pgdat, start_pfn, end_pfn,
4940 zones_size, zholes_size);
4941}
4942
4943#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4944
4945#if MAX_NUMNODES > 1
4946/*
4947 * Figure out the number of possible node ids.
4948 */
4949void __init setup_nr_node_ids(void)
4950{
4951 unsigned int node;
4952 unsigned int highest = 0;
4953
4954 for_each_node_mask(node, node_possible_map)
4955 highest = node;
4956 nr_node_ids = highest + 1;
4957}
4958#endif
4959
4960/**
4961 * node_map_pfn_alignment - determine the maximum internode alignment
4962 *
4963 * This function should be called after node map is populated and sorted.
4964 * It calculates the maximum power of two alignment which can distinguish
4965 * all the nodes.
4966 *
4967 * For example, if all nodes are 1GiB and aligned to 1GiB, the return value
4968 * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)). If the
4969 * nodes are shifted by 256MiB, 256MiB. Note that if only the last node is
4970 * shifted, 1GiB is enough and this function will indicate so.
4971 *
4972 * This is used to test whether pfn -> nid mapping of the chosen memory
4973 * model has fine enough granularity to avoid incorrect mapping for the
4974 * populated node map.
4975 *
4976 * Returns the determined alignment in pfn's. 0 if there is no alignment
4977 * requirement (single node).
4978 */
4979unsigned long __init node_map_pfn_alignment(void)
4980{
4981 unsigned long accl_mask = 0, last_end = 0;
4982 unsigned long start, end, mask;
4983 int last_nid = -1;
4984 int i, nid;
4985
4986 for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
4987 if (!start || last_nid < 0 || last_nid == nid) {
4988 last_nid = nid;
4989 last_end = end;
4990 continue;
4991 }
4992
4993 /*
4994 * Start with a mask granular enough to pin-point to the
4995 * start pfn and tick off bits one-by-one until it becomes
4996 * too coarse to separate the current node from the last.
4997 */
4998 mask = ~((1 << __ffs(start)) - 1);
4999 while (mask && last_end <= (start & (mask << 1)))
5000 mask <<= 1;
5001
5002 /* accumulate all internode masks */
5003 accl_mask |= mask;
5004 }
5005
5006 /* convert mask to number of pages */
5007 return ~accl_mask + 1;
5008}
5009
5010/* Find the lowest pfn for a node */
5011static unsigned long __init find_min_pfn_for_node(int nid)
5012{
5013 unsigned long min_pfn = ULONG_MAX;
5014 unsigned long start_pfn;
5015 int i;
5016
5017 for_each_mem_pfn_range(i, nid, &start_pfn, NULL, NULL)
5018 min_pfn = min(min_pfn, start_pfn);
5019
5020 if (min_pfn == ULONG_MAX) {
5021 printk(KERN_WARNING
5022 "Could not find start_pfn for node %d\n", nid);
5023 return 0;
5024 }
5025
5026 return min_pfn;
5027}
5028
5029/**
5030 * find_min_pfn_with_active_regions - Find the minimum PFN registered
5031 *
5032 * It returns the minimum PFN based on information provided via
5033 * add_active_range().
5034 */
5035unsigned long __init find_min_pfn_with_active_regions(void)
5036{
5037 return find_min_pfn_for_node(MAX_NUMNODES);
5038}
5039
5040/*
5041 * early_calculate_totalpages()
5042 * Sum pages in active regions for movable zone.
5043 * Populate N_MEMORY for calculating usable_nodes.
5044 */
5045static unsigned long __init early_calculate_totalpages(void)
5046{
5047 unsigned long totalpages = 0;
5048 unsigned long start_pfn, end_pfn;
5049 int i, nid;
5050
5051 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
5052 unsigned long pages = end_pfn - start_pfn;
5053
5054 totalpages += pages;
5055 if (pages)
5056 node_set_state(nid, N_MEMORY);
5057 }
5058 return totalpages;
5059}
5060
5061/*
5062 * Find the PFN the Movable zone begins in each node. Kernel memory
5063 * is spread evenly between nodes as long as the nodes have enough
5064 * memory. When they don't, some nodes will have more kernelcore than
5065 * others
5066 */
5067static void __init find_zone_movable_pfns_for_nodes(void)
5068{
5069 int i, nid;
5070 unsigned long usable_startpfn;
5071 unsigned long kernelcore_node, kernelcore_remaining;
5072 /* save the state before borrow the nodemask */
5073 nodemask_t saved_node_state = node_states[N_MEMORY];
5074 unsigned long totalpages = early_calculate_totalpages();
5075 int usable_nodes = nodes_weight(node_states[N_MEMORY]);
5076 struct memblock_region *r;
5077
5078 /* Need to find movable_zone earlier when movable_node is specified. */
5079 find_usable_zone_for_movable();
5080
5081 /*
5082 * If movable_node is specified, ignore kernelcore and movablecore
5083 * options.
5084 */
5085 if (movable_node_is_enabled()) {
5086 for_each_memblock(memory, r) {
5087 if (!memblock_is_hotpluggable(r))
5088 continue;
5089
5090 nid = r->nid;
5091
5092 usable_startpfn = PFN_DOWN(r->base);
5093 zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
5094 min(usable_startpfn, zone_movable_pfn[nid]) :
5095 usable_startpfn;
5096 }
5097
5098 goto out2;
5099 }
5100
5101 /*
5102 * If movablecore=nn[KMG] was specified, calculate what size of
5103 * kernelcore that corresponds so that memory usable for
5104 * any allocation type is evenly spread. If both kernelcore
5105 * and movablecore are specified, then the value of kernelcore
5106 * will be used for required_kernelcore if it's greater than
5107 * what movablecore would have allowed.
5108 */
5109 if (required_movablecore) {
5110 unsigned long corepages;
5111
5112 /*
5113 * Round-up so that ZONE_MOVABLE is at least as large as what
5114 * was requested by the user
5115 */
5116 required_movablecore =
5117 roundup(required_movablecore, MAX_ORDER_NR_PAGES);
5118 corepages = totalpages - required_movablecore;
5119
5120 required_kernelcore = max(required_kernelcore, corepages);
5121 }
5122
5123 /* If kernelcore was not specified, there is no ZONE_MOVABLE */
5124 if (!required_kernelcore)
5125 goto out;
5126
5127 /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
5128 usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
5129
5130restart:
5131 /* Spread kernelcore memory as evenly as possible throughout nodes */
5132 kernelcore_node = required_kernelcore / usable_nodes;
5133 for_each_node_state(nid, N_MEMORY) {
5134 unsigned long start_pfn, end_pfn;
5135
5136 /*
5137 * Recalculate kernelcore_node if the division per node
5138 * now exceeds what is necessary to satisfy the requested
5139 * amount of memory for the kernel
5140 */
5141 if (required_kernelcore < kernelcore_node)
5142 kernelcore_node = required_kernelcore / usable_nodes;
5143
5144 /*
5145 * As the map is walked, we track how much memory is usable
5146 * by the kernel using kernelcore_remaining. When it is
5147 * 0, the rest of the node is usable by ZONE_MOVABLE
5148 */
5149 kernelcore_remaining = kernelcore_node;
5150
5151 /* Go through each range of PFNs within this node */
5152 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
5153 unsigned long size_pages;
5154
5155 start_pfn = max(start_pfn, zone_movable_pfn[nid]);
5156 if (start_pfn >= end_pfn)
5157 continue;
5158
5159 /* Account for what is only usable for kernelcore */
5160 if (start_pfn < usable_startpfn) {
5161 unsigned long kernel_pages;
5162 kernel_pages = min(end_pfn, usable_startpfn)
5163 - start_pfn;
5164
5165 kernelcore_remaining -= min(kernel_pages,
5166 kernelcore_remaining);
5167 required_kernelcore -= min(kernel_pages,
5168 required_kernelcore);
5169
5170 /* Continue if range is now fully accounted */
5171 if (end_pfn <= usable_startpfn) {
5172
5173 /*
5174 * Push zone_movable_pfn to the end so
5175 * that if we have to rebalance
5176 * kernelcore across nodes, we will
5177 * not double account here
5178 */
5179 zone_movable_pfn[nid] = end_pfn;
5180 continue;
5181 }
5182 start_pfn = usable_startpfn;
5183 }
5184
5185 /*
5186 * The usable PFN range for ZONE_MOVABLE is from
5187 * start_pfn->end_pfn. Calculate size_pages as the
5188 * number of pages used as kernelcore
5189 */
5190 size_pages = end_pfn - start_pfn;
5191 if (size_pages > kernelcore_remaining)
5192 size_pages = kernelcore_remaining;
5193 zone_movable_pfn[nid] = start_pfn + size_pages;
5194
5195 /*
5196 * Some kernelcore has been met, update counts and
5197 * break if the kernelcore for this node has been
5198 * satisfied
5199 */
5200 required_kernelcore -= min(required_kernelcore,
5201 size_pages);
5202 kernelcore_remaining -= size_pages;
5203 if (!kernelcore_remaining)
5204 break;
5205 }
5206 }
5207
5208 /*
5209 * If there is still required_kernelcore, we do another pass with one
5210 * less node in the count. This will push zone_movable_pfn[nid] further
5211 * along on the nodes that still have memory until kernelcore is
5212 * satisfied
5213 */
5214 usable_nodes--;
5215 if (usable_nodes && required_kernelcore > usable_nodes)
5216 goto restart;
5217
5218out2:
5219 /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
5220 for (nid = 0; nid < MAX_NUMNODES; nid++)
5221 zone_movable_pfn[nid] =
5222 roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
5223
5224out:
5225 /* restore the node_state */
5226 node_states[N_MEMORY] = saved_node_state;
5227}
5228
5229/* Any regular or high memory on that node ? */
5230static void check_for_memory(pg_data_t *pgdat, int nid)
5231{
5232 enum zone_type zone_type;
5233
5234 if (N_MEMORY == N_NORMAL_MEMORY)
5235 return;
5236
5237 for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
5238 struct zone *zone = &pgdat->node_zones[zone_type];
5239 if (populated_zone(zone)) {
5240 node_set_state(nid, N_HIGH_MEMORY);
5241 if (N_NORMAL_MEMORY != N_HIGH_MEMORY &&
5242 zone_type <= ZONE_NORMAL)
5243 node_set_state(nid, N_NORMAL_MEMORY);
5244 break;
5245 }
5246 }
5247}
5248
5249/**
5250 * free_area_init_nodes - Initialise all pg_data_t and zone data
5251 * @max_zone_pfn: an array of max PFNs for each zone
5252 *
5253 * This will call free_area_init_node() for each active node in the system.
5254 * Using the page ranges provided by add_active_range(), the size of each
5255 * zone in each node and their holes is calculated. If the maximum PFN
5256 * between two adjacent zones match, it is assumed that the zone is empty.
5257 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
5258 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
5259 * starts where the previous one ended. For example, ZONE_DMA32 starts
5260 * at arch_max_dma_pfn.
5261 */
5262void __init free_area_init_nodes(unsigned long *max_zone_pfn)
5263{
5264 unsigned long start_pfn, end_pfn;
5265 int i, nid;
5266
5267 /* Record where the zone boundaries are */
5268 memset(arch_zone_lowest_possible_pfn, 0,
5269 sizeof(arch_zone_lowest_possible_pfn));
5270 memset(arch_zone_highest_possible_pfn, 0,
5271 sizeof(arch_zone_highest_possible_pfn));
5272 arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
5273 arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
5274 for (i = 1; i < MAX_NR_ZONES; i++) {
5275 if (i == ZONE_MOVABLE)
5276 continue;
5277 arch_zone_lowest_possible_pfn[i] =
5278 arch_zone_highest_possible_pfn[i-1];
5279 arch_zone_highest_possible_pfn[i] =
5280 max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
5281 }
5282 arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
5283 arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
5284
5285 /* Find the PFNs that ZONE_MOVABLE begins at in each node */
5286 memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
5287 find_zone_movable_pfns_for_nodes();
5288
5289 /* Print out the zone ranges */
5290 printk("Zone ranges:\n");
5291 for (i = 0; i < MAX_NR_ZONES; i++) {
5292 if (i == ZONE_MOVABLE)
5293 continue;
5294 printk(KERN_CONT " %-8s ", zone_names[i]);
5295 if (arch_zone_lowest_possible_pfn[i] ==
5296 arch_zone_highest_possible_pfn[i])
5297 printk(KERN_CONT "empty\n");
5298 else
5299 printk(KERN_CONT "[mem %0#10lx-%0#10lx]\n",
5300 arch_zone_lowest_possible_pfn[i] << PAGE_SHIFT,
5301 (arch_zone_highest_possible_pfn[i]
5302 << PAGE_SHIFT) - 1);
5303 }
5304
5305 /* Print out the PFNs ZONE_MOVABLE begins at in each node */
5306 printk("Movable zone start for each node\n");
5307 for (i = 0; i < MAX_NUMNODES; i++) {
5308 if (zone_movable_pfn[i])
5309 printk(" Node %d: %#010lx\n", i,
5310 zone_movable_pfn[i] << PAGE_SHIFT);
5311 }
5312
5313 /* Print out the early node map */
5314 printk("Early memory node ranges\n");
5315 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid)
5316 printk(" node %3d: [mem %#010lx-%#010lx]\n", nid,
5317 start_pfn << PAGE_SHIFT, (end_pfn << PAGE_SHIFT) - 1);
5318
5319 /* Initialise every node */
5320 mminit_verify_pageflags_layout();
5321 setup_nr_node_ids();
5322 for_each_online_node(nid) {
5323 pg_data_t *pgdat = NODE_DATA(nid);
5324 free_area_init_node(nid, NULL,
5325 find_min_pfn_for_node(nid), NULL);
5326
5327 /* Any memory on that node */
5328 if (pgdat->node_present_pages)
5329 node_set_state(nid, N_MEMORY);
5330 check_for_memory(pgdat, nid);
5331 }
5332}
5333
5334static int __init cmdline_parse_core(char *p, unsigned long *core)
5335{
5336 unsigned long long coremem;
5337 if (!p)
5338 return -EINVAL;
5339
5340 coremem = memparse(p, &p);
5341 *core = coremem >> PAGE_SHIFT;
5342
5343 /* Paranoid check that UL is enough for the coremem value */
5344 WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
5345
5346 return 0;
5347}
5348
5349/*
5350 * kernelcore=size sets the amount of memory for use for allocations that
5351 * cannot be reclaimed or migrated.
5352 */
5353static int __init cmdline_parse_kernelcore(char *p)
5354{
5355 return cmdline_parse_core(p, &required_kernelcore);
5356}
5357
5358/*
5359 * movablecore=size sets the amount of memory for use for allocations that
5360 * can be reclaimed or migrated.
5361 */
5362static int __init cmdline_parse_movablecore(char *p)
5363{
5364 return cmdline_parse_core(p, &required_movablecore);
5365}
5366
5367early_param("kernelcore", cmdline_parse_kernelcore);
5368early_param("movablecore", cmdline_parse_movablecore);
5369
5370#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
5371
5372void adjust_managed_page_count(struct page *page, long count)
5373{
5374 spin_lock(&managed_page_count_lock);
5375 page_zone(page)->managed_pages += count;
5376 totalram_pages += count;
5377#ifdef CONFIG_HIGHMEM
5378 if (PageHighMem(page))
5379 totalhigh_pages += count;
5380#endif
5381 spin_unlock(&managed_page_count_lock);
5382}
5383EXPORT_SYMBOL(adjust_managed_page_count);
5384
5385unsigned long free_reserved_area(void *start, void *end, int poison, char *s)
5386{
5387 void *pos;
5388 unsigned long pages = 0;
5389
5390 start = (void *)PAGE_ALIGN((unsigned long)start);
5391 end = (void *)((unsigned long)end & PAGE_MASK);
5392 for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
5393 if ((unsigned int)poison <= 0xFF)
5394 memset(pos, poison, PAGE_SIZE);
5395 free_reserved_page(virt_to_page(pos));
5396 }
5397
5398 if (pages && s)
5399 pr_info("Freeing %s memory: %ldK (%p - %p)\n",
5400 s, pages << (PAGE_SHIFT - 10), start, end);
5401
5402 return pages;
5403}
5404EXPORT_SYMBOL(free_reserved_area);
5405
5406#ifdef CONFIG_HIGHMEM
5407void free_highmem_page(struct page *page)
5408{
5409 __free_reserved_page(page);
5410 totalram_pages++;
5411 page_zone(page)->managed_pages++;
5412 totalhigh_pages++;
5413}
5414#endif
5415
5416
5417void __init mem_init_print_info(const char *str)
5418{
5419 unsigned long physpages, codesize, datasize, rosize, bss_size;
5420 unsigned long init_code_size, init_data_size;
5421
5422 physpages = get_num_physpages();
5423 codesize = _etext - _stext;
5424 datasize = _edata - _sdata;
5425 rosize = __end_rodata - __start_rodata;
5426 bss_size = __bss_stop - __bss_start;
5427 init_data_size = __init_end - __init_begin;
5428 init_code_size = _einittext - _sinittext;
5429
5430 /*
5431 * Detect special cases and adjust section sizes accordingly:
5432 * 1) .init.* may be embedded into .data sections
5433 * 2) .init.text.* may be out of [__init_begin, __init_end],
5434 * please refer to arch/tile/kernel/vmlinux.lds.S.
5435 * 3) .rodata.* may be embedded into .text or .data sections.
5436 */
5437#define adj_init_size(start, end, size, pos, adj) \
5438 do { \
5439 if (start <= pos && pos < end && size > adj) \
5440 size -= adj; \
5441 } while (0)
5442
5443 adj_init_size(__init_begin, __init_end, init_data_size,
5444 _sinittext, init_code_size);
5445 adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
5446 adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
5447 adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
5448 adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
5449
5450#undef adj_init_size
5451
5452 printk("Memory: %luK/%luK available "
5453 "(%luK kernel code, %luK rwdata, %luK rodata, "
5454 "%luK init, %luK bss, %luK reserved"
5455#ifdef CONFIG_HIGHMEM
5456 ", %luK highmem"
5457#endif
5458 "%s%s)\n",
5459 nr_free_pages() << (PAGE_SHIFT-10), physpages << (PAGE_SHIFT-10),
5460 codesize >> 10, datasize >> 10, rosize >> 10,
5461 (init_data_size + init_code_size) >> 10, bss_size >> 10,
5462 (physpages - totalram_pages) << (PAGE_SHIFT-10),
5463#ifdef CONFIG_HIGHMEM
5464 totalhigh_pages << (PAGE_SHIFT-10),
5465#endif
5466 str ? ", " : "", str ? str : "");
5467}
5468
5469/**
5470 * set_dma_reserve - set the specified number of pages reserved in the first zone
5471 * @new_dma_reserve: The number of pages to mark reserved
5472 *
5473 * The per-cpu batchsize and zone watermarks are determined by present_pages.
5474 * In the DMA zone, a significant percentage may be consumed by kernel image
5475 * and other unfreeable allocations which can skew the watermarks badly. This
5476 * function may optionally be used to account for unfreeable pages in the
5477 * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
5478 * smaller per-cpu batchsize.
5479 */
5480void __init set_dma_reserve(unsigned long new_dma_reserve)
5481{
5482 dma_reserve = new_dma_reserve;
5483}
5484
5485void __init free_area_init(unsigned long *zones_size)
5486{
5487 free_area_init_node(0, zones_size,
5488 __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
5489}
5490
5491static int page_alloc_cpu_notify(struct notifier_block *self,
5492 unsigned long action, void *hcpu)
5493{
5494 int cpu = (unsigned long)hcpu;
5495
5496 if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
5497 lru_add_drain_cpu(cpu);
5498 drain_pages(cpu);
5499
5500 /*
5501 * Spill the event counters of the dead processor
5502 * into the current processors event counters.
5503 * This artificially elevates the count of the current
5504 * processor.
5505 */
5506 vm_events_fold_cpu(cpu);
5507
5508 /*
5509 * Zero the differential counters of the dead processor
5510 * so that the vm statistics are consistent.
5511 *
5512 * This is only okay since the processor is dead and cannot
5513 * race with what we are doing.
5514 */
5515 cpu_vm_stats_fold(cpu);
5516 }
5517 return NOTIFY_OK;
5518}
5519
5520void __init page_alloc_init(void)
5521{
5522 hotcpu_notifier(page_alloc_cpu_notify, 0);
5523}
5524
5525/*
5526 * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
5527 * or min_free_kbytes changes.
5528 */
5529static void calculate_totalreserve_pages(void)
5530{
5531 struct pglist_data *pgdat;
5532 unsigned long reserve_pages = 0;
5533 enum zone_type i, j;
5534
5535 for_each_online_pgdat(pgdat) {
5536 for (i = 0; i < MAX_NR_ZONES; i++) {
5537 struct zone *zone = pgdat->node_zones + i;
5538 unsigned long max = 0;
5539
5540 /* Find valid and maximum lowmem_reserve in the zone */
5541 for (j = i; j < MAX_NR_ZONES; j++) {
5542 if (zone->lowmem_reserve[j] > max)
5543 max = zone->lowmem_reserve[j];
5544 }
5545
5546 /* we treat the high watermark as reserved pages. */
5547 max += high_wmark_pages(zone);
5548
5549 if (max > zone->managed_pages)
5550 max = zone->managed_pages;
5551 reserve_pages += max;
5552 /*
5553 * Lowmem reserves are not available to
5554 * GFP_HIGHUSER page cache allocations and
5555 * kswapd tries to balance zones to their high
5556 * watermark. As a result, neither should be
5557 * regarded as dirtyable memory, to prevent a
5558 * situation where reclaim has to clean pages
5559 * in order to balance the zones.
5560 */
5561 zone->dirty_balance_reserve = max;
5562 }
5563 }
5564 dirty_balance_reserve = reserve_pages;
5565 totalreserve_pages = reserve_pages;
5566}
5567
5568/*
5569 * setup_per_zone_lowmem_reserve - called whenever
5570 * sysctl_lower_zone_reserve_ratio changes. Ensures that each zone
5571 * has a correct pages reserved value, so an adequate number of
5572 * pages are left in the zone after a successful __alloc_pages().
5573 */
5574static void setup_per_zone_lowmem_reserve(void)
5575{
5576 struct pglist_data *pgdat;
5577 enum zone_type j, idx;
5578
5579 for_each_online_pgdat(pgdat) {
5580 for (j = 0; j < MAX_NR_ZONES; j++) {
5581 struct zone *zone = pgdat->node_zones + j;
5582 unsigned long managed_pages = zone->managed_pages;
5583
5584 zone->lowmem_reserve[j] = 0;
5585
5586 idx = j;
5587 while (idx) {
5588 struct zone *lower_zone;
5589
5590 idx--;
5591
5592 if (sysctl_lowmem_reserve_ratio[idx] < 1)
5593 sysctl_lowmem_reserve_ratio[idx] = 1;
5594
5595 lower_zone = pgdat->node_zones + idx;
5596 lower_zone->lowmem_reserve[j] = managed_pages /
5597 sysctl_lowmem_reserve_ratio[idx];
5598 managed_pages += lower_zone->managed_pages;
5599 }
5600 }
5601 }
5602
5603 /* update totalreserve_pages */
5604 calculate_totalreserve_pages();
5605}
5606
5607static void __setup_per_zone_wmarks(void)
5608{
5609 unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
5610 unsigned long lowmem_pages = 0;
5611 struct zone *zone;
5612 unsigned long flags;
5613
5614 /* Calculate total number of !ZONE_HIGHMEM pages */
5615 for_each_zone(zone) {
5616 if (!is_highmem(zone))
5617 lowmem_pages += zone->managed_pages;
5618 }
5619
5620 for_each_zone(zone) {
5621 u64 tmp;
5622
5623 spin_lock_irqsave(&zone->lock, flags);
5624 tmp = (u64)pages_min * zone->managed_pages;
5625 do_div(tmp, lowmem_pages);
5626 if (is_highmem(zone)) {
5627 /*
5628 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
5629 * need highmem pages, so cap pages_min to a small
5630 * value here.
5631 *
5632 * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
5633 * deltas controls asynch page reclaim, and so should
5634 * not be capped for highmem.
5635 */
5636 unsigned long min_pages;
5637
5638 min_pages = zone->managed_pages / 1024;
5639 min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
5640 zone->watermark[WMARK_MIN] = min_pages;
5641 } else {
5642 /*
5643 * If it's a lowmem zone, reserve a number of pages
5644 * proportionate to the zone's size.
5645 */
5646 zone->watermark[WMARK_MIN] = tmp;
5647 }
5648
5649 zone->watermark[WMARK_LOW] = min_wmark_pages(zone) + (tmp >> 2);
5650 zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1);
5651
5652 __mod_zone_page_state(zone, NR_ALLOC_BATCH,
5653 high_wmark_pages(zone) -
5654 low_wmark_pages(zone) -
5655 zone_page_state(zone, NR_ALLOC_BATCH));
5656
5657 setup_zone_migrate_reserve(zone);
5658 spin_unlock_irqrestore(&zone->lock, flags);
5659 }
5660
5661 /* update totalreserve_pages */
5662 calculate_totalreserve_pages();
5663}
5664
5665/**
5666 * setup_per_zone_wmarks - called when min_free_kbytes changes
5667 * or when memory is hot-{added|removed}
5668 *
5669 * Ensures that the watermark[min,low,high] values for each zone are set
5670 * correctly with respect to min_free_kbytes.
5671 */
5672void setup_per_zone_wmarks(void)
5673{
5674 mutex_lock(&zonelists_mutex);
5675 __setup_per_zone_wmarks();
5676 mutex_unlock(&zonelists_mutex);
5677}
5678
5679/*
5680 * The inactive anon list should be small enough that the VM never has to
5681 * do too much work, but large enough that each inactive page has a chance
5682 * to be referenced again before it is swapped out.
5683 *
5684 * The inactive_anon ratio is the target ratio of ACTIVE_ANON to
5685 * INACTIVE_ANON pages on this zone's LRU, maintained by the
5686 * pageout code. A zone->inactive_ratio of 3 means 3:1 or 25% of
5687 * the anonymous pages are kept on the inactive list.
5688 *
5689 * total target max
5690 * memory ratio inactive anon
5691 * -------------------------------------
5692 * 10MB 1 5MB
5693 * 100MB 1 50MB
5694 * 1GB 3 250MB
5695 * 10GB 10 0.9GB
5696 * 100GB 31 3GB
5697 * 1TB 101 10GB
5698 * 10TB 320 32GB
5699 */
5700static void __meminit calculate_zone_inactive_ratio(struct zone *zone)
5701{
5702 unsigned int gb, ratio;
5703
5704 /* Zone size in gigabytes */
5705 gb = zone->managed_pages >> (30 - PAGE_SHIFT);
5706 if (gb)
5707 ratio = int_sqrt(10 * gb);
5708 else
5709 ratio = 1;
5710
5711 zone->inactive_ratio = ratio;
5712}
5713
5714static void __meminit setup_per_zone_inactive_ratio(void)
5715{
5716 struct zone *zone;
5717
5718 for_each_zone(zone)
5719 calculate_zone_inactive_ratio(zone);
5720}
5721
5722/*
5723 * Initialise min_free_kbytes.
5724 *
5725 * For small machines we want it small (128k min). For large machines
5726 * we want it large (64MB max). But it is not linear, because network
5727 * bandwidth does not increase linearly with machine size. We use
5728 *
5729 * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
5730 * min_free_kbytes = sqrt(lowmem_kbytes * 16)
5731 *
5732 * which yields
5733 *
5734 * 16MB: 512k
5735 * 32MB: 724k
5736 * 64MB: 1024k
5737 * 128MB: 1448k
5738 * 256MB: 2048k
5739 * 512MB: 2896k
5740 * 1024MB: 4096k
5741 * 2048MB: 5792k
5742 * 4096MB: 8192k
5743 * 8192MB: 11584k
5744 * 16384MB: 16384k
5745 */
5746int __meminit init_per_zone_wmark_min(void)
5747{
5748 unsigned long lowmem_kbytes;
5749 int new_min_free_kbytes;
5750
5751 lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
5752 new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
5753
5754 if (new_min_free_kbytes > user_min_free_kbytes) {
5755 min_free_kbytes = new_min_free_kbytes;
5756 if (min_free_kbytes < 128)
5757 min_free_kbytes = 128;
5758 if (min_free_kbytes > 65536)
5759 min_free_kbytes = 65536;
5760 } else {
5761 pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n",
5762 new_min_free_kbytes, user_min_free_kbytes);
5763 }
5764 setup_per_zone_wmarks();
5765 refresh_zone_stat_thresholds();
5766 setup_per_zone_lowmem_reserve();
5767 setup_per_zone_inactive_ratio();
5768 return 0;
5769}
5770module_init(init_per_zone_wmark_min)
5771
5772/*
5773 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
5774 * that we can call two helper functions whenever min_free_kbytes
5775 * changes.
5776 */
5777int min_free_kbytes_sysctl_handler(ctl_table *table, int write,
5778 void __user *buffer, size_t *length, loff_t *ppos)
5779{
5780 int rc;
5781
5782 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5783 if (rc)
5784 return rc;
5785
5786 if (write) {
5787 user_min_free_kbytes = min_free_kbytes;
5788 setup_per_zone_wmarks();
5789 }
5790 return 0;
5791}
5792
5793#ifdef CONFIG_NUMA
5794int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
5795 void __user *buffer, size_t *length, loff_t *ppos)
5796{
5797 struct zone *zone;
5798 int rc;
5799
5800 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5801 if (rc)
5802 return rc;
5803
5804 for_each_zone(zone)
5805 zone->min_unmapped_pages = (zone->managed_pages *
5806 sysctl_min_unmapped_ratio) / 100;
5807 return 0;
5808}
5809
5810int sysctl_min_slab_ratio_sysctl_handler(ctl_table *table, int write,
5811 void __user *buffer, size_t *length, loff_t *ppos)
5812{
5813 struct zone *zone;
5814 int rc;
5815
5816 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5817 if (rc)
5818 return rc;
5819
5820 for_each_zone(zone)
5821 zone->min_slab_pages = (zone->managed_pages *
5822 sysctl_min_slab_ratio) / 100;
5823 return 0;
5824}
5825#endif
5826
5827/*
5828 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
5829 * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
5830 * whenever sysctl_lowmem_reserve_ratio changes.
5831 *
5832 * The reserve ratio obviously has absolutely no relation with the
5833 * minimum watermarks. The lowmem reserve ratio can only make sense
5834 * if in function of the boot time zone sizes.
5835 */
5836int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write,
5837 void __user *buffer, size_t *length, loff_t *ppos)
5838{
5839 proc_dointvec_minmax(table, write, buffer, length, ppos);
5840 setup_per_zone_lowmem_reserve();
5841 return 0;
5842}
5843
5844/*
5845 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
5846 * cpu. It is the fraction of total pages in each zone that a hot per cpu
5847 * pagelist can have before it gets flushed back to buddy allocator.
5848 */
5849int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
5850 void __user *buffer, size_t *length, loff_t *ppos)
5851{
5852 struct zone *zone;
5853 unsigned int cpu;
5854 int ret;
5855
5856 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
5857 if (!write || (ret < 0))
5858 return ret;
5859
5860 mutex_lock(&pcp_batch_high_lock);
5861 for_each_populated_zone(zone) {
5862 unsigned long high;
5863 high = zone->managed_pages / percpu_pagelist_fraction;
5864 for_each_possible_cpu(cpu)
5865 pageset_set_high(per_cpu_ptr(zone->pageset, cpu),
5866 high);
5867 }
5868 mutex_unlock(&pcp_batch_high_lock);
5869 return 0;
5870}
5871
5872int hashdist = HASHDIST_DEFAULT;
5873
5874#ifdef CONFIG_NUMA
5875static int __init set_hashdist(char *str)
5876{
5877 if (!str)
5878 return 0;
5879 hashdist = simple_strtoul(str, &str, 0);
5880 return 1;
5881}
5882__setup("hashdist=", set_hashdist);
5883#endif
5884
5885/*
5886 * allocate a large system hash table from bootmem
5887 * - it is assumed that the hash table must contain an exact power-of-2
5888 * quantity of entries
5889 * - limit is the number of hash buckets, not the total allocation size
5890 */
5891void *__init alloc_large_system_hash(const char *tablename,
5892 unsigned long bucketsize,
5893 unsigned long numentries,
5894 int scale,
5895 int flags,
5896 unsigned int *_hash_shift,
5897 unsigned int *_hash_mask,
5898 unsigned long low_limit,
5899 unsigned long high_limit)
5900{
5901 unsigned long long max = high_limit;
5902 unsigned long log2qty, size;
5903 void *table = NULL;
5904
5905 /* allow the kernel cmdline to have a say */
5906 if (!numentries) {
5907 /* round applicable memory size up to nearest megabyte */
5908 numentries = nr_kernel_pages;
5909
5910 /* It isn't necessary when PAGE_SIZE >= 1MB */
5911 if (PAGE_SHIFT < 20)
5912 numentries = round_up(numentries, (1<<20)/PAGE_SIZE);
5913
5914 /* limit to 1 bucket per 2^scale bytes of low memory */
5915 if (scale > PAGE_SHIFT)
5916 numentries >>= (scale - PAGE_SHIFT);
5917 else
5918 numentries <<= (PAGE_SHIFT - scale);
5919
5920 /* Make sure we've got at least a 0-order allocation.. */
5921 if (unlikely(flags & HASH_SMALL)) {
5922 /* Makes no sense without HASH_EARLY */
5923 WARN_ON(!(flags & HASH_EARLY));
5924 if (!(numentries >> *_hash_shift)) {
5925 numentries = 1UL << *_hash_shift;
5926 BUG_ON(!numentries);
5927 }
5928 } else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
5929 numentries = PAGE_SIZE / bucketsize;
5930 }
5931 numentries = roundup_pow_of_two(numentries);
5932
5933 /* limit allocation size to 1/16 total memory by default */
5934 if (max == 0) {
5935 max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
5936 do_div(max, bucketsize);
5937 }
5938 max = min(max, 0x80000000ULL);
5939
5940 if (numentries < low_limit)
5941 numentries = low_limit;
5942 if (numentries > max)
5943 numentries = max;
5944
5945 log2qty = ilog2(numentries);
5946
5947 do {
5948 size = bucketsize << log2qty;
5949 if (flags & HASH_EARLY)
5950 table = memblock_virt_alloc_nopanic(size, 0);
5951 else if (hashdist)
5952 table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
5953 else {
5954 /*
5955 * If bucketsize is not a power-of-two, we may free
5956 * some pages at the end of hash table which
5957 * alloc_pages_exact() automatically does
5958 */
5959 if (get_order(size) < MAX_ORDER) {
5960 table = alloc_pages_exact(size, GFP_ATOMIC);
5961 kmemleak_alloc(table, size, 1, GFP_ATOMIC);
5962 }
5963 }
5964 } while (!table && size > PAGE_SIZE && --log2qty);
5965
5966 if (!table)
5967 panic("Failed to allocate %s hash table\n", tablename);
5968
5969 printk(KERN_INFO "%s hash table entries: %ld (order: %d, %lu bytes)\n",
5970 tablename,
5971 (1UL << log2qty),
5972 ilog2(size) - PAGE_SHIFT,
5973 size);
5974
5975 if (_hash_shift)
5976 *_hash_shift = log2qty;
5977 if (_hash_mask)
5978 *_hash_mask = (1 << log2qty) - 1;
5979
5980 return table;
5981}
5982
5983/* Return a pointer to the bitmap storing bits affecting a block of pages */
5984static inline unsigned long *get_pageblock_bitmap(struct zone *zone,
5985 unsigned long pfn)
5986{
5987#ifdef CONFIG_SPARSEMEM
5988 return __pfn_to_section(pfn)->pageblock_flags;
5989#else
5990 return zone->pageblock_flags;
5991#endif /* CONFIG_SPARSEMEM */
5992}
5993
5994static inline int pfn_to_bitidx(struct zone *zone, unsigned long pfn)
5995{
5996#ifdef CONFIG_SPARSEMEM
5997 pfn &= (PAGES_PER_SECTION-1);
5998 return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
5999#else
6000 pfn = pfn - round_down(zone->zone_start_pfn, pageblock_nr_pages);
6001 return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
6002#endif /* CONFIG_SPARSEMEM */
6003}
6004
6005/**
6006 * get_pageblock_flags_group - Return the requested group of flags for the pageblock_nr_pages block of pages
6007 * @page: The page within the block of interest
6008 * @start_bitidx: The first bit of interest to retrieve
6009 * @end_bitidx: The last bit of interest
6010 * returns pageblock_bits flags
6011 */
6012unsigned long get_pageblock_flags_group(struct page *page,
6013 int start_bitidx, int end_bitidx)
6014{
6015 struct zone *zone;
6016 unsigned long *bitmap;
6017 unsigned long pfn, bitidx;
6018 unsigned long flags = 0;
6019 unsigned long value = 1;
6020
6021 zone = page_zone(page);
6022 pfn = page_to_pfn(page);
6023 bitmap = get_pageblock_bitmap(zone, pfn);
6024 bitidx = pfn_to_bitidx(zone, pfn);
6025
6026 for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
6027 if (test_bit(bitidx + start_bitidx, bitmap))
6028 flags |= value;
6029
6030 return flags;
6031}
6032
6033/**
6034 * set_pageblock_flags_group - Set the requested group of flags for a pageblock_nr_pages block of pages
6035 * @page: The page within the block of interest
6036 * @start_bitidx: The first bit of interest
6037 * @end_bitidx: The last bit of interest
6038 * @flags: The flags to set
6039 */
6040void set_pageblock_flags_group(struct page *page, unsigned long flags,
6041 int start_bitidx, int end_bitidx)
6042{
6043 struct zone *zone;
6044 unsigned long *bitmap;
6045 unsigned long pfn, bitidx;
6046 unsigned long value = 1;
6047
6048 zone = page_zone(page);
6049 pfn = page_to_pfn(page);
6050 bitmap = get_pageblock_bitmap(zone, pfn);
6051 bitidx = pfn_to_bitidx(zone, pfn);
6052 VM_BUG_ON_PAGE(!zone_spans_pfn(zone, pfn), page);
6053
6054 for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
6055 if (flags & value)
6056 __set_bit(bitidx + start_bitidx, bitmap);
6057 else
6058 __clear_bit(bitidx + start_bitidx, bitmap);
6059}
6060
6061/*
6062 * This function checks whether pageblock includes unmovable pages or not.
6063 * If @count is not zero, it is okay to include less @count unmovable pages
6064 *
6065 * PageLRU check without isolation or lru_lock could race so that
6066 * MIGRATE_MOVABLE block might include unmovable pages. It means you can't
6067 * expect this function should be exact.
6068 */
6069bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
6070 bool skip_hwpoisoned_pages)
6071{
6072 unsigned long pfn, iter, found;
6073 int mt;
6074
6075 /*
6076 * For avoiding noise data, lru_add_drain_all() should be called
6077 * If ZONE_MOVABLE, the zone never contains unmovable pages
6078 */
6079 if (zone_idx(zone) == ZONE_MOVABLE)
6080 return false;
6081 mt = get_pageblock_migratetype(page);
6082 if (mt == MIGRATE_MOVABLE || is_migrate_cma(mt))
6083 return false;
6084
6085 pfn = page_to_pfn(page);
6086 for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) {
6087 unsigned long check = pfn + iter;
6088
6089 if (!pfn_valid_within(check))
6090 continue;
6091
6092 page = pfn_to_page(check);
6093
6094 /*
6095 * Hugepages are not in LRU lists, but they're movable.
6096 * We need not scan over tail pages bacause we don't
6097 * handle each tail page individually in migration.
6098 */
6099 if (PageHuge(page)) {
6100 iter = round_up(iter + 1, 1<<compound_order(page)) - 1;
6101 continue;
6102 }
6103
6104 /*
6105 * We can't use page_count without pin a page
6106 * because another CPU can free compound page.
6107 * This check already skips compound tails of THP
6108 * because their page->_count is zero at all time.
6109 */
6110 if (!atomic_read(&page->_count)) {
6111 if (PageBuddy(page))
6112 iter += (1 << page_order(page)) - 1;
6113 continue;
6114 }
6115
6116 /*
6117 * The HWPoisoned page may be not in buddy system, and
6118 * page_count() is not 0.
6119 */
6120 if (skip_hwpoisoned_pages && PageHWPoison(page))
6121 continue;
6122
6123 if (!PageLRU(page))
6124 found++;
6125 /*
6126 * If there are RECLAIMABLE pages, we need to check it.
6127 * But now, memory offline itself doesn't call shrink_slab()
6128 * and it still to be fixed.
6129 */
6130 /*
6131 * If the page is not RAM, page_count()should be 0.
6132 * we don't need more check. This is an _used_ not-movable page.
6133 *
6134 * The problematic thing here is PG_reserved pages. PG_reserved
6135 * is set to both of a memory hole page and a _used_ kernel
6136 * page at boot.
6137 */
6138 if (found > count)
6139 return true;
6140 }
6141 return false;
6142}
6143
6144bool is_pageblock_removable_nolock(struct page *page)
6145{
6146 struct zone *zone;
6147 unsigned long pfn;
6148
6149 /*
6150 * We have to be careful here because we are iterating over memory
6151 * sections which are not zone aware so we might end up outside of
6152 * the zone but still within the section.
6153 * We have to take care about the node as well. If the node is offline
6154 * its NODE_DATA will be NULL - see page_zone.
6155 */
6156 if (!node_online(page_to_nid(page)))
6157 return false;
6158
6159 zone = page_zone(page);
6160 pfn = page_to_pfn(page);
6161 if (!zone_spans_pfn(zone, pfn))
6162 return false;
6163
6164 return !has_unmovable_pages(zone, page, 0, true);
6165}
6166
6167#ifdef CONFIG_CMA
6168
6169static unsigned long pfn_max_align_down(unsigned long pfn)
6170{
6171 return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES,
6172 pageblock_nr_pages) - 1);
6173}
6174
6175static unsigned long pfn_max_align_up(unsigned long pfn)
6176{
6177 return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES,
6178 pageblock_nr_pages));
6179}
6180
6181/* [start, end) must belong to a single zone. */
6182static int __alloc_contig_migrate_range(struct compact_control *cc,
6183 unsigned long start, unsigned long end)
6184{
6185 /* This function is based on compact_zone() from compaction.c. */
6186 unsigned long nr_reclaimed;
6187 unsigned long pfn = start;
6188 unsigned int tries = 0;
6189 int ret = 0;
6190
6191 migrate_prep();
6192
6193 while (pfn < end || !list_empty(&cc->migratepages)) {
6194 if (fatal_signal_pending(current)) {
6195 ret = -EINTR;
6196 break;
6197 }
6198
6199 if (list_empty(&cc->migratepages)) {
6200 cc->nr_migratepages = 0;
6201 pfn = isolate_migratepages_range(cc->zone, cc,
6202 pfn, end, true);
6203 if (!pfn) {
6204 ret = -EINTR;
6205 break;
6206 }
6207 tries = 0;
6208 } else if (++tries == 5) {
6209 ret = ret < 0 ? ret : -EBUSY;
6210 break;
6211 }
6212
6213 nr_reclaimed = reclaim_clean_pages_from_list(cc->zone,
6214 &cc->migratepages);
6215 cc->nr_migratepages -= nr_reclaimed;
6216
6217 ret = migrate_pages(&cc->migratepages, alloc_migrate_target,
6218 0, MIGRATE_SYNC, MR_CMA);
6219 }
6220 if (ret < 0) {
6221 putback_movable_pages(&cc->migratepages);
6222 return ret;
6223 }
6224 return 0;
6225}
6226
6227/**
6228 * alloc_contig_range() -- tries to allocate given range of pages
6229 * @start: start PFN to allocate
6230 * @end: one-past-the-last PFN to allocate
6231 * @migratetype: migratetype of the underlaying pageblocks (either
6232 * #MIGRATE_MOVABLE or #MIGRATE_CMA). All pageblocks
6233 * in range must have the same migratetype and it must
6234 * be either of the two.
6235 *
6236 * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
6237 * aligned, however it's the caller's responsibility to guarantee that
6238 * we are the only thread that changes migrate type of pageblocks the
6239 * pages fall in.
6240 *
6241 * The PFN range must belong to a single zone.
6242 *
6243 * Returns zero on success or negative error code. On success all
6244 * pages which PFN is in [start, end) are allocated for the caller and
6245 * need to be freed with free_contig_range().
6246 */
6247int alloc_contig_range(unsigned long start, unsigned long end,
6248 unsigned migratetype)
6249{
6250 unsigned long outer_start, outer_end;
6251 int ret = 0, order;
6252
6253 struct compact_control cc = {
6254 .nr_migratepages = 0,
6255 .order = -1,
6256 .zone = page_zone(pfn_to_page(start)),
6257 .sync = true,
6258 .ignore_skip_hint = true,
6259 };
6260 INIT_LIST_HEAD(&cc.migratepages);
6261
6262 /*
6263 * What we do here is we mark all pageblocks in range as
6264 * MIGRATE_ISOLATE. Because pageblock and max order pages may
6265 * have different sizes, and due to the way page allocator
6266 * work, we align the range to biggest of the two pages so
6267 * that page allocator won't try to merge buddies from
6268 * different pageblocks and change MIGRATE_ISOLATE to some
6269 * other migration type.
6270 *
6271 * Once the pageblocks are marked as MIGRATE_ISOLATE, we
6272 * migrate the pages from an unaligned range (ie. pages that
6273 * we are interested in). This will put all the pages in
6274 * range back to page allocator as MIGRATE_ISOLATE.
6275 *
6276 * When this is done, we take the pages in range from page
6277 * allocator removing them from the buddy system. This way
6278 * page allocator will never consider using them.
6279 *
6280 * This lets us mark the pageblocks back as
6281 * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
6282 * aligned range but not in the unaligned, original range are
6283 * put back to page allocator so that buddy can use them.
6284 */
6285
6286 ret = start_isolate_page_range(pfn_max_align_down(start),
6287 pfn_max_align_up(end), migratetype,
6288 false);
6289 if (ret)
6290 return ret;
6291
6292 ret = __alloc_contig_migrate_range(&cc, start, end);
6293 if (ret)
6294 goto done;
6295
6296 /*
6297 * Pages from [start, end) are within a MAX_ORDER_NR_PAGES
6298 * aligned blocks that are marked as MIGRATE_ISOLATE. What's
6299 * more, all pages in [start, end) are free in page allocator.
6300 * What we are going to do is to allocate all pages from
6301 * [start, end) (that is remove them from page allocator).
6302 *
6303 * The only problem is that pages at the beginning and at the
6304 * end of interesting range may be not aligned with pages that
6305 * page allocator holds, ie. they can be part of higher order
6306 * pages. Because of this, we reserve the bigger range and
6307 * once this is done free the pages we are not interested in.
6308 *
6309 * We don't have to hold zone->lock here because the pages are
6310 * isolated thus they won't get removed from buddy.
6311 */
6312
6313 lru_add_drain_all();
6314 drain_all_pages();
6315
6316 order = 0;
6317 outer_start = start;
6318 while (!PageBuddy(pfn_to_page(outer_start))) {
6319 if (++order >= MAX_ORDER) {
6320 ret = -EBUSY;
6321 goto done;
6322 }
6323 outer_start &= ~0UL << order;
6324 }
6325
6326 /* Make sure the range is really isolated. */
6327 if (test_pages_isolated(outer_start, end, false)) {
6328 pr_warn("alloc_contig_range test_pages_isolated(%lx, %lx) failed\n",
6329 outer_start, end);
6330 ret = -EBUSY;
6331 goto done;
6332 }
6333
6334
6335 /* Grab isolated pages from freelists. */
6336 outer_end = isolate_freepages_range(&cc, outer_start, end);
6337 if (!outer_end) {
6338 ret = -EBUSY;
6339 goto done;
6340 }
6341
6342 /* Free head and tail (if any) */
6343 if (start != outer_start)
6344 free_contig_range(outer_start, start - outer_start);
6345 if (end != outer_end)
6346 free_contig_range(end, outer_end - end);
6347
6348done:
6349 undo_isolate_page_range(pfn_max_align_down(start),
6350 pfn_max_align_up(end), migratetype);
6351 return ret;
6352}
6353
6354void free_contig_range(unsigned long pfn, unsigned nr_pages)
6355{
6356 unsigned int count = 0;
6357
6358 for (; nr_pages--; pfn++) {
6359 struct page *page = pfn_to_page(pfn);
6360
6361 count += page_count(page) != 1;
6362 __free_page(page);
6363 }
6364 WARN(count != 0, "%d pages are still in use!\n", count);
6365}
6366#endif
6367
6368#ifdef CONFIG_MEMORY_HOTPLUG
6369/*
6370 * The zone indicated has a new number of managed_pages; batch sizes and percpu
6371 * page high values need to be recalulated.
6372 */
6373void __meminit zone_pcp_update(struct zone *zone)
6374{
6375 unsigned cpu;
6376 mutex_lock(&pcp_batch_high_lock);
6377 for_each_possible_cpu(cpu)
6378 pageset_set_high_and_batch(zone,
6379 per_cpu_ptr(zone->pageset, cpu));
6380 mutex_unlock(&pcp_batch_high_lock);
6381}
6382#endif
6383
6384void zone_pcp_reset(struct zone *zone)
6385{
6386 unsigned long flags;
6387 int cpu;
6388 struct per_cpu_pageset *pset;
6389
6390 /* avoid races with drain_pages() */
6391 local_irq_save(flags);
6392 if (zone->pageset != &boot_pageset) {
6393 for_each_online_cpu(cpu) {
6394 pset = per_cpu_ptr(zone->pageset, cpu);
6395 drain_zonestat(zone, pset);
6396 }
6397 free_percpu(zone->pageset);
6398 zone->pageset = &boot_pageset;
6399 }
6400 local_irq_restore(flags);
6401}
6402
6403#ifdef CONFIG_MEMORY_HOTREMOVE
6404/*
6405 * All pages in the range must be isolated before calling this.
6406 */
6407void
6408__offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
6409{
6410 struct page *page;
6411 struct zone *zone;
6412 int order, i;
6413 unsigned long pfn;
6414 unsigned long flags;
6415 /* find the first valid pfn */
6416 for (pfn = start_pfn; pfn < end_pfn; pfn++)
6417 if (pfn_valid(pfn))
6418 break;
6419 if (pfn == end_pfn)
6420 return;
6421 zone = page_zone(pfn_to_page(pfn));
6422 spin_lock_irqsave(&zone->lock, flags);
6423 pfn = start_pfn;
6424 while (pfn < end_pfn) {
6425 if (!pfn_valid(pfn)) {
6426 pfn++;
6427 continue;
6428 }
6429 page = pfn_to_page(pfn);
6430 /*
6431 * The HWPoisoned page may be not in buddy system, and
6432 * page_count() is not 0.
6433 */
6434 if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
6435 pfn++;
6436 SetPageReserved(page);
6437 continue;
6438 }
6439
6440 BUG_ON(page_count(page));
6441 BUG_ON(!PageBuddy(page));
6442 order = page_order(page);
6443#ifdef CONFIG_DEBUG_VM
6444 printk(KERN_INFO "remove from free list %lx %d %lx\n",
6445 pfn, 1 << order, end_pfn);
6446#endif
6447 list_del(&page->lru);
6448 rmv_page_order(page);
6449 zone->free_area[order].nr_free--;
6450 for (i = 0; i < (1 << order); i++)
6451 SetPageReserved((page+i));
6452 pfn += (1 << order);
6453 }
6454 spin_unlock_irqrestore(&zone->lock, flags);
6455}
6456#endif
6457
6458#ifdef CONFIG_MEMORY_FAILURE
6459bool is_free_buddy_page(struct page *page)
6460{
6461 struct zone *zone = page_zone(page);
6462 unsigned long pfn = page_to_pfn(page);
6463 unsigned long flags;
6464 int order;
6465
6466 spin_lock_irqsave(&zone->lock, flags);
6467 for (order = 0; order < MAX_ORDER; order++) {
6468 struct page *page_head = page - (pfn & ((1 << order) - 1));
6469
6470 if (PageBuddy(page_head) && page_order(page_head) >= order)
6471 break;
6472 }
6473 spin_unlock_irqrestore(&zone->lock, flags);
6474
6475 return order < MAX_ORDER;
6476}
6477#endif
6478
6479static const struct trace_print_flags pageflag_names[] = {
6480 {1UL << PG_locked, "locked" },
6481 {1UL << PG_error, "error" },
6482 {1UL << PG_referenced, "referenced" },
6483 {1UL << PG_uptodate, "uptodate" },
6484 {1UL << PG_dirty, "dirty" },
6485 {1UL << PG_lru, "lru" },
6486 {1UL << PG_active, "active" },
6487 {1UL << PG_slab, "slab" },
6488 {1UL << PG_owner_priv_1, "owner_priv_1" },
6489 {1UL << PG_arch_1, "arch_1" },
6490 {1UL << PG_reserved, "reserved" },
6491 {1UL << PG_private, "private" },
6492 {1UL << PG_private_2, "private_2" },
6493 {1UL << PG_writeback, "writeback" },
6494#ifdef CONFIG_PAGEFLAGS_EXTENDED
6495 {1UL << PG_head, "head" },
6496 {1UL << PG_tail, "tail" },
6497#else
6498 {1UL << PG_compound, "compound" },
6499#endif
6500 {1UL << PG_swapcache, "swapcache" },
6501 {1UL << PG_mappedtodisk, "mappedtodisk" },
6502 {1UL << PG_reclaim, "reclaim" },
6503 {1UL << PG_swapbacked, "swapbacked" },
6504 {1UL << PG_unevictable, "unevictable" },
6505#ifdef CONFIG_MMU
6506 {1UL << PG_mlocked, "mlocked" },
6507#endif
6508#ifdef CONFIG_ARCH_USES_PG_UNCACHED
6509 {1UL << PG_uncached, "uncached" },
6510#endif
6511#ifdef CONFIG_MEMORY_FAILURE
6512 {1UL << PG_hwpoison, "hwpoison" },
6513#endif
6514#ifdef CONFIG_TRANSPARENT_HUGEPAGE
6515 {1UL << PG_compound_lock, "compound_lock" },
6516#endif
6517};
6518
6519static void dump_page_flags(unsigned long flags)
6520{
6521 const char *delim = "";
6522 unsigned long mask;
6523 int i;
6524
6525 BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS);
6526
6527 printk(KERN_ALERT "page flags: %#lx(", flags);
6528
6529 /* remove zone id */
6530 flags &= (1UL << NR_PAGEFLAGS) - 1;
6531
6532 for (i = 0; i < ARRAY_SIZE(pageflag_names) && flags; i++) {
6533
6534 mask = pageflag_names[i].mask;
6535 if ((flags & mask) != mask)
6536 continue;
6537
6538 flags &= ~mask;
6539 printk("%s%s", delim, pageflag_names[i].name);
6540 delim = "|";
6541 }
6542
6543 /* check for left over flags */
6544 if (flags)
6545 printk("%s%#lx", delim, flags);
6546
6547 printk(")\n");
6548}
6549
6550void dump_page_badflags(struct page *page, const char *reason,
6551 unsigned long badflags)
6552{
6553 printk(KERN_ALERT
6554 "page:%p count:%d mapcount:%d mapping:%p index:%#lx\n",
6555 page, atomic_read(&page->_count), page_mapcount(page),
6556 page->mapping, page->index);
6557 dump_page_flags(page->flags);
6558 if (reason)
6559 pr_alert("page dumped because: %s\n", reason);
6560 if (page->flags & badflags) {
6561 pr_alert("bad because of flags:\n");
6562 dump_page_flags(page->flags & badflags);
6563 }
6564 mem_cgroup_print_bad_page(page);
6565}
6566
6567void dump_page(struct page *page, const char *reason)
6568{
6569 dump_page_badflags(page, reason, 0);
6570}
6571EXPORT_SYMBOL(dump_page);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/mm/page_alloc.c
4 *
5 * Manages the free list, the system allocates free pages here.
6 * Note that kmalloc() lives in slab.c
7 *
8 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
9 * Swap reorganised 29.12.95, Stephen Tweedie
10 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
11 * Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
12 * Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
13 * Zone balancing, Kanoj Sarcar, SGI, Jan 2000
14 * Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
15 * (lots of bits borrowed from Ingo Molnar & Andrew Morton)
16 */
17
18#include <linux/stddef.h>
19#include <linux/mm.h>
20#include <linux/highmem.h>
21#include <linux/interrupt.h>
22#include <linux/jiffies.h>
23#include <linux/compiler.h>
24#include <linux/kernel.h>
25#include <linux/kasan.h>
26#include <linux/kmsan.h>
27#include <linux/module.h>
28#include <linux/suspend.h>
29#include <linux/ratelimit.h>
30#include <linux/oom.h>
31#include <linux/topology.h>
32#include <linux/sysctl.h>
33#include <linux/cpu.h>
34#include <linux/cpuset.h>
35#include <linux/pagevec.h>
36#include <linux/memory_hotplug.h>
37#include <linux/nodemask.h>
38#include <linux/vmstat.h>
39#include <linux/fault-inject.h>
40#include <linux/compaction.h>
41#include <trace/events/kmem.h>
42#include <trace/events/oom.h>
43#include <linux/prefetch.h>
44#include <linux/mm_inline.h>
45#include <linux/mmu_notifier.h>
46#include <linux/migrate.h>
47#include <linux/sched/mm.h>
48#include <linux/page_owner.h>
49#include <linux/page_table_check.h>
50#include <linux/memcontrol.h>
51#include <linux/ftrace.h>
52#include <linux/lockdep.h>
53#include <linux/psi.h>
54#include <linux/khugepaged.h>
55#include <linux/delayacct.h>
56#include <linux/cacheinfo.h>
57#include <asm/div64.h>
58#include "internal.h"
59#include "shuffle.h"
60#include "page_reporting.h"
61
62/* Free Page Internal flags: for internal, non-pcp variants of free_pages(). */
63typedef int __bitwise fpi_t;
64
65/* No special request */
66#define FPI_NONE ((__force fpi_t)0)
67
68/*
69 * Skip free page reporting notification for the (possibly merged) page.
70 * This does not hinder free page reporting from grabbing the page,
71 * reporting it and marking it "reported" - it only skips notifying
72 * the free page reporting infrastructure about a newly freed page. For
73 * example, used when temporarily pulling a page from a freelist and
74 * putting it back unmodified.
75 */
76#define FPI_SKIP_REPORT_NOTIFY ((__force fpi_t)BIT(0))
77
78/*
79 * Place the (possibly merged) page to the tail of the freelist. Will ignore
80 * page shuffling (relevant code - e.g., memory onlining - is expected to
81 * shuffle the whole zone).
82 *
83 * Note: No code should rely on this flag for correctness - it's purely
84 * to allow for optimizations when handing back either fresh pages
85 * (memory onlining) or untouched pages (page isolation, free page
86 * reporting).
87 */
88#define FPI_TO_TAIL ((__force fpi_t)BIT(1))
89
90/* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
91static DEFINE_MUTEX(pcp_batch_high_lock);
92#define MIN_PERCPU_PAGELIST_HIGH_FRACTION (8)
93
94#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
95/*
96 * On SMP, spin_trylock is sufficient protection.
97 * On PREEMPT_RT, spin_trylock is equivalent on both SMP and UP.
98 */
99#define pcp_trylock_prepare(flags) do { } while (0)
100#define pcp_trylock_finish(flag) do { } while (0)
101#else
102
103/* UP spin_trylock always succeeds so disable IRQs to prevent re-entrancy. */
104#define pcp_trylock_prepare(flags) local_irq_save(flags)
105#define pcp_trylock_finish(flags) local_irq_restore(flags)
106#endif
107
108/*
109 * Locking a pcp requires a PCP lookup followed by a spinlock. To avoid
110 * a migration causing the wrong PCP to be locked and remote memory being
111 * potentially allocated, pin the task to the CPU for the lookup+lock.
112 * preempt_disable is used on !RT because it is faster than migrate_disable.
113 * migrate_disable is used on RT because otherwise RT spinlock usage is
114 * interfered with and a high priority task cannot preempt the allocator.
115 */
116#ifndef CONFIG_PREEMPT_RT
117#define pcpu_task_pin() preempt_disable()
118#define pcpu_task_unpin() preempt_enable()
119#else
120#define pcpu_task_pin() migrate_disable()
121#define pcpu_task_unpin() migrate_enable()
122#endif
123
124/*
125 * Generic helper to lookup and a per-cpu variable with an embedded spinlock.
126 * Return value should be used with equivalent unlock helper.
127 */
128#define pcpu_spin_lock(type, member, ptr) \
129({ \
130 type *_ret; \
131 pcpu_task_pin(); \
132 _ret = this_cpu_ptr(ptr); \
133 spin_lock(&_ret->member); \
134 _ret; \
135})
136
137#define pcpu_spin_trylock(type, member, ptr) \
138({ \
139 type *_ret; \
140 pcpu_task_pin(); \
141 _ret = this_cpu_ptr(ptr); \
142 if (!spin_trylock(&_ret->member)) { \
143 pcpu_task_unpin(); \
144 _ret = NULL; \
145 } \
146 _ret; \
147})
148
149#define pcpu_spin_unlock(member, ptr) \
150({ \
151 spin_unlock(&ptr->member); \
152 pcpu_task_unpin(); \
153})
154
155/* struct per_cpu_pages specific helpers. */
156#define pcp_spin_lock(ptr) \
157 pcpu_spin_lock(struct per_cpu_pages, lock, ptr)
158
159#define pcp_spin_trylock(ptr) \
160 pcpu_spin_trylock(struct per_cpu_pages, lock, ptr)
161
162#define pcp_spin_unlock(ptr) \
163 pcpu_spin_unlock(lock, ptr)
164
165#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
166DEFINE_PER_CPU(int, numa_node);
167EXPORT_PER_CPU_SYMBOL(numa_node);
168#endif
169
170DEFINE_STATIC_KEY_TRUE(vm_numa_stat_key);
171
172#ifdef CONFIG_HAVE_MEMORYLESS_NODES
173/*
174 * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
175 * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
176 * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
177 * defined in <linux/topology.h>.
178 */
179DEFINE_PER_CPU(int, _numa_mem_); /* Kernel "local memory" node */
180EXPORT_PER_CPU_SYMBOL(_numa_mem_);
181#endif
182
183static DEFINE_MUTEX(pcpu_drain_mutex);
184
185#ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
186volatile unsigned long latent_entropy __latent_entropy;
187EXPORT_SYMBOL(latent_entropy);
188#endif
189
190/*
191 * Array of node states.
192 */
193nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
194 [N_POSSIBLE] = NODE_MASK_ALL,
195 [N_ONLINE] = { { [0] = 1UL } },
196#ifndef CONFIG_NUMA
197 [N_NORMAL_MEMORY] = { { [0] = 1UL } },
198#ifdef CONFIG_HIGHMEM
199 [N_HIGH_MEMORY] = { { [0] = 1UL } },
200#endif
201 [N_MEMORY] = { { [0] = 1UL } },
202 [N_CPU] = { { [0] = 1UL } },
203#endif /* NUMA */
204};
205EXPORT_SYMBOL(node_states);
206
207gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
208
209/*
210 * A cached value of the page's pageblock's migratetype, used when the page is
211 * put on a pcplist. Used to avoid the pageblock migratetype lookup when
212 * freeing from pcplists in most cases, at the cost of possibly becoming stale.
213 * Also the migratetype set in the page does not necessarily match the pcplist
214 * index, e.g. page might have MIGRATE_CMA set but be on a pcplist with any
215 * other index - this ensures that it will be put on the correct CMA freelist.
216 */
217static inline int get_pcppage_migratetype(struct page *page)
218{
219 return page->index;
220}
221
222static inline void set_pcppage_migratetype(struct page *page, int migratetype)
223{
224 page->index = migratetype;
225}
226
227#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
228unsigned int pageblock_order __read_mostly;
229#endif
230
231static void __free_pages_ok(struct page *page, unsigned int order,
232 fpi_t fpi_flags);
233
234/*
235 * results with 256, 32 in the lowmem_reserve sysctl:
236 * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
237 * 1G machine -> (16M dma, 784M normal, 224M high)
238 * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
239 * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
240 * HIGHMEM allocation will leave (224M+784M)/256 of ram reserved in ZONE_DMA
241 *
242 * TBD: should special case ZONE_DMA32 machines here - in those we normally
243 * don't need any ZONE_NORMAL reservation
244 */
245static int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES] = {
246#ifdef CONFIG_ZONE_DMA
247 [ZONE_DMA] = 256,
248#endif
249#ifdef CONFIG_ZONE_DMA32
250 [ZONE_DMA32] = 256,
251#endif
252 [ZONE_NORMAL] = 32,
253#ifdef CONFIG_HIGHMEM
254 [ZONE_HIGHMEM] = 0,
255#endif
256 [ZONE_MOVABLE] = 0,
257};
258
259char * const zone_names[MAX_NR_ZONES] = {
260#ifdef CONFIG_ZONE_DMA
261 "DMA",
262#endif
263#ifdef CONFIG_ZONE_DMA32
264 "DMA32",
265#endif
266 "Normal",
267#ifdef CONFIG_HIGHMEM
268 "HighMem",
269#endif
270 "Movable",
271#ifdef CONFIG_ZONE_DEVICE
272 "Device",
273#endif
274};
275
276const char * const migratetype_names[MIGRATE_TYPES] = {
277 "Unmovable",
278 "Movable",
279 "Reclaimable",
280 "HighAtomic",
281#ifdef CONFIG_CMA
282 "CMA",
283#endif
284#ifdef CONFIG_MEMORY_ISOLATION
285 "Isolate",
286#endif
287};
288
289int min_free_kbytes = 1024;
290int user_min_free_kbytes = -1;
291static int watermark_boost_factor __read_mostly = 15000;
292static int watermark_scale_factor = 10;
293
294/* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
295int movable_zone;
296EXPORT_SYMBOL(movable_zone);
297
298#if MAX_NUMNODES > 1
299unsigned int nr_node_ids __read_mostly = MAX_NUMNODES;
300unsigned int nr_online_nodes __read_mostly = 1;
301EXPORT_SYMBOL(nr_node_ids);
302EXPORT_SYMBOL(nr_online_nodes);
303#endif
304
305static bool page_contains_unaccepted(struct page *page, unsigned int order);
306static void accept_page(struct page *page, unsigned int order);
307static bool try_to_accept_memory(struct zone *zone, unsigned int order);
308static inline bool has_unaccepted_memory(void);
309static bool __free_unaccepted(struct page *page);
310
311int page_group_by_mobility_disabled __read_mostly;
312
313#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
314/*
315 * During boot we initialize deferred pages on-demand, as needed, but once
316 * page_alloc_init_late() has finished, the deferred pages are all initialized,
317 * and we can permanently disable that path.
318 */
319DEFINE_STATIC_KEY_TRUE(deferred_pages);
320
321static inline bool deferred_pages_enabled(void)
322{
323 return static_branch_unlikely(&deferred_pages);
324}
325
326/*
327 * deferred_grow_zone() is __init, but it is called from
328 * get_page_from_freelist() during early boot until deferred_pages permanently
329 * disables this call. This is why we have refdata wrapper to avoid warning,
330 * and to ensure that the function body gets unloaded.
331 */
332static bool __ref
333_deferred_grow_zone(struct zone *zone, unsigned int order)
334{
335 return deferred_grow_zone(zone, order);
336}
337#else
338static inline bool deferred_pages_enabled(void)
339{
340 return false;
341}
342#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
343
344/* Return a pointer to the bitmap storing bits affecting a block of pages */
345static inline unsigned long *get_pageblock_bitmap(const struct page *page,
346 unsigned long pfn)
347{
348#ifdef CONFIG_SPARSEMEM
349 return section_to_usemap(__pfn_to_section(pfn));
350#else
351 return page_zone(page)->pageblock_flags;
352#endif /* CONFIG_SPARSEMEM */
353}
354
355static inline int pfn_to_bitidx(const struct page *page, unsigned long pfn)
356{
357#ifdef CONFIG_SPARSEMEM
358 pfn &= (PAGES_PER_SECTION-1);
359#else
360 pfn = pfn - pageblock_start_pfn(page_zone(page)->zone_start_pfn);
361#endif /* CONFIG_SPARSEMEM */
362 return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
363}
364
365/**
366 * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages
367 * @page: The page within the block of interest
368 * @pfn: The target page frame number
369 * @mask: mask of bits that the caller is interested in
370 *
371 * Return: pageblock_bits flags
372 */
373unsigned long get_pfnblock_flags_mask(const struct page *page,
374 unsigned long pfn, unsigned long mask)
375{
376 unsigned long *bitmap;
377 unsigned long bitidx, word_bitidx;
378 unsigned long word;
379
380 bitmap = get_pageblock_bitmap(page, pfn);
381 bitidx = pfn_to_bitidx(page, pfn);
382 word_bitidx = bitidx / BITS_PER_LONG;
383 bitidx &= (BITS_PER_LONG-1);
384 /*
385 * This races, without locks, with set_pfnblock_flags_mask(). Ensure
386 * a consistent read of the memory array, so that results, even though
387 * racy, are not corrupted.
388 */
389 word = READ_ONCE(bitmap[word_bitidx]);
390 return (word >> bitidx) & mask;
391}
392
393static __always_inline int get_pfnblock_migratetype(const struct page *page,
394 unsigned long pfn)
395{
396 return get_pfnblock_flags_mask(page, pfn, MIGRATETYPE_MASK);
397}
398
399/**
400 * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages
401 * @page: The page within the block of interest
402 * @flags: The flags to set
403 * @pfn: The target page frame number
404 * @mask: mask of bits that the caller is interested in
405 */
406void set_pfnblock_flags_mask(struct page *page, unsigned long flags,
407 unsigned long pfn,
408 unsigned long mask)
409{
410 unsigned long *bitmap;
411 unsigned long bitidx, word_bitidx;
412 unsigned long word;
413
414 BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4);
415 BUILD_BUG_ON(MIGRATE_TYPES > (1 << PB_migratetype_bits));
416
417 bitmap = get_pageblock_bitmap(page, pfn);
418 bitidx = pfn_to_bitidx(page, pfn);
419 word_bitidx = bitidx / BITS_PER_LONG;
420 bitidx &= (BITS_PER_LONG-1);
421
422 VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
423
424 mask <<= bitidx;
425 flags <<= bitidx;
426
427 word = READ_ONCE(bitmap[word_bitidx]);
428 do {
429 } while (!try_cmpxchg(&bitmap[word_bitidx], &word, (word & ~mask) | flags));
430}
431
432void set_pageblock_migratetype(struct page *page, int migratetype)
433{
434 if (unlikely(page_group_by_mobility_disabled &&
435 migratetype < MIGRATE_PCPTYPES))
436 migratetype = MIGRATE_UNMOVABLE;
437
438 set_pfnblock_flags_mask(page, (unsigned long)migratetype,
439 page_to_pfn(page), MIGRATETYPE_MASK);
440}
441
442#ifdef CONFIG_DEBUG_VM
443static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
444{
445 int ret;
446 unsigned seq;
447 unsigned long pfn = page_to_pfn(page);
448 unsigned long sp, start_pfn;
449
450 do {
451 seq = zone_span_seqbegin(zone);
452 start_pfn = zone->zone_start_pfn;
453 sp = zone->spanned_pages;
454 ret = !zone_spans_pfn(zone, pfn);
455 } while (zone_span_seqretry(zone, seq));
456
457 if (ret)
458 pr_err("page 0x%lx outside node %d zone %s [ 0x%lx - 0x%lx ]\n",
459 pfn, zone_to_nid(zone), zone->name,
460 start_pfn, start_pfn + sp);
461
462 return ret;
463}
464
465/*
466 * Temporary debugging check for pages not lying within a given zone.
467 */
468static bool __maybe_unused bad_range(struct zone *zone, struct page *page)
469{
470 if (page_outside_zone_boundaries(zone, page))
471 return true;
472 if (zone != page_zone(page))
473 return true;
474
475 return false;
476}
477#else
478static inline bool __maybe_unused bad_range(struct zone *zone, struct page *page)
479{
480 return false;
481}
482#endif
483
484static void bad_page(struct page *page, const char *reason)
485{
486 static unsigned long resume;
487 static unsigned long nr_shown;
488 static unsigned long nr_unshown;
489
490 /*
491 * Allow a burst of 60 reports, then keep quiet for that minute;
492 * or allow a steady drip of one report per second.
493 */
494 if (nr_shown == 60) {
495 if (time_before(jiffies, resume)) {
496 nr_unshown++;
497 goto out;
498 }
499 if (nr_unshown) {
500 pr_alert(
501 "BUG: Bad page state: %lu messages suppressed\n",
502 nr_unshown);
503 nr_unshown = 0;
504 }
505 nr_shown = 0;
506 }
507 if (nr_shown++ == 0)
508 resume = jiffies + 60 * HZ;
509
510 pr_alert("BUG: Bad page state in process %s pfn:%05lx\n",
511 current->comm, page_to_pfn(page));
512 dump_page(page, reason);
513
514 print_modules();
515 dump_stack();
516out:
517 /* Leave bad fields for debug, except PageBuddy could make trouble */
518 page_mapcount_reset(page); /* remove PageBuddy */
519 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
520}
521
522static inline unsigned int order_to_pindex(int migratetype, int order)
523{
524#ifdef CONFIG_TRANSPARENT_HUGEPAGE
525 if (order > PAGE_ALLOC_COSTLY_ORDER) {
526 VM_BUG_ON(order != pageblock_order);
527 return NR_LOWORDER_PCP_LISTS;
528 }
529#else
530 VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER);
531#endif
532
533 return (MIGRATE_PCPTYPES * order) + migratetype;
534}
535
536static inline int pindex_to_order(unsigned int pindex)
537{
538 int order = pindex / MIGRATE_PCPTYPES;
539
540#ifdef CONFIG_TRANSPARENT_HUGEPAGE
541 if (pindex == NR_LOWORDER_PCP_LISTS)
542 order = pageblock_order;
543#else
544 VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER);
545#endif
546
547 return order;
548}
549
550static inline bool pcp_allowed_order(unsigned int order)
551{
552 if (order <= PAGE_ALLOC_COSTLY_ORDER)
553 return true;
554#ifdef CONFIG_TRANSPARENT_HUGEPAGE
555 if (order == pageblock_order)
556 return true;
557#endif
558 return false;
559}
560
561static inline void free_the_page(struct page *page, unsigned int order)
562{
563 if (pcp_allowed_order(order)) /* Via pcp? */
564 free_unref_page(page, order);
565 else
566 __free_pages_ok(page, order, FPI_NONE);
567}
568
569/*
570 * Higher-order pages are called "compound pages". They are structured thusly:
571 *
572 * The first PAGE_SIZE page is called the "head page" and have PG_head set.
573 *
574 * The remaining PAGE_SIZE pages are called "tail pages". PageTail() is encoded
575 * in bit 0 of page->compound_head. The rest of bits is pointer to head page.
576 *
577 * The first tail page's ->compound_order holds the order of allocation.
578 * This usage means that zero-order pages may not be compound.
579 */
580
581void prep_compound_page(struct page *page, unsigned int order)
582{
583 int i;
584 int nr_pages = 1 << order;
585
586 __SetPageHead(page);
587 for (i = 1; i < nr_pages; i++)
588 prep_compound_tail(page, i);
589
590 prep_compound_head(page, order);
591}
592
593void destroy_large_folio(struct folio *folio)
594{
595 if (folio_test_hugetlb(folio)) {
596 free_huge_folio(folio);
597 return;
598 }
599
600 if (folio_test_large_rmappable(folio))
601 folio_undo_large_rmappable(folio);
602
603 mem_cgroup_uncharge(folio);
604 free_the_page(&folio->page, folio_order(folio));
605}
606
607static inline void set_buddy_order(struct page *page, unsigned int order)
608{
609 set_page_private(page, order);
610 __SetPageBuddy(page);
611}
612
613#ifdef CONFIG_COMPACTION
614static inline struct capture_control *task_capc(struct zone *zone)
615{
616 struct capture_control *capc = current->capture_control;
617
618 return unlikely(capc) &&
619 !(current->flags & PF_KTHREAD) &&
620 !capc->page &&
621 capc->cc->zone == zone ? capc : NULL;
622}
623
624static inline bool
625compaction_capture(struct capture_control *capc, struct page *page,
626 int order, int migratetype)
627{
628 if (!capc || order != capc->cc->order)
629 return false;
630
631 /* Do not accidentally pollute CMA or isolated regions*/
632 if (is_migrate_cma(migratetype) ||
633 is_migrate_isolate(migratetype))
634 return false;
635
636 /*
637 * Do not let lower order allocations pollute a movable pageblock.
638 * This might let an unmovable request use a reclaimable pageblock
639 * and vice-versa but no more than normal fallback logic which can
640 * have trouble finding a high-order free page.
641 */
642 if (order < pageblock_order && migratetype == MIGRATE_MOVABLE)
643 return false;
644
645 capc->page = page;
646 return true;
647}
648
649#else
650static inline struct capture_control *task_capc(struct zone *zone)
651{
652 return NULL;
653}
654
655static inline bool
656compaction_capture(struct capture_control *capc, struct page *page,
657 int order, int migratetype)
658{
659 return false;
660}
661#endif /* CONFIG_COMPACTION */
662
663/* Used for pages not on another list */
664static inline void add_to_free_list(struct page *page, struct zone *zone,
665 unsigned int order, int migratetype)
666{
667 struct free_area *area = &zone->free_area[order];
668
669 list_add(&page->buddy_list, &area->free_list[migratetype]);
670 area->nr_free++;
671}
672
673/* Used for pages not on another list */
674static inline void add_to_free_list_tail(struct page *page, struct zone *zone,
675 unsigned int order, int migratetype)
676{
677 struct free_area *area = &zone->free_area[order];
678
679 list_add_tail(&page->buddy_list, &area->free_list[migratetype]);
680 area->nr_free++;
681}
682
683/*
684 * Used for pages which are on another list. Move the pages to the tail
685 * of the list - so the moved pages won't immediately be considered for
686 * allocation again (e.g., optimization for memory onlining).
687 */
688static inline void move_to_free_list(struct page *page, struct zone *zone,
689 unsigned int order, int migratetype)
690{
691 struct free_area *area = &zone->free_area[order];
692
693 list_move_tail(&page->buddy_list, &area->free_list[migratetype]);
694}
695
696static inline void del_page_from_free_list(struct page *page, struct zone *zone,
697 unsigned int order)
698{
699 /* clear reported state and update reported page count */
700 if (page_reported(page))
701 __ClearPageReported(page);
702
703 list_del(&page->buddy_list);
704 __ClearPageBuddy(page);
705 set_page_private(page, 0);
706 zone->free_area[order].nr_free--;
707}
708
709static inline struct page *get_page_from_free_area(struct free_area *area,
710 int migratetype)
711{
712 return list_first_entry_or_null(&area->free_list[migratetype],
713 struct page, buddy_list);
714}
715
716/*
717 * If this is not the largest possible page, check if the buddy
718 * of the next-highest order is free. If it is, it's possible
719 * that pages are being freed that will coalesce soon. In case,
720 * that is happening, add the free page to the tail of the list
721 * so it's less likely to be used soon and more likely to be merged
722 * as a higher order page
723 */
724static inline bool
725buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn,
726 struct page *page, unsigned int order)
727{
728 unsigned long higher_page_pfn;
729 struct page *higher_page;
730
731 if (order >= MAX_PAGE_ORDER - 1)
732 return false;
733
734 higher_page_pfn = buddy_pfn & pfn;
735 higher_page = page + (higher_page_pfn - pfn);
736
737 return find_buddy_page_pfn(higher_page, higher_page_pfn, order + 1,
738 NULL) != NULL;
739}
740
741/*
742 * Freeing function for a buddy system allocator.
743 *
744 * The concept of a buddy system is to maintain direct-mapped table
745 * (containing bit values) for memory blocks of various "orders".
746 * The bottom level table contains the map for the smallest allocatable
747 * units of memory (here, pages), and each level above it describes
748 * pairs of units from the levels below, hence, "buddies".
749 * At a high level, all that happens here is marking the table entry
750 * at the bottom level available, and propagating the changes upward
751 * as necessary, plus some accounting needed to play nicely with other
752 * parts of the VM system.
753 * At each level, we keep a list of pages, which are heads of continuous
754 * free pages of length of (1 << order) and marked with PageBuddy.
755 * Page's order is recorded in page_private(page) field.
756 * So when we are allocating or freeing one, we can derive the state of the
757 * other. That is, if we allocate a small block, and both were
758 * free, the remainder of the region must be split into blocks.
759 * If a block is freed, and its buddy is also free, then this
760 * triggers coalescing into a block of larger size.
761 *
762 * -- nyc
763 */
764
765static inline void __free_one_page(struct page *page,
766 unsigned long pfn,
767 struct zone *zone, unsigned int order,
768 int migratetype, fpi_t fpi_flags)
769{
770 struct capture_control *capc = task_capc(zone);
771 unsigned long buddy_pfn = 0;
772 unsigned long combined_pfn;
773 struct page *buddy;
774 bool to_tail;
775
776 VM_BUG_ON(!zone_is_initialized(zone));
777 VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page);
778
779 VM_BUG_ON(migratetype == -1);
780 if (likely(!is_migrate_isolate(migratetype)))
781 __mod_zone_freepage_state(zone, 1 << order, migratetype);
782
783 VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page);
784 VM_BUG_ON_PAGE(bad_range(zone, page), page);
785
786 while (order < MAX_PAGE_ORDER) {
787 if (compaction_capture(capc, page, order, migratetype)) {
788 __mod_zone_freepage_state(zone, -(1 << order),
789 migratetype);
790 return;
791 }
792
793 buddy = find_buddy_page_pfn(page, pfn, order, &buddy_pfn);
794 if (!buddy)
795 goto done_merging;
796
797 if (unlikely(order >= pageblock_order)) {
798 /*
799 * We want to prevent merge between freepages on pageblock
800 * without fallbacks and normal pageblock. Without this,
801 * pageblock isolation could cause incorrect freepage or CMA
802 * accounting or HIGHATOMIC accounting.
803 */
804 int buddy_mt = get_pfnblock_migratetype(buddy, buddy_pfn);
805
806 if (migratetype != buddy_mt
807 && (!migratetype_is_mergeable(migratetype) ||
808 !migratetype_is_mergeable(buddy_mt)))
809 goto done_merging;
810 }
811
812 /*
813 * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
814 * merge with it and move up one order.
815 */
816 if (page_is_guard(buddy))
817 clear_page_guard(zone, buddy, order, migratetype);
818 else
819 del_page_from_free_list(buddy, zone, order);
820 combined_pfn = buddy_pfn & pfn;
821 page = page + (combined_pfn - pfn);
822 pfn = combined_pfn;
823 order++;
824 }
825
826done_merging:
827 set_buddy_order(page, order);
828
829 if (fpi_flags & FPI_TO_TAIL)
830 to_tail = true;
831 else if (is_shuffle_order(order))
832 to_tail = shuffle_pick_tail();
833 else
834 to_tail = buddy_merge_likely(pfn, buddy_pfn, page, order);
835
836 if (to_tail)
837 add_to_free_list_tail(page, zone, order, migratetype);
838 else
839 add_to_free_list(page, zone, order, migratetype);
840
841 /* Notify page reporting subsystem of freed page */
842 if (!(fpi_flags & FPI_SKIP_REPORT_NOTIFY))
843 page_reporting_notify_free(order);
844}
845
846/**
847 * split_free_page() -- split a free page at split_pfn_offset
848 * @free_page: the original free page
849 * @order: the order of the page
850 * @split_pfn_offset: split offset within the page
851 *
852 * Return -ENOENT if the free page is changed, otherwise 0
853 *
854 * It is used when the free page crosses two pageblocks with different migratetypes
855 * at split_pfn_offset within the page. The split free page will be put into
856 * separate migratetype lists afterwards. Otherwise, the function achieves
857 * nothing.
858 */
859int split_free_page(struct page *free_page,
860 unsigned int order, unsigned long split_pfn_offset)
861{
862 struct zone *zone = page_zone(free_page);
863 unsigned long free_page_pfn = page_to_pfn(free_page);
864 unsigned long pfn;
865 unsigned long flags;
866 int free_page_order;
867 int mt;
868 int ret = 0;
869
870 if (split_pfn_offset == 0)
871 return ret;
872
873 spin_lock_irqsave(&zone->lock, flags);
874
875 if (!PageBuddy(free_page) || buddy_order(free_page) != order) {
876 ret = -ENOENT;
877 goto out;
878 }
879
880 mt = get_pfnblock_migratetype(free_page, free_page_pfn);
881 if (likely(!is_migrate_isolate(mt)))
882 __mod_zone_freepage_state(zone, -(1UL << order), mt);
883
884 del_page_from_free_list(free_page, zone, order);
885 for (pfn = free_page_pfn;
886 pfn < free_page_pfn + (1UL << order);) {
887 int mt = get_pfnblock_migratetype(pfn_to_page(pfn), pfn);
888
889 free_page_order = min_t(unsigned int,
890 pfn ? __ffs(pfn) : order,
891 __fls(split_pfn_offset));
892 __free_one_page(pfn_to_page(pfn), pfn, zone, free_page_order,
893 mt, FPI_NONE);
894 pfn += 1UL << free_page_order;
895 split_pfn_offset -= (1UL << free_page_order);
896 /* we have done the first part, now switch to second part */
897 if (split_pfn_offset == 0)
898 split_pfn_offset = (1UL << order) - (pfn - free_page_pfn);
899 }
900out:
901 spin_unlock_irqrestore(&zone->lock, flags);
902 return ret;
903}
904/*
905 * A bad page could be due to a number of fields. Instead of multiple branches,
906 * try and check multiple fields with one check. The caller must do a detailed
907 * check if necessary.
908 */
909static inline bool page_expected_state(struct page *page,
910 unsigned long check_flags)
911{
912 if (unlikely(atomic_read(&page->_mapcount) != -1))
913 return false;
914
915 if (unlikely((unsigned long)page->mapping |
916 page_ref_count(page) |
917#ifdef CONFIG_MEMCG
918 page->memcg_data |
919#endif
920#ifdef CONFIG_PAGE_POOL
921 ((page->pp_magic & ~0x3UL) == PP_SIGNATURE) |
922#endif
923 (page->flags & check_flags)))
924 return false;
925
926 return true;
927}
928
929static const char *page_bad_reason(struct page *page, unsigned long flags)
930{
931 const char *bad_reason = NULL;
932
933 if (unlikely(atomic_read(&page->_mapcount) != -1))
934 bad_reason = "nonzero mapcount";
935 if (unlikely(page->mapping != NULL))
936 bad_reason = "non-NULL mapping";
937 if (unlikely(page_ref_count(page) != 0))
938 bad_reason = "nonzero _refcount";
939 if (unlikely(page->flags & flags)) {
940 if (flags == PAGE_FLAGS_CHECK_AT_PREP)
941 bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag(s) set";
942 else
943 bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
944 }
945#ifdef CONFIG_MEMCG
946 if (unlikely(page->memcg_data))
947 bad_reason = "page still charged to cgroup";
948#endif
949#ifdef CONFIG_PAGE_POOL
950 if (unlikely((page->pp_magic & ~0x3UL) == PP_SIGNATURE))
951 bad_reason = "page_pool leak";
952#endif
953 return bad_reason;
954}
955
956static void free_page_is_bad_report(struct page *page)
957{
958 bad_page(page,
959 page_bad_reason(page, PAGE_FLAGS_CHECK_AT_FREE));
960}
961
962static inline bool free_page_is_bad(struct page *page)
963{
964 if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE)))
965 return false;
966
967 /* Something has gone sideways, find it */
968 free_page_is_bad_report(page);
969 return true;
970}
971
972static inline bool is_check_pages_enabled(void)
973{
974 return static_branch_unlikely(&check_pages_enabled);
975}
976
977static int free_tail_page_prepare(struct page *head_page, struct page *page)
978{
979 struct folio *folio = (struct folio *)head_page;
980 int ret = 1;
981
982 /*
983 * We rely page->lru.next never has bit 0 set, unless the page
984 * is PageTail(). Let's make sure that's true even for poisoned ->lru.
985 */
986 BUILD_BUG_ON((unsigned long)LIST_POISON1 & 1);
987
988 if (!is_check_pages_enabled()) {
989 ret = 0;
990 goto out;
991 }
992 switch (page - head_page) {
993 case 1:
994 /* the first tail page: these may be in place of ->mapping */
995 if (unlikely(folio_entire_mapcount(folio))) {
996 bad_page(page, "nonzero entire_mapcount");
997 goto out;
998 }
999 if (unlikely(atomic_read(&folio->_nr_pages_mapped))) {
1000 bad_page(page, "nonzero nr_pages_mapped");
1001 goto out;
1002 }
1003 if (unlikely(atomic_read(&folio->_pincount))) {
1004 bad_page(page, "nonzero pincount");
1005 goto out;
1006 }
1007 break;
1008 case 2:
1009 /*
1010 * the second tail page: ->mapping is
1011 * deferred_list.next -- ignore value.
1012 */
1013 break;
1014 default:
1015 if (page->mapping != TAIL_MAPPING) {
1016 bad_page(page, "corrupted mapping in tail page");
1017 goto out;
1018 }
1019 break;
1020 }
1021 if (unlikely(!PageTail(page))) {
1022 bad_page(page, "PageTail not set");
1023 goto out;
1024 }
1025 if (unlikely(compound_head(page) != head_page)) {
1026 bad_page(page, "compound_head not consistent");
1027 goto out;
1028 }
1029 ret = 0;
1030out:
1031 page->mapping = NULL;
1032 clear_compound_head(page);
1033 return ret;
1034}
1035
1036/*
1037 * Skip KASAN memory poisoning when either:
1038 *
1039 * 1. For generic KASAN: deferred memory initialization has not yet completed.
1040 * Tag-based KASAN modes skip pages freed via deferred memory initialization
1041 * using page tags instead (see below).
1042 * 2. For tag-based KASAN modes: the page has a match-all KASAN tag, indicating
1043 * that error detection is disabled for accesses via the page address.
1044 *
1045 * Pages will have match-all tags in the following circumstances:
1046 *
1047 * 1. Pages are being initialized for the first time, including during deferred
1048 * memory init; see the call to page_kasan_tag_reset in __init_single_page.
1049 * 2. The allocation was not unpoisoned due to __GFP_SKIP_KASAN, with the
1050 * exception of pages unpoisoned by kasan_unpoison_vmalloc.
1051 * 3. The allocation was excluded from being checked due to sampling,
1052 * see the call to kasan_unpoison_pages.
1053 *
1054 * Poisoning pages during deferred memory init will greatly lengthen the
1055 * process and cause problem in large memory systems as the deferred pages
1056 * initialization is done with interrupt disabled.
1057 *
1058 * Assuming that there will be no reference to those newly initialized
1059 * pages before they are ever allocated, this should have no effect on
1060 * KASAN memory tracking as the poison will be properly inserted at page
1061 * allocation time. The only corner case is when pages are allocated by
1062 * on-demand allocation and then freed again before the deferred pages
1063 * initialization is done, but this is not likely to happen.
1064 */
1065static inline bool should_skip_kasan_poison(struct page *page)
1066{
1067 if (IS_ENABLED(CONFIG_KASAN_GENERIC))
1068 return deferred_pages_enabled();
1069
1070 return page_kasan_tag(page) == KASAN_TAG_KERNEL;
1071}
1072
1073static void kernel_init_pages(struct page *page, int numpages)
1074{
1075 int i;
1076
1077 /* s390's use of memset() could override KASAN redzones. */
1078 kasan_disable_current();
1079 for (i = 0; i < numpages; i++)
1080 clear_highpage_kasan_tagged(page + i);
1081 kasan_enable_current();
1082}
1083
1084__always_inline bool free_pages_prepare(struct page *page,
1085 unsigned int order)
1086{
1087 int bad = 0;
1088 bool skip_kasan_poison = should_skip_kasan_poison(page);
1089 bool init = want_init_on_free();
1090 bool compound = PageCompound(page);
1091
1092 VM_BUG_ON_PAGE(PageTail(page), page);
1093
1094 trace_mm_page_free(page, order);
1095 kmsan_free_page(page, order);
1096
1097 if (memcg_kmem_online() && PageMemcgKmem(page))
1098 __memcg_kmem_uncharge_page(page, order);
1099
1100 if (unlikely(PageHWPoison(page)) && !order) {
1101 /* Do not let hwpoison pages hit pcplists/buddy */
1102 reset_page_owner(page, order);
1103 page_table_check_free(page, order);
1104 return false;
1105 }
1106
1107 VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);
1108
1109 /*
1110 * Check tail pages before head page information is cleared to
1111 * avoid checking PageCompound for order-0 pages.
1112 */
1113 if (unlikely(order)) {
1114 int i;
1115
1116 if (compound)
1117 page[1].flags &= ~PAGE_FLAGS_SECOND;
1118 for (i = 1; i < (1 << order); i++) {
1119 if (compound)
1120 bad += free_tail_page_prepare(page, page + i);
1121 if (is_check_pages_enabled()) {
1122 if (free_page_is_bad(page + i)) {
1123 bad++;
1124 continue;
1125 }
1126 }
1127 (page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
1128 }
1129 }
1130 if (PageMappingFlags(page))
1131 page->mapping = NULL;
1132 if (is_check_pages_enabled()) {
1133 if (free_page_is_bad(page))
1134 bad++;
1135 if (bad)
1136 return false;
1137 }
1138
1139 page_cpupid_reset_last(page);
1140 page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
1141 reset_page_owner(page, order);
1142 page_table_check_free(page, order);
1143
1144 if (!PageHighMem(page)) {
1145 debug_check_no_locks_freed(page_address(page),
1146 PAGE_SIZE << order);
1147 debug_check_no_obj_freed(page_address(page),
1148 PAGE_SIZE << order);
1149 }
1150
1151 kernel_poison_pages(page, 1 << order);
1152
1153 /*
1154 * As memory initialization might be integrated into KASAN,
1155 * KASAN poisoning and memory initialization code must be
1156 * kept together to avoid discrepancies in behavior.
1157 *
1158 * With hardware tag-based KASAN, memory tags must be set before the
1159 * page becomes unavailable via debug_pagealloc or arch_free_page.
1160 */
1161 if (!skip_kasan_poison) {
1162 kasan_poison_pages(page, order, init);
1163
1164 /* Memory is already initialized if KASAN did it internally. */
1165 if (kasan_has_integrated_init())
1166 init = false;
1167 }
1168 if (init)
1169 kernel_init_pages(page, 1 << order);
1170
1171 /*
1172 * arch_free_page() can make the page's contents inaccessible. s390
1173 * does this. So nothing which can access the page's contents should
1174 * happen after this.
1175 */
1176 arch_free_page(page, order);
1177
1178 debug_pagealloc_unmap_pages(page, 1 << order);
1179
1180 return true;
1181}
1182
1183/*
1184 * Frees a number of pages from the PCP lists
1185 * Assumes all pages on list are in same zone.
1186 * count is the number of pages to free.
1187 */
1188static void free_pcppages_bulk(struct zone *zone, int count,
1189 struct per_cpu_pages *pcp,
1190 int pindex)
1191{
1192 unsigned long flags;
1193 unsigned int order;
1194 bool isolated_pageblocks;
1195 struct page *page;
1196
1197 /*
1198 * Ensure proper count is passed which otherwise would stuck in the
1199 * below while (list_empty(list)) loop.
1200 */
1201 count = min(pcp->count, count);
1202
1203 /* Ensure requested pindex is drained first. */
1204 pindex = pindex - 1;
1205
1206 spin_lock_irqsave(&zone->lock, flags);
1207 isolated_pageblocks = has_isolate_pageblock(zone);
1208
1209 while (count > 0) {
1210 struct list_head *list;
1211 int nr_pages;
1212
1213 /* Remove pages from lists in a round-robin fashion. */
1214 do {
1215 if (++pindex > NR_PCP_LISTS - 1)
1216 pindex = 0;
1217 list = &pcp->lists[pindex];
1218 } while (list_empty(list));
1219
1220 order = pindex_to_order(pindex);
1221 nr_pages = 1 << order;
1222 do {
1223 int mt;
1224
1225 page = list_last_entry(list, struct page, pcp_list);
1226 mt = get_pcppage_migratetype(page);
1227
1228 /* must delete to avoid corrupting pcp list */
1229 list_del(&page->pcp_list);
1230 count -= nr_pages;
1231 pcp->count -= nr_pages;
1232
1233 /* MIGRATE_ISOLATE page should not go to pcplists */
1234 VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
1235 /* Pageblock could have been isolated meanwhile */
1236 if (unlikely(isolated_pageblocks))
1237 mt = get_pageblock_migratetype(page);
1238
1239 __free_one_page(page, page_to_pfn(page), zone, order, mt, FPI_NONE);
1240 trace_mm_page_pcpu_drain(page, order, mt);
1241 } while (count > 0 && !list_empty(list));
1242 }
1243
1244 spin_unlock_irqrestore(&zone->lock, flags);
1245}
1246
1247static void free_one_page(struct zone *zone,
1248 struct page *page, unsigned long pfn,
1249 unsigned int order,
1250 int migratetype, fpi_t fpi_flags)
1251{
1252 unsigned long flags;
1253
1254 spin_lock_irqsave(&zone->lock, flags);
1255 if (unlikely(has_isolate_pageblock(zone) ||
1256 is_migrate_isolate(migratetype))) {
1257 migratetype = get_pfnblock_migratetype(page, pfn);
1258 }
1259 __free_one_page(page, pfn, zone, order, migratetype, fpi_flags);
1260 spin_unlock_irqrestore(&zone->lock, flags);
1261}
1262
1263static void __free_pages_ok(struct page *page, unsigned int order,
1264 fpi_t fpi_flags)
1265{
1266 int migratetype;
1267 unsigned long pfn = page_to_pfn(page);
1268 struct zone *zone = page_zone(page);
1269
1270 if (!free_pages_prepare(page, order))
1271 return;
1272
1273 /*
1274 * Calling get_pfnblock_migratetype() without spin_lock_irqsave() here
1275 * is used to avoid calling get_pfnblock_migratetype() under the lock.
1276 * This will reduce the lock holding time.
1277 */
1278 migratetype = get_pfnblock_migratetype(page, pfn);
1279
1280 free_one_page(zone, page, pfn, order, migratetype, fpi_flags);
1281
1282 __count_vm_events(PGFREE, 1 << order);
1283}
1284
1285void __free_pages_core(struct page *page, unsigned int order)
1286{
1287 unsigned int nr_pages = 1 << order;
1288 struct page *p = page;
1289 unsigned int loop;
1290
1291 /*
1292 * When initializing the memmap, __init_single_page() sets the refcount
1293 * of all pages to 1 ("allocated"/"not free"). We have to set the
1294 * refcount of all involved pages to 0.
1295 */
1296 prefetchw(p);
1297 for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
1298 prefetchw(p + 1);
1299 __ClearPageReserved(p);
1300 set_page_count(p, 0);
1301 }
1302 __ClearPageReserved(p);
1303 set_page_count(p, 0);
1304
1305 atomic_long_add(nr_pages, &page_zone(page)->managed_pages);
1306
1307 if (page_contains_unaccepted(page, order)) {
1308 if (order == MAX_PAGE_ORDER && __free_unaccepted(page))
1309 return;
1310
1311 accept_page(page, order);
1312 }
1313
1314 /*
1315 * Bypass PCP and place fresh pages right to the tail, primarily
1316 * relevant for memory onlining.
1317 */
1318 __free_pages_ok(page, order, FPI_TO_TAIL);
1319}
1320
1321/*
1322 * Check that the whole (or subset of) a pageblock given by the interval of
1323 * [start_pfn, end_pfn) is valid and within the same zone, before scanning it
1324 * with the migration of free compaction scanner.
1325 *
1326 * Return struct page pointer of start_pfn, or NULL if checks were not passed.
1327 *
1328 * It's possible on some configurations to have a setup like node0 node1 node0
1329 * i.e. it's possible that all pages within a zones range of pages do not
1330 * belong to a single zone. We assume that a border between node0 and node1
1331 * can occur within a single pageblock, but not a node0 node1 node0
1332 * interleaving within a single pageblock. It is therefore sufficient to check
1333 * the first and last page of a pageblock and avoid checking each individual
1334 * page in a pageblock.
1335 *
1336 * Note: the function may return non-NULL struct page even for a page block
1337 * which contains a memory hole (i.e. there is no physical memory for a subset
1338 * of the pfn range). For example, if the pageblock order is MAX_PAGE_ORDER, which
1339 * will fall into 2 sub-sections, and the end pfn of the pageblock may be hole
1340 * even though the start pfn is online and valid. This should be safe most of
1341 * the time because struct pages are still initialized via init_unavailable_range()
1342 * and pfn walkers shouldn't touch any physical memory range for which they do
1343 * not recognize any specific metadata in struct pages.
1344 */
1345struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
1346 unsigned long end_pfn, struct zone *zone)
1347{
1348 struct page *start_page;
1349 struct page *end_page;
1350
1351 /* end_pfn is one past the range we are checking */
1352 end_pfn--;
1353
1354 if (!pfn_valid(end_pfn))
1355 return NULL;
1356
1357 start_page = pfn_to_online_page(start_pfn);
1358 if (!start_page)
1359 return NULL;
1360
1361 if (page_zone(start_page) != zone)
1362 return NULL;
1363
1364 end_page = pfn_to_page(end_pfn);
1365
1366 /* This gives a shorter code than deriving page_zone(end_page) */
1367 if (page_zone_id(start_page) != page_zone_id(end_page))
1368 return NULL;
1369
1370 return start_page;
1371}
1372
1373/*
1374 * The order of subdivision here is critical for the IO subsystem.
1375 * Please do not alter this order without good reasons and regression
1376 * testing. Specifically, as large blocks of memory are subdivided,
1377 * the order in which smaller blocks are delivered depends on the order
1378 * they're subdivided in this function. This is the primary factor
1379 * influencing the order in which pages are delivered to the IO
1380 * subsystem according to empirical testing, and this is also justified
1381 * by considering the behavior of a buddy system containing a single
1382 * large block of memory acted on by a series of small allocations.
1383 * This behavior is a critical factor in sglist merging's success.
1384 *
1385 * -- nyc
1386 */
1387static inline void expand(struct zone *zone, struct page *page,
1388 int low, int high, int migratetype)
1389{
1390 unsigned long size = 1 << high;
1391
1392 while (high > low) {
1393 high--;
1394 size >>= 1;
1395 VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]);
1396
1397 /*
1398 * Mark as guard pages (or page), that will allow to
1399 * merge back to allocator when buddy will be freed.
1400 * Corresponding page table entries will not be touched,
1401 * pages will stay not present in virtual address space
1402 */
1403 if (set_page_guard(zone, &page[size], high, migratetype))
1404 continue;
1405
1406 add_to_free_list(&page[size], zone, high, migratetype);
1407 set_buddy_order(&page[size], high);
1408 }
1409}
1410
1411static void check_new_page_bad(struct page *page)
1412{
1413 if (unlikely(page->flags & __PG_HWPOISON)) {
1414 /* Don't complain about hwpoisoned pages */
1415 page_mapcount_reset(page); /* remove PageBuddy */
1416 return;
1417 }
1418
1419 bad_page(page,
1420 page_bad_reason(page, PAGE_FLAGS_CHECK_AT_PREP));
1421}
1422
1423/*
1424 * This page is about to be returned from the page allocator
1425 */
1426static bool check_new_page(struct page *page)
1427{
1428 if (likely(page_expected_state(page,
1429 PAGE_FLAGS_CHECK_AT_PREP|__PG_HWPOISON)))
1430 return false;
1431
1432 check_new_page_bad(page);
1433 return true;
1434}
1435
1436static inline bool check_new_pages(struct page *page, unsigned int order)
1437{
1438 if (is_check_pages_enabled()) {
1439 for (int i = 0; i < (1 << order); i++) {
1440 struct page *p = page + i;
1441
1442 if (check_new_page(p))
1443 return true;
1444 }
1445 }
1446
1447 return false;
1448}
1449
1450static inline bool should_skip_kasan_unpoison(gfp_t flags)
1451{
1452 /* Don't skip if a software KASAN mode is enabled. */
1453 if (IS_ENABLED(CONFIG_KASAN_GENERIC) ||
1454 IS_ENABLED(CONFIG_KASAN_SW_TAGS))
1455 return false;
1456
1457 /* Skip, if hardware tag-based KASAN is not enabled. */
1458 if (!kasan_hw_tags_enabled())
1459 return true;
1460
1461 /*
1462 * With hardware tag-based KASAN enabled, skip if this has been
1463 * requested via __GFP_SKIP_KASAN.
1464 */
1465 return flags & __GFP_SKIP_KASAN;
1466}
1467
1468static inline bool should_skip_init(gfp_t flags)
1469{
1470 /* Don't skip, if hardware tag-based KASAN is not enabled. */
1471 if (!kasan_hw_tags_enabled())
1472 return false;
1473
1474 /* For hardware tag-based KASAN, skip if requested. */
1475 return (flags & __GFP_SKIP_ZERO);
1476}
1477
1478inline void post_alloc_hook(struct page *page, unsigned int order,
1479 gfp_t gfp_flags)
1480{
1481 bool init = !want_init_on_free() && want_init_on_alloc(gfp_flags) &&
1482 !should_skip_init(gfp_flags);
1483 bool zero_tags = init && (gfp_flags & __GFP_ZEROTAGS);
1484 int i;
1485
1486 set_page_private(page, 0);
1487 set_page_refcounted(page);
1488
1489 arch_alloc_page(page, order);
1490 debug_pagealloc_map_pages(page, 1 << order);
1491
1492 /*
1493 * Page unpoisoning must happen before memory initialization.
1494 * Otherwise, the poison pattern will be overwritten for __GFP_ZERO
1495 * allocations and the page unpoisoning code will complain.
1496 */
1497 kernel_unpoison_pages(page, 1 << order);
1498
1499 /*
1500 * As memory initialization might be integrated into KASAN,
1501 * KASAN unpoisoning and memory initializion code must be
1502 * kept together to avoid discrepancies in behavior.
1503 */
1504
1505 /*
1506 * If memory tags should be zeroed
1507 * (which happens only when memory should be initialized as well).
1508 */
1509 if (zero_tags) {
1510 /* Initialize both memory and memory tags. */
1511 for (i = 0; i != 1 << order; ++i)
1512 tag_clear_highpage(page + i);
1513
1514 /* Take note that memory was initialized by the loop above. */
1515 init = false;
1516 }
1517 if (!should_skip_kasan_unpoison(gfp_flags) &&
1518 kasan_unpoison_pages(page, order, init)) {
1519 /* Take note that memory was initialized by KASAN. */
1520 if (kasan_has_integrated_init())
1521 init = false;
1522 } else {
1523 /*
1524 * If memory tags have not been set by KASAN, reset the page
1525 * tags to ensure page_address() dereferencing does not fault.
1526 */
1527 for (i = 0; i != 1 << order; ++i)
1528 page_kasan_tag_reset(page + i);
1529 }
1530 /* If memory is still not initialized, initialize it now. */
1531 if (init)
1532 kernel_init_pages(page, 1 << order);
1533
1534 set_page_owner(page, order, gfp_flags);
1535 page_table_check_alloc(page, order);
1536}
1537
1538static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
1539 unsigned int alloc_flags)
1540{
1541 post_alloc_hook(page, order, gfp_flags);
1542
1543 if (order && (gfp_flags & __GFP_COMP))
1544 prep_compound_page(page, order);
1545
1546 /*
1547 * page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to
1548 * allocate the page. The expectation is that the caller is taking
1549 * steps that will free more memory. The caller should avoid the page
1550 * being used for !PFMEMALLOC purposes.
1551 */
1552 if (alloc_flags & ALLOC_NO_WATERMARKS)
1553 set_page_pfmemalloc(page);
1554 else
1555 clear_page_pfmemalloc(page);
1556}
1557
1558/*
1559 * Go through the free lists for the given migratetype and remove
1560 * the smallest available page from the freelists
1561 */
1562static __always_inline
1563struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
1564 int migratetype)
1565{
1566 unsigned int current_order;
1567 struct free_area *area;
1568 struct page *page;
1569
1570 /* Find a page of the appropriate size in the preferred list */
1571 for (current_order = order; current_order < NR_PAGE_ORDERS; ++current_order) {
1572 area = &(zone->free_area[current_order]);
1573 page = get_page_from_free_area(area, migratetype);
1574 if (!page)
1575 continue;
1576 del_page_from_free_list(page, zone, current_order);
1577 expand(zone, page, order, current_order, migratetype);
1578 set_pcppage_migratetype(page, migratetype);
1579 trace_mm_page_alloc_zone_locked(page, order, migratetype,
1580 pcp_allowed_order(order) &&
1581 migratetype < MIGRATE_PCPTYPES);
1582 return page;
1583 }
1584
1585 return NULL;
1586}
1587
1588
1589/*
1590 * This array describes the order lists are fallen back to when
1591 * the free lists for the desirable migrate type are depleted
1592 *
1593 * The other migratetypes do not have fallbacks.
1594 */
1595static int fallbacks[MIGRATE_TYPES][MIGRATE_PCPTYPES - 1] = {
1596 [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE },
1597 [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE },
1598 [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE },
1599};
1600
1601#ifdef CONFIG_CMA
1602static __always_inline struct page *__rmqueue_cma_fallback(struct zone *zone,
1603 unsigned int order)
1604{
1605 return __rmqueue_smallest(zone, order, MIGRATE_CMA);
1606}
1607#else
1608static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
1609 unsigned int order) { return NULL; }
1610#endif
1611
1612/*
1613 * Move the free pages in a range to the freelist tail of the requested type.
1614 * Note that start_page and end_pages are not aligned on a pageblock
1615 * boundary. If alignment is required, use move_freepages_block()
1616 */
1617static int move_freepages(struct zone *zone,
1618 unsigned long start_pfn, unsigned long end_pfn,
1619 int migratetype, int *num_movable)
1620{
1621 struct page *page;
1622 unsigned long pfn;
1623 unsigned int order;
1624 int pages_moved = 0;
1625
1626 for (pfn = start_pfn; pfn <= end_pfn;) {
1627 page = pfn_to_page(pfn);
1628 if (!PageBuddy(page)) {
1629 /*
1630 * We assume that pages that could be isolated for
1631 * migration are movable. But we don't actually try
1632 * isolating, as that would be expensive.
1633 */
1634 if (num_movable &&
1635 (PageLRU(page) || __PageMovable(page)))
1636 (*num_movable)++;
1637 pfn++;
1638 continue;
1639 }
1640
1641 /* Make sure we are not inadvertently changing nodes */
1642 VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
1643 VM_BUG_ON_PAGE(page_zone(page) != zone, page);
1644
1645 order = buddy_order(page);
1646 move_to_free_list(page, zone, order, migratetype);
1647 pfn += 1 << order;
1648 pages_moved += 1 << order;
1649 }
1650
1651 return pages_moved;
1652}
1653
1654int move_freepages_block(struct zone *zone, struct page *page,
1655 int migratetype, int *num_movable)
1656{
1657 unsigned long start_pfn, end_pfn, pfn;
1658
1659 if (num_movable)
1660 *num_movable = 0;
1661
1662 pfn = page_to_pfn(page);
1663 start_pfn = pageblock_start_pfn(pfn);
1664 end_pfn = pageblock_end_pfn(pfn) - 1;
1665
1666 /* Do not cross zone boundaries */
1667 if (!zone_spans_pfn(zone, start_pfn))
1668 start_pfn = pfn;
1669 if (!zone_spans_pfn(zone, end_pfn))
1670 return 0;
1671
1672 return move_freepages(zone, start_pfn, end_pfn, migratetype,
1673 num_movable);
1674}
1675
1676static void change_pageblock_range(struct page *pageblock_page,
1677 int start_order, int migratetype)
1678{
1679 int nr_pageblocks = 1 << (start_order - pageblock_order);
1680
1681 while (nr_pageblocks--) {
1682 set_pageblock_migratetype(pageblock_page, migratetype);
1683 pageblock_page += pageblock_nr_pages;
1684 }
1685}
1686
1687/*
1688 * When we are falling back to another migratetype during allocation, try to
1689 * steal extra free pages from the same pageblocks to satisfy further
1690 * allocations, instead of polluting multiple pageblocks.
1691 *
1692 * If we are stealing a relatively large buddy page, it is likely there will
1693 * be more free pages in the pageblock, so try to steal them all. For
1694 * reclaimable and unmovable allocations, we steal regardless of page size,
1695 * as fragmentation caused by those allocations polluting movable pageblocks
1696 * is worse than movable allocations stealing from unmovable and reclaimable
1697 * pageblocks.
1698 */
1699static bool can_steal_fallback(unsigned int order, int start_mt)
1700{
1701 /*
1702 * Leaving this order check is intended, although there is
1703 * relaxed order check in next check. The reason is that
1704 * we can actually steal whole pageblock if this condition met,
1705 * but, below check doesn't guarantee it and that is just heuristic
1706 * so could be changed anytime.
1707 */
1708 if (order >= pageblock_order)
1709 return true;
1710
1711 if (order >= pageblock_order / 2 ||
1712 start_mt == MIGRATE_RECLAIMABLE ||
1713 start_mt == MIGRATE_UNMOVABLE ||
1714 page_group_by_mobility_disabled)
1715 return true;
1716
1717 return false;
1718}
1719
1720static inline bool boost_watermark(struct zone *zone)
1721{
1722 unsigned long max_boost;
1723
1724 if (!watermark_boost_factor)
1725 return false;
1726 /*
1727 * Don't bother in zones that are unlikely to produce results.
1728 * On small machines, including kdump capture kernels running
1729 * in a small area, boosting the watermark can cause an out of
1730 * memory situation immediately.
1731 */
1732 if ((pageblock_nr_pages * 4) > zone_managed_pages(zone))
1733 return false;
1734
1735 max_boost = mult_frac(zone->_watermark[WMARK_HIGH],
1736 watermark_boost_factor, 10000);
1737
1738 /*
1739 * high watermark may be uninitialised if fragmentation occurs
1740 * very early in boot so do not boost. We do not fall
1741 * through and boost by pageblock_nr_pages as failing
1742 * allocations that early means that reclaim is not going
1743 * to help and it may even be impossible to reclaim the
1744 * boosted watermark resulting in a hang.
1745 */
1746 if (!max_boost)
1747 return false;
1748
1749 max_boost = max(pageblock_nr_pages, max_boost);
1750
1751 zone->watermark_boost = min(zone->watermark_boost + pageblock_nr_pages,
1752 max_boost);
1753
1754 return true;
1755}
1756
1757/*
1758 * This function implements actual steal behaviour. If order is large enough,
1759 * we can steal whole pageblock. If not, we first move freepages in this
1760 * pageblock to our migratetype and determine how many already-allocated pages
1761 * are there in the pageblock with a compatible migratetype. If at least half
1762 * of pages are free or compatible, we can change migratetype of the pageblock
1763 * itself, so pages freed in the future will be put on the correct free list.
1764 */
1765static void steal_suitable_fallback(struct zone *zone, struct page *page,
1766 unsigned int alloc_flags, int start_type, bool whole_block)
1767{
1768 unsigned int current_order = buddy_order(page);
1769 int free_pages, movable_pages, alike_pages;
1770 int old_block_type;
1771
1772 old_block_type = get_pageblock_migratetype(page);
1773
1774 /*
1775 * This can happen due to races and we want to prevent broken
1776 * highatomic accounting.
1777 */
1778 if (is_migrate_highatomic(old_block_type))
1779 goto single_page;
1780
1781 /* Take ownership for orders >= pageblock_order */
1782 if (current_order >= pageblock_order) {
1783 change_pageblock_range(page, current_order, start_type);
1784 goto single_page;
1785 }
1786
1787 /*
1788 * Boost watermarks to increase reclaim pressure to reduce the
1789 * likelihood of future fallbacks. Wake kswapd now as the node
1790 * may be balanced overall and kswapd will not wake naturally.
1791 */
1792 if (boost_watermark(zone) && (alloc_flags & ALLOC_KSWAPD))
1793 set_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
1794
1795 /* We are not allowed to try stealing from the whole block */
1796 if (!whole_block)
1797 goto single_page;
1798
1799 free_pages = move_freepages_block(zone, page, start_type,
1800 &movable_pages);
1801 /* moving whole block can fail due to zone boundary conditions */
1802 if (!free_pages)
1803 goto single_page;
1804
1805 /*
1806 * Determine how many pages are compatible with our allocation.
1807 * For movable allocation, it's the number of movable pages which
1808 * we just obtained. For other types it's a bit more tricky.
1809 */
1810 if (start_type == MIGRATE_MOVABLE) {
1811 alike_pages = movable_pages;
1812 } else {
1813 /*
1814 * If we are falling back a RECLAIMABLE or UNMOVABLE allocation
1815 * to MOVABLE pageblock, consider all non-movable pages as
1816 * compatible. If it's UNMOVABLE falling back to RECLAIMABLE or
1817 * vice versa, be conservative since we can't distinguish the
1818 * exact migratetype of non-movable pages.
1819 */
1820 if (old_block_type == MIGRATE_MOVABLE)
1821 alike_pages = pageblock_nr_pages
1822 - (free_pages + movable_pages);
1823 else
1824 alike_pages = 0;
1825 }
1826 /*
1827 * If a sufficient number of pages in the block are either free or of
1828 * compatible migratability as our allocation, claim the whole block.
1829 */
1830 if (free_pages + alike_pages >= (1 << (pageblock_order-1)) ||
1831 page_group_by_mobility_disabled)
1832 set_pageblock_migratetype(page, start_type);
1833
1834 return;
1835
1836single_page:
1837 move_to_free_list(page, zone, current_order, start_type);
1838}
1839
1840/*
1841 * Check whether there is a suitable fallback freepage with requested order.
1842 * If only_stealable is true, this function returns fallback_mt only if
1843 * we can steal other freepages all together. This would help to reduce
1844 * fragmentation due to mixed migratetype pages in one pageblock.
1845 */
1846int find_suitable_fallback(struct free_area *area, unsigned int order,
1847 int migratetype, bool only_stealable, bool *can_steal)
1848{
1849 int i;
1850 int fallback_mt;
1851
1852 if (area->nr_free == 0)
1853 return -1;
1854
1855 *can_steal = false;
1856 for (i = 0; i < MIGRATE_PCPTYPES - 1 ; i++) {
1857 fallback_mt = fallbacks[migratetype][i];
1858 if (free_area_empty(area, fallback_mt))
1859 continue;
1860
1861 if (can_steal_fallback(order, migratetype))
1862 *can_steal = true;
1863
1864 if (!only_stealable)
1865 return fallback_mt;
1866
1867 if (*can_steal)
1868 return fallback_mt;
1869 }
1870
1871 return -1;
1872}
1873
1874/*
1875 * Reserve a pageblock for exclusive use of high-order atomic allocations if
1876 * there are no empty page blocks that contain a page with a suitable order
1877 */
1878static void reserve_highatomic_pageblock(struct page *page, struct zone *zone)
1879{
1880 int mt;
1881 unsigned long max_managed, flags;
1882
1883 /*
1884 * The number reserved as: minimum is 1 pageblock, maximum is
1885 * roughly 1% of a zone. But if 1% of a zone falls below a
1886 * pageblock size, then don't reserve any pageblocks.
1887 * Check is race-prone but harmless.
1888 */
1889 if ((zone_managed_pages(zone) / 100) < pageblock_nr_pages)
1890 return;
1891 max_managed = ALIGN((zone_managed_pages(zone) / 100), pageblock_nr_pages);
1892 if (zone->nr_reserved_highatomic >= max_managed)
1893 return;
1894
1895 spin_lock_irqsave(&zone->lock, flags);
1896
1897 /* Recheck the nr_reserved_highatomic limit under the lock */
1898 if (zone->nr_reserved_highatomic >= max_managed)
1899 goto out_unlock;
1900
1901 /* Yoink! */
1902 mt = get_pageblock_migratetype(page);
1903 /* Only reserve normal pageblocks (i.e., they can merge with others) */
1904 if (migratetype_is_mergeable(mt)) {
1905 zone->nr_reserved_highatomic += pageblock_nr_pages;
1906 set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC);
1907 move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL);
1908 }
1909
1910out_unlock:
1911 spin_unlock_irqrestore(&zone->lock, flags);
1912}
1913
1914/*
1915 * Used when an allocation is about to fail under memory pressure. This
1916 * potentially hurts the reliability of high-order allocations when under
1917 * intense memory pressure but failed atomic allocations should be easier
1918 * to recover from than an OOM.
1919 *
1920 * If @force is true, try to unreserve a pageblock even though highatomic
1921 * pageblock is exhausted.
1922 */
1923static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
1924 bool force)
1925{
1926 struct zonelist *zonelist = ac->zonelist;
1927 unsigned long flags;
1928 struct zoneref *z;
1929 struct zone *zone;
1930 struct page *page;
1931 int order;
1932 bool ret;
1933
1934 for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->highest_zoneidx,
1935 ac->nodemask) {
1936 /*
1937 * Preserve at least one pageblock unless memory pressure
1938 * is really high.
1939 */
1940 if (!force && zone->nr_reserved_highatomic <=
1941 pageblock_nr_pages)
1942 continue;
1943
1944 spin_lock_irqsave(&zone->lock, flags);
1945 for (order = 0; order < NR_PAGE_ORDERS; order++) {
1946 struct free_area *area = &(zone->free_area[order]);
1947
1948 page = get_page_from_free_area(area, MIGRATE_HIGHATOMIC);
1949 if (!page)
1950 continue;
1951
1952 /*
1953 * In page freeing path, migratetype change is racy so
1954 * we can counter several free pages in a pageblock
1955 * in this loop although we changed the pageblock type
1956 * from highatomic to ac->migratetype. So we should
1957 * adjust the count once.
1958 */
1959 if (is_migrate_highatomic_page(page)) {
1960 /*
1961 * It should never happen but changes to
1962 * locking could inadvertently allow a per-cpu
1963 * drain to add pages to MIGRATE_HIGHATOMIC
1964 * while unreserving so be safe and watch for
1965 * underflows.
1966 */
1967 zone->nr_reserved_highatomic -= min(
1968 pageblock_nr_pages,
1969 zone->nr_reserved_highatomic);
1970 }
1971
1972 /*
1973 * Convert to ac->migratetype and avoid the normal
1974 * pageblock stealing heuristics. Minimally, the caller
1975 * is doing the work and needs the pages. More
1976 * importantly, if the block was always converted to
1977 * MIGRATE_UNMOVABLE or another type then the number
1978 * of pageblocks that cannot be completely freed
1979 * may increase.
1980 */
1981 set_pageblock_migratetype(page, ac->migratetype);
1982 ret = move_freepages_block(zone, page, ac->migratetype,
1983 NULL);
1984 if (ret) {
1985 spin_unlock_irqrestore(&zone->lock, flags);
1986 return ret;
1987 }
1988 }
1989 spin_unlock_irqrestore(&zone->lock, flags);
1990 }
1991
1992 return false;
1993}
1994
1995/*
1996 * Try finding a free buddy page on the fallback list and put it on the free
1997 * list of requested migratetype, possibly along with other pages from the same
1998 * block, depending on fragmentation avoidance heuristics. Returns true if
1999 * fallback was found so that __rmqueue_smallest() can grab it.
2000 *
2001 * The use of signed ints for order and current_order is a deliberate
2002 * deviation from the rest of this file, to make the for loop
2003 * condition simpler.
2004 */
2005static __always_inline bool
2006__rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
2007 unsigned int alloc_flags)
2008{
2009 struct free_area *area;
2010 int current_order;
2011 int min_order = order;
2012 struct page *page;
2013 int fallback_mt;
2014 bool can_steal;
2015
2016 /*
2017 * Do not steal pages from freelists belonging to other pageblocks
2018 * i.e. orders < pageblock_order. If there are no local zones free,
2019 * the zonelists will be reiterated without ALLOC_NOFRAGMENT.
2020 */
2021 if (order < pageblock_order && alloc_flags & ALLOC_NOFRAGMENT)
2022 min_order = pageblock_order;
2023
2024 /*
2025 * Find the largest available free page in the other list. This roughly
2026 * approximates finding the pageblock with the most free pages, which
2027 * would be too costly to do exactly.
2028 */
2029 for (current_order = MAX_PAGE_ORDER; current_order >= min_order;
2030 --current_order) {
2031 area = &(zone->free_area[current_order]);
2032 fallback_mt = find_suitable_fallback(area, current_order,
2033 start_migratetype, false, &can_steal);
2034 if (fallback_mt == -1)
2035 continue;
2036
2037 /*
2038 * We cannot steal all free pages from the pageblock and the
2039 * requested migratetype is movable. In that case it's better to
2040 * steal and split the smallest available page instead of the
2041 * largest available page, because even if the next movable
2042 * allocation falls back into a different pageblock than this
2043 * one, it won't cause permanent fragmentation.
2044 */
2045 if (!can_steal && start_migratetype == MIGRATE_MOVABLE
2046 && current_order > order)
2047 goto find_smallest;
2048
2049 goto do_steal;
2050 }
2051
2052 return false;
2053
2054find_smallest:
2055 for (current_order = order; current_order < NR_PAGE_ORDERS; current_order++) {
2056 area = &(zone->free_area[current_order]);
2057 fallback_mt = find_suitable_fallback(area, current_order,
2058 start_migratetype, false, &can_steal);
2059 if (fallback_mt != -1)
2060 break;
2061 }
2062
2063 /*
2064 * This should not happen - we already found a suitable fallback
2065 * when looking for the largest page.
2066 */
2067 VM_BUG_ON(current_order > MAX_PAGE_ORDER);
2068
2069do_steal:
2070 page = get_page_from_free_area(area, fallback_mt);
2071
2072 steal_suitable_fallback(zone, page, alloc_flags, start_migratetype,
2073 can_steal);
2074
2075 trace_mm_page_alloc_extfrag(page, order, current_order,
2076 start_migratetype, fallback_mt);
2077
2078 return true;
2079
2080}
2081
2082/*
2083 * Do the hard work of removing an element from the buddy allocator.
2084 * Call me with the zone->lock already held.
2085 */
2086static __always_inline struct page *
2087__rmqueue(struct zone *zone, unsigned int order, int migratetype,
2088 unsigned int alloc_flags)
2089{
2090 struct page *page;
2091
2092 if (IS_ENABLED(CONFIG_CMA)) {
2093 /*
2094 * Balance movable allocations between regular and CMA areas by
2095 * allocating from CMA when over half of the zone's free memory
2096 * is in the CMA area.
2097 */
2098 if (alloc_flags & ALLOC_CMA &&
2099 zone_page_state(zone, NR_FREE_CMA_PAGES) >
2100 zone_page_state(zone, NR_FREE_PAGES) / 2) {
2101 page = __rmqueue_cma_fallback(zone, order);
2102 if (page)
2103 return page;
2104 }
2105 }
2106retry:
2107 page = __rmqueue_smallest(zone, order, migratetype);
2108 if (unlikely(!page)) {
2109 if (alloc_flags & ALLOC_CMA)
2110 page = __rmqueue_cma_fallback(zone, order);
2111
2112 if (!page && __rmqueue_fallback(zone, order, migratetype,
2113 alloc_flags))
2114 goto retry;
2115 }
2116 return page;
2117}
2118
2119/*
2120 * Obtain a specified number of elements from the buddy allocator, all under
2121 * a single hold of the lock, for efficiency. Add them to the supplied list.
2122 * Returns the number of new pages which were placed at *list.
2123 */
2124static int rmqueue_bulk(struct zone *zone, unsigned int order,
2125 unsigned long count, struct list_head *list,
2126 int migratetype, unsigned int alloc_flags)
2127{
2128 unsigned long flags;
2129 int i;
2130
2131 spin_lock_irqsave(&zone->lock, flags);
2132 for (i = 0; i < count; ++i) {
2133 struct page *page = __rmqueue(zone, order, migratetype,
2134 alloc_flags);
2135 if (unlikely(page == NULL))
2136 break;
2137
2138 /*
2139 * Split buddy pages returned by expand() are received here in
2140 * physical page order. The page is added to the tail of
2141 * caller's list. From the callers perspective, the linked list
2142 * is ordered by page number under some conditions. This is
2143 * useful for IO devices that can forward direction from the
2144 * head, thus also in the physical page order. This is useful
2145 * for IO devices that can merge IO requests if the physical
2146 * pages are ordered properly.
2147 */
2148 list_add_tail(&page->pcp_list, list);
2149 if (is_migrate_cma(get_pcppage_migratetype(page)))
2150 __mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
2151 -(1 << order));
2152 }
2153
2154 __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
2155 spin_unlock_irqrestore(&zone->lock, flags);
2156
2157 return i;
2158}
2159
2160/*
2161 * Called from the vmstat counter updater to decay the PCP high.
2162 * Return whether there are addition works to do.
2163 */
2164int decay_pcp_high(struct zone *zone, struct per_cpu_pages *pcp)
2165{
2166 int high_min, to_drain, batch;
2167 int todo = 0;
2168
2169 high_min = READ_ONCE(pcp->high_min);
2170 batch = READ_ONCE(pcp->batch);
2171 /*
2172 * Decrease pcp->high periodically to try to free possible
2173 * idle PCP pages. And, avoid to free too many pages to
2174 * control latency. This caps pcp->high decrement too.
2175 */
2176 if (pcp->high > high_min) {
2177 pcp->high = max3(pcp->count - (batch << CONFIG_PCP_BATCH_SCALE_MAX),
2178 pcp->high - (pcp->high >> 3), high_min);
2179 if (pcp->high > high_min)
2180 todo++;
2181 }
2182
2183 to_drain = pcp->count - pcp->high;
2184 if (to_drain > 0) {
2185 spin_lock(&pcp->lock);
2186 free_pcppages_bulk(zone, to_drain, pcp, 0);
2187 spin_unlock(&pcp->lock);
2188 todo++;
2189 }
2190
2191 return todo;
2192}
2193
2194#ifdef CONFIG_NUMA
2195/*
2196 * Called from the vmstat counter updater to drain pagesets of this
2197 * currently executing processor on remote nodes after they have
2198 * expired.
2199 */
2200void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
2201{
2202 int to_drain, batch;
2203
2204 batch = READ_ONCE(pcp->batch);
2205 to_drain = min(pcp->count, batch);
2206 if (to_drain > 0) {
2207 spin_lock(&pcp->lock);
2208 free_pcppages_bulk(zone, to_drain, pcp, 0);
2209 spin_unlock(&pcp->lock);
2210 }
2211}
2212#endif
2213
2214/*
2215 * Drain pcplists of the indicated processor and zone.
2216 */
2217static void drain_pages_zone(unsigned int cpu, struct zone *zone)
2218{
2219 struct per_cpu_pages *pcp;
2220
2221 pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu);
2222 if (pcp->count) {
2223 spin_lock(&pcp->lock);
2224 free_pcppages_bulk(zone, pcp->count, pcp, 0);
2225 spin_unlock(&pcp->lock);
2226 }
2227}
2228
2229/*
2230 * Drain pcplists of all zones on the indicated processor.
2231 */
2232static void drain_pages(unsigned int cpu)
2233{
2234 struct zone *zone;
2235
2236 for_each_populated_zone(zone) {
2237 drain_pages_zone(cpu, zone);
2238 }
2239}
2240
2241/*
2242 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
2243 */
2244void drain_local_pages(struct zone *zone)
2245{
2246 int cpu = smp_processor_id();
2247
2248 if (zone)
2249 drain_pages_zone(cpu, zone);
2250 else
2251 drain_pages(cpu);
2252}
2253
2254/*
2255 * The implementation of drain_all_pages(), exposing an extra parameter to
2256 * drain on all cpus.
2257 *
2258 * drain_all_pages() is optimized to only execute on cpus where pcplists are
2259 * not empty. The check for non-emptiness can however race with a free to
2260 * pcplist that has not yet increased the pcp->count from 0 to 1. Callers
2261 * that need the guarantee that every CPU has drained can disable the
2262 * optimizing racy check.
2263 */
2264static void __drain_all_pages(struct zone *zone, bool force_all_cpus)
2265{
2266 int cpu;
2267
2268 /*
2269 * Allocate in the BSS so we won't require allocation in
2270 * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
2271 */
2272 static cpumask_t cpus_with_pcps;
2273
2274 /*
2275 * Do not drain if one is already in progress unless it's specific to
2276 * a zone. Such callers are primarily CMA and memory hotplug and need
2277 * the drain to be complete when the call returns.
2278 */
2279 if (unlikely(!mutex_trylock(&pcpu_drain_mutex))) {
2280 if (!zone)
2281 return;
2282 mutex_lock(&pcpu_drain_mutex);
2283 }
2284
2285 /*
2286 * We don't care about racing with CPU hotplug event
2287 * as offline notification will cause the notified
2288 * cpu to drain that CPU pcps and on_each_cpu_mask
2289 * disables preemption as part of its processing
2290 */
2291 for_each_online_cpu(cpu) {
2292 struct per_cpu_pages *pcp;
2293 struct zone *z;
2294 bool has_pcps = false;
2295
2296 if (force_all_cpus) {
2297 /*
2298 * The pcp.count check is racy, some callers need a
2299 * guarantee that no cpu is missed.
2300 */
2301 has_pcps = true;
2302 } else if (zone) {
2303 pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu);
2304 if (pcp->count)
2305 has_pcps = true;
2306 } else {
2307 for_each_populated_zone(z) {
2308 pcp = per_cpu_ptr(z->per_cpu_pageset, cpu);
2309 if (pcp->count) {
2310 has_pcps = true;
2311 break;
2312 }
2313 }
2314 }
2315
2316 if (has_pcps)
2317 cpumask_set_cpu(cpu, &cpus_with_pcps);
2318 else
2319 cpumask_clear_cpu(cpu, &cpus_with_pcps);
2320 }
2321
2322 for_each_cpu(cpu, &cpus_with_pcps) {
2323 if (zone)
2324 drain_pages_zone(cpu, zone);
2325 else
2326 drain_pages(cpu);
2327 }
2328
2329 mutex_unlock(&pcpu_drain_mutex);
2330}
2331
2332/*
2333 * Spill all the per-cpu pages from all CPUs back into the buddy allocator.
2334 *
2335 * When zone parameter is non-NULL, spill just the single zone's pages.
2336 */
2337void drain_all_pages(struct zone *zone)
2338{
2339 __drain_all_pages(zone, false);
2340}
2341
2342static bool free_unref_page_prepare(struct page *page, unsigned long pfn,
2343 unsigned int order)
2344{
2345 int migratetype;
2346
2347 if (!free_pages_prepare(page, order))
2348 return false;
2349
2350 migratetype = get_pfnblock_migratetype(page, pfn);
2351 set_pcppage_migratetype(page, migratetype);
2352 return true;
2353}
2354
2355static int nr_pcp_free(struct per_cpu_pages *pcp, int batch, int high, bool free_high)
2356{
2357 int min_nr_free, max_nr_free;
2358
2359 /* Free as much as possible if batch freeing high-order pages. */
2360 if (unlikely(free_high))
2361 return min(pcp->count, batch << CONFIG_PCP_BATCH_SCALE_MAX);
2362
2363 /* Check for PCP disabled or boot pageset */
2364 if (unlikely(high < batch))
2365 return 1;
2366
2367 /* Leave at least pcp->batch pages on the list */
2368 min_nr_free = batch;
2369 max_nr_free = high - batch;
2370
2371 /*
2372 * Increase the batch number to the number of the consecutive
2373 * freed pages to reduce zone lock contention.
2374 */
2375 batch = clamp_t(int, pcp->free_count, min_nr_free, max_nr_free);
2376
2377 return batch;
2378}
2379
2380static int nr_pcp_high(struct per_cpu_pages *pcp, struct zone *zone,
2381 int batch, bool free_high)
2382{
2383 int high, high_min, high_max;
2384
2385 high_min = READ_ONCE(pcp->high_min);
2386 high_max = READ_ONCE(pcp->high_max);
2387 high = pcp->high = clamp(pcp->high, high_min, high_max);
2388
2389 if (unlikely(!high))
2390 return 0;
2391
2392 if (unlikely(free_high)) {
2393 pcp->high = max(high - (batch << CONFIG_PCP_BATCH_SCALE_MAX),
2394 high_min);
2395 return 0;
2396 }
2397
2398 /*
2399 * If reclaim is active, limit the number of pages that can be
2400 * stored on pcp lists
2401 */
2402 if (test_bit(ZONE_RECLAIM_ACTIVE, &zone->flags)) {
2403 int free_count = max_t(int, pcp->free_count, batch);
2404
2405 pcp->high = max(high - free_count, high_min);
2406 return min(batch << 2, pcp->high);
2407 }
2408
2409 if (high_min == high_max)
2410 return high;
2411
2412 if (test_bit(ZONE_BELOW_HIGH, &zone->flags)) {
2413 int free_count = max_t(int, pcp->free_count, batch);
2414
2415 pcp->high = max(high - free_count, high_min);
2416 high = max(pcp->count, high_min);
2417 } else if (pcp->count >= high) {
2418 int need_high = pcp->free_count + batch;
2419
2420 /* pcp->high should be large enough to hold batch freed pages */
2421 if (pcp->high < need_high)
2422 pcp->high = clamp(need_high, high_min, high_max);
2423 }
2424
2425 return high;
2426}
2427
2428static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp,
2429 struct page *page, int migratetype,
2430 unsigned int order)
2431{
2432 int high, batch;
2433 int pindex;
2434 bool free_high = false;
2435
2436 /*
2437 * On freeing, reduce the number of pages that are batch allocated.
2438 * See nr_pcp_alloc() where alloc_factor is increased for subsequent
2439 * allocations.
2440 */
2441 pcp->alloc_factor >>= 1;
2442 __count_vm_events(PGFREE, 1 << order);
2443 pindex = order_to_pindex(migratetype, order);
2444 list_add(&page->pcp_list, &pcp->lists[pindex]);
2445 pcp->count += 1 << order;
2446
2447 batch = READ_ONCE(pcp->batch);
2448 /*
2449 * As high-order pages other than THP's stored on PCP can contribute
2450 * to fragmentation, limit the number stored when PCP is heavily
2451 * freeing without allocation. The remainder after bulk freeing
2452 * stops will be drained from vmstat refresh context.
2453 */
2454 if (order && order <= PAGE_ALLOC_COSTLY_ORDER) {
2455 free_high = (pcp->free_count >= batch &&
2456 (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) &&
2457 (!(pcp->flags & PCPF_FREE_HIGH_BATCH) ||
2458 pcp->count >= READ_ONCE(batch)));
2459 pcp->flags |= PCPF_PREV_FREE_HIGH_ORDER;
2460 } else if (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) {
2461 pcp->flags &= ~PCPF_PREV_FREE_HIGH_ORDER;
2462 }
2463 if (pcp->free_count < (batch << CONFIG_PCP_BATCH_SCALE_MAX))
2464 pcp->free_count += (1 << order);
2465 high = nr_pcp_high(pcp, zone, batch, free_high);
2466 if (pcp->count >= high) {
2467 free_pcppages_bulk(zone, nr_pcp_free(pcp, batch, high, free_high),
2468 pcp, pindex);
2469 if (test_bit(ZONE_BELOW_HIGH, &zone->flags) &&
2470 zone_watermark_ok(zone, 0, high_wmark_pages(zone),
2471 ZONE_MOVABLE, 0))
2472 clear_bit(ZONE_BELOW_HIGH, &zone->flags);
2473 }
2474}
2475
2476/*
2477 * Free a pcp page
2478 */
2479void free_unref_page(struct page *page, unsigned int order)
2480{
2481 unsigned long __maybe_unused UP_flags;
2482 struct per_cpu_pages *pcp;
2483 struct zone *zone;
2484 unsigned long pfn = page_to_pfn(page);
2485 int migratetype, pcpmigratetype;
2486
2487 if (!free_unref_page_prepare(page, pfn, order))
2488 return;
2489
2490 /*
2491 * We only track unmovable, reclaimable and movable on pcp lists.
2492 * Place ISOLATE pages on the isolated list because they are being
2493 * offlined but treat HIGHATOMIC and CMA as movable pages so we can
2494 * get those areas back if necessary. Otherwise, we may have to free
2495 * excessively into the page allocator
2496 */
2497 migratetype = pcpmigratetype = get_pcppage_migratetype(page);
2498 if (unlikely(migratetype >= MIGRATE_PCPTYPES)) {
2499 if (unlikely(is_migrate_isolate(migratetype))) {
2500 free_one_page(page_zone(page), page, pfn, order, migratetype, FPI_NONE);
2501 return;
2502 }
2503 pcpmigratetype = MIGRATE_MOVABLE;
2504 }
2505
2506 zone = page_zone(page);
2507 pcp_trylock_prepare(UP_flags);
2508 pcp = pcp_spin_trylock(zone->per_cpu_pageset);
2509 if (pcp) {
2510 free_unref_page_commit(zone, pcp, page, pcpmigratetype, order);
2511 pcp_spin_unlock(pcp);
2512 } else {
2513 free_one_page(zone, page, pfn, order, migratetype, FPI_NONE);
2514 }
2515 pcp_trylock_finish(UP_flags);
2516}
2517
2518/*
2519 * Free a batch of folios
2520 */
2521void free_unref_folios(struct folio_batch *folios)
2522{
2523 unsigned long __maybe_unused UP_flags;
2524 struct per_cpu_pages *pcp = NULL;
2525 struct zone *locked_zone = NULL;
2526 int i, j, migratetype;
2527
2528 /* Prepare folios for freeing */
2529 for (i = 0, j = 0; i < folios->nr; i++) {
2530 struct folio *folio = folios->folios[i];
2531 unsigned long pfn = folio_pfn(folio);
2532 unsigned int order = folio_order(folio);
2533
2534 if (order > 0 && folio_test_large_rmappable(folio))
2535 folio_undo_large_rmappable(folio);
2536 if (!free_unref_page_prepare(&folio->page, pfn, order))
2537 continue;
2538
2539 /*
2540 * Free isolated folios and orders not handled on the PCP
2541 * directly to the allocator, see comment in free_unref_page.
2542 */
2543 migratetype = get_pcppage_migratetype(&folio->page);
2544 if (!pcp_allowed_order(order) ||
2545 is_migrate_isolate(migratetype)) {
2546 free_one_page(folio_zone(folio), &folio->page, pfn,
2547 order, migratetype, FPI_NONE);
2548 continue;
2549 }
2550 folio->private = (void *)(unsigned long)order;
2551 if (j != i)
2552 folios->folios[j] = folio;
2553 j++;
2554 }
2555 folios->nr = j;
2556
2557 for (i = 0; i < folios->nr; i++) {
2558 struct folio *folio = folios->folios[i];
2559 struct zone *zone = folio_zone(folio);
2560 unsigned int order = (unsigned long)folio->private;
2561
2562 folio->private = NULL;
2563 migratetype = get_pcppage_migratetype(&folio->page);
2564
2565 /* Different zone requires a different pcp lock */
2566 if (zone != locked_zone) {
2567 if (pcp) {
2568 pcp_spin_unlock(pcp);
2569 pcp_trylock_finish(UP_flags);
2570 }
2571
2572 /*
2573 * trylock is necessary as folios may be getting freed
2574 * from IRQ or SoftIRQ context after an IO completion.
2575 */
2576 pcp_trylock_prepare(UP_flags);
2577 pcp = pcp_spin_trylock(zone->per_cpu_pageset);
2578 if (unlikely(!pcp)) {
2579 pcp_trylock_finish(UP_flags);
2580 free_one_page(zone, &folio->page,
2581 folio_pfn(folio), order,
2582 migratetype, FPI_NONE);
2583 locked_zone = NULL;
2584 continue;
2585 }
2586 locked_zone = zone;
2587 }
2588
2589 /*
2590 * Non-isolated types over MIGRATE_PCPTYPES get added
2591 * to the MIGRATE_MOVABLE pcp list.
2592 */
2593 if (unlikely(migratetype >= MIGRATE_PCPTYPES))
2594 migratetype = MIGRATE_MOVABLE;
2595
2596 trace_mm_page_free_batched(&folio->page);
2597 free_unref_page_commit(zone, pcp, &folio->page, migratetype,
2598 order);
2599 }
2600
2601 if (pcp) {
2602 pcp_spin_unlock(pcp);
2603 pcp_trylock_finish(UP_flags);
2604 }
2605 folio_batch_reinit(folios);
2606}
2607
2608/*
2609 * split_page takes a non-compound higher-order page, and splits it into
2610 * n (1<<order) sub-pages: page[0..n]
2611 * Each sub-page must be freed individually.
2612 *
2613 * Note: this is probably too low level an operation for use in drivers.
2614 * Please consult with lkml before using this in your driver.
2615 */
2616void split_page(struct page *page, unsigned int order)
2617{
2618 int i;
2619
2620 VM_BUG_ON_PAGE(PageCompound(page), page);
2621 VM_BUG_ON_PAGE(!page_count(page), page);
2622
2623 for (i = 1; i < (1 << order); i++)
2624 set_page_refcounted(page + i);
2625 split_page_owner(page, order, 0);
2626 split_page_memcg(page, order, 0);
2627}
2628EXPORT_SYMBOL_GPL(split_page);
2629
2630int __isolate_free_page(struct page *page, unsigned int order)
2631{
2632 struct zone *zone = page_zone(page);
2633 int mt = get_pageblock_migratetype(page);
2634
2635 if (!is_migrate_isolate(mt)) {
2636 unsigned long watermark;
2637 /*
2638 * Obey watermarks as if the page was being allocated. We can
2639 * emulate a high-order watermark check with a raised order-0
2640 * watermark, because we already know our high-order page
2641 * exists.
2642 */
2643 watermark = zone->_watermark[WMARK_MIN] + (1UL << order);
2644 if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA))
2645 return 0;
2646
2647 __mod_zone_freepage_state(zone, -(1UL << order), mt);
2648 }
2649
2650 del_page_from_free_list(page, zone, order);
2651
2652 /*
2653 * Set the pageblock if the isolated page is at least half of a
2654 * pageblock
2655 */
2656 if (order >= pageblock_order - 1) {
2657 struct page *endpage = page + (1 << order) - 1;
2658 for (; page < endpage; page += pageblock_nr_pages) {
2659 int mt = get_pageblock_migratetype(page);
2660 /*
2661 * Only change normal pageblocks (i.e., they can merge
2662 * with others)
2663 */
2664 if (migratetype_is_mergeable(mt))
2665 set_pageblock_migratetype(page,
2666 MIGRATE_MOVABLE);
2667 }
2668 }
2669
2670 return 1UL << order;
2671}
2672
2673/**
2674 * __putback_isolated_page - Return a now-isolated page back where we got it
2675 * @page: Page that was isolated
2676 * @order: Order of the isolated page
2677 * @mt: The page's pageblock's migratetype
2678 *
2679 * This function is meant to return a page pulled from the free lists via
2680 * __isolate_free_page back to the free lists they were pulled from.
2681 */
2682void __putback_isolated_page(struct page *page, unsigned int order, int mt)
2683{
2684 struct zone *zone = page_zone(page);
2685
2686 /* zone lock should be held when this function is called */
2687 lockdep_assert_held(&zone->lock);
2688
2689 /* Return isolated page to tail of freelist. */
2690 __free_one_page(page, page_to_pfn(page), zone, order, mt,
2691 FPI_SKIP_REPORT_NOTIFY | FPI_TO_TAIL);
2692}
2693
2694/*
2695 * Update NUMA hit/miss statistics
2696 */
2697static inline void zone_statistics(struct zone *preferred_zone, struct zone *z,
2698 long nr_account)
2699{
2700#ifdef CONFIG_NUMA
2701 enum numa_stat_item local_stat = NUMA_LOCAL;
2702
2703 /* skip numa counters update if numa stats is disabled */
2704 if (!static_branch_likely(&vm_numa_stat_key))
2705 return;
2706
2707 if (zone_to_nid(z) != numa_node_id())
2708 local_stat = NUMA_OTHER;
2709
2710 if (zone_to_nid(z) == zone_to_nid(preferred_zone))
2711 __count_numa_events(z, NUMA_HIT, nr_account);
2712 else {
2713 __count_numa_events(z, NUMA_MISS, nr_account);
2714 __count_numa_events(preferred_zone, NUMA_FOREIGN, nr_account);
2715 }
2716 __count_numa_events(z, local_stat, nr_account);
2717#endif
2718}
2719
2720static __always_inline
2721struct page *rmqueue_buddy(struct zone *preferred_zone, struct zone *zone,
2722 unsigned int order, unsigned int alloc_flags,
2723 int migratetype)
2724{
2725 struct page *page;
2726 unsigned long flags;
2727
2728 do {
2729 page = NULL;
2730 spin_lock_irqsave(&zone->lock, flags);
2731 if (alloc_flags & ALLOC_HIGHATOMIC)
2732 page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
2733 if (!page) {
2734 page = __rmqueue(zone, order, migratetype, alloc_flags);
2735
2736 /*
2737 * If the allocation fails, allow OOM handling access
2738 * to HIGHATOMIC reserves as failing now is worse than
2739 * failing a high-order atomic allocation in the
2740 * future.
2741 */
2742 if (!page && (alloc_flags & ALLOC_OOM))
2743 page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
2744
2745 if (!page) {
2746 spin_unlock_irqrestore(&zone->lock, flags);
2747 return NULL;
2748 }
2749 }
2750 __mod_zone_freepage_state(zone, -(1 << order),
2751 get_pcppage_migratetype(page));
2752 spin_unlock_irqrestore(&zone->lock, flags);
2753 } while (check_new_pages(page, order));
2754
2755 __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
2756 zone_statistics(preferred_zone, zone, 1);
2757
2758 return page;
2759}
2760
2761static int nr_pcp_alloc(struct per_cpu_pages *pcp, struct zone *zone, int order)
2762{
2763 int high, base_batch, batch, max_nr_alloc;
2764 int high_max, high_min;
2765
2766 base_batch = READ_ONCE(pcp->batch);
2767 high_min = READ_ONCE(pcp->high_min);
2768 high_max = READ_ONCE(pcp->high_max);
2769 high = pcp->high = clamp(pcp->high, high_min, high_max);
2770
2771 /* Check for PCP disabled or boot pageset */
2772 if (unlikely(high < base_batch))
2773 return 1;
2774
2775 if (order)
2776 batch = base_batch;
2777 else
2778 batch = (base_batch << pcp->alloc_factor);
2779
2780 /*
2781 * If we had larger pcp->high, we could avoid to allocate from
2782 * zone.
2783 */
2784 if (high_min != high_max && !test_bit(ZONE_BELOW_HIGH, &zone->flags))
2785 high = pcp->high = min(high + batch, high_max);
2786
2787 if (!order) {
2788 max_nr_alloc = max(high - pcp->count - base_batch, base_batch);
2789 /*
2790 * Double the number of pages allocated each time there is
2791 * subsequent allocation of order-0 pages without any freeing.
2792 */
2793 if (batch <= max_nr_alloc &&
2794 pcp->alloc_factor < CONFIG_PCP_BATCH_SCALE_MAX)
2795 pcp->alloc_factor++;
2796 batch = min(batch, max_nr_alloc);
2797 }
2798
2799 /*
2800 * Scale batch relative to order if batch implies free pages
2801 * can be stored on the PCP. Batch can be 1 for small zones or
2802 * for boot pagesets which should never store free pages as
2803 * the pages may belong to arbitrary zones.
2804 */
2805 if (batch > 1)
2806 batch = max(batch >> order, 2);
2807
2808 return batch;
2809}
2810
2811/* Remove page from the per-cpu list, caller must protect the list */
2812static inline
2813struct page *__rmqueue_pcplist(struct zone *zone, unsigned int order,
2814 int migratetype,
2815 unsigned int alloc_flags,
2816 struct per_cpu_pages *pcp,
2817 struct list_head *list)
2818{
2819 struct page *page;
2820
2821 do {
2822 if (list_empty(list)) {
2823 int batch = nr_pcp_alloc(pcp, zone, order);
2824 int alloced;
2825
2826 alloced = rmqueue_bulk(zone, order,
2827 batch, list,
2828 migratetype, alloc_flags);
2829
2830 pcp->count += alloced << order;
2831 if (unlikely(list_empty(list)))
2832 return NULL;
2833 }
2834
2835 page = list_first_entry(list, struct page, pcp_list);
2836 list_del(&page->pcp_list);
2837 pcp->count -= 1 << order;
2838 } while (check_new_pages(page, order));
2839
2840 return page;
2841}
2842
2843/* Lock and remove page from the per-cpu list */
2844static struct page *rmqueue_pcplist(struct zone *preferred_zone,
2845 struct zone *zone, unsigned int order,
2846 int migratetype, unsigned int alloc_flags)
2847{
2848 struct per_cpu_pages *pcp;
2849 struct list_head *list;
2850 struct page *page;
2851 unsigned long __maybe_unused UP_flags;
2852
2853 /* spin_trylock may fail due to a parallel drain or IRQ reentrancy. */
2854 pcp_trylock_prepare(UP_flags);
2855 pcp = pcp_spin_trylock(zone->per_cpu_pageset);
2856 if (!pcp) {
2857 pcp_trylock_finish(UP_flags);
2858 return NULL;
2859 }
2860
2861 /*
2862 * On allocation, reduce the number of pages that are batch freed.
2863 * See nr_pcp_free() where free_factor is increased for subsequent
2864 * frees.
2865 */
2866 pcp->free_count >>= 1;
2867 list = &pcp->lists[order_to_pindex(migratetype, order)];
2868 page = __rmqueue_pcplist(zone, order, migratetype, alloc_flags, pcp, list);
2869 pcp_spin_unlock(pcp);
2870 pcp_trylock_finish(UP_flags);
2871 if (page) {
2872 __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
2873 zone_statistics(preferred_zone, zone, 1);
2874 }
2875 return page;
2876}
2877
2878/*
2879 * Allocate a page from the given zone.
2880 * Use pcplists for THP or "cheap" high-order allocations.
2881 */
2882
2883/*
2884 * Do not instrument rmqueue() with KMSAN. This function may call
2885 * __msan_poison_alloca() through a call to set_pfnblock_flags_mask().
2886 * If __msan_poison_alloca() attempts to allocate pages for the stack depot, it
2887 * may call rmqueue() again, which will result in a deadlock.
2888 */
2889__no_sanitize_memory
2890static inline
2891struct page *rmqueue(struct zone *preferred_zone,
2892 struct zone *zone, unsigned int order,
2893 gfp_t gfp_flags, unsigned int alloc_flags,
2894 int migratetype)
2895{
2896 struct page *page;
2897
2898 /*
2899 * We most definitely don't want callers attempting to
2900 * allocate greater than order-1 page units with __GFP_NOFAIL.
2901 */
2902 WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
2903
2904 if (likely(pcp_allowed_order(order))) {
2905 page = rmqueue_pcplist(preferred_zone, zone, order,
2906 migratetype, alloc_flags);
2907 if (likely(page))
2908 goto out;
2909 }
2910
2911 page = rmqueue_buddy(preferred_zone, zone, order, alloc_flags,
2912 migratetype);
2913
2914out:
2915 /* Separate test+clear to avoid unnecessary atomics */
2916 if ((alloc_flags & ALLOC_KSWAPD) &&
2917 unlikely(test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags))) {
2918 clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
2919 wakeup_kswapd(zone, 0, 0, zone_idx(zone));
2920 }
2921
2922 VM_BUG_ON_PAGE(page && bad_range(zone, page), page);
2923 return page;
2924}
2925
2926noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
2927{
2928 return __should_fail_alloc_page(gfp_mask, order);
2929}
2930ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE);
2931
2932static inline long __zone_watermark_unusable_free(struct zone *z,
2933 unsigned int order, unsigned int alloc_flags)
2934{
2935 long unusable_free = (1 << order) - 1;
2936
2937 /*
2938 * If the caller does not have rights to reserves below the min
2939 * watermark then subtract the high-atomic reserves. This will
2940 * over-estimate the size of the atomic reserve but it avoids a search.
2941 */
2942 if (likely(!(alloc_flags & ALLOC_RESERVES)))
2943 unusable_free += z->nr_reserved_highatomic;
2944
2945#ifdef CONFIG_CMA
2946 /* If allocation can't use CMA areas don't use free CMA pages */
2947 if (!(alloc_flags & ALLOC_CMA))
2948 unusable_free += zone_page_state(z, NR_FREE_CMA_PAGES);
2949#endif
2950#ifdef CONFIG_UNACCEPTED_MEMORY
2951 unusable_free += zone_page_state(z, NR_UNACCEPTED);
2952#endif
2953
2954 return unusable_free;
2955}
2956
2957/*
2958 * Return true if free base pages are above 'mark'. For high-order checks it
2959 * will return true of the order-0 watermark is reached and there is at least
2960 * one free page of a suitable size. Checking now avoids taking the zone lock
2961 * to check in the allocation paths if no pages are free.
2962 */
2963bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
2964 int highest_zoneidx, unsigned int alloc_flags,
2965 long free_pages)
2966{
2967 long min = mark;
2968 int o;
2969
2970 /* free_pages may go negative - that's OK */
2971 free_pages -= __zone_watermark_unusable_free(z, order, alloc_flags);
2972
2973 if (unlikely(alloc_flags & ALLOC_RESERVES)) {
2974 /*
2975 * __GFP_HIGH allows access to 50% of the min reserve as well
2976 * as OOM.
2977 */
2978 if (alloc_flags & ALLOC_MIN_RESERVE) {
2979 min -= min / 2;
2980
2981 /*
2982 * Non-blocking allocations (e.g. GFP_ATOMIC) can
2983 * access more reserves than just __GFP_HIGH. Other
2984 * non-blocking allocations requests such as GFP_NOWAIT
2985 * or (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) do not get
2986 * access to the min reserve.
2987 */
2988 if (alloc_flags & ALLOC_NON_BLOCK)
2989 min -= min / 4;
2990 }
2991
2992 /*
2993 * OOM victims can try even harder than the normal reserve
2994 * users on the grounds that it's definitely going to be in
2995 * the exit path shortly and free memory. Any allocation it
2996 * makes during the free path will be small and short-lived.
2997 */
2998 if (alloc_flags & ALLOC_OOM)
2999 min -= min / 2;
3000 }
3001
3002 /*
3003 * Check watermarks for an order-0 allocation request. If these
3004 * are not met, then a high-order request also cannot go ahead
3005 * even if a suitable page happened to be free.
3006 */
3007 if (free_pages <= min + z->lowmem_reserve[highest_zoneidx])
3008 return false;
3009
3010 /* If this is an order-0 request then the watermark is fine */
3011 if (!order)
3012 return true;
3013
3014 /* For a high-order request, check at least one suitable page is free */
3015 for (o = order; o < NR_PAGE_ORDERS; o++) {
3016 struct free_area *area = &z->free_area[o];
3017 int mt;
3018
3019 if (!area->nr_free)
3020 continue;
3021
3022 for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) {
3023 if (!free_area_empty(area, mt))
3024 return true;
3025 }
3026
3027#ifdef CONFIG_CMA
3028 if ((alloc_flags & ALLOC_CMA) &&
3029 !free_area_empty(area, MIGRATE_CMA)) {
3030 return true;
3031 }
3032#endif
3033 if ((alloc_flags & (ALLOC_HIGHATOMIC|ALLOC_OOM)) &&
3034 !free_area_empty(area, MIGRATE_HIGHATOMIC)) {
3035 return true;
3036 }
3037 }
3038 return false;
3039}
3040
3041bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
3042 int highest_zoneidx, unsigned int alloc_flags)
3043{
3044 return __zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags,
3045 zone_page_state(z, NR_FREE_PAGES));
3046}
3047
3048static inline bool zone_watermark_fast(struct zone *z, unsigned int order,
3049 unsigned long mark, int highest_zoneidx,
3050 unsigned int alloc_flags, gfp_t gfp_mask)
3051{
3052 long free_pages;
3053
3054 free_pages = zone_page_state(z, NR_FREE_PAGES);
3055
3056 /*
3057 * Fast check for order-0 only. If this fails then the reserves
3058 * need to be calculated.
3059 */
3060 if (!order) {
3061 long usable_free;
3062 long reserved;
3063
3064 usable_free = free_pages;
3065 reserved = __zone_watermark_unusable_free(z, 0, alloc_flags);
3066
3067 /* reserved may over estimate high-atomic reserves. */
3068 usable_free -= min(usable_free, reserved);
3069 if (usable_free > mark + z->lowmem_reserve[highest_zoneidx])
3070 return true;
3071 }
3072
3073 if (__zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags,
3074 free_pages))
3075 return true;
3076
3077 /*
3078 * Ignore watermark boosting for __GFP_HIGH order-0 allocations
3079 * when checking the min watermark. The min watermark is the
3080 * point where boosting is ignored so that kswapd is woken up
3081 * when below the low watermark.
3082 */
3083 if (unlikely(!order && (alloc_flags & ALLOC_MIN_RESERVE) && z->watermark_boost
3084 && ((alloc_flags & ALLOC_WMARK_MASK) == WMARK_MIN))) {
3085 mark = z->_watermark[WMARK_MIN];
3086 return __zone_watermark_ok(z, order, mark, highest_zoneidx,
3087 alloc_flags, free_pages);
3088 }
3089
3090 return false;
3091}
3092
3093bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
3094 unsigned long mark, int highest_zoneidx)
3095{
3096 long free_pages = zone_page_state(z, NR_FREE_PAGES);
3097
3098 if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
3099 free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
3100
3101 return __zone_watermark_ok(z, order, mark, highest_zoneidx, 0,
3102 free_pages);
3103}
3104
3105#ifdef CONFIG_NUMA
3106int __read_mostly node_reclaim_distance = RECLAIM_DISTANCE;
3107
3108static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
3109{
3110 return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <=
3111 node_reclaim_distance;
3112}
3113#else /* CONFIG_NUMA */
3114static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
3115{
3116 return true;
3117}
3118#endif /* CONFIG_NUMA */
3119
3120/*
3121 * The restriction on ZONE_DMA32 as being a suitable zone to use to avoid
3122 * fragmentation is subtle. If the preferred zone was HIGHMEM then
3123 * premature use of a lower zone may cause lowmem pressure problems that
3124 * are worse than fragmentation. If the next zone is ZONE_DMA then it is
3125 * probably too small. It only makes sense to spread allocations to avoid
3126 * fragmentation between the Normal and DMA32 zones.
3127 */
3128static inline unsigned int
3129alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask)
3130{
3131 unsigned int alloc_flags;
3132
3133 /*
3134 * __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD
3135 * to save a branch.
3136 */
3137 alloc_flags = (__force int) (gfp_mask & __GFP_KSWAPD_RECLAIM);
3138
3139#ifdef CONFIG_ZONE_DMA32
3140 if (!zone)
3141 return alloc_flags;
3142
3143 if (zone_idx(zone) != ZONE_NORMAL)
3144 return alloc_flags;
3145
3146 /*
3147 * If ZONE_DMA32 exists, assume it is the one after ZONE_NORMAL and
3148 * the pointer is within zone->zone_pgdat->node_zones[]. Also assume
3149 * on UMA that if Normal is populated then so is DMA32.
3150 */
3151 BUILD_BUG_ON(ZONE_NORMAL - ZONE_DMA32 != 1);
3152 if (nr_online_nodes > 1 && !populated_zone(--zone))
3153 return alloc_flags;
3154
3155 alloc_flags |= ALLOC_NOFRAGMENT;
3156#endif /* CONFIG_ZONE_DMA32 */
3157 return alloc_flags;
3158}
3159
3160/* Must be called after current_gfp_context() which can change gfp_mask */
3161static inline unsigned int gfp_to_alloc_flags_cma(gfp_t gfp_mask,
3162 unsigned int alloc_flags)
3163{
3164#ifdef CONFIG_CMA
3165 if (gfp_migratetype(gfp_mask) == MIGRATE_MOVABLE)
3166 alloc_flags |= ALLOC_CMA;
3167#endif
3168 return alloc_flags;
3169}
3170
3171/*
3172 * get_page_from_freelist goes through the zonelist trying to allocate
3173 * a page.
3174 */
3175static struct page *
3176get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
3177 const struct alloc_context *ac)
3178{
3179 struct zoneref *z;
3180 struct zone *zone;
3181 struct pglist_data *last_pgdat = NULL;
3182 bool last_pgdat_dirty_ok = false;
3183 bool no_fallback;
3184
3185retry:
3186 /*
3187 * Scan zonelist, looking for a zone with enough free.
3188 * See also cpuset_node_allowed() comment in kernel/cgroup/cpuset.c.
3189 */
3190 no_fallback = alloc_flags & ALLOC_NOFRAGMENT;
3191 z = ac->preferred_zoneref;
3192 for_next_zone_zonelist_nodemask(zone, z, ac->highest_zoneidx,
3193 ac->nodemask) {
3194 struct page *page;
3195 unsigned long mark;
3196
3197 if (cpusets_enabled() &&
3198 (alloc_flags & ALLOC_CPUSET) &&
3199 !__cpuset_zone_allowed(zone, gfp_mask))
3200 continue;
3201 /*
3202 * When allocating a page cache page for writing, we
3203 * want to get it from a node that is within its dirty
3204 * limit, such that no single node holds more than its
3205 * proportional share of globally allowed dirty pages.
3206 * The dirty limits take into account the node's
3207 * lowmem reserves and high watermark so that kswapd
3208 * should be able to balance it without having to
3209 * write pages from its LRU list.
3210 *
3211 * XXX: For now, allow allocations to potentially
3212 * exceed the per-node dirty limit in the slowpath
3213 * (spread_dirty_pages unset) before going into reclaim,
3214 * which is important when on a NUMA setup the allowed
3215 * nodes are together not big enough to reach the
3216 * global limit. The proper fix for these situations
3217 * will require awareness of nodes in the
3218 * dirty-throttling and the flusher threads.
3219 */
3220 if (ac->spread_dirty_pages) {
3221 if (last_pgdat != zone->zone_pgdat) {
3222 last_pgdat = zone->zone_pgdat;
3223 last_pgdat_dirty_ok = node_dirty_ok(zone->zone_pgdat);
3224 }
3225
3226 if (!last_pgdat_dirty_ok)
3227 continue;
3228 }
3229
3230 if (no_fallback && nr_online_nodes > 1 &&
3231 zone != ac->preferred_zoneref->zone) {
3232 int local_nid;
3233
3234 /*
3235 * If moving to a remote node, retry but allow
3236 * fragmenting fallbacks. Locality is more important
3237 * than fragmentation avoidance.
3238 */
3239 local_nid = zone_to_nid(ac->preferred_zoneref->zone);
3240 if (zone_to_nid(zone) != local_nid) {
3241 alloc_flags &= ~ALLOC_NOFRAGMENT;
3242 goto retry;
3243 }
3244 }
3245
3246 /*
3247 * Detect whether the number of free pages is below high
3248 * watermark. If so, we will decrease pcp->high and free
3249 * PCP pages in free path to reduce the possibility of
3250 * premature page reclaiming. Detection is done here to
3251 * avoid to do that in hotter free path.
3252 */
3253 if (test_bit(ZONE_BELOW_HIGH, &zone->flags))
3254 goto check_alloc_wmark;
3255
3256 mark = high_wmark_pages(zone);
3257 if (zone_watermark_fast(zone, order, mark,
3258 ac->highest_zoneidx, alloc_flags,
3259 gfp_mask))
3260 goto try_this_zone;
3261 else
3262 set_bit(ZONE_BELOW_HIGH, &zone->flags);
3263
3264check_alloc_wmark:
3265 mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK);
3266 if (!zone_watermark_fast(zone, order, mark,
3267 ac->highest_zoneidx, alloc_flags,
3268 gfp_mask)) {
3269 int ret;
3270
3271 if (has_unaccepted_memory()) {
3272 if (try_to_accept_memory(zone, order))
3273 goto try_this_zone;
3274 }
3275
3276#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
3277 /*
3278 * Watermark failed for this zone, but see if we can
3279 * grow this zone if it contains deferred pages.
3280 */
3281 if (deferred_pages_enabled()) {
3282 if (_deferred_grow_zone(zone, order))
3283 goto try_this_zone;
3284 }
3285#endif
3286 /* Checked here to keep the fast path fast */
3287 BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
3288 if (alloc_flags & ALLOC_NO_WATERMARKS)
3289 goto try_this_zone;
3290
3291 if (!node_reclaim_enabled() ||
3292 !zone_allows_reclaim(ac->preferred_zoneref->zone, zone))
3293 continue;
3294
3295 ret = node_reclaim(zone->zone_pgdat, gfp_mask, order);
3296 switch (ret) {
3297 case NODE_RECLAIM_NOSCAN:
3298 /* did not scan */
3299 continue;
3300 case NODE_RECLAIM_FULL:
3301 /* scanned but unreclaimable */
3302 continue;
3303 default:
3304 /* did we reclaim enough */
3305 if (zone_watermark_ok(zone, order, mark,
3306 ac->highest_zoneidx, alloc_flags))
3307 goto try_this_zone;
3308
3309 continue;
3310 }
3311 }
3312
3313try_this_zone:
3314 page = rmqueue(ac->preferred_zoneref->zone, zone, order,
3315 gfp_mask, alloc_flags, ac->migratetype);
3316 if (page) {
3317 prep_new_page(page, order, gfp_mask, alloc_flags);
3318
3319 /*
3320 * If this is a high-order atomic allocation then check
3321 * if the pageblock should be reserved for the future
3322 */
3323 if (unlikely(alloc_flags & ALLOC_HIGHATOMIC))
3324 reserve_highatomic_pageblock(page, zone);
3325
3326 return page;
3327 } else {
3328 if (has_unaccepted_memory()) {
3329 if (try_to_accept_memory(zone, order))
3330 goto try_this_zone;
3331 }
3332
3333#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
3334 /* Try again if zone has deferred pages */
3335 if (deferred_pages_enabled()) {
3336 if (_deferred_grow_zone(zone, order))
3337 goto try_this_zone;
3338 }
3339#endif
3340 }
3341 }
3342
3343 /*
3344 * It's possible on a UMA machine to get through all zones that are
3345 * fragmented. If avoiding fragmentation, reset and try again.
3346 */
3347 if (no_fallback) {
3348 alloc_flags &= ~ALLOC_NOFRAGMENT;
3349 goto retry;
3350 }
3351
3352 return NULL;
3353}
3354
3355static void warn_alloc_show_mem(gfp_t gfp_mask, nodemask_t *nodemask)
3356{
3357 unsigned int filter = SHOW_MEM_FILTER_NODES;
3358
3359 /*
3360 * This documents exceptions given to allocations in certain
3361 * contexts that are allowed to allocate outside current's set
3362 * of allowed nodes.
3363 */
3364 if (!(gfp_mask & __GFP_NOMEMALLOC))
3365 if (tsk_is_oom_victim(current) ||
3366 (current->flags & (PF_MEMALLOC | PF_EXITING)))
3367 filter &= ~SHOW_MEM_FILTER_NODES;
3368 if (!in_task() || !(gfp_mask & __GFP_DIRECT_RECLAIM))
3369 filter &= ~SHOW_MEM_FILTER_NODES;
3370
3371 __show_mem(filter, nodemask, gfp_zone(gfp_mask));
3372}
3373
3374void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...)
3375{
3376 struct va_format vaf;
3377 va_list args;
3378 static DEFINE_RATELIMIT_STATE(nopage_rs, 10*HZ, 1);
3379
3380 if ((gfp_mask & __GFP_NOWARN) ||
3381 !__ratelimit(&nopage_rs) ||
3382 ((gfp_mask & __GFP_DMA) && !has_managed_dma()))
3383 return;
3384
3385 va_start(args, fmt);
3386 vaf.fmt = fmt;
3387 vaf.va = &args;
3388 pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=%*pbl",
3389 current->comm, &vaf, gfp_mask, &gfp_mask,
3390 nodemask_pr_args(nodemask));
3391 va_end(args);
3392
3393 cpuset_print_current_mems_allowed();
3394 pr_cont("\n");
3395 dump_stack();
3396 warn_alloc_show_mem(gfp_mask, nodemask);
3397}
3398
3399static inline struct page *
3400__alloc_pages_cpuset_fallback(gfp_t gfp_mask, unsigned int order,
3401 unsigned int alloc_flags,
3402 const struct alloc_context *ac)
3403{
3404 struct page *page;
3405
3406 page = get_page_from_freelist(gfp_mask, order,
3407 alloc_flags|ALLOC_CPUSET, ac);
3408 /*
3409 * fallback to ignore cpuset restriction if our nodes
3410 * are depleted
3411 */
3412 if (!page)
3413 page = get_page_from_freelist(gfp_mask, order,
3414 alloc_flags, ac);
3415
3416 return page;
3417}
3418
3419static inline struct page *
3420__alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
3421 const struct alloc_context *ac, unsigned long *did_some_progress)
3422{
3423 struct oom_control oc = {
3424 .zonelist = ac->zonelist,
3425 .nodemask = ac->nodemask,
3426 .memcg = NULL,
3427 .gfp_mask = gfp_mask,
3428 .order = order,
3429 };
3430 struct page *page;
3431
3432 *did_some_progress = 0;
3433
3434 /*
3435 * Acquire the oom lock. If that fails, somebody else is
3436 * making progress for us.
3437 */
3438 if (!mutex_trylock(&oom_lock)) {
3439 *did_some_progress = 1;
3440 schedule_timeout_uninterruptible(1);
3441 return NULL;
3442 }
3443
3444 /*
3445 * Go through the zonelist yet one more time, keep very high watermark
3446 * here, this is only to catch a parallel oom killing, we must fail if
3447 * we're still under heavy pressure. But make sure that this reclaim
3448 * attempt shall not depend on __GFP_DIRECT_RECLAIM && !__GFP_NORETRY
3449 * allocation which will never fail due to oom_lock already held.
3450 */
3451 page = get_page_from_freelist((gfp_mask | __GFP_HARDWALL) &
3452 ~__GFP_DIRECT_RECLAIM, order,
3453 ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac);
3454 if (page)
3455 goto out;
3456
3457 /* Coredumps can quickly deplete all memory reserves */
3458 if (current->flags & PF_DUMPCORE)
3459 goto out;
3460 /* The OOM killer will not help higher order allocs */
3461 if (order > PAGE_ALLOC_COSTLY_ORDER)
3462 goto out;
3463 /*
3464 * We have already exhausted all our reclaim opportunities without any
3465 * success so it is time to admit defeat. We will skip the OOM killer
3466 * because it is very likely that the caller has a more reasonable
3467 * fallback than shooting a random task.
3468 *
3469 * The OOM killer may not free memory on a specific node.
3470 */
3471 if (gfp_mask & (__GFP_RETRY_MAYFAIL | __GFP_THISNODE))
3472 goto out;
3473 /* The OOM killer does not needlessly kill tasks for lowmem */
3474 if (ac->highest_zoneidx < ZONE_NORMAL)
3475 goto out;
3476 if (pm_suspended_storage())
3477 goto out;
3478 /*
3479 * XXX: GFP_NOFS allocations should rather fail than rely on
3480 * other request to make a forward progress.
3481 * We are in an unfortunate situation where out_of_memory cannot
3482 * do much for this context but let's try it to at least get
3483 * access to memory reserved if the current task is killed (see
3484 * out_of_memory). Once filesystems are ready to handle allocation
3485 * failures more gracefully we should just bail out here.
3486 */
3487
3488 /* Exhausted what can be done so it's blame time */
3489 if (out_of_memory(&oc) ||
3490 WARN_ON_ONCE_GFP(gfp_mask & __GFP_NOFAIL, gfp_mask)) {
3491 *did_some_progress = 1;
3492
3493 /*
3494 * Help non-failing allocations by giving them access to memory
3495 * reserves
3496 */
3497 if (gfp_mask & __GFP_NOFAIL)
3498 page = __alloc_pages_cpuset_fallback(gfp_mask, order,
3499 ALLOC_NO_WATERMARKS, ac);
3500 }
3501out:
3502 mutex_unlock(&oom_lock);
3503 return page;
3504}
3505
3506/*
3507 * Maximum number of compaction retries with a progress before OOM
3508 * killer is consider as the only way to move forward.
3509 */
3510#define MAX_COMPACT_RETRIES 16
3511
3512#ifdef CONFIG_COMPACTION
3513/* Try memory compaction for high-order allocations before reclaim */
3514static struct page *
3515__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
3516 unsigned int alloc_flags, const struct alloc_context *ac,
3517 enum compact_priority prio, enum compact_result *compact_result)
3518{
3519 struct page *page = NULL;
3520 unsigned long pflags;
3521 unsigned int noreclaim_flag;
3522
3523 if (!order)
3524 return NULL;
3525
3526 psi_memstall_enter(&pflags);
3527 delayacct_compact_start();
3528 noreclaim_flag = memalloc_noreclaim_save();
3529
3530 *compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac,
3531 prio, &page);
3532
3533 memalloc_noreclaim_restore(noreclaim_flag);
3534 psi_memstall_leave(&pflags);
3535 delayacct_compact_end();
3536
3537 if (*compact_result == COMPACT_SKIPPED)
3538 return NULL;
3539 /*
3540 * At least in one zone compaction wasn't deferred or skipped, so let's
3541 * count a compaction stall
3542 */
3543 count_vm_event(COMPACTSTALL);
3544
3545 /* Prep a captured page if available */
3546 if (page)
3547 prep_new_page(page, order, gfp_mask, alloc_flags);
3548
3549 /* Try get a page from the freelist if available */
3550 if (!page)
3551 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
3552
3553 if (page) {
3554 struct zone *zone = page_zone(page);
3555
3556 zone->compact_blockskip_flush = false;
3557 compaction_defer_reset(zone, order, true);
3558 count_vm_event(COMPACTSUCCESS);
3559 return page;
3560 }
3561
3562 /*
3563 * It's bad if compaction run occurs and fails. The most likely reason
3564 * is that pages exist, but not enough to satisfy watermarks.
3565 */
3566 count_vm_event(COMPACTFAIL);
3567
3568 cond_resched();
3569
3570 return NULL;
3571}
3572
3573static inline bool
3574should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
3575 enum compact_result compact_result,
3576 enum compact_priority *compact_priority,
3577 int *compaction_retries)
3578{
3579 int max_retries = MAX_COMPACT_RETRIES;
3580 int min_priority;
3581 bool ret = false;
3582 int retries = *compaction_retries;
3583 enum compact_priority priority = *compact_priority;
3584
3585 if (!order)
3586 return false;
3587
3588 if (fatal_signal_pending(current))
3589 return false;
3590
3591 /*
3592 * Compaction was skipped due to a lack of free order-0
3593 * migration targets. Continue if reclaim can help.
3594 */
3595 if (compact_result == COMPACT_SKIPPED) {
3596 ret = compaction_zonelist_suitable(ac, order, alloc_flags);
3597 goto out;
3598 }
3599
3600 /*
3601 * Compaction managed to coalesce some page blocks, but the
3602 * allocation failed presumably due to a race. Retry some.
3603 */
3604 if (compact_result == COMPACT_SUCCESS) {
3605 /*
3606 * !costly requests are much more important than
3607 * __GFP_RETRY_MAYFAIL costly ones because they are de
3608 * facto nofail and invoke OOM killer to move on while
3609 * costly can fail and users are ready to cope with
3610 * that. 1/4 retries is rather arbitrary but we would
3611 * need much more detailed feedback from compaction to
3612 * make a better decision.
3613 */
3614 if (order > PAGE_ALLOC_COSTLY_ORDER)
3615 max_retries /= 4;
3616
3617 if (++(*compaction_retries) <= max_retries) {
3618 ret = true;
3619 goto out;
3620 }
3621 }
3622
3623 /*
3624 * Compaction failed. Retry with increasing priority.
3625 */
3626 min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ?
3627 MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY;
3628
3629 if (*compact_priority > min_priority) {
3630 (*compact_priority)--;
3631 *compaction_retries = 0;
3632 ret = true;
3633 }
3634out:
3635 trace_compact_retry(order, priority, compact_result, retries, max_retries, ret);
3636 return ret;
3637}
3638#else
3639static inline struct page *
3640__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
3641 unsigned int alloc_flags, const struct alloc_context *ac,
3642 enum compact_priority prio, enum compact_result *compact_result)
3643{
3644 *compact_result = COMPACT_SKIPPED;
3645 return NULL;
3646}
3647
3648static inline bool
3649should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags,
3650 enum compact_result compact_result,
3651 enum compact_priority *compact_priority,
3652 int *compaction_retries)
3653{
3654 struct zone *zone;
3655 struct zoneref *z;
3656
3657 if (!order || order > PAGE_ALLOC_COSTLY_ORDER)
3658 return false;
3659
3660 /*
3661 * There are setups with compaction disabled which would prefer to loop
3662 * inside the allocator rather than hit the oom killer prematurely.
3663 * Let's give them a good hope and keep retrying while the order-0
3664 * watermarks are OK.
3665 */
3666 for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
3667 ac->highest_zoneidx, ac->nodemask) {
3668 if (zone_watermark_ok(zone, 0, min_wmark_pages(zone),
3669 ac->highest_zoneidx, alloc_flags))
3670 return true;
3671 }
3672 return false;
3673}
3674#endif /* CONFIG_COMPACTION */
3675
3676#ifdef CONFIG_LOCKDEP
3677static struct lockdep_map __fs_reclaim_map =
3678 STATIC_LOCKDEP_MAP_INIT("fs_reclaim", &__fs_reclaim_map);
3679
3680static bool __need_reclaim(gfp_t gfp_mask)
3681{
3682 /* no reclaim without waiting on it */
3683 if (!(gfp_mask & __GFP_DIRECT_RECLAIM))
3684 return false;
3685
3686 /* this guy won't enter reclaim */
3687 if (current->flags & PF_MEMALLOC)
3688 return false;
3689
3690 if (gfp_mask & __GFP_NOLOCKDEP)
3691 return false;
3692
3693 return true;
3694}
3695
3696void __fs_reclaim_acquire(unsigned long ip)
3697{
3698 lock_acquire_exclusive(&__fs_reclaim_map, 0, 0, NULL, ip);
3699}
3700
3701void __fs_reclaim_release(unsigned long ip)
3702{
3703 lock_release(&__fs_reclaim_map, ip);
3704}
3705
3706void fs_reclaim_acquire(gfp_t gfp_mask)
3707{
3708 gfp_mask = current_gfp_context(gfp_mask);
3709
3710 if (__need_reclaim(gfp_mask)) {
3711 if (gfp_mask & __GFP_FS)
3712 __fs_reclaim_acquire(_RET_IP_);
3713
3714#ifdef CONFIG_MMU_NOTIFIER
3715 lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
3716 lock_map_release(&__mmu_notifier_invalidate_range_start_map);
3717#endif
3718
3719 }
3720}
3721EXPORT_SYMBOL_GPL(fs_reclaim_acquire);
3722
3723void fs_reclaim_release(gfp_t gfp_mask)
3724{
3725 gfp_mask = current_gfp_context(gfp_mask);
3726
3727 if (__need_reclaim(gfp_mask)) {
3728 if (gfp_mask & __GFP_FS)
3729 __fs_reclaim_release(_RET_IP_);
3730 }
3731}
3732EXPORT_SYMBOL_GPL(fs_reclaim_release);
3733#endif
3734
3735/*
3736 * Zonelists may change due to hotplug during allocation. Detect when zonelists
3737 * have been rebuilt so allocation retries. Reader side does not lock and
3738 * retries the allocation if zonelist changes. Writer side is protected by the
3739 * embedded spin_lock.
3740 */
3741static DEFINE_SEQLOCK(zonelist_update_seq);
3742
3743static unsigned int zonelist_iter_begin(void)
3744{
3745 if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
3746 return read_seqbegin(&zonelist_update_seq);
3747
3748 return 0;
3749}
3750
3751static unsigned int check_retry_zonelist(unsigned int seq)
3752{
3753 if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
3754 return read_seqretry(&zonelist_update_seq, seq);
3755
3756 return seq;
3757}
3758
3759/* Perform direct synchronous page reclaim */
3760static unsigned long
3761__perform_reclaim(gfp_t gfp_mask, unsigned int order,
3762 const struct alloc_context *ac)
3763{
3764 unsigned int noreclaim_flag;
3765 unsigned long progress;
3766
3767 cond_resched();
3768
3769 /* We now go into synchronous reclaim */
3770 cpuset_memory_pressure_bump();
3771 fs_reclaim_acquire(gfp_mask);
3772 noreclaim_flag = memalloc_noreclaim_save();
3773
3774 progress = try_to_free_pages(ac->zonelist, order, gfp_mask,
3775 ac->nodemask);
3776
3777 memalloc_noreclaim_restore(noreclaim_flag);
3778 fs_reclaim_release(gfp_mask);
3779
3780 cond_resched();
3781
3782 return progress;
3783}
3784
3785/* The really slow allocator path where we enter direct reclaim */
3786static inline struct page *
3787__alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
3788 unsigned int alloc_flags, const struct alloc_context *ac,
3789 unsigned long *did_some_progress)
3790{
3791 struct page *page = NULL;
3792 unsigned long pflags;
3793 bool drained = false;
3794
3795 psi_memstall_enter(&pflags);
3796 *did_some_progress = __perform_reclaim(gfp_mask, order, ac);
3797 if (unlikely(!(*did_some_progress)))
3798 goto out;
3799
3800retry:
3801 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
3802
3803 /*
3804 * If an allocation failed after direct reclaim, it could be because
3805 * pages are pinned on the per-cpu lists or in high alloc reserves.
3806 * Shrink them and try again
3807 */
3808 if (!page && !drained) {
3809 unreserve_highatomic_pageblock(ac, false);
3810 drain_all_pages(NULL);
3811 drained = true;
3812 goto retry;
3813 }
3814out:
3815 psi_memstall_leave(&pflags);
3816
3817 return page;
3818}
3819
3820static void wake_all_kswapds(unsigned int order, gfp_t gfp_mask,
3821 const struct alloc_context *ac)
3822{
3823 struct zoneref *z;
3824 struct zone *zone;
3825 pg_data_t *last_pgdat = NULL;
3826 enum zone_type highest_zoneidx = ac->highest_zoneidx;
3827
3828 for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, highest_zoneidx,
3829 ac->nodemask) {
3830 if (!managed_zone(zone))
3831 continue;
3832 if (last_pgdat != zone->zone_pgdat) {
3833 wakeup_kswapd(zone, gfp_mask, order, highest_zoneidx);
3834 last_pgdat = zone->zone_pgdat;
3835 }
3836 }
3837}
3838
3839static inline unsigned int
3840gfp_to_alloc_flags(gfp_t gfp_mask, unsigned int order)
3841{
3842 unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
3843
3844 /*
3845 * __GFP_HIGH is assumed to be the same as ALLOC_MIN_RESERVE
3846 * and __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD
3847 * to save two branches.
3848 */
3849 BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_MIN_RESERVE);
3850 BUILD_BUG_ON(__GFP_KSWAPD_RECLAIM != (__force gfp_t) ALLOC_KSWAPD);
3851
3852 /*
3853 * The caller may dip into page reserves a bit more if the caller
3854 * cannot run direct reclaim, or if the caller has realtime scheduling
3855 * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
3856 * set both ALLOC_NON_BLOCK and ALLOC_MIN_RESERVE(__GFP_HIGH).
3857 */
3858 alloc_flags |= (__force int)
3859 (gfp_mask & (__GFP_HIGH | __GFP_KSWAPD_RECLAIM));
3860
3861 if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) {
3862 /*
3863 * Not worth trying to allocate harder for __GFP_NOMEMALLOC even
3864 * if it can't schedule.
3865 */
3866 if (!(gfp_mask & __GFP_NOMEMALLOC)) {
3867 alloc_flags |= ALLOC_NON_BLOCK;
3868
3869 if (order > 0)
3870 alloc_flags |= ALLOC_HIGHATOMIC;
3871 }
3872
3873 /*
3874 * Ignore cpuset mems for non-blocking __GFP_HIGH (probably
3875 * GFP_ATOMIC) rather than fail, see the comment for
3876 * cpuset_node_allowed().
3877 */
3878 if (alloc_flags & ALLOC_MIN_RESERVE)
3879 alloc_flags &= ~ALLOC_CPUSET;
3880 } else if (unlikely(rt_task(current)) && in_task())
3881 alloc_flags |= ALLOC_MIN_RESERVE;
3882
3883 alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, alloc_flags);
3884
3885 return alloc_flags;
3886}
3887
3888static bool oom_reserves_allowed(struct task_struct *tsk)
3889{
3890 if (!tsk_is_oom_victim(tsk))
3891 return false;
3892
3893 /*
3894 * !MMU doesn't have oom reaper so give access to memory reserves
3895 * only to the thread with TIF_MEMDIE set
3896 */
3897 if (!IS_ENABLED(CONFIG_MMU) && !test_thread_flag(TIF_MEMDIE))
3898 return false;
3899
3900 return true;
3901}
3902
3903/*
3904 * Distinguish requests which really need access to full memory
3905 * reserves from oom victims which can live with a portion of it
3906 */
3907static inline int __gfp_pfmemalloc_flags(gfp_t gfp_mask)
3908{
3909 if (unlikely(gfp_mask & __GFP_NOMEMALLOC))
3910 return 0;
3911 if (gfp_mask & __GFP_MEMALLOC)
3912 return ALLOC_NO_WATERMARKS;
3913 if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
3914 return ALLOC_NO_WATERMARKS;
3915 if (!in_interrupt()) {
3916 if (current->flags & PF_MEMALLOC)
3917 return ALLOC_NO_WATERMARKS;
3918 else if (oom_reserves_allowed(current))
3919 return ALLOC_OOM;
3920 }
3921
3922 return 0;
3923}
3924
3925bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
3926{
3927 return !!__gfp_pfmemalloc_flags(gfp_mask);
3928}
3929
3930/*
3931 * Checks whether it makes sense to retry the reclaim to make a forward progress
3932 * for the given allocation request.
3933 *
3934 * We give up when we either have tried MAX_RECLAIM_RETRIES in a row
3935 * without success, or when we couldn't even meet the watermark if we
3936 * reclaimed all remaining pages on the LRU lists.
3937 *
3938 * Returns true if a retry is viable or false to enter the oom path.
3939 */
3940static inline bool
3941should_reclaim_retry(gfp_t gfp_mask, unsigned order,
3942 struct alloc_context *ac, int alloc_flags,
3943 bool did_some_progress, int *no_progress_loops)
3944{
3945 struct zone *zone;
3946 struct zoneref *z;
3947 bool ret = false;
3948
3949 /*
3950 * Costly allocations might have made a progress but this doesn't mean
3951 * their order will become available due to high fragmentation so
3952 * always increment the no progress counter for them
3953 */
3954 if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER)
3955 *no_progress_loops = 0;
3956 else
3957 (*no_progress_loops)++;
3958
3959 if (*no_progress_loops > MAX_RECLAIM_RETRIES)
3960 goto out;
3961
3962
3963 /*
3964 * Keep reclaiming pages while there is a chance this will lead
3965 * somewhere. If none of the target zones can satisfy our allocation
3966 * request even if all reclaimable pages are considered then we are
3967 * screwed and have to go OOM.
3968 */
3969 for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
3970 ac->highest_zoneidx, ac->nodemask) {
3971 unsigned long available;
3972 unsigned long reclaimable;
3973 unsigned long min_wmark = min_wmark_pages(zone);
3974 bool wmark;
3975
3976 available = reclaimable = zone_reclaimable_pages(zone);
3977 available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
3978
3979 /*
3980 * Would the allocation succeed if we reclaimed all
3981 * reclaimable pages?
3982 */
3983 wmark = __zone_watermark_ok(zone, order, min_wmark,
3984 ac->highest_zoneidx, alloc_flags, available);
3985 trace_reclaim_retry_zone(z, order, reclaimable,
3986 available, min_wmark, *no_progress_loops, wmark);
3987 if (wmark) {
3988 ret = true;
3989 break;
3990 }
3991 }
3992
3993 /*
3994 * Memory allocation/reclaim might be called from a WQ context and the
3995 * current implementation of the WQ concurrency control doesn't
3996 * recognize that a particular WQ is congested if the worker thread is
3997 * looping without ever sleeping. Therefore we have to do a short sleep
3998 * here rather than calling cond_resched().
3999 */
4000 if (current->flags & PF_WQ_WORKER)
4001 schedule_timeout_uninterruptible(1);
4002 else
4003 cond_resched();
4004out:
4005 /* Before OOM, exhaust highatomic_reserve */
4006 if (!ret)
4007 return unreserve_highatomic_pageblock(ac, true);
4008
4009 return ret;
4010}
4011
4012static inline bool
4013check_retry_cpuset(int cpuset_mems_cookie, struct alloc_context *ac)
4014{
4015 /*
4016 * It's possible that cpuset's mems_allowed and the nodemask from
4017 * mempolicy don't intersect. This should be normally dealt with by
4018 * policy_nodemask(), but it's possible to race with cpuset update in
4019 * such a way the check therein was true, and then it became false
4020 * before we got our cpuset_mems_cookie here.
4021 * This assumes that for all allocations, ac->nodemask can come only
4022 * from MPOL_BIND mempolicy (whose documented semantics is to be ignored
4023 * when it does not intersect with the cpuset restrictions) or the
4024 * caller can deal with a violated nodemask.
4025 */
4026 if (cpusets_enabled() && ac->nodemask &&
4027 !cpuset_nodemask_valid_mems_allowed(ac->nodemask)) {
4028 ac->nodemask = NULL;
4029 return true;
4030 }
4031
4032 /*
4033 * When updating a task's mems_allowed or mempolicy nodemask, it is
4034 * possible to race with parallel threads in such a way that our
4035 * allocation can fail while the mask is being updated. If we are about
4036 * to fail, check if the cpuset changed during allocation and if so,
4037 * retry.
4038 */
4039 if (read_mems_allowed_retry(cpuset_mems_cookie))
4040 return true;
4041
4042 return false;
4043}
4044
4045static inline struct page *
4046__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
4047 struct alloc_context *ac)
4048{
4049 bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM;
4050 bool can_compact = gfp_compaction_allowed(gfp_mask);
4051 const bool costly_order = order > PAGE_ALLOC_COSTLY_ORDER;
4052 struct page *page = NULL;
4053 unsigned int alloc_flags;
4054 unsigned long did_some_progress;
4055 enum compact_priority compact_priority;
4056 enum compact_result compact_result;
4057 int compaction_retries;
4058 int no_progress_loops;
4059 unsigned int cpuset_mems_cookie;
4060 unsigned int zonelist_iter_cookie;
4061 int reserve_flags;
4062
4063restart:
4064 compaction_retries = 0;
4065 no_progress_loops = 0;
4066 compact_priority = DEF_COMPACT_PRIORITY;
4067 cpuset_mems_cookie = read_mems_allowed_begin();
4068 zonelist_iter_cookie = zonelist_iter_begin();
4069
4070 /*
4071 * The fast path uses conservative alloc_flags to succeed only until
4072 * kswapd needs to be woken up, and to avoid the cost of setting up
4073 * alloc_flags precisely. So we do that now.
4074 */
4075 alloc_flags = gfp_to_alloc_flags(gfp_mask, order);
4076
4077 /*
4078 * We need to recalculate the starting point for the zonelist iterator
4079 * because we might have used different nodemask in the fast path, or
4080 * there was a cpuset modification and we are retrying - otherwise we
4081 * could end up iterating over non-eligible zones endlessly.
4082 */
4083 ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
4084 ac->highest_zoneidx, ac->nodemask);
4085 if (!ac->preferred_zoneref->zone)
4086 goto nopage;
4087
4088 /*
4089 * Check for insane configurations where the cpuset doesn't contain
4090 * any suitable zone to satisfy the request - e.g. non-movable
4091 * GFP_HIGHUSER allocations from MOVABLE nodes only.
4092 */
4093 if (cpusets_insane_config() && (gfp_mask & __GFP_HARDWALL)) {
4094 struct zoneref *z = first_zones_zonelist(ac->zonelist,
4095 ac->highest_zoneidx,
4096 &cpuset_current_mems_allowed);
4097 if (!z->zone)
4098 goto nopage;
4099 }
4100
4101 if (alloc_flags & ALLOC_KSWAPD)
4102 wake_all_kswapds(order, gfp_mask, ac);
4103
4104 /*
4105 * The adjusted alloc_flags might result in immediate success, so try
4106 * that first
4107 */
4108 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4109 if (page)
4110 goto got_pg;
4111
4112 /*
4113 * For costly allocations, try direct compaction first, as it's likely
4114 * that we have enough base pages and don't need to reclaim. For non-
4115 * movable high-order allocations, do that as well, as compaction will
4116 * try prevent permanent fragmentation by migrating from blocks of the
4117 * same migratetype.
4118 * Don't try this for allocations that are allowed to ignore
4119 * watermarks, as the ALLOC_NO_WATERMARKS attempt didn't yet happen.
4120 */
4121 if (can_direct_reclaim && can_compact &&
4122 (costly_order ||
4123 (order > 0 && ac->migratetype != MIGRATE_MOVABLE))
4124 && !gfp_pfmemalloc_allowed(gfp_mask)) {
4125 page = __alloc_pages_direct_compact(gfp_mask, order,
4126 alloc_flags, ac,
4127 INIT_COMPACT_PRIORITY,
4128 &compact_result);
4129 if (page)
4130 goto got_pg;
4131
4132 /*
4133 * Checks for costly allocations with __GFP_NORETRY, which
4134 * includes some THP page fault allocations
4135 */
4136 if (costly_order && (gfp_mask & __GFP_NORETRY)) {
4137 /*
4138 * If allocating entire pageblock(s) and compaction
4139 * failed because all zones are below low watermarks
4140 * or is prohibited because it recently failed at this
4141 * order, fail immediately unless the allocator has
4142 * requested compaction and reclaim retry.
4143 *
4144 * Reclaim is
4145 * - potentially very expensive because zones are far
4146 * below their low watermarks or this is part of very
4147 * bursty high order allocations,
4148 * - not guaranteed to help because isolate_freepages()
4149 * may not iterate over freed pages as part of its
4150 * linear scan, and
4151 * - unlikely to make entire pageblocks free on its
4152 * own.
4153 */
4154 if (compact_result == COMPACT_SKIPPED ||
4155 compact_result == COMPACT_DEFERRED)
4156 goto nopage;
4157
4158 /*
4159 * Looks like reclaim/compaction is worth trying, but
4160 * sync compaction could be very expensive, so keep
4161 * using async compaction.
4162 */
4163 compact_priority = INIT_COMPACT_PRIORITY;
4164 }
4165 }
4166
4167retry:
4168 /* Ensure kswapd doesn't accidentally go to sleep as long as we loop */
4169 if (alloc_flags & ALLOC_KSWAPD)
4170 wake_all_kswapds(order, gfp_mask, ac);
4171
4172 reserve_flags = __gfp_pfmemalloc_flags(gfp_mask);
4173 if (reserve_flags)
4174 alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags) |
4175 (alloc_flags & ALLOC_KSWAPD);
4176
4177 /*
4178 * Reset the nodemask and zonelist iterators if memory policies can be
4179 * ignored. These allocations are high priority and system rather than
4180 * user oriented.
4181 */
4182 if (!(alloc_flags & ALLOC_CPUSET) || reserve_flags) {
4183 ac->nodemask = NULL;
4184 ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
4185 ac->highest_zoneidx, ac->nodemask);
4186 }
4187
4188 /* Attempt with potentially adjusted zonelist and alloc_flags */
4189 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4190 if (page)
4191 goto got_pg;
4192
4193 /* Caller is not willing to reclaim, we can't balance anything */
4194 if (!can_direct_reclaim)
4195 goto nopage;
4196
4197 /* Avoid recursion of direct reclaim */
4198 if (current->flags & PF_MEMALLOC)
4199 goto nopage;
4200
4201 /* Try direct reclaim and then allocating */
4202 page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac,
4203 &did_some_progress);
4204 if (page)
4205 goto got_pg;
4206
4207 /* Try direct compaction and then allocating */
4208 page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac,
4209 compact_priority, &compact_result);
4210 if (page)
4211 goto got_pg;
4212
4213 /* Do not loop if specifically requested */
4214 if (gfp_mask & __GFP_NORETRY)
4215 goto nopage;
4216
4217 /*
4218 * Do not retry costly high order allocations unless they are
4219 * __GFP_RETRY_MAYFAIL and we can compact
4220 */
4221 if (costly_order && (!can_compact ||
4222 !(gfp_mask & __GFP_RETRY_MAYFAIL)))
4223 goto nopage;
4224
4225 if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags,
4226 did_some_progress > 0, &no_progress_loops))
4227 goto retry;
4228
4229 /*
4230 * It doesn't make any sense to retry for the compaction if the order-0
4231 * reclaim is not able to make any progress because the current
4232 * implementation of the compaction depends on the sufficient amount
4233 * of free memory (see __compaction_suitable)
4234 */
4235 if (did_some_progress > 0 && can_compact &&
4236 should_compact_retry(ac, order, alloc_flags,
4237 compact_result, &compact_priority,
4238 &compaction_retries))
4239 goto retry;
4240
4241
4242 /*
4243 * Deal with possible cpuset update races or zonelist updates to avoid
4244 * a unnecessary OOM kill.
4245 */
4246 if (check_retry_cpuset(cpuset_mems_cookie, ac) ||
4247 check_retry_zonelist(zonelist_iter_cookie))
4248 goto restart;
4249
4250 /* Reclaim has failed us, start killing things */
4251 page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
4252 if (page)
4253 goto got_pg;
4254
4255 /* Avoid allocations with no watermarks from looping endlessly */
4256 if (tsk_is_oom_victim(current) &&
4257 (alloc_flags & ALLOC_OOM ||
4258 (gfp_mask & __GFP_NOMEMALLOC)))
4259 goto nopage;
4260
4261 /* Retry as long as the OOM killer is making progress */
4262 if (did_some_progress) {
4263 no_progress_loops = 0;
4264 goto retry;
4265 }
4266
4267nopage:
4268 /*
4269 * Deal with possible cpuset update races or zonelist updates to avoid
4270 * a unnecessary OOM kill.
4271 */
4272 if (check_retry_cpuset(cpuset_mems_cookie, ac) ||
4273 check_retry_zonelist(zonelist_iter_cookie))
4274 goto restart;
4275
4276 /*
4277 * Make sure that __GFP_NOFAIL request doesn't leak out and make sure
4278 * we always retry
4279 */
4280 if (gfp_mask & __GFP_NOFAIL) {
4281 /*
4282 * All existing users of the __GFP_NOFAIL are blockable, so warn
4283 * of any new users that actually require GFP_NOWAIT
4284 */
4285 if (WARN_ON_ONCE_GFP(!can_direct_reclaim, gfp_mask))
4286 goto fail;
4287
4288 /*
4289 * PF_MEMALLOC request from this context is rather bizarre
4290 * because we cannot reclaim anything and only can loop waiting
4291 * for somebody to do a work for us
4292 */
4293 WARN_ON_ONCE_GFP(current->flags & PF_MEMALLOC, gfp_mask);
4294
4295 /*
4296 * non failing costly orders are a hard requirement which we
4297 * are not prepared for much so let's warn about these users
4298 * so that we can identify them and convert them to something
4299 * else.
4300 */
4301 WARN_ON_ONCE_GFP(costly_order, gfp_mask);
4302
4303 /*
4304 * Help non-failing allocations by giving some access to memory
4305 * reserves normally used for high priority non-blocking
4306 * allocations but do not use ALLOC_NO_WATERMARKS because this
4307 * could deplete whole memory reserves which would just make
4308 * the situation worse.
4309 */
4310 page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_MIN_RESERVE, ac);
4311 if (page)
4312 goto got_pg;
4313
4314 cond_resched();
4315 goto retry;
4316 }
4317fail:
4318 warn_alloc(gfp_mask, ac->nodemask,
4319 "page allocation failure: order:%u", order);
4320got_pg:
4321 return page;
4322}
4323
4324static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
4325 int preferred_nid, nodemask_t *nodemask,
4326 struct alloc_context *ac, gfp_t *alloc_gfp,
4327 unsigned int *alloc_flags)
4328{
4329 ac->highest_zoneidx = gfp_zone(gfp_mask);
4330 ac->zonelist = node_zonelist(preferred_nid, gfp_mask);
4331 ac->nodemask = nodemask;
4332 ac->migratetype = gfp_migratetype(gfp_mask);
4333
4334 if (cpusets_enabled()) {
4335 *alloc_gfp |= __GFP_HARDWALL;
4336 /*
4337 * When we are in the interrupt context, it is irrelevant
4338 * to the current task context. It means that any node ok.
4339 */
4340 if (in_task() && !ac->nodemask)
4341 ac->nodemask = &cpuset_current_mems_allowed;
4342 else
4343 *alloc_flags |= ALLOC_CPUSET;
4344 }
4345
4346 might_alloc(gfp_mask);
4347
4348 if (should_fail_alloc_page(gfp_mask, order))
4349 return false;
4350
4351 *alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, *alloc_flags);
4352
4353 /* Dirty zone balancing only done in the fast path */
4354 ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE);
4355
4356 /*
4357 * The preferred zone is used for statistics but crucially it is
4358 * also used as the starting point for the zonelist iterator. It
4359 * may get reset for allocations that ignore memory policies.
4360 */
4361 ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
4362 ac->highest_zoneidx, ac->nodemask);
4363
4364 return true;
4365}
4366
4367/*
4368 * __alloc_pages_bulk - Allocate a number of order-0 pages to a list or array
4369 * @gfp: GFP flags for the allocation
4370 * @preferred_nid: The preferred NUMA node ID to allocate from
4371 * @nodemask: Set of nodes to allocate from, may be NULL
4372 * @nr_pages: The number of pages desired on the list or array
4373 * @page_list: Optional list to store the allocated pages
4374 * @page_array: Optional array to store the pages
4375 *
4376 * This is a batched version of the page allocator that attempts to
4377 * allocate nr_pages quickly. Pages are added to page_list if page_list
4378 * is not NULL, otherwise it is assumed that the page_array is valid.
4379 *
4380 * For lists, nr_pages is the number of pages that should be allocated.
4381 *
4382 * For arrays, only NULL elements are populated with pages and nr_pages
4383 * is the maximum number of pages that will be stored in the array.
4384 *
4385 * Returns the number of pages on the list or array.
4386 */
4387unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid,
4388 nodemask_t *nodemask, int nr_pages,
4389 struct list_head *page_list,
4390 struct page **page_array)
4391{
4392 struct page *page;
4393 unsigned long __maybe_unused UP_flags;
4394 struct zone *zone;
4395 struct zoneref *z;
4396 struct per_cpu_pages *pcp;
4397 struct list_head *pcp_list;
4398 struct alloc_context ac;
4399 gfp_t alloc_gfp;
4400 unsigned int alloc_flags = ALLOC_WMARK_LOW;
4401 int nr_populated = 0, nr_account = 0;
4402
4403 /*
4404 * Skip populated array elements to determine if any pages need
4405 * to be allocated before disabling IRQs.
4406 */
4407 while (page_array && nr_populated < nr_pages && page_array[nr_populated])
4408 nr_populated++;
4409
4410 /* No pages requested? */
4411 if (unlikely(nr_pages <= 0))
4412 goto out;
4413
4414 /* Already populated array? */
4415 if (unlikely(page_array && nr_pages - nr_populated == 0))
4416 goto out;
4417
4418 /* Bulk allocator does not support memcg accounting. */
4419 if (memcg_kmem_online() && (gfp & __GFP_ACCOUNT))
4420 goto failed;
4421
4422 /* Use the single page allocator for one page. */
4423 if (nr_pages - nr_populated == 1)
4424 goto failed;
4425
4426#ifdef CONFIG_PAGE_OWNER
4427 /*
4428 * PAGE_OWNER may recurse into the allocator to allocate space to
4429 * save the stack with pagesets.lock held. Releasing/reacquiring
4430 * removes much of the performance benefit of bulk allocation so
4431 * force the caller to allocate one page at a time as it'll have
4432 * similar performance to added complexity to the bulk allocator.
4433 */
4434 if (static_branch_unlikely(&page_owner_inited))
4435 goto failed;
4436#endif
4437
4438 /* May set ALLOC_NOFRAGMENT, fragmentation will return 1 page. */
4439 gfp &= gfp_allowed_mask;
4440 alloc_gfp = gfp;
4441 if (!prepare_alloc_pages(gfp, 0, preferred_nid, nodemask, &ac, &alloc_gfp, &alloc_flags))
4442 goto out;
4443 gfp = alloc_gfp;
4444
4445 /* Find an allowed local zone that meets the low watermark. */
4446 for_each_zone_zonelist_nodemask(zone, z, ac.zonelist, ac.highest_zoneidx, ac.nodemask) {
4447 unsigned long mark;
4448
4449 if (cpusets_enabled() && (alloc_flags & ALLOC_CPUSET) &&
4450 !__cpuset_zone_allowed(zone, gfp)) {
4451 continue;
4452 }
4453
4454 if (nr_online_nodes > 1 && zone != ac.preferred_zoneref->zone &&
4455 zone_to_nid(zone) != zone_to_nid(ac.preferred_zoneref->zone)) {
4456 goto failed;
4457 }
4458
4459 mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK) + nr_pages;
4460 if (zone_watermark_fast(zone, 0, mark,
4461 zonelist_zone_idx(ac.preferred_zoneref),
4462 alloc_flags, gfp)) {
4463 break;
4464 }
4465 }
4466
4467 /*
4468 * If there are no allowed local zones that meets the watermarks then
4469 * try to allocate a single page and reclaim if necessary.
4470 */
4471 if (unlikely(!zone))
4472 goto failed;
4473
4474 /* spin_trylock may fail due to a parallel drain or IRQ reentrancy. */
4475 pcp_trylock_prepare(UP_flags);
4476 pcp = pcp_spin_trylock(zone->per_cpu_pageset);
4477 if (!pcp)
4478 goto failed_irq;
4479
4480 /* Attempt the batch allocation */
4481 pcp_list = &pcp->lists[order_to_pindex(ac.migratetype, 0)];
4482 while (nr_populated < nr_pages) {
4483
4484 /* Skip existing pages */
4485 if (page_array && page_array[nr_populated]) {
4486 nr_populated++;
4487 continue;
4488 }
4489
4490 page = __rmqueue_pcplist(zone, 0, ac.migratetype, alloc_flags,
4491 pcp, pcp_list);
4492 if (unlikely(!page)) {
4493 /* Try and allocate at least one page */
4494 if (!nr_account) {
4495 pcp_spin_unlock(pcp);
4496 goto failed_irq;
4497 }
4498 break;
4499 }
4500 nr_account++;
4501
4502 prep_new_page(page, 0, gfp, 0);
4503 if (page_list)
4504 list_add(&page->lru, page_list);
4505 else
4506 page_array[nr_populated] = page;
4507 nr_populated++;
4508 }
4509
4510 pcp_spin_unlock(pcp);
4511 pcp_trylock_finish(UP_flags);
4512
4513 __count_zid_vm_events(PGALLOC, zone_idx(zone), nr_account);
4514 zone_statistics(ac.preferred_zoneref->zone, zone, nr_account);
4515
4516out:
4517 return nr_populated;
4518
4519failed_irq:
4520 pcp_trylock_finish(UP_flags);
4521
4522failed:
4523 page = __alloc_pages(gfp, 0, preferred_nid, nodemask);
4524 if (page) {
4525 if (page_list)
4526 list_add(&page->lru, page_list);
4527 else
4528 page_array[nr_populated] = page;
4529 nr_populated++;
4530 }
4531
4532 goto out;
4533}
4534EXPORT_SYMBOL_GPL(__alloc_pages_bulk);
4535
4536/*
4537 * This is the 'heart' of the zoned buddy allocator.
4538 */
4539struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid,
4540 nodemask_t *nodemask)
4541{
4542 struct page *page;
4543 unsigned int alloc_flags = ALLOC_WMARK_LOW;
4544 gfp_t alloc_gfp; /* The gfp_t that was actually used for allocation */
4545 struct alloc_context ac = { };
4546
4547 /*
4548 * There are several places where we assume that the order value is sane
4549 * so bail out early if the request is out of bound.
4550 */
4551 if (WARN_ON_ONCE_GFP(order > MAX_PAGE_ORDER, gfp))
4552 return NULL;
4553
4554 gfp &= gfp_allowed_mask;
4555 /*
4556 * Apply scoped allocation constraints. This is mainly about GFP_NOFS
4557 * resp. GFP_NOIO which has to be inherited for all allocation requests
4558 * from a particular context which has been marked by
4559 * memalloc_no{fs,io}_{save,restore}. And PF_MEMALLOC_PIN which ensures
4560 * movable zones are not used during allocation.
4561 */
4562 gfp = current_gfp_context(gfp);
4563 alloc_gfp = gfp;
4564 if (!prepare_alloc_pages(gfp, order, preferred_nid, nodemask, &ac,
4565 &alloc_gfp, &alloc_flags))
4566 return NULL;
4567
4568 /*
4569 * Forbid the first pass from falling back to types that fragment
4570 * memory until all local zones are considered.
4571 */
4572 alloc_flags |= alloc_flags_nofragment(ac.preferred_zoneref->zone, gfp);
4573
4574 /* First allocation attempt */
4575 page = get_page_from_freelist(alloc_gfp, order, alloc_flags, &ac);
4576 if (likely(page))
4577 goto out;
4578
4579 alloc_gfp = gfp;
4580 ac.spread_dirty_pages = false;
4581
4582 /*
4583 * Restore the original nodemask if it was potentially replaced with
4584 * &cpuset_current_mems_allowed to optimize the fast-path attempt.
4585 */
4586 ac.nodemask = nodemask;
4587
4588 page = __alloc_pages_slowpath(alloc_gfp, order, &ac);
4589
4590out:
4591 if (memcg_kmem_online() && (gfp & __GFP_ACCOUNT) && page &&
4592 unlikely(__memcg_kmem_charge_page(page, gfp, order) != 0)) {
4593 __free_pages(page, order);
4594 page = NULL;
4595 }
4596
4597 trace_mm_page_alloc(page, order, alloc_gfp, ac.migratetype);
4598 kmsan_alloc_page(page, order, alloc_gfp);
4599
4600 return page;
4601}
4602EXPORT_SYMBOL(__alloc_pages);
4603
4604struct folio *__folio_alloc(gfp_t gfp, unsigned int order, int preferred_nid,
4605 nodemask_t *nodemask)
4606{
4607 struct page *page = __alloc_pages(gfp | __GFP_COMP, order,
4608 preferred_nid, nodemask);
4609 return page_rmappable_folio(page);
4610}
4611EXPORT_SYMBOL(__folio_alloc);
4612
4613/*
4614 * Common helper functions. Never use with __GFP_HIGHMEM because the returned
4615 * address cannot represent highmem pages. Use alloc_pages and then kmap if
4616 * you need to access high mem.
4617 */
4618unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
4619{
4620 struct page *page;
4621
4622 page = alloc_pages(gfp_mask & ~__GFP_HIGHMEM, order);
4623 if (!page)
4624 return 0;
4625 return (unsigned long) page_address(page);
4626}
4627EXPORT_SYMBOL(__get_free_pages);
4628
4629unsigned long get_zeroed_page(gfp_t gfp_mask)
4630{
4631 return __get_free_page(gfp_mask | __GFP_ZERO);
4632}
4633EXPORT_SYMBOL(get_zeroed_page);
4634
4635/**
4636 * __free_pages - Free pages allocated with alloc_pages().
4637 * @page: The page pointer returned from alloc_pages().
4638 * @order: The order of the allocation.
4639 *
4640 * This function can free multi-page allocations that are not compound
4641 * pages. It does not check that the @order passed in matches that of
4642 * the allocation, so it is easy to leak memory. Freeing more memory
4643 * than was allocated will probably emit a warning.
4644 *
4645 * If the last reference to this page is speculative, it will be released
4646 * by put_page() which only frees the first page of a non-compound
4647 * allocation. To prevent the remaining pages from being leaked, we free
4648 * the subsequent pages here. If you want to use the page's reference
4649 * count to decide when to free the allocation, you should allocate a
4650 * compound page, and use put_page() instead of __free_pages().
4651 *
4652 * Context: May be called in interrupt context or while holding a normal
4653 * spinlock, but not in NMI context or while holding a raw spinlock.
4654 */
4655void __free_pages(struct page *page, unsigned int order)
4656{
4657 /* get PageHead before we drop reference */
4658 int head = PageHead(page);
4659
4660 if (put_page_testzero(page))
4661 free_the_page(page, order);
4662 else if (!head)
4663 while (order-- > 0)
4664 free_the_page(page + (1 << order), order);
4665}
4666EXPORT_SYMBOL(__free_pages);
4667
4668void free_pages(unsigned long addr, unsigned int order)
4669{
4670 if (addr != 0) {
4671 VM_BUG_ON(!virt_addr_valid((void *)addr));
4672 __free_pages(virt_to_page((void *)addr), order);
4673 }
4674}
4675
4676EXPORT_SYMBOL(free_pages);
4677
4678/*
4679 * Page Fragment:
4680 * An arbitrary-length arbitrary-offset area of memory which resides
4681 * within a 0 or higher order page. Multiple fragments within that page
4682 * are individually refcounted, in the page's reference counter.
4683 *
4684 * The page_frag functions below provide a simple allocation framework for
4685 * page fragments. This is used by the network stack and network device
4686 * drivers to provide a backing region of memory for use as either an
4687 * sk_buff->head, or to be used in the "frags" portion of skb_shared_info.
4688 */
4689static struct page *__page_frag_cache_refill(struct page_frag_cache *nc,
4690 gfp_t gfp_mask)
4691{
4692 struct page *page = NULL;
4693 gfp_t gfp = gfp_mask;
4694
4695#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
4696 gfp_mask = (gfp_mask & ~__GFP_DIRECT_RECLAIM) | __GFP_COMP |
4697 __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC;
4698 page = alloc_pages_node(NUMA_NO_NODE, gfp_mask,
4699 PAGE_FRAG_CACHE_MAX_ORDER);
4700 nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE;
4701#endif
4702 if (unlikely(!page))
4703 page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
4704
4705 nc->va = page ? page_address(page) : NULL;
4706
4707 return page;
4708}
4709
4710void page_frag_cache_drain(struct page_frag_cache *nc)
4711{
4712 if (!nc->va)
4713 return;
4714
4715 __page_frag_cache_drain(virt_to_head_page(nc->va), nc->pagecnt_bias);
4716 nc->va = NULL;
4717}
4718EXPORT_SYMBOL(page_frag_cache_drain);
4719
4720void __page_frag_cache_drain(struct page *page, unsigned int count)
4721{
4722 VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
4723
4724 if (page_ref_sub_and_test(page, count))
4725 free_the_page(page, compound_order(page));
4726}
4727EXPORT_SYMBOL(__page_frag_cache_drain);
4728
4729void *__page_frag_alloc_align(struct page_frag_cache *nc,
4730 unsigned int fragsz, gfp_t gfp_mask,
4731 unsigned int align_mask)
4732{
4733 unsigned int size = PAGE_SIZE;
4734 struct page *page;
4735 int offset;
4736
4737 if (unlikely(!nc->va)) {
4738refill:
4739 page = __page_frag_cache_refill(nc, gfp_mask);
4740 if (!page)
4741 return NULL;
4742
4743#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
4744 /* if size can vary use size else just use PAGE_SIZE */
4745 size = nc->size;
4746#endif
4747 /* Even if we own the page, we do not use atomic_set().
4748 * This would break get_page_unless_zero() users.
4749 */
4750 page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE);
4751
4752 /* reset page count bias and offset to start of new frag */
4753 nc->pfmemalloc = page_is_pfmemalloc(page);
4754 nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
4755 nc->offset = size;
4756 }
4757
4758 offset = nc->offset - fragsz;
4759 if (unlikely(offset < 0)) {
4760 page = virt_to_page(nc->va);
4761
4762 if (!page_ref_sub_and_test(page, nc->pagecnt_bias))
4763 goto refill;
4764
4765 if (unlikely(nc->pfmemalloc)) {
4766 free_the_page(page, compound_order(page));
4767 goto refill;
4768 }
4769
4770#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
4771 /* if size can vary use size else just use PAGE_SIZE */
4772 size = nc->size;
4773#endif
4774 /* OK, page count is 0, we can safely set it */
4775 set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1);
4776
4777 /* reset page count bias and offset to start of new frag */
4778 nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
4779 offset = size - fragsz;
4780 if (unlikely(offset < 0)) {
4781 /*
4782 * The caller is trying to allocate a fragment
4783 * with fragsz > PAGE_SIZE but the cache isn't big
4784 * enough to satisfy the request, this may
4785 * happen in low memory conditions.
4786 * We don't release the cache page because
4787 * it could make memory pressure worse
4788 * so we simply return NULL here.
4789 */
4790 return NULL;
4791 }
4792 }
4793
4794 nc->pagecnt_bias--;
4795 offset &= align_mask;
4796 nc->offset = offset;
4797
4798 return nc->va + offset;
4799}
4800EXPORT_SYMBOL(__page_frag_alloc_align);
4801
4802/*
4803 * Frees a page fragment allocated out of either a compound or order 0 page.
4804 */
4805void page_frag_free(void *addr)
4806{
4807 struct page *page = virt_to_head_page(addr);
4808
4809 if (unlikely(put_page_testzero(page)))
4810 free_the_page(page, compound_order(page));
4811}
4812EXPORT_SYMBOL(page_frag_free);
4813
4814static void *make_alloc_exact(unsigned long addr, unsigned int order,
4815 size_t size)
4816{
4817 if (addr) {
4818 unsigned long nr = DIV_ROUND_UP(size, PAGE_SIZE);
4819 struct page *page = virt_to_page((void *)addr);
4820 struct page *last = page + nr;
4821
4822 split_page_owner(page, order, 0);
4823 split_page_memcg(page, order, 0);
4824 while (page < --last)
4825 set_page_refcounted(last);
4826
4827 last = page + (1UL << order);
4828 for (page += nr; page < last; page++)
4829 __free_pages_ok(page, 0, FPI_TO_TAIL);
4830 }
4831 return (void *)addr;
4832}
4833
4834/**
4835 * alloc_pages_exact - allocate an exact number physically-contiguous pages.
4836 * @size: the number of bytes to allocate
4837 * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
4838 *
4839 * This function is similar to alloc_pages(), except that it allocates the
4840 * minimum number of pages to satisfy the request. alloc_pages() can only
4841 * allocate memory in power-of-two pages.
4842 *
4843 * This function is also limited by MAX_PAGE_ORDER.
4844 *
4845 * Memory allocated by this function must be released by free_pages_exact().
4846 *
4847 * Return: pointer to the allocated area or %NULL in case of error.
4848 */
4849void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
4850{
4851 unsigned int order = get_order(size);
4852 unsigned long addr;
4853
4854 if (WARN_ON_ONCE(gfp_mask & (__GFP_COMP | __GFP_HIGHMEM)))
4855 gfp_mask &= ~(__GFP_COMP | __GFP_HIGHMEM);
4856
4857 addr = __get_free_pages(gfp_mask, order);
4858 return make_alloc_exact(addr, order, size);
4859}
4860EXPORT_SYMBOL(alloc_pages_exact);
4861
4862/**
4863 * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
4864 * pages on a node.
4865 * @nid: the preferred node ID where memory should be allocated
4866 * @size: the number of bytes to allocate
4867 * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
4868 *
4869 * Like alloc_pages_exact(), but try to allocate on node nid first before falling
4870 * back.
4871 *
4872 * Return: pointer to the allocated area or %NULL in case of error.
4873 */
4874void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
4875{
4876 unsigned int order = get_order(size);
4877 struct page *p;
4878
4879 if (WARN_ON_ONCE(gfp_mask & (__GFP_COMP | __GFP_HIGHMEM)))
4880 gfp_mask &= ~(__GFP_COMP | __GFP_HIGHMEM);
4881
4882 p = alloc_pages_node(nid, gfp_mask, order);
4883 if (!p)
4884 return NULL;
4885 return make_alloc_exact((unsigned long)page_address(p), order, size);
4886}
4887
4888/**
4889 * free_pages_exact - release memory allocated via alloc_pages_exact()
4890 * @virt: the value returned by alloc_pages_exact.
4891 * @size: size of allocation, same value as passed to alloc_pages_exact().
4892 *
4893 * Release the memory allocated by a previous call to alloc_pages_exact.
4894 */
4895void free_pages_exact(void *virt, size_t size)
4896{
4897 unsigned long addr = (unsigned long)virt;
4898 unsigned long end = addr + PAGE_ALIGN(size);
4899
4900 while (addr < end) {
4901 free_page(addr);
4902 addr += PAGE_SIZE;
4903 }
4904}
4905EXPORT_SYMBOL(free_pages_exact);
4906
4907/**
4908 * nr_free_zone_pages - count number of pages beyond high watermark
4909 * @offset: The zone index of the highest zone
4910 *
4911 * nr_free_zone_pages() counts the number of pages which are beyond the
4912 * high watermark within all zones at or below a given zone index. For each
4913 * zone, the number of pages is calculated as:
4914 *
4915 * nr_free_zone_pages = managed_pages - high_pages
4916 *
4917 * Return: number of pages beyond high watermark.
4918 */
4919static unsigned long nr_free_zone_pages(int offset)
4920{
4921 struct zoneref *z;
4922 struct zone *zone;
4923
4924 /* Just pick one node, since fallback list is circular */
4925 unsigned long sum = 0;
4926
4927 struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
4928
4929 for_each_zone_zonelist(zone, z, zonelist, offset) {
4930 unsigned long size = zone_managed_pages(zone);
4931 unsigned long high = high_wmark_pages(zone);
4932 if (size > high)
4933 sum += size - high;
4934 }
4935
4936 return sum;
4937}
4938
4939/**
4940 * nr_free_buffer_pages - count number of pages beyond high watermark
4941 *
4942 * nr_free_buffer_pages() counts the number of pages which are beyond the high
4943 * watermark within ZONE_DMA and ZONE_NORMAL.
4944 *
4945 * Return: number of pages beyond high watermark within ZONE_DMA and
4946 * ZONE_NORMAL.
4947 */
4948unsigned long nr_free_buffer_pages(void)
4949{
4950 return nr_free_zone_pages(gfp_zone(GFP_USER));
4951}
4952EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
4953
4954static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
4955{
4956 zoneref->zone = zone;
4957 zoneref->zone_idx = zone_idx(zone);
4958}
4959
4960/*
4961 * Builds allocation fallback zone lists.
4962 *
4963 * Add all populated zones of a node to the zonelist.
4964 */
4965static int build_zonerefs_node(pg_data_t *pgdat, struct zoneref *zonerefs)
4966{
4967 struct zone *zone;
4968 enum zone_type zone_type = MAX_NR_ZONES;
4969 int nr_zones = 0;
4970
4971 do {
4972 zone_type--;
4973 zone = pgdat->node_zones + zone_type;
4974 if (populated_zone(zone)) {
4975 zoneref_set_zone(zone, &zonerefs[nr_zones++]);
4976 check_highest_zone(zone_type);
4977 }
4978 } while (zone_type);
4979
4980 return nr_zones;
4981}
4982
4983#ifdef CONFIG_NUMA
4984
4985static int __parse_numa_zonelist_order(char *s)
4986{
4987 /*
4988 * We used to support different zonelists modes but they turned
4989 * out to be just not useful. Let's keep the warning in place
4990 * if somebody still use the cmd line parameter so that we do
4991 * not fail it silently
4992 */
4993 if (!(*s == 'd' || *s == 'D' || *s == 'n' || *s == 'N')) {
4994 pr_warn("Ignoring unsupported numa_zonelist_order value: %s\n", s);
4995 return -EINVAL;
4996 }
4997 return 0;
4998}
4999
5000static char numa_zonelist_order[] = "Node";
5001#define NUMA_ZONELIST_ORDER_LEN 16
5002/*
5003 * sysctl handler for numa_zonelist_order
5004 */
5005static int numa_zonelist_order_handler(struct ctl_table *table, int write,
5006 void *buffer, size_t *length, loff_t *ppos)
5007{
5008 if (write)
5009 return __parse_numa_zonelist_order(buffer);
5010 return proc_dostring(table, write, buffer, length, ppos);
5011}
5012
5013static int node_load[MAX_NUMNODES];
5014
5015/**
5016 * find_next_best_node - find the next node that should appear in a given node's fallback list
5017 * @node: node whose fallback list we're appending
5018 * @used_node_mask: nodemask_t of already used nodes
5019 *
5020 * We use a number of factors to determine which is the next node that should
5021 * appear on a given node's fallback list. The node should not have appeared
5022 * already in @node's fallback list, and it should be the next closest node
5023 * according to the distance array (which contains arbitrary distance values
5024 * from each node to each node in the system), and should also prefer nodes
5025 * with no CPUs, since presumably they'll have very little allocation pressure
5026 * on them otherwise.
5027 *
5028 * Return: node id of the found node or %NUMA_NO_NODE if no node is found.
5029 */
5030int find_next_best_node(int node, nodemask_t *used_node_mask)
5031{
5032 int n, val;
5033 int min_val = INT_MAX;
5034 int best_node = NUMA_NO_NODE;
5035
5036 /*
5037 * Use the local node if we haven't already, but for memoryless local
5038 * node, we should skip it and fall back to other nodes.
5039 */
5040 if (!node_isset(node, *used_node_mask) && node_state(node, N_MEMORY)) {
5041 node_set(node, *used_node_mask);
5042 return node;
5043 }
5044
5045 for_each_node_state(n, N_MEMORY) {
5046
5047 /* Don't want a node to appear more than once */
5048 if (node_isset(n, *used_node_mask))
5049 continue;
5050
5051 /* Use the distance array to find the distance */
5052 val = node_distance(node, n);
5053
5054 /* Penalize nodes under us ("prefer the next node") */
5055 val += (n < node);
5056
5057 /* Give preference to headless and unused nodes */
5058 if (!cpumask_empty(cpumask_of_node(n)))
5059 val += PENALTY_FOR_NODE_WITH_CPUS;
5060
5061 /* Slight preference for less loaded node */
5062 val *= MAX_NUMNODES;
5063 val += node_load[n];
5064
5065 if (val < min_val) {
5066 min_val = val;
5067 best_node = n;
5068 }
5069 }
5070
5071 if (best_node >= 0)
5072 node_set(best_node, *used_node_mask);
5073
5074 return best_node;
5075}
5076
5077
5078/*
5079 * Build zonelists ordered by node and zones within node.
5080 * This results in maximum locality--normal zone overflows into local
5081 * DMA zone, if any--but risks exhausting DMA zone.
5082 */
5083static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order,
5084 unsigned nr_nodes)
5085{
5086 struct zoneref *zonerefs;
5087 int i;
5088
5089 zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;
5090
5091 for (i = 0; i < nr_nodes; i++) {
5092 int nr_zones;
5093
5094 pg_data_t *node = NODE_DATA(node_order[i]);
5095
5096 nr_zones = build_zonerefs_node(node, zonerefs);
5097 zonerefs += nr_zones;
5098 }
5099 zonerefs->zone = NULL;
5100 zonerefs->zone_idx = 0;
5101}
5102
5103/*
5104 * Build gfp_thisnode zonelists
5105 */
5106static void build_thisnode_zonelists(pg_data_t *pgdat)
5107{
5108 struct zoneref *zonerefs;
5109 int nr_zones;
5110
5111 zonerefs = pgdat->node_zonelists[ZONELIST_NOFALLBACK]._zonerefs;
5112 nr_zones = build_zonerefs_node(pgdat, zonerefs);
5113 zonerefs += nr_zones;
5114 zonerefs->zone = NULL;
5115 zonerefs->zone_idx = 0;
5116}
5117
5118/*
5119 * Build zonelists ordered by zone and nodes within zones.
5120 * This results in conserving DMA zone[s] until all Normal memory is
5121 * exhausted, but results in overflowing to remote node while memory
5122 * may still exist in local DMA zone.
5123 */
5124
5125static void build_zonelists(pg_data_t *pgdat)
5126{
5127 static int node_order[MAX_NUMNODES];
5128 int node, nr_nodes = 0;
5129 nodemask_t used_mask = NODE_MASK_NONE;
5130 int local_node, prev_node;
5131
5132 /* NUMA-aware ordering of nodes */
5133 local_node = pgdat->node_id;
5134 prev_node = local_node;
5135
5136 memset(node_order, 0, sizeof(node_order));
5137 while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
5138 /*
5139 * We don't want to pressure a particular node.
5140 * So adding penalty to the first node in same
5141 * distance group to make it round-robin.
5142 */
5143 if (node_distance(local_node, node) !=
5144 node_distance(local_node, prev_node))
5145 node_load[node] += 1;
5146
5147 node_order[nr_nodes++] = node;
5148 prev_node = node;
5149 }
5150
5151 build_zonelists_in_node_order(pgdat, node_order, nr_nodes);
5152 build_thisnode_zonelists(pgdat);
5153 pr_info("Fallback order for Node %d: ", local_node);
5154 for (node = 0; node < nr_nodes; node++)
5155 pr_cont("%d ", node_order[node]);
5156 pr_cont("\n");
5157}
5158
5159#ifdef CONFIG_HAVE_MEMORYLESS_NODES
5160/*
5161 * Return node id of node used for "local" allocations.
5162 * I.e., first node id of first zone in arg node's generic zonelist.
5163 * Used for initializing percpu 'numa_mem', which is used primarily
5164 * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
5165 */
5166int local_memory_node(int node)
5167{
5168 struct zoneref *z;
5169
5170 z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
5171 gfp_zone(GFP_KERNEL),
5172 NULL);
5173 return zone_to_nid(z->zone);
5174}
5175#endif
5176
5177static void setup_min_unmapped_ratio(void);
5178static void setup_min_slab_ratio(void);
5179#else /* CONFIG_NUMA */
5180
5181static void build_zonelists(pg_data_t *pgdat)
5182{
5183 int node, local_node;
5184 struct zoneref *zonerefs;
5185 int nr_zones;
5186
5187 local_node = pgdat->node_id;
5188
5189 zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;
5190 nr_zones = build_zonerefs_node(pgdat, zonerefs);
5191 zonerefs += nr_zones;
5192
5193 /*
5194 * Now we build the zonelist so that it contains the zones
5195 * of all the other nodes.
5196 * We don't want to pressure a particular node, so when
5197 * building the zones for node N, we make sure that the
5198 * zones coming right after the local ones are those from
5199 * node N+1 (modulo N)
5200 */
5201 for (node = local_node + 1; node < MAX_NUMNODES; node++) {
5202 if (!node_online(node))
5203 continue;
5204 nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
5205 zonerefs += nr_zones;
5206 }
5207 for (node = 0; node < local_node; node++) {
5208 if (!node_online(node))
5209 continue;
5210 nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
5211 zonerefs += nr_zones;
5212 }
5213
5214 zonerefs->zone = NULL;
5215 zonerefs->zone_idx = 0;
5216}
5217
5218#endif /* CONFIG_NUMA */
5219
5220/*
5221 * Boot pageset table. One per cpu which is going to be used for all
5222 * zones and all nodes. The parameters will be set in such a way
5223 * that an item put on a list will immediately be handed over to
5224 * the buddy list. This is safe since pageset manipulation is done
5225 * with interrupts disabled.
5226 *
5227 * The boot_pagesets must be kept even after bootup is complete for
5228 * unused processors and/or zones. They do play a role for bootstrapping
5229 * hotplugged processors.
5230 *
5231 * zoneinfo_show() and maybe other functions do
5232 * not check if the processor is online before following the pageset pointer.
5233 * Other parts of the kernel may not check if the zone is available.
5234 */
5235static void per_cpu_pages_init(struct per_cpu_pages *pcp, struct per_cpu_zonestat *pzstats);
5236/* These effectively disable the pcplists in the boot pageset completely */
5237#define BOOT_PAGESET_HIGH 0
5238#define BOOT_PAGESET_BATCH 1
5239static DEFINE_PER_CPU(struct per_cpu_pages, boot_pageset);
5240static DEFINE_PER_CPU(struct per_cpu_zonestat, boot_zonestats);
5241
5242static void __build_all_zonelists(void *data)
5243{
5244 int nid;
5245 int __maybe_unused cpu;
5246 pg_data_t *self = data;
5247 unsigned long flags;
5248
5249 /*
5250 * The zonelist_update_seq must be acquired with irqsave because the
5251 * reader can be invoked from IRQ with GFP_ATOMIC.
5252 */
5253 write_seqlock_irqsave(&zonelist_update_seq, flags);
5254 /*
5255 * Also disable synchronous printk() to prevent any printk() from
5256 * trying to hold port->lock, for
5257 * tty_insert_flip_string_and_push_buffer() on other CPU might be
5258 * calling kmalloc(GFP_ATOMIC | __GFP_NOWARN) with port->lock held.
5259 */
5260 printk_deferred_enter();
5261
5262#ifdef CONFIG_NUMA
5263 memset(node_load, 0, sizeof(node_load));
5264#endif
5265
5266 /*
5267 * This node is hotadded and no memory is yet present. So just
5268 * building zonelists is fine - no need to touch other nodes.
5269 */
5270 if (self && !node_online(self->node_id)) {
5271 build_zonelists(self);
5272 } else {
5273 /*
5274 * All possible nodes have pgdat preallocated
5275 * in free_area_init
5276 */
5277 for_each_node(nid) {
5278 pg_data_t *pgdat = NODE_DATA(nid);
5279
5280 build_zonelists(pgdat);
5281 }
5282
5283#ifdef CONFIG_HAVE_MEMORYLESS_NODES
5284 /*
5285 * We now know the "local memory node" for each node--
5286 * i.e., the node of the first zone in the generic zonelist.
5287 * Set up numa_mem percpu variable for on-line cpus. During
5288 * boot, only the boot cpu should be on-line; we'll init the
5289 * secondary cpus' numa_mem as they come on-line. During
5290 * node/memory hotplug, we'll fixup all on-line cpus.
5291 */
5292 for_each_online_cpu(cpu)
5293 set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
5294#endif
5295 }
5296
5297 printk_deferred_exit();
5298 write_sequnlock_irqrestore(&zonelist_update_seq, flags);
5299}
5300
5301static noinline void __init
5302build_all_zonelists_init(void)
5303{
5304 int cpu;
5305
5306 __build_all_zonelists(NULL);
5307
5308 /*
5309 * Initialize the boot_pagesets that are going to be used
5310 * for bootstrapping processors. The real pagesets for
5311 * each zone will be allocated later when the per cpu
5312 * allocator is available.
5313 *
5314 * boot_pagesets are used also for bootstrapping offline
5315 * cpus if the system is already booted because the pagesets
5316 * are needed to initialize allocators on a specific cpu too.
5317 * F.e. the percpu allocator needs the page allocator which
5318 * needs the percpu allocator in order to allocate its pagesets
5319 * (a chicken-egg dilemma).
5320 */
5321 for_each_possible_cpu(cpu)
5322 per_cpu_pages_init(&per_cpu(boot_pageset, cpu), &per_cpu(boot_zonestats, cpu));
5323
5324 mminit_verify_zonelist();
5325 cpuset_init_current_mems_allowed();
5326}
5327
5328/*
5329 * unless system_state == SYSTEM_BOOTING.
5330 *
5331 * __ref due to call of __init annotated helper build_all_zonelists_init
5332 * [protected by SYSTEM_BOOTING].
5333 */
5334void __ref build_all_zonelists(pg_data_t *pgdat)
5335{
5336 unsigned long vm_total_pages;
5337
5338 if (system_state == SYSTEM_BOOTING) {
5339 build_all_zonelists_init();
5340 } else {
5341 __build_all_zonelists(pgdat);
5342 /* cpuset refresh routine should be here */
5343 }
5344 /* Get the number of free pages beyond high watermark in all zones. */
5345 vm_total_pages = nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
5346 /*
5347 * Disable grouping by mobility if the number of pages in the
5348 * system is too low to allow the mechanism to work. It would be
5349 * more accurate, but expensive to check per-zone. This check is
5350 * made on memory-hotadd so a system can start with mobility
5351 * disabled and enable it later
5352 */
5353 if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
5354 page_group_by_mobility_disabled = 1;
5355 else
5356 page_group_by_mobility_disabled = 0;
5357
5358 pr_info("Built %u zonelists, mobility grouping %s. Total pages: %ld\n",
5359 nr_online_nodes,
5360 page_group_by_mobility_disabled ? "off" : "on",
5361 vm_total_pages);
5362#ifdef CONFIG_NUMA
5363 pr_info("Policy zone: %s\n", zone_names[policy_zone]);
5364#endif
5365}
5366
5367static int zone_batchsize(struct zone *zone)
5368{
5369#ifdef CONFIG_MMU
5370 int batch;
5371
5372 /*
5373 * The number of pages to batch allocate is either ~0.1%
5374 * of the zone or 1MB, whichever is smaller. The batch
5375 * size is striking a balance between allocation latency
5376 * and zone lock contention.
5377 */
5378 batch = min(zone_managed_pages(zone) >> 10, SZ_1M / PAGE_SIZE);
5379 batch /= 4; /* We effectively *= 4 below */
5380 if (batch < 1)
5381 batch = 1;
5382
5383 /*
5384 * Clamp the batch to a 2^n - 1 value. Having a power
5385 * of 2 value was found to be more likely to have
5386 * suboptimal cache aliasing properties in some cases.
5387 *
5388 * For example if 2 tasks are alternately allocating
5389 * batches of pages, one task can end up with a lot
5390 * of pages of one half of the possible page colors
5391 * and the other with pages of the other colors.
5392 */
5393 batch = rounddown_pow_of_two(batch + batch/2) - 1;
5394
5395 return batch;
5396
5397#else
5398 /* The deferral and batching of frees should be suppressed under NOMMU
5399 * conditions.
5400 *
5401 * The problem is that NOMMU needs to be able to allocate large chunks
5402 * of contiguous memory as there's no hardware page translation to
5403 * assemble apparent contiguous memory from discontiguous pages.
5404 *
5405 * Queueing large contiguous runs of pages for batching, however,
5406 * causes the pages to actually be freed in smaller chunks. As there
5407 * can be a significant delay between the individual batches being
5408 * recycled, this leads to the once large chunks of space being
5409 * fragmented and becoming unavailable for high-order allocations.
5410 */
5411 return 0;
5412#endif
5413}
5414
5415static int percpu_pagelist_high_fraction;
5416static int zone_highsize(struct zone *zone, int batch, int cpu_online,
5417 int high_fraction)
5418{
5419#ifdef CONFIG_MMU
5420 int high;
5421 int nr_split_cpus;
5422 unsigned long total_pages;
5423
5424 if (!high_fraction) {
5425 /*
5426 * By default, the high value of the pcp is based on the zone
5427 * low watermark so that if they are full then background
5428 * reclaim will not be started prematurely.
5429 */
5430 total_pages = low_wmark_pages(zone);
5431 } else {
5432 /*
5433 * If percpu_pagelist_high_fraction is configured, the high
5434 * value is based on a fraction of the managed pages in the
5435 * zone.
5436 */
5437 total_pages = zone_managed_pages(zone) / high_fraction;
5438 }
5439
5440 /*
5441 * Split the high value across all online CPUs local to the zone. Note
5442 * that early in boot that CPUs may not be online yet and that during
5443 * CPU hotplug that the cpumask is not yet updated when a CPU is being
5444 * onlined. For memory nodes that have no CPUs, split the high value
5445 * across all online CPUs to mitigate the risk that reclaim is triggered
5446 * prematurely due to pages stored on pcp lists.
5447 */
5448 nr_split_cpus = cpumask_weight(cpumask_of_node(zone_to_nid(zone))) + cpu_online;
5449 if (!nr_split_cpus)
5450 nr_split_cpus = num_online_cpus();
5451 high = total_pages / nr_split_cpus;
5452
5453 /*
5454 * Ensure high is at least batch*4. The multiple is based on the
5455 * historical relationship between high and batch.
5456 */
5457 high = max(high, batch << 2);
5458
5459 return high;
5460#else
5461 return 0;
5462#endif
5463}
5464
5465/*
5466 * pcp->high and pcp->batch values are related and generally batch is lower
5467 * than high. They are also related to pcp->count such that count is lower
5468 * than high, and as soon as it reaches high, the pcplist is flushed.
5469 *
5470 * However, guaranteeing these relations at all times would require e.g. write
5471 * barriers here but also careful usage of read barriers at the read side, and
5472 * thus be prone to error and bad for performance. Thus the update only prevents
5473 * store tearing. Any new users of pcp->batch, pcp->high_min and pcp->high_max
5474 * should ensure they can cope with those fields changing asynchronously, and
5475 * fully trust only the pcp->count field on the local CPU with interrupts
5476 * disabled.
5477 *
5478 * mutex_is_locked(&pcp_batch_high_lock) required when calling this function
5479 * outside of boot time (or some other assurance that no concurrent updaters
5480 * exist).
5481 */
5482static void pageset_update(struct per_cpu_pages *pcp, unsigned long high_min,
5483 unsigned long high_max, unsigned long batch)
5484{
5485 WRITE_ONCE(pcp->batch, batch);
5486 WRITE_ONCE(pcp->high_min, high_min);
5487 WRITE_ONCE(pcp->high_max, high_max);
5488}
5489
5490static void per_cpu_pages_init(struct per_cpu_pages *pcp, struct per_cpu_zonestat *pzstats)
5491{
5492 int pindex;
5493
5494 memset(pcp, 0, sizeof(*pcp));
5495 memset(pzstats, 0, sizeof(*pzstats));
5496
5497 spin_lock_init(&pcp->lock);
5498 for (pindex = 0; pindex < NR_PCP_LISTS; pindex++)
5499 INIT_LIST_HEAD(&pcp->lists[pindex]);
5500
5501 /*
5502 * Set batch and high values safe for a boot pageset. A true percpu
5503 * pageset's initialization will update them subsequently. Here we don't
5504 * need to be as careful as pageset_update() as nobody can access the
5505 * pageset yet.
5506 */
5507 pcp->high_min = BOOT_PAGESET_HIGH;
5508 pcp->high_max = BOOT_PAGESET_HIGH;
5509 pcp->batch = BOOT_PAGESET_BATCH;
5510 pcp->free_count = 0;
5511}
5512
5513static void __zone_set_pageset_high_and_batch(struct zone *zone, unsigned long high_min,
5514 unsigned long high_max, unsigned long batch)
5515{
5516 struct per_cpu_pages *pcp;
5517 int cpu;
5518
5519 for_each_possible_cpu(cpu) {
5520 pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu);
5521 pageset_update(pcp, high_min, high_max, batch);
5522 }
5523}
5524
5525/*
5526 * Calculate and set new high and batch values for all per-cpu pagesets of a
5527 * zone based on the zone's size.
5528 */
5529static void zone_set_pageset_high_and_batch(struct zone *zone, int cpu_online)
5530{
5531 int new_high_min, new_high_max, new_batch;
5532
5533 new_batch = max(1, zone_batchsize(zone));
5534 if (percpu_pagelist_high_fraction) {
5535 new_high_min = zone_highsize(zone, new_batch, cpu_online,
5536 percpu_pagelist_high_fraction);
5537 /*
5538 * PCP high is tuned manually, disable auto-tuning via
5539 * setting high_min and high_max to the manual value.
5540 */
5541 new_high_max = new_high_min;
5542 } else {
5543 new_high_min = zone_highsize(zone, new_batch, cpu_online, 0);
5544 new_high_max = zone_highsize(zone, new_batch, cpu_online,
5545 MIN_PERCPU_PAGELIST_HIGH_FRACTION);
5546 }
5547
5548 if (zone->pageset_high_min == new_high_min &&
5549 zone->pageset_high_max == new_high_max &&
5550 zone->pageset_batch == new_batch)
5551 return;
5552
5553 zone->pageset_high_min = new_high_min;
5554 zone->pageset_high_max = new_high_max;
5555 zone->pageset_batch = new_batch;
5556
5557 __zone_set_pageset_high_and_batch(zone, new_high_min, new_high_max,
5558 new_batch);
5559}
5560
5561void __meminit setup_zone_pageset(struct zone *zone)
5562{
5563 int cpu;
5564
5565 /* Size may be 0 on !SMP && !NUMA */
5566 if (sizeof(struct per_cpu_zonestat) > 0)
5567 zone->per_cpu_zonestats = alloc_percpu(struct per_cpu_zonestat);
5568
5569 zone->per_cpu_pageset = alloc_percpu(struct per_cpu_pages);
5570 for_each_possible_cpu(cpu) {
5571 struct per_cpu_pages *pcp;
5572 struct per_cpu_zonestat *pzstats;
5573
5574 pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu);
5575 pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
5576 per_cpu_pages_init(pcp, pzstats);
5577 }
5578
5579 zone_set_pageset_high_and_batch(zone, 0);
5580}
5581
5582/*
5583 * The zone indicated has a new number of managed_pages; batch sizes and percpu
5584 * page high values need to be recalculated.
5585 */
5586static void zone_pcp_update(struct zone *zone, int cpu_online)
5587{
5588 mutex_lock(&pcp_batch_high_lock);
5589 zone_set_pageset_high_and_batch(zone, cpu_online);
5590 mutex_unlock(&pcp_batch_high_lock);
5591}
5592
5593static void zone_pcp_update_cacheinfo(struct zone *zone, unsigned int cpu)
5594{
5595 struct per_cpu_pages *pcp;
5596 struct cpu_cacheinfo *cci;
5597
5598 pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu);
5599 cci = get_cpu_cacheinfo(cpu);
5600 /*
5601 * If data cache slice of CPU is large enough, "pcp->batch"
5602 * pages can be preserved in PCP before draining PCP for
5603 * consecutive high-order pages freeing without allocation.
5604 * This can reduce zone lock contention without hurting
5605 * cache-hot pages sharing.
5606 */
5607 spin_lock(&pcp->lock);
5608 if ((cci->per_cpu_data_slice_size >> PAGE_SHIFT) > 3 * pcp->batch)
5609 pcp->flags |= PCPF_FREE_HIGH_BATCH;
5610 else
5611 pcp->flags &= ~PCPF_FREE_HIGH_BATCH;
5612 spin_unlock(&pcp->lock);
5613}
5614
5615void setup_pcp_cacheinfo(unsigned int cpu)
5616{
5617 struct zone *zone;
5618
5619 for_each_populated_zone(zone)
5620 zone_pcp_update_cacheinfo(zone, cpu);
5621}
5622
5623/*
5624 * Allocate per cpu pagesets and initialize them.
5625 * Before this call only boot pagesets were available.
5626 */
5627void __init setup_per_cpu_pageset(void)
5628{
5629 struct pglist_data *pgdat;
5630 struct zone *zone;
5631 int __maybe_unused cpu;
5632
5633 for_each_populated_zone(zone)
5634 setup_zone_pageset(zone);
5635
5636#ifdef CONFIG_NUMA
5637 /*
5638 * Unpopulated zones continue using the boot pagesets.
5639 * The numa stats for these pagesets need to be reset.
5640 * Otherwise, they will end up skewing the stats of
5641 * the nodes these zones are associated with.
5642 */
5643 for_each_possible_cpu(cpu) {
5644 struct per_cpu_zonestat *pzstats = &per_cpu(boot_zonestats, cpu);
5645 memset(pzstats->vm_numa_event, 0,
5646 sizeof(pzstats->vm_numa_event));
5647 }
5648#endif
5649
5650 for_each_online_pgdat(pgdat)
5651 pgdat->per_cpu_nodestats =
5652 alloc_percpu(struct per_cpu_nodestat);
5653}
5654
5655__meminit void zone_pcp_init(struct zone *zone)
5656{
5657 /*
5658 * per cpu subsystem is not up at this point. The following code
5659 * relies on the ability of the linker to provide the
5660 * offset of a (static) per cpu variable into the per cpu area.
5661 */
5662 zone->per_cpu_pageset = &boot_pageset;
5663 zone->per_cpu_zonestats = &boot_zonestats;
5664 zone->pageset_high_min = BOOT_PAGESET_HIGH;
5665 zone->pageset_high_max = BOOT_PAGESET_HIGH;
5666 zone->pageset_batch = BOOT_PAGESET_BATCH;
5667
5668 if (populated_zone(zone))
5669 pr_debug(" %s zone: %lu pages, LIFO batch:%u\n", zone->name,
5670 zone->present_pages, zone_batchsize(zone));
5671}
5672
5673void adjust_managed_page_count(struct page *page, long count)
5674{
5675 atomic_long_add(count, &page_zone(page)->managed_pages);
5676 totalram_pages_add(count);
5677#ifdef CONFIG_HIGHMEM
5678 if (PageHighMem(page))
5679 totalhigh_pages_add(count);
5680#endif
5681}
5682EXPORT_SYMBOL(adjust_managed_page_count);
5683
5684unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
5685{
5686 void *pos;
5687 unsigned long pages = 0;
5688
5689 start = (void *)PAGE_ALIGN((unsigned long)start);
5690 end = (void *)((unsigned long)end & PAGE_MASK);
5691 for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
5692 struct page *page = virt_to_page(pos);
5693 void *direct_map_addr;
5694
5695 /*
5696 * 'direct_map_addr' might be different from 'pos'
5697 * because some architectures' virt_to_page()
5698 * work with aliases. Getting the direct map
5699 * address ensures that we get a _writeable_
5700 * alias for the memset().
5701 */
5702 direct_map_addr = page_address(page);
5703 /*
5704 * Perform a kasan-unchecked memset() since this memory
5705 * has not been initialized.
5706 */
5707 direct_map_addr = kasan_reset_tag(direct_map_addr);
5708 if ((unsigned int)poison <= 0xFF)
5709 memset(direct_map_addr, poison, PAGE_SIZE);
5710
5711 free_reserved_page(page);
5712 }
5713
5714 if (pages && s)
5715 pr_info("Freeing %s memory: %ldK\n", s, K(pages));
5716
5717 return pages;
5718}
5719
5720static int page_alloc_cpu_dead(unsigned int cpu)
5721{
5722 struct zone *zone;
5723
5724 lru_add_drain_cpu(cpu);
5725 mlock_drain_remote(cpu);
5726 drain_pages(cpu);
5727
5728 /*
5729 * Spill the event counters of the dead processor
5730 * into the current processors event counters.
5731 * This artificially elevates the count of the current
5732 * processor.
5733 */
5734 vm_events_fold_cpu(cpu);
5735
5736 /*
5737 * Zero the differential counters of the dead processor
5738 * so that the vm statistics are consistent.
5739 *
5740 * This is only okay since the processor is dead and cannot
5741 * race with what we are doing.
5742 */
5743 cpu_vm_stats_fold(cpu);
5744
5745 for_each_populated_zone(zone)
5746 zone_pcp_update(zone, 0);
5747
5748 return 0;
5749}
5750
5751static int page_alloc_cpu_online(unsigned int cpu)
5752{
5753 struct zone *zone;
5754
5755 for_each_populated_zone(zone)
5756 zone_pcp_update(zone, 1);
5757 return 0;
5758}
5759
5760void __init page_alloc_init_cpuhp(void)
5761{
5762 int ret;
5763
5764 ret = cpuhp_setup_state_nocalls(CPUHP_PAGE_ALLOC,
5765 "mm/page_alloc:pcp",
5766 page_alloc_cpu_online,
5767 page_alloc_cpu_dead);
5768 WARN_ON(ret < 0);
5769}
5770
5771/*
5772 * calculate_totalreserve_pages - called when sysctl_lowmem_reserve_ratio
5773 * or min_free_kbytes changes.
5774 */
5775static void calculate_totalreserve_pages(void)
5776{
5777 struct pglist_data *pgdat;
5778 unsigned long reserve_pages = 0;
5779 enum zone_type i, j;
5780
5781 for_each_online_pgdat(pgdat) {
5782
5783 pgdat->totalreserve_pages = 0;
5784
5785 for (i = 0; i < MAX_NR_ZONES; i++) {
5786 struct zone *zone = pgdat->node_zones + i;
5787 long max = 0;
5788 unsigned long managed_pages = zone_managed_pages(zone);
5789
5790 /* Find valid and maximum lowmem_reserve in the zone */
5791 for (j = i; j < MAX_NR_ZONES; j++) {
5792 if (zone->lowmem_reserve[j] > max)
5793 max = zone->lowmem_reserve[j];
5794 }
5795
5796 /* we treat the high watermark as reserved pages. */
5797 max += high_wmark_pages(zone);
5798
5799 if (max > managed_pages)
5800 max = managed_pages;
5801
5802 pgdat->totalreserve_pages += max;
5803
5804 reserve_pages += max;
5805 }
5806 }
5807 totalreserve_pages = reserve_pages;
5808}
5809
5810/*
5811 * setup_per_zone_lowmem_reserve - called whenever
5812 * sysctl_lowmem_reserve_ratio changes. Ensures that each zone
5813 * has a correct pages reserved value, so an adequate number of
5814 * pages are left in the zone after a successful __alloc_pages().
5815 */
5816static void setup_per_zone_lowmem_reserve(void)
5817{
5818 struct pglist_data *pgdat;
5819 enum zone_type i, j;
5820
5821 for_each_online_pgdat(pgdat) {
5822 for (i = 0; i < MAX_NR_ZONES - 1; i++) {
5823 struct zone *zone = &pgdat->node_zones[i];
5824 int ratio = sysctl_lowmem_reserve_ratio[i];
5825 bool clear = !ratio || !zone_managed_pages(zone);
5826 unsigned long managed_pages = 0;
5827
5828 for (j = i + 1; j < MAX_NR_ZONES; j++) {
5829 struct zone *upper_zone = &pgdat->node_zones[j];
5830
5831 managed_pages += zone_managed_pages(upper_zone);
5832
5833 if (clear)
5834 zone->lowmem_reserve[j] = 0;
5835 else
5836 zone->lowmem_reserve[j] = managed_pages / ratio;
5837 }
5838 }
5839 }
5840
5841 /* update totalreserve_pages */
5842 calculate_totalreserve_pages();
5843}
5844
5845static void __setup_per_zone_wmarks(void)
5846{
5847 unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
5848 unsigned long lowmem_pages = 0;
5849 struct zone *zone;
5850 unsigned long flags;
5851
5852 /* Calculate total number of !ZONE_HIGHMEM and !ZONE_MOVABLE pages */
5853 for_each_zone(zone) {
5854 if (!is_highmem(zone) && zone_idx(zone) != ZONE_MOVABLE)
5855 lowmem_pages += zone_managed_pages(zone);
5856 }
5857
5858 for_each_zone(zone) {
5859 u64 tmp;
5860
5861 spin_lock_irqsave(&zone->lock, flags);
5862 tmp = (u64)pages_min * zone_managed_pages(zone);
5863 tmp = div64_ul(tmp, lowmem_pages);
5864 if (is_highmem(zone) || zone_idx(zone) == ZONE_MOVABLE) {
5865 /*
5866 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
5867 * need highmem and movable zones pages, so cap pages_min
5868 * to a small value here.
5869 *
5870 * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
5871 * deltas control async page reclaim, and so should
5872 * not be capped for highmem and movable zones.
5873 */
5874 unsigned long min_pages;
5875
5876 min_pages = zone_managed_pages(zone) / 1024;
5877 min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
5878 zone->_watermark[WMARK_MIN] = min_pages;
5879 } else {
5880 /*
5881 * If it's a lowmem zone, reserve a number of pages
5882 * proportionate to the zone's size.
5883 */
5884 zone->_watermark[WMARK_MIN] = tmp;
5885 }
5886
5887 /*
5888 * Set the kswapd watermarks distance according to the
5889 * scale factor in proportion to available memory, but
5890 * ensure a minimum size on small systems.
5891 */
5892 tmp = max_t(u64, tmp >> 2,
5893 mult_frac(zone_managed_pages(zone),
5894 watermark_scale_factor, 10000));
5895
5896 zone->watermark_boost = 0;
5897 zone->_watermark[WMARK_LOW] = min_wmark_pages(zone) + tmp;
5898 zone->_watermark[WMARK_HIGH] = low_wmark_pages(zone) + tmp;
5899 zone->_watermark[WMARK_PROMO] = high_wmark_pages(zone) + tmp;
5900
5901 spin_unlock_irqrestore(&zone->lock, flags);
5902 }
5903
5904 /* update totalreserve_pages */
5905 calculate_totalreserve_pages();
5906}
5907
5908/**
5909 * setup_per_zone_wmarks - called when min_free_kbytes changes
5910 * or when memory is hot-{added|removed}
5911 *
5912 * Ensures that the watermark[min,low,high] values for each zone are set
5913 * correctly with respect to min_free_kbytes.
5914 */
5915void setup_per_zone_wmarks(void)
5916{
5917 struct zone *zone;
5918 static DEFINE_SPINLOCK(lock);
5919
5920 spin_lock(&lock);
5921 __setup_per_zone_wmarks();
5922 spin_unlock(&lock);
5923
5924 /*
5925 * The watermark size have changed so update the pcpu batch
5926 * and high limits or the limits may be inappropriate.
5927 */
5928 for_each_zone(zone)
5929 zone_pcp_update(zone, 0);
5930}
5931
5932/*
5933 * Initialise min_free_kbytes.
5934 *
5935 * For small machines we want it small (128k min). For large machines
5936 * we want it large (256MB max). But it is not linear, because network
5937 * bandwidth does not increase linearly with machine size. We use
5938 *
5939 * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
5940 * min_free_kbytes = sqrt(lowmem_kbytes * 16)
5941 *
5942 * which yields
5943 *
5944 * 16MB: 512k
5945 * 32MB: 724k
5946 * 64MB: 1024k
5947 * 128MB: 1448k
5948 * 256MB: 2048k
5949 * 512MB: 2896k
5950 * 1024MB: 4096k
5951 * 2048MB: 5792k
5952 * 4096MB: 8192k
5953 * 8192MB: 11584k
5954 * 16384MB: 16384k
5955 */
5956void calculate_min_free_kbytes(void)
5957{
5958 unsigned long lowmem_kbytes;
5959 int new_min_free_kbytes;
5960
5961 lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
5962 new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
5963
5964 if (new_min_free_kbytes > user_min_free_kbytes)
5965 min_free_kbytes = clamp(new_min_free_kbytes, 128, 262144);
5966 else
5967 pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n",
5968 new_min_free_kbytes, user_min_free_kbytes);
5969
5970}
5971
5972int __meminit init_per_zone_wmark_min(void)
5973{
5974 calculate_min_free_kbytes();
5975 setup_per_zone_wmarks();
5976 refresh_zone_stat_thresholds();
5977 setup_per_zone_lowmem_reserve();
5978
5979#ifdef CONFIG_NUMA
5980 setup_min_unmapped_ratio();
5981 setup_min_slab_ratio();
5982#endif
5983
5984 khugepaged_min_free_kbytes_update();
5985
5986 return 0;
5987}
5988postcore_initcall(init_per_zone_wmark_min)
5989
5990/*
5991 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
5992 * that we can call two helper functions whenever min_free_kbytes
5993 * changes.
5994 */
5995static int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write,
5996 void *buffer, size_t *length, loff_t *ppos)
5997{
5998 int rc;
5999
6000 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
6001 if (rc)
6002 return rc;
6003
6004 if (write) {
6005 user_min_free_kbytes = min_free_kbytes;
6006 setup_per_zone_wmarks();
6007 }
6008 return 0;
6009}
6010
6011static int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write,
6012 void *buffer, size_t *length, loff_t *ppos)
6013{
6014 int rc;
6015
6016 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
6017 if (rc)
6018 return rc;
6019
6020 if (write)
6021 setup_per_zone_wmarks();
6022
6023 return 0;
6024}
6025
6026#ifdef CONFIG_NUMA
6027static void setup_min_unmapped_ratio(void)
6028{
6029 pg_data_t *pgdat;
6030 struct zone *zone;
6031
6032 for_each_online_pgdat(pgdat)
6033 pgdat->min_unmapped_pages = 0;
6034
6035 for_each_zone(zone)
6036 zone->zone_pgdat->min_unmapped_pages += (zone_managed_pages(zone) *
6037 sysctl_min_unmapped_ratio) / 100;
6038}
6039
6040
6041static int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
6042 void *buffer, size_t *length, loff_t *ppos)
6043{
6044 int rc;
6045
6046 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
6047 if (rc)
6048 return rc;
6049
6050 setup_min_unmapped_ratio();
6051
6052 return 0;
6053}
6054
6055static void setup_min_slab_ratio(void)
6056{
6057 pg_data_t *pgdat;
6058 struct zone *zone;
6059
6060 for_each_online_pgdat(pgdat)
6061 pgdat->min_slab_pages = 0;
6062
6063 for_each_zone(zone)
6064 zone->zone_pgdat->min_slab_pages += (zone_managed_pages(zone) *
6065 sysctl_min_slab_ratio) / 100;
6066}
6067
6068static int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
6069 void *buffer, size_t *length, loff_t *ppos)
6070{
6071 int rc;
6072
6073 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
6074 if (rc)
6075 return rc;
6076
6077 setup_min_slab_ratio();
6078
6079 return 0;
6080}
6081#endif
6082
6083/*
6084 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
6085 * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
6086 * whenever sysctl_lowmem_reserve_ratio changes.
6087 *
6088 * The reserve ratio obviously has absolutely no relation with the
6089 * minimum watermarks. The lowmem reserve ratio can only make sense
6090 * if in function of the boot time zone sizes.
6091 */
6092static int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table,
6093 int write, void *buffer, size_t *length, loff_t *ppos)
6094{
6095 int i;
6096
6097 proc_dointvec_minmax(table, write, buffer, length, ppos);
6098
6099 for (i = 0; i < MAX_NR_ZONES; i++) {
6100 if (sysctl_lowmem_reserve_ratio[i] < 1)
6101 sysctl_lowmem_reserve_ratio[i] = 0;
6102 }
6103
6104 setup_per_zone_lowmem_reserve();
6105 return 0;
6106}
6107
6108/*
6109 * percpu_pagelist_high_fraction - changes the pcp->high for each zone on each
6110 * cpu. It is the fraction of total pages in each zone that a hot per cpu
6111 * pagelist can have before it gets flushed back to buddy allocator.
6112 */
6113static int percpu_pagelist_high_fraction_sysctl_handler(struct ctl_table *table,
6114 int write, void *buffer, size_t *length, loff_t *ppos)
6115{
6116 struct zone *zone;
6117 int old_percpu_pagelist_high_fraction;
6118 int ret;
6119
6120 mutex_lock(&pcp_batch_high_lock);
6121 old_percpu_pagelist_high_fraction = percpu_pagelist_high_fraction;
6122
6123 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
6124 if (!write || ret < 0)
6125 goto out;
6126
6127 /* Sanity checking to avoid pcp imbalance */
6128 if (percpu_pagelist_high_fraction &&
6129 percpu_pagelist_high_fraction < MIN_PERCPU_PAGELIST_HIGH_FRACTION) {
6130 percpu_pagelist_high_fraction = old_percpu_pagelist_high_fraction;
6131 ret = -EINVAL;
6132 goto out;
6133 }
6134
6135 /* No change? */
6136 if (percpu_pagelist_high_fraction == old_percpu_pagelist_high_fraction)
6137 goto out;
6138
6139 for_each_populated_zone(zone)
6140 zone_set_pageset_high_and_batch(zone, 0);
6141out:
6142 mutex_unlock(&pcp_batch_high_lock);
6143 return ret;
6144}
6145
6146static struct ctl_table page_alloc_sysctl_table[] = {
6147 {
6148 .procname = "min_free_kbytes",
6149 .data = &min_free_kbytes,
6150 .maxlen = sizeof(min_free_kbytes),
6151 .mode = 0644,
6152 .proc_handler = min_free_kbytes_sysctl_handler,
6153 .extra1 = SYSCTL_ZERO,
6154 },
6155 {
6156 .procname = "watermark_boost_factor",
6157 .data = &watermark_boost_factor,
6158 .maxlen = sizeof(watermark_boost_factor),
6159 .mode = 0644,
6160 .proc_handler = proc_dointvec_minmax,
6161 .extra1 = SYSCTL_ZERO,
6162 },
6163 {
6164 .procname = "watermark_scale_factor",
6165 .data = &watermark_scale_factor,
6166 .maxlen = sizeof(watermark_scale_factor),
6167 .mode = 0644,
6168 .proc_handler = watermark_scale_factor_sysctl_handler,
6169 .extra1 = SYSCTL_ONE,
6170 .extra2 = SYSCTL_THREE_THOUSAND,
6171 },
6172 {
6173 .procname = "percpu_pagelist_high_fraction",
6174 .data = &percpu_pagelist_high_fraction,
6175 .maxlen = sizeof(percpu_pagelist_high_fraction),
6176 .mode = 0644,
6177 .proc_handler = percpu_pagelist_high_fraction_sysctl_handler,
6178 .extra1 = SYSCTL_ZERO,
6179 },
6180 {
6181 .procname = "lowmem_reserve_ratio",
6182 .data = &sysctl_lowmem_reserve_ratio,
6183 .maxlen = sizeof(sysctl_lowmem_reserve_ratio),
6184 .mode = 0644,
6185 .proc_handler = lowmem_reserve_ratio_sysctl_handler,
6186 },
6187#ifdef CONFIG_NUMA
6188 {
6189 .procname = "numa_zonelist_order",
6190 .data = &numa_zonelist_order,
6191 .maxlen = NUMA_ZONELIST_ORDER_LEN,
6192 .mode = 0644,
6193 .proc_handler = numa_zonelist_order_handler,
6194 },
6195 {
6196 .procname = "min_unmapped_ratio",
6197 .data = &sysctl_min_unmapped_ratio,
6198 .maxlen = sizeof(sysctl_min_unmapped_ratio),
6199 .mode = 0644,
6200 .proc_handler = sysctl_min_unmapped_ratio_sysctl_handler,
6201 .extra1 = SYSCTL_ZERO,
6202 .extra2 = SYSCTL_ONE_HUNDRED,
6203 },
6204 {
6205 .procname = "min_slab_ratio",
6206 .data = &sysctl_min_slab_ratio,
6207 .maxlen = sizeof(sysctl_min_slab_ratio),
6208 .mode = 0644,
6209 .proc_handler = sysctl_min_slab_ratio_sysctl_handler,
6210 .extra1 = SYSCTL_ZERO,
6211 .extra2 = SYSCTL_ONE_HUNDRED,
6212 },
6213#endif
6214 {}
6215};
6216
6217void __init page_alloc_sysctl_init(void)
6218{
6219 register_sysctl_init("vm", page_alloc_sysctl_table);
6220}
6221
6222#ifdef CONFIG_CONTIG_ALLOC
6223/* Usage: See admin-guide/dynamic-debug-howto.rst */
6224static void alloc_contig_dump_pages(struct list_head *page_list)
6225{
6226 DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, "migrate failure");
6227
6228 if (DYNAMIC_DEBUG_BRANCH(descriptor)) {
6229 struct page *page;
6230
6231 dump_stack();
6232 list_for_each_entry(page, page_list, lru)
6233 dump_page(page, "migration failure");
6234 }
6235}
6236
6237/*
6238 * [start, end) must belong to a single zone.
6239 * @migratetype: using migratetype to filter the type of migration in
6240 * trace_mm_alloc_contig_migrate_range_info.
6241 */
6242int __alloc_contig_migrate_range(struct compact_control *cc,
6243 unsigned long start, unsigned long end,
6244 int migratetype)
6245{
6246 /* This function is based on compact_zone() from compaction.c. */
6247 unsigned int nr_reclaimed;
6248 unsigned long pfn = start;
6249 unsigned int tries = 0;
6250 int ret = 0;
6251 struct migration_target_control mtc = {
6252 .nid = zone_to_nid(cc->zone),
6253 .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
6254 };
6255 struct page *page;
6256 unsigned long total_mapped = 0;
6257 unsigned long total_migrated = 0;
6258 unsigned long total_reclaimed = 0;
6259
6260 lru_cache_disable();
6261
6262 while (pfn < end || !list_empty(&cc->migratepages)) {
6263 if (fatal_signal_pending(current)) {
6264 ret = -EINTR;
6265 break;
6266 }
6267
6268 if (list_empty(&cc->migratepages)) {
6269 cc->nr_migratepages = 0;
6270 ret = isolate_migratepages_range(cc, pfn, end);
6271 if (ret && ret != -EAGAIN)
6272 break;
6273 pfn = cc->migrate_pfn;
6274 tries = 0;
6275 } else if (++tries == 5) {
6276 ret = -EBUSY;
6277 break;
6278 }
6279
6280 nr_reclaimed = reclaim_clean_pages_from_list(cc->zone,
6281 &cc->migratepages);
6282 cc->nr_migratepages -= nr_reclaimed;
6283
6284 if (trace_mm_alloc_contig_migrate_range_info_enabled()) {
6285 total_reclaimed += nr_reclaimed;
6286 list_for_each_entry(page, &cc->migratepages, lru)
6287 total_mapped += page_mapcount(page);
6288 }
6289
6290 ret = migrate_pages(&cc->migratepages, alloc_migration_target,
6291 NULL, (unsigned long)&mtc, cc->mode, MR_CONTIG_RANGE, NULL);
6292
6293 if (trace_mm_alloc_contig_migrate_range_info_enabled() && !ret)
6294 total_migrated += cc->nr_migratepages;
6295
6296 /*
6297 * On -ENOMEM, migrate_pages() bails out right away. It is pointless
6298 * to retry again over this error, so do the same here.
6299 */
6300 if (ret == -ENOMEM)
6301 break;
6302 }
6303
6304 lru_cache_enable();
6305 if (ret < 0) {
6306 if (!(cc->gfp_mask & __GFP_NOWARN) && ret == -EBUSY)
6307 alloc_contig_dump_pages(&cc->migratepages);
6308 putback_movable_pages(&cc->migratepages);
6309 }
6310
6311 trace_mm_alloc_contig_migrate_range_info(start, end, migratetype,
6312 total_migrated,
6313 total_reclaimed,
6314 total_mapped);
6315 return (ret < 0) ? ret : 0;
6316}
6317
6318/**
6319 * alloc_contig_range() -- tries to allocate given range of pages
6320 * @start: start PFN to allocate
6321 * @end: one-past-the-last PFN to allocate
6322 * @migratetype: migratetype of the underlying pageblocks (either
6323 * #MIGRATE_MOVABLE or #MIGRATE_CMA). All pageblocks
6324 * in range must have the same migratetype and it must
6325 * be either of the two.
6326 * @gfp_mask: GFP mask to use during compaction
6327 *
6328 * The PFN range does not have to be pageblock aligned. The PFN range must
6329 * belong to a single zone.
6330 *
6331 * The first thing this routine does is attempt to MIGRATE_ISOLATE all
6332 * pageblocks in the range. Once isolated, the pageblocks should not
6333 * be modified by others.
6334 *
6335 * Return: zero on success or negative error code. On success all
6336 * pages which PFN is in [start, end) are allocated for the caller and
6337 * need to be freed with free_contig_range().
6338 */
6339int alloc_contig_range(unsigned long start, unsigned long end,
6340 unsigned migratetype, gfp_t gfp_mask)
6341{
6342 unsigned long outer_start, outer_end;
6343 int order;
6344 int ret = 0;
6345
6346 struct compact_control cc = {
6347 .nr_migratepages = 0,
6348 .order = -1,
6349 .zone = page_zone(pfn_to_page(start)),
6350 .mode = MIGRATE_SYNC,
6351 .ignore_skip_hint = true,
6352 .no_set_skip_hint = true,
6353 .gfp_mask = current_gfp_context(gfp_mask),
6354 .alloc_contig = true,
6355 };
6356 INIT_LIST_HEAD(&cc.migratepages);
6357
6358 /*
6359 * What we do here is we mark all pageblocks in range as
6360 * MIGRATE_ISOLATE. Because pageblock and max order pages may
6361 * have different sizes, and due to the way page allocator
6362 * work, start_isolate_page_range() has special handlings for this.
6363 *
6364 * Once the pageblocks are marked as MIGRATE_ISOLATE, we
6365 * migrate the pages from an unaligned range (ie. pages that
6366 * we are interested in). This will put all the pages in
6367 * range back to page allocator as MIGRATE_ISOLATE.
6368 *
6369 * When this is done, we take the pages in range from page
6370 * allocator removing them from the buddy system. This way
6371 * page allocator will never consider using them.
6372 *
6373 * This lets us mark the pageblocks back as
6374 * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
6375 * aligned range but not in the unaligned, original range are
6376 * put back to page allocator so that buddy can use them.
6377 */
6378
6379 ret = start_isolate_page_range(start, end, migratetype, 0, gfp_mask);
6380 if (ret)
6381 goto done;
6382
6383 drain_all_pages(cc.zone);
6384
6385 /*
6386 * In case of -EBUSY, we'd like to know which page causes problem.
6387 * So, just fall through. test_pages_isolated() has a tracepoint
6388 * which will report the busy page.
6389 *
6390 * It is possible that busy pages could become available before
6391 * the call to test_pages_isolated, and the range will actually be
6392 * allocated. So, if we fall through be sure to clear ret so that
6393 * -EBUSY is not accidentally used or returned to caller.
6394 */
6395 ret = __alloc_contig_migrate_range(&cc, start, end, migratetype);
6396 if (ret && ret != -EBUSY)
6397 goto done;
6398 ret = 0;
6399
6400 /*
6401 * Pages from [start, end) are within a pageblock_nr_pages
6402 * aligned blocks that are marked as MIGRATE_ISOLATE. What's
6403 * more, all pages in [start, end) are free in page allocator.
6404 * What we are going to do is to allocate all pages from
6405 * [start, end) (that is remove them from page allocator).
6406 *
6407 * The only problem is that pages at the beginning and at the
6408 * end of interesting range may be not aligned with pages that
6409 * page allocator holds, ie. they can be part of higher order
6410 * pages. Because of this, we reserve the bigger range and
6411 * once this is done free the pages we are not interested in.
6412 *
6413 * We don't have to hold zone->lock here because the pages are
6414 * isolated thus they won't get removed from buddy.
6415 */
6416
6417 order = 0;
6418 outer_start = start;
6419 while (!PageBuddy(pfn_to_page(outer_start))) {
6420 if (++order > MAX_PAGE_ORDER) {
6421 outer_start = start;
6422 break;
6423 }
6424 outer_start &= ~0UL << order;
6425 }
6426
6427 if (outer_start != start) {
6428 order = buddy_order(pfn_to_page(outer_start));
6429
6430 /*
6431 * outer_start page could be small order buddy page and
6432 * it doesn't include start page. Adjust outer_start
6433 * in this case to report failed page properly
6434 * on tracepoint in test_pages_isolated()
6435 */
6436 if (outer_start + (1UL << order) <= start)
6437 outer_start = start;
6438 }
6439
6440 /* Make sure the range is really isolated. */
6441 if (test_pages_isolated(outer_start, end, 0)) {
6442 ret = -EBUSY;
6443 goto done;
6444 }
6445
6446 /* Grab isolated pages from freelists. */
6447 outer_end = isolate_freepages_range(&cc, outer_start, end);
6448 if (!outer_end) {
6449 ret = -EBUSY;
6450 goto done;
6451 }
6452
6453 /* Free head and tail (if any) */
6454 if (start != outer_start)
6455 free_contig_range(outer_start, start - outer_start);
6456 if (end != outer_end)
6457 free_contig_range(end, outer_end - end);
6458
6459done:
6460 undo_isolate_page_range(start, end, migratetype);
6461 return ret;
6462}
6463EXPORT_SYMBOL(alloc_contig_range);
6464
6465static int __alloc_contig_pages(unsigned long start_pfn,
6466 unsigned long nr_pages, gfp_t gfp_mask)
6467{
6468 unsigned long end_pfn = start_pfn + nr_pages;
6469
6470 return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE,
6471 gfp_mask);
6472}
6473
6474static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn,
6475 unsigned long nr_pages)
6476{
6477 unsigned long i, end_pfn = start_pfn + nr_pages;
6478 struct page *page;
6479
6480 for (i = start_pfn; i < end_pfn; i++) {
6481 page = pfn_to_online_page(i);
6482 if (!page)
6483 return false;
6484
6485 if (page_zone(page) != z)
6486 return false;
6487
6488 if (PageReserved(page))
6489 return false;
6490
6491 if (PageHuge(page))
6492 return false;
6493 }
6494 return true;
6495}
6496
6497static bool zone_spans_last_pfn(const struct zone *zone,
6498 unsigned long start_pfn, unsigned long nr_pages)
6499{
6500 unsigned long last_pfn = start_pfn + nr_pages - 1;
6501
6502 return zone_spans_pfn(zone, last_pfn);
6503}
6504
6505/**
6506 * alloc_contig_pages() -- tries to find and allocate contiguous range of pages
6507 * @nr_pages: Number of contiguous pages to allocate
6508 * @gfp_mask: GFP mask to limit search and used during compaction
6509 * @nid: Target node
6510 * @nodemask: Mask for other possible nodes
6511 *
6512 * This routine is a wrapper around alloc_contig_range(). It scans over zones
6513 * on an applicable zonelist to find a contiguous pfn range which can then be
6514 * tried for allocation with alloc_contig_range(). This routine is intended
6515 * for allocation requests which can not be fulfilled with the buddy allocator.
6516 *
6517 * The allocated memory is always aligned to a page boundary. If nr_pages is a
6518 * power of two, then allocated range is also guaranteed to be aligned to same
6519 * nr_pages (e.g. 1GB request would be aligned to 1GB).
6520 *
6521 * Allocated pages can be freed with free_contig_range() or by manually calling
6522 * __free_page() on each allocated page.
6523 *
6524 * Return: pointer to contiguous pages on success, or NULL if not successful.
6525 */
6526struct page *alloc_contig_pages(unsigned long nr_pages, gfp_t gfp_mask,
6527 int nid, nodemask_t *nodemask)
6528{
6529 unsigned long ret, pfn, flags;
6530 struct zonelist *zonelist;
6531 struct zone *zone;
6532 struct zoneref *z;
6533
6534 zonelist = node_zonelist(nid, gfp_mask);
6535 for_each_zone_zonelist_nodemask(zone, z, zonelist,
6536 gfp_zone(gfp_mask), nodemask) {
6537 spin_lock_irqsave(&zone->lock, flags);
6538
6539 pfn = ALIGN(zone->zone_start_pfn, nr_pages);
6540 while (zone_spans_last_pfn(zone, pfn, nr_pages)) {
6541 if (pfn_range_valid_contig(zone, pfn, nr_pages)) {
6542 /*
6543 * We release the zone lock here because
6544 * alloc_contig_range() will also lock the zone
6545 * at some point. If there's an allocation
6546 * spinning on this lock, it may win the race
6547 * and cause alloc_contig_range() to fail...
6548 */
6549 spin_unlock_irqrestore(&zone->lock, flags);
6550 ret = __alloc_contig_pages(pfn, nr_pages,
6551 gfp_mask);
6552 if (!ret)
6553 return pfn_to_page(pfn);
6554 spin_lock_irqsave(&zone->lock, flags);
6555 }
6556 pfn += nr_pages;
6557 }
6558 spin_unlock_irqrestore(&zone->lock, flags);
6559 }
6560 return NULL;
6561}
6562#endif /* CONFIG_CONTIG_ALLOC */
6563
6564void free_contig_range(unsigned long pfn, unsigned long nr_pages)
6565{
6566 unsigned long count = 0;
6567
6568 for (; nr_pages--; pfn++) {
6569 struct page *page = pfn_to_page(pfn);
6570
6571 count += page_count(page) != 1;
6572 __free_page(page);
6573 }
6574 WARN(count != 0, "%lu pages are still in use!\n", count);
6575}
6576EXPORT_SYMBOL(free_contig_range);
6577
6578/*
6579 * Effectively disable pcplists for the zone by setting the high limit to 0
6580 * and draining all cpus. A concurrent page freeing on another CPU that's about
6581 * to put the page on pcplist will either finish before the drain and the page
6582 * will be drained, or observe the new high limit and skip the pcplist.
6583 *
6584 * Must be paired with a call to zone_pcp_enable().
6585 */
6586void zone_pcp_disable(struct zone *zone)
6587{
6588 mutex_lock(&pcp_batch_high_lock);
6589 __zone_set_pageset_high_and_batch(zone, 0, 0, 1);
6590 __drain_all_pages(zone, true);
6591}
6592
6593void zone_pcp_enable(struct zone *zone)
6594{
6595 __zone_set_pageset_high_and_batch(zone, zone->pageset_high_min,
6596 zone->pageset_high_max, zone->pageset_batch);
6597 mutex_unlock(&pcp_batch_high_lock);
6598}
6599
6600void zone_pcp_reset(struct zone *zone)
6601{
6602 int cpu;
6603 struct per_cpu_zonestat *pzstats;
6604
6605 if (zone->per_cpu_pageset != &boot_pageset) {
6606 for_each_online_cpu(cpu) {
6607 pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
6608 drain_zonestat(zone, pzstats);
6609 }
6610 free_percpu(zone->per_cpu_pageset);
6611 zone->per_cpu_pageset = &boot_pageset;
6612 if (zone->per_cpu_zonestats != &boot_zonestats) {
6613 free_percpu(zone->per_cpu_zonestats);
6614 zone->per_cpu_zonestats = &boot_zonestats;
6615 }
6616 }
6617}
6618
6619#ifdef CONFIG_MEMORY_HOTREMOVE
6620/*
6621 * All pages in the range must be in a single zone, must not contain holes,
6622 * must span full sections, and must be isolated before calling this function.
6623 */
6624void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
6625{
6626 unsigned long pfn = start_pfn;
6627 struct page *page;
6628 struct zone *zone;
6629 unsigned int order;
6630 unsigned long flags;
6631
6632 offline_mem_sections(pfn, end_pfn);
6633 zone = page_zone(pfn_to_page(pfn));
6634 spin_lock_irqsave(&zone->lock, flags);
6635 while (pfn < end_pfn) {
6636 page = pfn_to_page(pfn);
6637 /*
6638 * The HWPoisoned page may be not in buddy system, and
6639 * page_count() is not 0.
6640 */
6641 if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
6642 pfn++;
6643 continue;
6644 }
6645 /*
6646 * At this point all remaining PageOffline() pages have a
6647 * reference count of 0 and can simply be skipped.
6648 */
6649 if (PageOffline(page)) {
6650 BUG_ON(page_count(page));
6651 BUG_ON(PageBuddy(page));
6652 pfn++;
6653 continue;
6654 }
6655
6656 BUG_ON(page_count(page));
6657 BUG_ON(!PageBuddy(page));
6658 order = buddy_order(page);
6659 del_page_from_free_list(page, zone, order);
6660 pfn += (1 << order);
6661 }
6662 spin_unlock_irqrestore(&zone->lock, flags);
6663}
6664#endif
6665
6666/*
6667 * This function returns a stable result only if called under zone lock.
6668 */
6669bool is_free_buddy_page(struct page *page)
6670{
6671 unsigned long pfn = page_to_pfn(page);
6672 unsigned int order;
6673
6674 for (order = 0; order < NR_PAGE_ORDERS; order++) {
6675 struct page *page_head = page - (pfn & ((1 << order) - 1));
6676
6677 if (PageBuddy(page_head) &&
6678 buddy_order_unsafe(page_head) >= order)
6679 break;
6680 }
6681
6682 return order <= MAX_PAGE_ORDER;
6683}
6684EXPORT_SYMBOL(is_free_buddy_page);
6685
6686#ifdef CONFIG_MEMORY_FAILURE
6687/*
6688 * Break down a higher-order page in sub-pages, and keep our target out of
6689 * buddy allocator.
6690 */
6691static void break_down_buddy_pages(struct zone *zone, struct page *page,
6692 struct page *target, int low, int high,
6693 int migratetype)
6694{
6695 unsigned long size = 1 << high;
6696 struct page *current_buddy;
6697
6698 while (high > low) {
6699 high--;
6700 size >>= 1;
6701
6702 if (target >= &page[size]) {
6703 current_buddy = page;
6704 page = page + size;
6705 } else {
6706 current_buddy = page + size;
6707 }
6708
6709 if (set_page_guard(zone, current_buddy, high, migratetype))
6710 continue;
6711
6712 add_to_free_list(current_buddy, zone, high, migratetype);
6713 set_buddy_order(current_buddy, high);
6714 }
6715}
6716
6717/*
6718 * Take a page that will be marked as poisoned off the buddy allocator.
6719 */
6720bool take_page_off_buddy(struct page *page)
6721{
6722 struct zone *zone = page_zone(page);
6723 unsigned long pfn = page_to_pfn(page);
6724 unsigned long flags;
6725 unsigned int order;
6726 bool ret = false;
6727
6728 spin_lock_irqsave(&zone->lock, flags);
6729 for (order = 0; order < NR_PAGE_ORDERS; order++) {
6730 struct page *page_head = page - (pfn & ((1 << order) - 1));
6731 int page_order = buddy_order(page_head);
6732
6733 if (PageBuddy(page_head) && page_order >= order) {
6734 unsigned long pfn_head = page_to_pfn(page_head);
6735 int migratetype = get_pfnblock_migratetype(page_head,
6736 pfn_head);
6737
6738 del_page_from_free_list(page_head, zone, page_order);
6739 break_down_buddy_pages(zone, page_head, page, 0,
6740 page_order, migratetype);
6741 SetPageHWPoisonTakenOff(page);
6742 if (!is_migrate_isolate(migratetype))
6743 __mod_zone_freepage_state(zone, -1, migratetype);
6744 ret = true;
6745 break;
6746 }
6747 if (page_count(page_head) > 0)
6748 break;
6749 }
6750 spin_unlock_irqrestore(&zone->lock, flags);
6751 return ret;
6752}
6753
6754/*
6755 * Cancel takeoff done by take_page_off_buddy().
6756 */
6757bool put_page_back_buddy(struct page *page)
6758{
6759 struct zone *zone = page_zone(page);
6760 unsigned long pfn = page_to_pfn(page);
6761 unsigned long flags;
6762 int migratetype = get_pfnblock_migratetype(page, pfn);
6763 bool ret = false;
6764
6765 spin_lock_irqsave(&zone->lock, flags);
6766 if (put_page_testzero(page)) {
6767 ClearPageHWPoisonTakenOff(page);
6768 __free_one_page(page, pfn, zone, 0, migratetype, FPI_NONE);
6769 if (TestClearPageHWPoison(page)) {
6770 ret = true;
6771 }
6772 }
6773 spin_unlock_irqrestore(&zone->lock, flags);
6774
6775 return ret;
6776}
6777#endif
6778
6779#ifdef CONFIG_ZONE_DMA
6780bool has_managed_dma(void)
6781{
6782 struct pglist_data *pgdat;
6783
6784 for_each_online_pgdat(pgdat) {
6785 struct zone *zone = &pgdat->node_zones[ZONE_DMA];
6786
6787 if (managed_zone(zone))
6788 return true;
6789 }
6790 return false;
6791}
6792#endif /* CONFIG_ZONE_DMA */
6793
6794#ifdef CONFIG_UNACCEPTED_MEMORY
6795
6796/* Counts number of zones with unaccepted pages. */
6797static DEFINE_STATIC_KEY_FALSE(zones_with_unaccepted_pages);
6798
6799static bool lazy_accept = true;
6800
6801static int __init accept_memory_parse(char *p)
6802{
6803 if (!strcmp(p, "lazy")) {
6804 lazy_accept = true;
6805 return 0;
6806 } else if (!strcmp(p, "eager")) {
6807 lazy_accept = false;
6808 return 0;
6809 } else {
6810 return -EINVAL;
6811 }
6812}
6813early_param("accept_memory", accept_memory_parse);
6814
6815static bool page_contains_unaccepted(struct page *page, unsigned int order)
6816{
6817 phys_addr_t start = page_to_phys(page);
6818 phys_addr_t end = start + (PAGE_SIZE << order);
6819
6820 return range_contains_unaccepted_memory(start, end);
6821}
6822
6823static void accept_page(struct page *page, unsigned int order)
6824{
6825 phys_addr_t start = page_to_phys(page);
6826
6827 accept_memory(start, start + (PAGE_SIZE << order));
6828}
6829
6830static bool try_to_accept_memory_one(struct zone *zone)
6831{
6832 unsigned long flags;
6833 struct page *page;
6834 bool last;
6835
6836 if (list_empty(&zone->unaccepted_pages))
6837 return false;
6838
6839 spin_lock_irqsave(&zone->lock, flags);
6840 page = list_first_entry_or_null(&zone->unaccepted_pages,
6841 struct page, lru);
6842 if (!page) {
6843 spin_unlock_irqrestore(&zone->lock, flags);
6844 return false;
6845 }
6846
6847 list_del(&page->lru);
6848 last = list_empty(&zone->unaccepted_pages);
6849
6850 __mod_zone_freepage_state(zone, -MAX_ORDER_NR_PAGES, MIGRATE_MOVABLE);
6851 __mod_zone_page_state(zone, NR_UNACCEPTED, -MAX_ORDER_NR_PAGES);
6852 spin_unlock_irqrestore(&zone->lock, flags);
6853
6854 accept_page(page, MAX_PAGE_ORDER);
6855
6856 __free_pages_ok(page, MAX_PAGE_ORDER, FPI_TO_TAIL);
6857
6858 if (last)
6859 static_branch_dec(&zones_with_unaccepted_pages);
6860
6861 return true;
6862}
6863
6864static bool try_to_accept_memory(struct zone *zone, unsigned int order)
6865{
6866 long to_accept;
6867 int ret = false;
6868
6869 /* How much to accept to get to high watermark? */
6870 to_accept = high_wmark_pages(zone) -
6871 (zone_page_state(zone, NR_FREE_PAGES) -
6872 __zone_watermark_unusable_free(zone, order, 0));
6873
6874 /* Accept at least one page */
6875 do {
6876 if (!try_to_accept_memory_one(zone))
6877 break;
6878 ret = true;
6879 to_accept -= MAX_ORDER_NR_PAGES;
6880 } while (to_accept > 0);
6881
6882 return ret;
6883}
6884
6885static inline bool has_unaccepted_memory(void)
6886{
6887 return static_branch_unlikely(&zones_with_unaccepted_pages);
6888}
6889
6890static bool __free_unaccepted(struct page *page)
6891{
6892 struct zone *zone = page_zone(page);
6893 unsigned long flags;
6894 bool first = false;
6895
6896 if (!lazy_accept)
6897 return false;
6898
6899 spin_lock_irqsave(&zone->lock, flags);
6900 first = list_empty(&zone->unaccepted_pages);
6901 list_add_tail(&page->lru, &zone->unaccepted_pages);
6902 __mod_zone_freepage_state(zone, MAX_ORDER_NR_PAGES, MIGRATE_MOVABLE);
6903 __mod_zone_page_state(zone, NR_UNACCEPTED, MAX_ORDER_NR_PAGES);
6904 spin_unlock_irqrestore(&zone->lock, flags);
6905
6906 if (first)
6907 static_branch_inc(&zones_with_unaccepted_pages);
6908
6909 return true;
6910}
6911
6912#else
6913
6914static bool page_contains_unaccepted(struct page *page, unsigned int order)
6915{
6916 return false;
6917}
6918
6919static void accept_page(struct page *page, unsigned int order)
6920{
6921}
6922
6923static bool try_to_accept_memory(struct zone *zone, unsigned int order)
6924{
6925 return false;
6926}
6927
6928static inline bool has_unaccepted_memory(void)
6929{
6930 return false;
6931}
6932
6933static bool __free_unaccepted(struct page *page)
6934{
6935 BUILD_BUG();
6936 return false;
6937}
6938
6939#endif /* CONFIG_UNACCEPTED_MEMORY */