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1/*
2 * linux/mm/memory_hotplug.c
3 *
4 * Copyright (C)
5 */
6
7#include <linux/stddef.h>
8#include <linux/mm.h>
9#include <linux/swap.h>
10#include <linux/interrupt.h>
11#include <linux/pagemap.h>
12#include <linux/bootmem.h>
13#include <linux/compiler.h>
14#include <linux/module.h>
15#include <linux/pagevec.h>
16#include <linux/writeback.h>
17#include <linux/slab.h>
18#include <linux/sysctl.h>
19#include <linux/cpu.h>
20#include <linux/memory.h>
21#include <linux/memory_hotplug.h>
22#include <linux/highmem.h>
23#include <linux/vmalloc.h>
24#include <linux/ioport.h>
25#include <linux/delay.h>
26#include <linux/migrate.h>
27#include <linux/page-isolation.h>
28#include <linux/pfn.h>
29#include <linux/suspend.h>
30#include <linux/mm_inline.h>
31#include <linux/firmware-map.h>
32
33#include <asm/tlbflush.h>
34
35#include "internal.h"
36
37/*
38 * online_page_callback contains pointer to current page onlining function.
39 * Initially it is generic_online_page(). If it is required it could be
40 * changed by calling set_online_page_callback() for callback registration
41 * and restore_online_page_callback() for generic callback restore.
42 */
43
44static void generic_online_page(struct page *page);
45
46static online_page_callback_t online_page_callback = generic_online_page;
47
48DEFINE_MUTEX(mem_hotplug_mutex);
49
50void lock_memory_hotplug(void)
51{
52 mutex_lock(&mem_hotplug_mutex);
53
54 /* for exclusive hibernation if CONFIG_HIBERNATION=y */
55 lock_system_sleep();
56}
57
58void unlock_memory_hotplug(void)
59{
60 unlock_system_sleep();
61 mutex_unlock(&mem_hotplug_mutex);
62}
63
64
65/* add this memory to iomem resource */
66static struct resource *register_memory_resource(u64 start, u64 size)
67{
68 struct resource *res;
69 res = kzalloc(sizeof(struct resource), GFP_KERNEL);
70 BUG_ON(!res);
71
72 res->name = "System RAM";
73 res->start = start;
74 res->end = start + size - 1;
75 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
76 if (request_resource(&iomem_resource, res) < 0) {
77 printk("System RAM resource %llx - %llx cannot be added\n",
78 (unsigned long long)res->start, (unsigned long long)res->end);
79 kfree(res);
80 res = NULL;
81 }
82 return res;
83}
84
85static void release_memory_resource(struct resource *res)
86{
87 if (!res)
88 return;
89 release_resource(res);
90 kfree(res);
91 return;
92}
93
94#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
95#ifndef CONFIG_SPARSEMEM_VMEMMAP
96static void get_page_bootmem(unsigned long info, struct page *page,
97 unsigned long type)
98{
99 page->lru.next = (struct list_head *) type;
100 SetPagePrivate(page);
101 set_page_private(page, info);
102 atomic_inc(&page->_count);
103}
104
105/* reference to __meminit __free_pages_bootmem is valid
106 * so use __ref to tell modpost not to generate a warning */
107void __ref put_page_bootmem(struct page *page)
108{
109 unsigned long type;
110
111 type = (unsigned long) page->lru.next;
112 BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
113 type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
114
115 if (atomic_dec_return(&page->_count) == 1) {
116 ClearPagePrivate(page);
117 set_page_private(page, 0);
118 INIT_LIST_HEAD(&page->lru);
119 __free_pages_bootmem(page, 0);
120 }
121
122}
123
124static void register_page_bootmem_info_section(unsigned long start_pfn)
125{
126 unsigned long *usemap, mapsize, section_nr, i;
127 struct mem_section *ms;
128 struct page *page, *memmap;
129
130 if (!pfn_valid(start_pfn))
131 return;
132
133 section_nr = pfn_to_section_nr(start_pfn);
134 ms = __nr_to_section(section_nr);
135
136 /* Get section's memmap address */
137 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
138
139 /*
140 * Get page for the memmap's phys address
141 * XXX: need more consideration for sparse_vmemmap...
142 */
143 page = virt_to_page(memmap);
144 mapsize = sizeof(struct page) * PAGES_PER_SECTION;
145 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
146
147 /* remember memmap's page */
148 for (i = 0; i < mapsize; i++, page++)
149 get_page_bootmem(section_nr, page, SECTION_INFO);
150
151 usemap = __nr_to_section(section_nr)->pageblock_flags;
152 page = virt_to_page(usemap);
153
154 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
155
156 for (i = 0; i < mapsize; i++, page++)
157 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
158
159}
160
161void register_page_bootmem_info_node(struct pglist_data *pgdat)
162{
163 unsigned long i, pfn, end_pfn, nr_pages;
164 int node = pgdat->node_id;
165 struct page *page;
166 struct zone *zone;
167
168 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
169 page = virt_to_page(pgdat);
170
171 for (i = 0; i < nr_pages; i++, page++)
172 get_page_bootmem(node, page, NODE_INFO);
173
174 zone = &pgdat->node_zones[0];
175 for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
176 if (zone->wait_table) {
177 nr_pages = zone->wait_table_hash_nr_entries
178 * sizeof(wait_queue_head_t);
179 nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
180 page = virt_to_page(zone->wait_table);
181
182 for (i = 0; i < nr_pages; i++, page++)
183 get_page_bootmem(node, page, NODE_INFO);
184 }
185 }
186
187 pfn = pgdat->node_start_pfn;
188 end_pfn = pfn + pgdat->node_spanned_pages;
189
190 /* register_section info */
191 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION)
192 register_page_bootmem_info_section(pfn);
193
194}
195#endif /* !CONFIG_SPARSEMEM_VMEMMAP */
196
197static void grow_zone_span(struct zone *zone, unsigned long start_pfn,
198 unsigned long end_pfn)
199{
200 unsigned long old_zone_end_pfn;
201
202 zone_span_writelock(zone);
203
204 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
205 if (start_pfn < zone->zone_start_pfn)
206 zone->zone_start_pfn = start_pfn;
207
208 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
209 zone->zone_start_pfn;
210
211 zone_span_writeunlock(zone);
212}
213
214static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
215 unsigned long end_pfn)
216{
217 unsigned long old_pgdat_end_pfn =
218 pgdat->node_start_pfn + pgdat->node_spanned_pages;
219
220 if (start_pfn < pgdat->node_start_pfn)
221 pgdat->node_start_pfn = start_pfn;
222
223 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
224 pgdat->node_start_pfn;
225}
226
227static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
228{
229 struct pglist_data *pgdat = zone->zone_pgdat;
230 int nr_pages = PAGES_PER_SECTION;
231 int nid = pgdat->node_id;
232 int zone_type;
233 unsigned long flags;
234
235 zone_type = zone - pgdat->node_zones;
236 if (!zone->wait_table) {
237 int ret;
238
239 ret = init_currently_empty_zone(zone, phys_start_pfn,
240 nr_pages, MEMMAP_HOTPLUG);
241 if (ret)
242 return ret;
243 }
244 pgdat_resize_lock(zone->zone_pgdat, &flags);
245 grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
246 grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
247 phys_start_pfn + nr_pages);
248 pgdat_resize_unlock(zone->zone_pgdat, &flags);
249 memmap_init_zone(nr_pages, nid, zone_type,
250 phys_start_pfn, MEMMAP_HOTPLUG);
251 return 0;
252}
253
254static int __meminit __add_section(int nid, struct zone *zone,
255 unsigned long phys_start_pfn)
256{
257 int nr_pages = PAGES_PER_SECTION;
258 int ret;
259
260 if (pfn_valid(phys_start_pfn))
261 return -EEXIST;
262
263 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
264
265 if (ret < 0)
266 return ret;
267
268 ret = __add_zone(zone, phys_start_pfn);
269
270 if (ret < 0)
271 return ret;
272
273 return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
274}
275
276#ifdef CONFIG_SPARSEMEM_VMEMMAP
277static int __remove_section(struct zone *zone, struct mem_section *ms)
278{
279 /*
280 * XXX: Freeing memmap with vmemmap is not implement yet.
281 * This should be removed later.
282 */
283 return -EBUSY;
284}
285#else
286static int __remove_section(struct zone *zone, struct mem_section *ms)
287{
288 unsigned long flags;
289 struct pglist_data *pgdat = zone->zone_pgdat;
290 int ret = -EINVAL;
291
292 if (!valid_section(ms))
293 return ret;
294
295 ret = unregister_memory_section(ms);
296 if (ret)
297 return ret;
298
299 pgdat_resize_lock(pgdat, &flags);
300 sparse_remove_one_section(zone, ms);
301 pgdat_resize_unlock(pgdat, &flags);
302 return 0;
303}
304#endif
305
306/*
307 * Reasonably generic function for adding memory. It is
308 * expected that archs that support memory hotplug will
309 * call this function after deciding the zone to which to
310 * add the new pages.
311 */
312int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
313 unsigned long nr_pages)
314{
315 unsigned long i;
316 int err = 0;
317 int start_sec, end_sec;
318 /* during initialize mem_map, align hot-added range to section */
319 start_sec = pfn_to_section_nr(phys_start_pfn);
320 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
321
322 for (i = start_sec; i <= end_sec; i++) {
323 err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);
324
325 /*
326 * EEXIST is finally dealt with by ioresource collision
327 * check. see add_memory() => register_memory_resource()
328 * Warning will be printed if there is collision.
329 */
330 if (err && (err != -EEXIST))
331 break;
332 err = 0;
333 }
334
335 return err;
336}
337EXPORT_SYMBOL_GPL(__add_pages);
338
339/**
340 * __remove_pages() - remove sections of pages from a zone
341 * @zone: zone from which pages need to be removed
342 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
343 * @nr_pages: number of pages to remove (must be multiple of section size)
344 *
345 * Generic helper function to remove section mappings and sysfs entries
346 * for the section of the memory we are removing. Caller needs to make
347 * sure that pages are marked reserved and zones are adjust properly by
348 * calling offline_pages().
349 */
350int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
351 unsigned long nr_pages)
352{
353 unsigned long i, ret = 0;
354 int sections_to_remove;
355
356 /*
357 * We can only remove entire sections
358 */
359 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
360 BUG_ON(nr_pages % PAGES_PER_SECTION);
361
362 sections_to_remove = nr_pages / PAGES_PER_SECTION;
363 for (i = 0; i < sections_to_remove; i++) {
364 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
365 release_mem_region(pfn << PAGE_SHIFT,
366 PAGES_PER_SECTION << PAGE_SHIFT);
367 ret = __remove_section(zone, __pfn_to_section(pfn));
368 if (ret)
369 break;
370 }
371 return ret;
372}
373EXPORT_SYMBOL_GPL(__remove_pages);
374
375int set_online_page_callback(online_page_callback_t callback)
376{
377 int rc = -EINVAL;
378
379 lock_memory_hotplug();
380
381 if (online_page_callback == generic_online_page) {
382 online_page_callback = callback;
383 rc = 0;
384 }
385
386 unlock_memory_hotplug();
387
388 return rc;
389}
390EXPORT_SYMBOL_GPL(set_online_page_callback);
391
392int restore_online_page_callback(online_page_callback_t callback)
393{
394 int rc = -EINVAL;
395
396 lock_memory_hotplug();
397
398 if (online_page_callback == callback) {
399 online_page_callback = generic_online_page;
400 rc = 0;
401 }
402
403 unlock_memory_hotplug();
404
405 return rc;
406}
407EXPORT_SYMBOL_GPL(restore_online_page_callback);
408
409void __online_page_set_limits(struct page *page)
410{
411 unsigned long pfn = page_to_pfn(page);
412
413 if (pfn >= num_physpages)
414 num_physpages = pfn + 1;
415}
416EXPORT_SYMBOL_GPL(__online_page_set_limits);
417
418void __online_page_increment_counters(struct page *page)
419{
420 totalram_pages++;
421
422#ifdef CONFIG_HIGHMEM
423 if (PageHighMem(page))
424 totalhigh_pages++;
425#endif
426}
427EXPORT_SYMBOL_GPL(__online_page_increment_counters);
428
429void __online_page_free(struct page *page)
430{
431 ClearPageReserved(page);
432 init_page_count(page);
433 __free_page(page);
434}
435EXPORT_SYMBOL_GPL(__online_page_free);
436
437static void generic_online_page(struct page *page)
438{
439 __online_page_set_limits(page);
440 __online_page_increment_counters(page);
441 __online_page_free(page);
442}
443
444static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
445 void *arg)
446{
447 unsigned long i;
448 unsigned long onlined_pages = *(unsigned long *)arg;
449 struct page *page;
450 if (PageReserved(pfn_to_page(start_pfn)))
451 for (i = 0; i < nr_pages; i++) {
452 page = pfn_to_page(start_pfn + i);
453 (*online_page_callback)(page);
454 onlined_pages++;
455 }
456 *(unsigned long *)arg = onlined_pages;
457 return 0;
458}
459
460
461int __ref online_pages(unsigned long pfn, unsigned long nr_pages)
462{
463 unsigned long onlined_pages = 0;
464 struct zone *zone;
465 int need_zonelists_rebuild = 0;
466 int nid;
467 int ret;
468 struct memory_notify arg;
469
470 lock_memory_hotplug();
471 arg.start_pfn = pfn;
472 arg.nr_pages = nr_pages;
473 arg.status_change_nid = -1;
474
475 nid = page_to_nid(pfn_to_page(pfn));
476 if (node_present_pages(nid) == 0)
477 arg.status_change_nid = nid;
478
479 ret = memory_notify(MEM_GOING_ONLINE, &arg);
480 ret = notifier_to_errno(ret);
481 if (ret) {
482 memory_notify(MEM_CANCEL_ONLINE, &arg);
483 unlock_memory_hotplug();
484 return ret;
485 }
486 /*
487 * This doesn't need a lock to do pfn_to_page().
488 * The section can't be removed here because of the
489 * memory_block->state_mutex.
490 */
491 zone = page_zone(pfn_to_page(pfn));
492 /*
493 * If this zone is not populated, then it is not in zonelist.
494 * This means the page allocator ignores this zone.
495 * So, zonelist must be updated after online.
496 */
497 mutex_lock(&zonelists_mutex);
498 if (!populated_zone(zone))
499 need_zonelists_rebuild = 1;
500
501 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
502 online_pages_range);
503 if (ret) {
504 mutex_unlock(&zonelists_mutex);
505 printk(KERN_DEBUG "online_pages %lx at %lx failed\n",
506 nr_pages, pfn);
507 memory_notify(MEM_CANCEL_ONLINE, &arg);
508 unlock_memory_hotplug();
509 return ret;
510 }
511
512 zone->present_pages += onlined_pages;
513 zone->zone_pgdat->node_present_pages += onlined_pages;
514 if (need_zonelists_rebuild)
515 build_all_zonelists(zone);
516 else
517 zone_pcp_update(zone);
518
519 mutex_unlock(&zonelists_mutex);
520
521 init_per_zone_wmark_min();
522
523 if (onlined_pages) {
524 kswapd_run(zone_to_nid(zone));
525 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY);
526 }
527
528 vm_total_pages = nr_free_pagecache_pages();
529
530 writeback_set_ratelimit();
531
532 if (onlined_pages)
533 memory_notify(MEM_ONLINE, &arg);
534 unlock_memory_hotplug();
535
536 return 0;
537}
538#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
539
540/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
541static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
542{
543 struct pglist_data *pgdat;
544 unsigned long zones_size[MAX_NR_ZONES] = {0};
545 unsigned long zholes_size[MAX_NR_ZONES] = {0};
546 unsigned long start_pfn = start >> PAGE_SHIFT;
547
548 pgdat = arch_alloc_nodedata(nid);
549 if (!pgdat)
550 return NULL;
551
552 arch_refresh_nodedata(nid, pgdat);
553
554 /* we can use NODE_DATA(nid) from here */
555
556 /* init node's zones as empty zones, we don't have any present pages.*/
557 free_area_init_node(nid, zones_size, start_pfn, zholes_size);
558
559 /*
560 * The node we allocated has no zone fallback lists. For avoiding
561 * to access not-initialized zonelist, build here.
562 */
563 mutex_lock(&zonelists_mutex);
564 build_all_zonelists(NULL);
565 mutex_unlock(&zonelists_mutex);
566
567 return pgdat;
568}
569
570static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
571{
572 arch_refresh_nodedata(nid, NULL);
573 arch_free_nodedata(pgdat);
574 return;
575}
576
577
578/*
579 * called by cpu_up() to online a node without onlined memory.
580 */
581int mem_online_node(int nid)
582{
583 pg_data_t *pgdat;
584 int ret;
585
586 lock_memory_hotplug();
587 pgdat = hotadd_new_pgdat(nid, 0);
588 if (!pgdat) {
589 ret = -ENOMEM;
590 goto out;
591 }
592 node_set_online(nid);
593 ret = register_one_node(nid);
594 BUG_ON(ret);
595
596out:
597 unlock_memory_hotplug();
598 return ret;
599}
600
601/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
602int __ref add_memory(int nid, u64 start, u64 size)
603{
604 pg_data_t *pgdat = NULL;
605 int new_pgdat = 0;
606 struct resource *res;
607 int ret;
608
609 lock_memory_hotplug();
610
611 res = register_memory_resource(start, size);
612 ret = -EEXIST;
613 if (!res)
614 goto out;
615
616 if (!node_online(nid)) {
617 pgdat = hotadd_new_pgdat(nid, start);
618 ret = -ENOMEM;
619 if (!pgdat)
620 goto out;
621 new_pgdat = 1;
622 }
623
624 /* call arch's memory hotadd */
625 ret = arch_add_memory(nid, start, size);
626
627 if (ret < 0)
628 goto error;
629
630 /* we online node here. we can't roll back from here. */
631 node_set_online(nid);
632
633 if (new_pgdat) {
634 ret = register_one_node(nid);
635 /*
636 * If sysfs file of new node can't create, cpu on the node
637 * can't be hot-added. There is no rollback way now.
638 * So, check by BUG_ON() to catch it reluctantly..
639 */
640 BUG_ON(ret);
641 }
642
643 /* create new memmap entry */
644 firmware_map_add_hotplug(start, start + size, "System RAM");
645
646 goto out;
647
648error:
649 /* rollback pgdat allocation and others */
650 if (new_pgdat)
651 rollback_node_hotadd(nid, pgdat);
652 if (res)
653 release_memory_resource(res);
654
655out:
656 unlock_memory_hotplug();
657 return ret;
658}
659EXPORT_SYMBOL_GPL(add_memory);
660
661#ifdef CONFIG_MEMORY_HOTREMOVE
662/*
663 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
664 * set and the size of the free page is given by page_order(). Using this,
665 * the function determines if the pageblock contains only free pages.
666 * Due to buddy contraints, a free page at least the size of a pageblock will
667 * be located at the start of the pageblock
668 */
669static inline int pageblock_free(struct page *page)
670{
671 return PageBuddy(page) && page_order(page) >= pageblock_order;
672}
673
674/* Return the start of the next active pageblock after a given page */
675static struct page *next_active_pageblock(struct page *page)
676{
677 /* Ensure the starting page is pageblock-aligned */
678 BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
679
680 /* If the entire pageblock is free, move to the end of free page */
681 if (pageblock_free(page)) {
682 int order;
683 /* be careful. we don't have locks, page_order can be changed.*/
684 order = page_order(page);
685 if ((order < MAX_ORDER) && (order >= pageblock_order))
686 return page + (1 << order);
687 }
688
689 return page + pageblock_nr_pages;
690}
691
692/* Checks if this range of memory is likely to be hot-removable. */
693int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
694{
695 struct page *page = pfn_to_page(start_pfn);
696 struct page *end_page = page + nr_pages;
697
698 /* Check the starting page of each pageblock within the range */
699 for (; page < end_page; page = next_active_pageblock(page)) {
700 if (!is_pageblock_removable_nolock(page))
701 return 0;
702 cond_resched();
703 }
704
705 /* All pageblocks in the memory block are likely to be hot-removable */
706 return 1;
707}
708
709/*
710 * Confirm all pages in a range [start, end) is belongs to the same zone.
711 */
712static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
713{
714 unsigned long pfn;
715 struct zone *zone = NULL;
716 struct page *page;
717 int i;
718 for (pfn = start_pfn;
719 pfn < end_pfn;
720 pfn += MAX_ORDER_NR_PAGES) {
721 i = 0;
722 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
723 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
724 i++;
725 if (i == MAX_ORDER_NR_PAGES)
726 continue;
727 page = pfn_to_page(pfn + i);
728 if (zone && page_zone(page) != zone)
729 return 0;
730 zone = page_zone(page);
731 }
732 return 1;
733}
734
735/*
736 * Scanning pfn is much easier than scanning lru list.
737 * Scan pfn from start to end and Find LRU page.
738 */
739static unsigned long scan_lru_pages(unsigned long start, unsigned long end)
740{
741 unsigned long pfn;
742 struct page *page;
743 for (pfn = start; pfn < end; pfn++) {
744 if (pfn_valid(pfn)) {
745 page = pfn_to_page(pfn);
746 if (PageLRU(page))
747 return pfn;
748 }
749 }
750 return 0;
751}
752
753static struct page *
754hotremove_migrate_alloc(struct page *page, unsigned long private, int **x)
755{
756 /* This should be improooooved!! */
757 return alloc_page(GFP_HIGHUSER_MOVABLE);
758}
759
760#define NR_OFFLINE_AT_ONCE_PAGES (256)
761static int
762do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
763{
764 unsigned long pfn;
765 struct page *page;
766 int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
767 int not_managed = 0;
768 int ret = 0;
769 LIST_HEAD(source);
770
771 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
772 if (!pfn_valid(pfn))
773 continue;
774 page = pfn_to_page(pfn);
775 if (!get_page_unless_zero(page))
776 continue;
777 /*
778 * We can skip free pages. And we can only deal with pages on
779 * LRU.
780 */
781 ret = isolate_lru_page(page);
782 if (!ret) { /* Success */
783 put_page(page);
784 list_add_tail(&page->lru, &source);
785 move_pages--;
786 inc_zone_page_state(page, NR_ISOLATED_ANON +
787 page_is_file_cache(page));
788
789 } else {
790#ifdef CONFIG_DEBUG_VM
791 printk(KERN_ALERT "removing pfn %lx from LRU failed\n",
792 pfn);
793 dump_page(page);
794#endif
795 put_page(page);
796 /* Because we don't have big zone->lock. we should
797 check this again here. */
798 if (page_count(page)) {
799 not_managed++;
800 ret = -EBUSY;
801 break;
802 }
803 }
804 }
805 if (!list_empty(&source)) {
806 if (not_managed) {
807 putback_lru_pages(&source);
808 goto out;
809 }
810 /* this function returns # of failed pages */
811 ret = migrate_pages(&source, hotremove_migrate_alloc, 0,
812 true, true);
813 if (ret)
814 putback_lru_pages(&source);
815 }
816out:
817 return ret;
818}
819
820/*
821 * remove from free_area[] and mark all as Reserved.
822 */
823static int
824offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
825 void *data)
826{
827 __offline_isolated_pages(start, start + nr_pages);
828 return 0;
829}
830
831static void
832offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
833{
834 walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
835 offline_isolated_pages_cb);
836}
837
838/*
839 * Check all pages in range, recoreded as memory resource, are isolated.
840 */
841static int
842check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
843 void *data)
844{
845 int ret;
846 long offlined = *(long *)data;
847 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages);
848 offlined = nr_pages;
849 if (!ret)
850 *(long *)data += offlined;
851 return ret;
852}
853
854static long
855check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
856{
857 long offlined = 0;
858 int ret;
859
860 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
861 check_pages_isolated_cb);
862 if (ret < 0)
863 offlined = (long)ret;
864 return offlined;
865}
866
867static int __ref offline_pages(unsigned long start_pfn,
868 unsigned long end_pfn, unsigned long timeout)
869{
870 unsigned long pfn, nr_pages, expire;
871 long offlined_pages;
872 int ret, drain, retry_max, node;
873 struct zone *zone;
874 struct memory_notify arg;
875
876 BUG_ON(start_pfn >= end_pfn);
877 /* at least, alignment against pageblock is necessary */
878 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
879 return -EINVAL;
880 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
881 return -EINVAL;
882 /* This makes hotplug much easier...and readable.
883 we assume this for now. .*/
884 if (!test_pages_in_a_zone(start_pfn, end_pfn))
885 return -EINVAL;
886
887 lock_memory_hotplug();
888
889 zone = page_zone(pfn_to_page(start_pfn));
890 node = zone_to_nid(zone);
891 nr_pages = end_pfn - start_pfn;
892
893 /* set above range as isolated */
894 ret = start_isolate_page_range(start_pfn, end_pfn);
895 if (ret)
896 goto out;
897
898 arg.start_pfn = start_pfn;
899 arg.nr_pages = nr_pages;
900 arg.status_change_nid = -1;
901 if (nr_pages >= node_present_pages(node))
902 arg.status_change_nid = node;
903
904 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
905 ret = notifier_to_errno(ret);
906 if (ret)
907 goto failed_removal;
908
909 pfn = start_pfn;
910 expire = jiffies + timeout;
911 drain = 0;
912 retry_max = 5;
913repeat:
914 /* start memory hot removal */
915 ret = -EAGAIN;
916 if (time_after(jiffies, expire))
917 goto failed_removal;
918 ret = -EINTR;
919 if (signal_pending(current))
920 goto failed_removal;
921 ret = 0;
922 if (drain) {
923 lru_add_drain_all();
924 cond_resched();
925 drain_all_pages();
926 }
927
928 pfn = scan_lru_pages(start_pfn, end_pfn);
929 if (pfn) { /* We have page on LRU */
930 ret = do_migrate_range(pfn, end_pfn);
931 if (!ret) {
932 drain = 1;
933 goto repeat;
934 } else {
935 if (ret < 0)
936 if (--retry_max == 0)
937 goto failed_removal;
938 yield();
939 drain = 1;
940 goto repeat;
941 }
942 }
943 /* drain all zone's lru pagevec, this is asyncronous... */
944 lru_add_drain_all();
945 yield();
946 /* drain pcp pages , this is synchrouns. */
947 drain_all_pages();
948 /* check again */
949 offlined_pages = check_pages_isolated(start_pfn, end_pfn);
950 if (offlined_pages < 0) {
951 ret = -EBUSY;
952 goto failed_removal;
953 }
954 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
955 /* Ok, all of our target is islaoted.
956 We cannot do rollback at this point. */
957 offline_isolated_pages(start_pfn, end_pfn);
958 /* reset pagetype flags and makes migrate type to be MOVABLE */
959 undo_isolate_page_range(start_pfn, end_pfn);
960 /* removal success */
961 zone->present_pages -= offlined_pages;
962 zone->zone_pgdat->node_present_pages -= offlined_pages;
963 totalram_pages -= offlined_pages;
964
965 init_per_zone_wmark_min();
966
967 if (!node_present_pages(node)) {
968 node_clear_state(node, N_HIGH_MEMORY);
969 kswapd_stop(node);
970 }
971
972 vm_total_pages = nr_free_pagecache_pages();
973 writeback_set_ratelimit();
974
975 memory_notify(MEM_OFFLINE, &arg);
976 unlock_memory_hotplug();
977 return 0;
978
979failed_removal:
980 printk(KERN_INFO "memory offlining %lx to %lx failed\n",
981 start_pfn, end_pfn);
982 memory_notify(MEM_CANCEL_OFFLINE, &arg);
983 /* pushback to free area */
984 undo_isolate_page_range(start_pfn, end_pfn);
985
986out:
987 unlock_memory_hotplug();
988 return ret;
989}
990
991int remove_memory(u64 start, u64 size)
992{
993 unsigned long start_pfn, end_pfn;
994
995 start_pfn = PFN_DOWN(start);
996 end_pfn = start_pfn + PFN_DOWN(size);
997 return offline_pages(start_pfn, end_pfn, 120 * HZ);
998}
999#else
1000int remove_memory(u64 start, u64 size)
1001{
1002 return -EINVAL;
1003}
1004#endif /* CONFIG_MEMORY_HOTREMOVE */
1005EXPORT_SYMBOL_GPL(remove_memory);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/mm/memory_hotplug.c
4 *
5 * Copyright (C)
6 */
7
8#include <linux/stddef.h>
9#include <linux/mm.h>
10#include <linux/sched/signal.h>
11#include <linux/swap.h>
12#include <linux/interrupt.h>
13#include <linux/pagemap.h>
14#include <linux/compiler.h>
15#include <linux/export.h>
16#include <linux/pagevec.h>
17#include <linux/writeback.h>
18#include <linux/slab.h>
19#include <linux/sysctl.h>
20#include <linux/cpu.h>
21#include <linux/memory.h>
22#include <linux/memremap.h>
23#include <linux/memory_hotplug.h>
24#include <linux/vmalloc.h>
25#include <linux/ioport.h>
26#include <linux/delay.h>
27#include <linux/migrate.h>
28#include <linux/page-isolation.h>
29#include <linux/pfn.h>
30#include <linux/suspend.h>
31#include <linux/mm_inline.h>
32#include <linux/firmware-map.h>
33#include <linux/stop_machine.h>
34#include <linux/hugetlb.h>
35#include <linux/memblock.h>
36#include <linux/compaction.h>
37#include <linux/rmap.h>
38#include <linux/module.h>
39
40#include <asm/tlbflush.h>
41
42#include "internal.h"
43#include "shuffle.h"
44
45#ifdef CONFIG_MHP_MEMMAP_ON_MEMORY
46/*
47 * memory_hotplug.memmap_on_memory parameter
48 */
49static bool memmap_on_memory __ro_after_init;
50module_param(memmap_on_memory, bool, 0444);
51MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug");
52
53static inline bool mhp_memmap_on_memory(void)
54{
55 return memmap_on_memory;
56}
57#else
58static inline bool mhp_memmap_on_memory(void)
59{
60 return false;
61}
62#endif
63
64enum {
65 ONLINE_POLICY_CONTIG_ZONES = 0,
66 ONLINE_POLICY_AUTO_MOVABLE,
67};
68
69static const char * const online_policy_to_str[] = {
70 [ONLINE_POLICY_CONTIG_ZONES] = "contig-zones",
71 [ONLINE_POLICY_AUTO_MOVABLE] = "auto-movable",
72};
73
74static int set_online_policy(const char *val, const struct kernel_param *kp)
75{
76 int ret = sysfs_match_string(online_policy_to_str, val);
77
78 if (ret < 0)
79 return ret;
80 *((int *)kp->arg) = ret;
81 return 0;
82}
83
84static int get_online_policy(char *buffer, const struct kernel_param *kp)
85{
86 return sprintf(buffer, "%s\n", online_policy_to_str[*((int *)kp->arg)]);
87}
88
89/*
90 * memory_hotplug.online_policy: configure online behavior when onlining without
91 * specifying a zone (MMOP_ONLINE)
92 *
93 * "contig-zones": keep zone contiguous
94 * "auto-movable": online memory to ZONE_MOVABLE if the configuration
95 * (auto_movable_ratio, auto_movable_numa_aware) allows for it
96 */
97static int online_policy __read_mostly = ONLINE_POLICY_CONTIG_ZONES;
98static const struct kernel_param_ops online_policy_ops = {
99 .set = set_online_policy,
100 .get = get_online_policy,
101};
102module_param_cb(online_policy, &online_policy_ops, &online_policy, 0644);
103MODULE_PARM_DESC(online_policy,
104 "Set the online policy (\"contig-zones\", \"auto-movable\") "
105 "Default: \"contig-zones\"");
106
107/*
108 * memory_hotplug.auto_movable_ratio: specify maximum MOVABLE:KERNEL ratio
109 *
110 * The ratio represent an upper limit and the kernel might decide to not
111 * online some memory to ZONE_MOVABLE -- e.g., because hotplugged KERNEL memory
112 * doesn't allow for more MOVABLE memory.
113 */
114static unsigned int auto_movable_ratio __read_mostly = 301;
115module_param(auto_movable_ratio, uint, 0644);
116MODULE_PARM_DESC(auto_movable_ratio,
117 "Set the maximum ratio of MOVABLE:KERNEL memory in the system "
118 "in percent for \"auto-movable\" online policy. Default: 301");
119
120/*
121 * memory_hotplug.auto_movable_numa_aware: consider numa node stats
122 */
123#ifdef CONFIG_NUMA
124static bool auto_movable_numa_aware __read_mostly = true;
125module_param(auto_movable_numa_aware, bool, 0644);
126MODULE_PARM_DESC(auto_movable_numa_aware,
127 "Consider numa node stats in addition to global stats in "
128 "\"auto-movable\" online policy. Default: true");
129#endif /* CONFIG_NUMA */
130
131/*
132 * online_page_callback contains pointer to current page onlining function.
133 * Initially it is generic_online_page(). If it is required it could be
134 * changed by calling set_online_page_callback() for callback registration
135 * and restore_online_page_callback() for generic callback restore.
136 */
137
138static online_page_callback_t online_page_callback = generic_online_page;
139static DEFINE_MUTEX(online_page_callback_lock);
140
141DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock);
142
143void get_online_mems(void)
144{
145 percpu_down_read(&mem_hotplug_lock);
146}
147
148void put_online_mems(void)
149{
150 percpu_up_read(&mem_hotplug_lock);
151}
152
153bool movable_node_enabled = false;
154
155#ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
156int mhp_default_online_type = MMOP_OFFLINE;
157#else
158int mhp_default_online_type = MMOP_ONLINE;
159#endif
160
161static int __init setup_memhp_default_state(char *str)
162{
163 const int online_type = mhp_online_type_from_str(str);
164
165 if (online_type >= 0)
166 mhp_default_online_type = online_type;
167
168 return 1;
169}
170__setup("memhp_default_state=", setup_memhp_default_state);
171
172void mem_hotplug_begin(void)
173{
174 cpus_read_lock();
175 percpu_down_write(&mem_hotplug_lock);
176}
177
178void mem_hotplug_done(void)
179{
180 percpu_up_write(&mem_hotplug_lock);
181 cpus_read_unlock();
182}
183
184u64 max_mem_size = U64_MAX;
185
186/* add this memory to iomem resource */
187static struct resource *register_memory_resource(u64 start, u64 size,
188 const char *resource_name)
189{
190 struct resource *res;
191 unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
192
193 if (strcmp(resource_name, "System RAM"))
194 flags |= IORESOURCE_SYSRAM_DRIVER_MANAGED;
195
196 if (!mhp_range_allowed(start, size, true))
197 return ERR_PTR(-E2BIG);
198
199 /*
200 * Make sure value parsed from 'mem=' only restricts memory adding
201 * while booting, so that memory hotplug won't be impacted. Please
202 * refer to document of 'mem=' in kernel-parameters.txt for more
203 * details.
204 */
205 if (start + size > max_mem_size && system_state < SYSTEM_RUNNING)
206 return ERR_PTR(-E2BIG);
207
208 /*
209 * Request ownership of the new memory range. This might be
210 * a child of an existing resource that was present but
211 * not marked as busy.
212 */
213 res = __request_region(&iomem_resource, start, size,
214 resource_name, flags);
215
216 if (!res) {
217 pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n",
218 start, start + size);
219 return ERR_PTR(-EEXIST);
220 }
221 return res;
222}
223
224static void release_memory_resource(struct resource *res)
225{
226 if (!res)
227 return;
228 release_resource(res);
229 kfree(res);
230}
231
232static int check_pfn_span(unsigned long pfn, unsigned long nr_pages)
233{
234 /*
235 * Disallow all operations smaller than a sub-section and only
236 * allow operations smaller than a section for
237 * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range()
238 * enforces a larger memory_block_size_bytes() granularity for
239 * memory that will be marked online, so this check should only
240 * fire for direct arch_{add,remove}_memory() users outside of
241 * add_memory_resource().
242 */
243 unsigned long min_align;
244
245 if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
246 min_align = PAGES_PER_SUBSECTION;
247 else
248 min_align = PAGES_PER_SECTION;
249 if (!IS_ALIGNED(pfn | nr_pages, min_align))
250 return -EINVAL;
251 return 0;
252}
253
254/*
255 * Return page for the valid pfn only if the page is online. All pfn
256 * walkers which rely on the fully initialized page->flags and others
257 * should use this rather than pfn_valid && pfn_to_page
258 */
259struct page *pfn_to_online_page(unsigned long pfn)
260{
261 unsigned long nr = pfn_to_section_nr(pfn);
262 struct dev_pagemap *pgmap;
263 struct mem_section *ms;
264
265 if (nr >= NR_MEM_SECTIONS)
266 return NULL;
267
268 ms = __nr_to_section(nr);
269 if (!online_section(ms))
270 return NULL;
271
272 /*
273 * Save some code text when online_section() +
274 * pfn_section_valid() are sufficient.
275 */
276 if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) && !pfn_valid(pfn))
277 return NULL;
278
279 if (!pfn_section_valid(ms, pfn))
280 return NULL;
281
282 if (!online_device_section(ms))
283 return pfn_to_page(pfn);
284
285 /*
286 * Slowpath: when ZONE_DEVICE collides with
287 * ZONE_{NORMAL,MOVABLE} within the same section some pfns in
288 * the section may be 'offline' but 'valid'. Only
289 * get_dev_pagemap() can determine sub-section online status.
290 */
291 pgmap = get_dev_pagemap(pfn, NULL);
292 put_dev_pagemap(pgmap);
293
294 /* The presence of a pgmap indicates ZONE_DEVICE offline pfn */
295 if (pgmap)
296 return NULL;
297
298 return pfn_to_page(pfn);
299}
300EXPORT_SYMBOL_GPL(pfn_to_online_page);
301
302int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
303 struct mhp_params *params)
304{
305 const unsigned long end_pfn = pfn + nr_pages;
306 unsigned long cur_nr_pages;
307 int err;
308 struct vmem_altmap *altmap = params->altmap;
309
310 if (WARN_ON_ONCE(!pgprot_val(params->pgprot)))
311 return -EINVAL;
312
313 VM_BUG_ON(!mhp_range_allowed(PFN_PHYS(pfn), nr_pages * PAGE_SIZE, false));
314
315 if (altmap) {
316 /*
317 * Validate altmap is within bounds of the total request
318 */
319 if (altmap->base_pfn != pfn
320 || vmem_altmap_offset(altmap) > nr_pages) {
321 pr_warn_once("memory add fail, invalid altmap\n");
322 return -EINVAL;
323 }
324 altmap->alloc = 0;
325 }
326
327 if (check_pfn_span(pfn, nr_pages)) {
328 WARN(1, "Misaligned %s start: %#lx end: #%lx\n", __func__, pfn, pfn + nr_pages - 1);
329 return -EINVAL;
330 }
331
332 for (; pfn < end_pfn; pfn += cur_nr_pages) {
333 /* Select all remaining pages up to the next section boundary */
334 cur_nr_pages = min(end_pfn - pfn,
335 SECTION_ALIGN_UP(pfn + 1) - pfn);
336 err = sparse_add_section(nid, pfn, cur_nr_pages, altmap,
337 params->pgmap);
338 if (err)
339 break;
340 cond_resched();
341 }
342 vmemmap_populate_print_last();
343 return err;
344}
345
346/* find the smallest valid pfn in the range [start_pfn, end_pfn) */
347static unsigned long find_smallest_section_pfn(int nid, struct zone *zone,
348 unsigned long start_pfn,
349 unsigned long end_pfn)
350{
351 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) {
352 if (unlikely(!pfn_to_online_page(start_pfn)))
353 continue;
354
355 if (unlikely(pfn_to_nid(start_pfn) != nid))
356 continue;
357
358 if (zone != page_zone(pfn_to_page(start_pfn)))
359 continue;
360
361 return start_pfn;
362 }
363
364 return 0;
365}
366
367/* find the biggest valid pfn in the range [start_pfn, end_pfn). */
368static unsigned long find_biggest_section_pfn(int nid, struct zone *zone,
369 unsigned long start_pfn,
370 unsigned long end_pfn)
371{
372 unsigned long pfn;
373
374 /* pfn is the end pfn of a memory section. */
375 pfn = end_pfn - 1;
376 for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) {
377 if (unlikely(!pfn_to_online_page(pfn)))
378 continue;
379
380 if (unlikely(pfn_to_nid(pfn) != nid))
381 continue;
382
383 if (zone != page_zone(pfn_to_page(pfn)))
384 continue;
385
386 return pfn;
387 }
388
389 return 0;
390}
391
392static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
393 unsigned long end_pfn)
394{
395 unsigned long pfn;
396 int nid = zone_to_nid(zone);
397
398 if (zone->zone_start_pfn == start_pfn) {
399 /*
400 * If the section is smallest section in the zone, it need
401 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
402 * In this case, we find second smallest valid mem_section
403 * for shrinking zone.
404 */
405 pfn = find_smallest_section_pfn(nid, zone, end_pfn,
406 zone_end_pfn(zone));
407 if (pfn) {
408 zone->spanned_pages = zone_end_pfn(zone) - pfn;
409 zone->zone_start_pfn = pfn;
410 } else {
411 zone->zone_start_pfn = 0;
412 zone->spanned_pages = 0;
413 }
414 } else if (zone_end_pfn(zone) == end_pfn) {
415 /*
416 * If the section is biggest section in the zone, it need
417 * shrink zone->spanned_pages.
418 * In this case, we find second biggest valid mem_section for
419 * shrinking zone.
420 */
421 pfn = find_biggest_section_pfn(nid, zone, zone->zone_start_pfn,
422 start_pfn);
423 if (pfn)
424 zone->spanned_pages = pfn - zone->zone_start_pfn + 1;
425 else {
426 zone->zone_start_pfn = 0;
427 zone->spanned_pages = 0;
428 }
429 }
430}
431
432static void update_pgdat_span(struct pglist_data *pgdat)
433{
434 unsigned long node_start_pfn = 0, node_end_pfn = 0;
435 struct zone *zone;
436
437 for (zone = pgdat->node_zones;
438 zone < pgdat->node_zones + MAX_NR_ZONES; zone++) {
439 unsigned long end_pfn = zone_end_pfn(zone);
440
441 /* No need to lock the zones, they can't change. */
442 if (!zone->spanned_pages)
443 continue;
444 if (!node_end_pfn) {
445 node_start_pfn = zone->zone_start_pfn;
446 node_end_pfn = end_pfn;
447 continue;
448 }
449
450 if (end_pfn > node_end_pfn)
451 node_end_pfn = end_pfn;
452 if (zone->zone_start_pfn < node_start_pfn)
453 node_start_pfn = zone->zone_start_pfn;
454 }
455
456 pgdat->node_start_pfn = node_start_pfn;
457 pgdat->node_spanned_pages = node_end_pfn - node_start_pfn;
458}
459
460void __ref remove_pfn_range_from_zone(struct zone *zone,
461 unsigned long start_pfn,
462 unsigned long nr_pages)
463{
464 const unsigned long end_pfn = start_pfn + nr_pages;
465 struct pglist_data *pgdat = zone->zone_pgdat;
466 unsigned long pfn, cur_nr_pages;
467
468 /* Poison struct pages because they are now uninitialized again. */
469 for (pfn = start_pfn; pfn < end_pfn; pfn += cur_nr_pages) {
470 cond_resched();
471
472 /* Select all remaining pages up to the next section boundary */
473 cur_nr_pages =
474 min(end_pfn - pfn, SECTION_ALIGN_UP(pfn + 1) - pfn);
475 page_init_poison(pfn_to_page(pfn),
476 sizeof(struct page) * cur_nr_pages);
477 }
478
479 /*
480 * Zone shrinking code cannot properly deal with ZONE_DEVICE. So
481 * we will not try to shrink the zones - which is okay as
482 * set_zone_contiguous() cannot deal with ZONE_DEVICE either way.
483 */
484 if (zone_is_zone_device(zone))
485 return;
486
487 clear_zone_contiguous(zone);
488
489 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
490 update_pgdat_span(pgdat);
491
492 set_zone_contiguous(zone);
493}
494
495static void __remove_section(unsigned long pfn, unsigned long nr_pages,
496 unsigned long map_offset,
497 struct vmem_altmap *altmap)
498{
499 struct mem_section *ms = __pfn_to_section(pfn);
500
501 if (WARN_ON_ONCE(!valid_section(ms)))
502 return;
503
504 sparse_remove_section(ms, pfn, nr_pages, map_offset, altmap);
505}
506
507/**
508 * __remove_pages() - remove sections of pages
509 * @pfn: starting pageframe (must be aligned to start of a section)
510 * @nr_pages: number of pages to remove (must be multiple of section size)
511 * @altmap: alternative device page map or %NULL if default memmap is used
512 *
513 * Generic helper function to remove section mappings and sysfs entries
514 * for the section of the memory we are removing. Caller needs to make
515 * sure that pages are marked reserved and zones are adjust properly by
516 * calling offline_pages().
517 */
518void __remove_pages(unsigned long pfn, unsigned long nr_pages,
519 struct vmem_altmap *altmap)
520{
521 const unsigned long end_pfn = pfn + nr_pages;
522 unsigned long cur_nr_pages;
523 unsigned long map_offset = 0;
524
525 map_offset = vmem_altmap_offset(altmap);
526
527 if (check_pfn_span(pfn, nr_pages)) {
528 WARN(1, "Misaligned %s start: %#lx end: #%lx\n", __func__, pfn, pfn + nr_pages - 1);
529 return;
530 }
531
532 for (; pfn < end_pfn; pfn += cur_nr_pages) {
533 cond_resched();
534 /* Select all remaining pages up to the next section boundary */
535 cur_nr_pages = min(end_pfn - pfn,
536 SECTION_ALIGN_UP(pfn + 1) - pfn);
537 __remove_section(pfn, cur_nr_pages, map_offset, altmap);
538 map_offset = 0;
539 }
540}
541
542int set_online_page_callback(online_page_callback_t callback)
543{
544 int rc = -EINVAL;
545
546 get_online_mems();
547 mutex_lock(&online_page_callback_lock);
548
549 if (online_page_callback == generic_online_page) {
550 online_page_callback = callback;
551 rc = 0;
552 }
553
554 mutex_unlock(&online_page_callback_lock);
555 put_online_mems();
556
557 return rc;
558}
559EXPORT_SYMBOL_GPL(set_online_page_callback);
560
561int restore_online_page_callback(online_page_callback_t callback)
562{
563 int rc = -EINVAL;
564
565 get_online_mems();
566 mutex_lock(&online_page_callback_lock);
567
568 if (online_page_callback == callback) {
569 online_page_callback = generic_online_page;
570 rc = 0;
571 }
572
573 mutex_unlock(&online_page_callback_lock);
574 put_online_mems();
575
576 return rc;
577}
578EXPORT_SYMBOL_GPL(restore_online_page_callback);
579
580void generic_online_page(struct page *page, unsigned int order)
581{
582 /*
583 * Freeing the page with debug_pagealloc enabled will try to unmap it,
584 * so we should map it first. This is better than introducing a special
585 * case in page freeing fast path.
586 */
587 debug_pagealloc_map_pages(page, 1 << order);
588 __free_pages_core(page, order);
589 totalram_pages_add(1UL << order);
590}
591EXPORT_SYMBOL_GPL(generic_online_page);
592
593static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages)
594{
595 const unsigned long end_pfn = start_pfn + nr_pages;
596 unsigned long pfn;
597
598 /*
599 * Online the pages in MAX_ORDER - 1 aligned chunks. The callback might
600 * decide to not expose all pages to the buddy (e.g., expose them
601 * later). We account all pages as being online and belonging to this
602 * zone ("present").
603 * When using memmap_on_memory, the range might not be aligned to
604 * MAX_ORDER_NR_PAGES - 1, but pageblock aligned. __ffs() will detect
605 * this and the first chunk to online will be pageblock_nr_pages.
606 */
607 for (pfn = start_pfn; pfn < end_pfn;) {
608 int order = min(MAX_ORDER - 1UL, __ffs(pfn));
609
610 (*online_page_callback)(pfn_to_page(pfn), order);
611 pfn += (1UL << order);
612 }
613
614 /* mark all involved sections as online */
615 online_mem_sections(start_pfn, end_pfn);
616}
617
618/* check which state of node_states will be changed when online memory */
619static void node_states_check_changes_online(unsigned long nr_pages,
620 struct zone *zone, struct memory_notify *arg)
621{
622 int nid = zone_to_nid(zone);
623
624 arg->status_change_nid = NUMA_NO_NODE;
625 arg->status_change_nid_normal = NUMA_NO_NODE;
626
627 if (!node_state(nid, N_MEMORY))
628 arg->status_change_nid = nid;
629 if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY))
630 arg->status_change_nid_normal = nid;
631}
632
633static void node_states_set_node(int node, struct memory_notify *arg)
634{
635 if (arg->status_change_nid_normal >= 0)
636 node_set_state(node, N_NORMAL_MEMORY);
637
638 if (arg->status_change_nid >= 0)
639 node_set_state(node, N_MEMORY);
640}
641
642static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
643 unsigned long nr_pages)
644{
645 unsigned long old_end_pfn = zone_end_pfn(zone);
646
647 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
648 zone->zone_start_pfn = start_pfn;
649
650 zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn;
651}
652
653static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn,
654 unsigned long nr_pages)
655{
656 unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
657
658 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
659 pgdat->node_start_pfn = start_pfn;
660
661 pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn;
662
663}
664
665#ifdef CONFIG_ZONE_DEVICE
666static void section_taint_zone_device(unsigned long pfn)
667{
668 struct mem_section *ms = __pfn_to_section(pfn);
669
670 ms->section_mem_map |= SECTION_TAINT_ZONE_DEVICE;
671}
672#else
673static inline void section_taint_zone_device(unsigned long pfn)
674{
675}
676#endif
677
678/*
679 * Associate the pfn range with the given zone, initializing the memmaps
680 * and resizing the pgdat/zone data to span the added pages. After this
681 * call, all affected pages are PG_reserved.
682 *
683 * All aligned pageblocks are initialized to the specified migratetype
684 * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related
685 * zone stats (e.g., nr_isolate_pageblock) are touched.
686 */
687void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
688 unsigned long nr_pages,
689 struct vmem_altmap *altmap, int migratetype)
690{
691 struct pglist_data *pgdat = zone->zone_pgdat;
692 int nid = pgdat->node_id;
693
694 clear_zone_contiguous(zone);
695
696 if (zone_is_empty(zone))
697 init_currently_empty_zone(zone, start_pfn, nr_pages);
698 resize_zone_range(zone, start_pfn, nr_pages);
699 resize_pgdat_range(pgdat, start_pfn, nr_pages);
700
701 /*
702 * Subsection population requires care in pfn_to_online_page().
703 * Set the taint to enable the slow path detection of
704 * ZONE_DEVICE pages in an otherwise ZONE_{NORMAL,MOVABLE}
705 * section.
706 */
707 if (zone_is_zone_device(zone)) {
708 if (!IS_ALIGNED(start_pfn, PAGES_PER_SECTION))
709 section_taint_zone_device(start_pfn);
710 if (!IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION))
711 section_taint_zone_device(start_pfn + nr_pages);
712 }
713
714 /*
715 * TODO now we have a visible range of pages which are not associated
716 * with their zone properly. Not nice but set_pfnblock_flags_mask
717 * expects the zone spans the pfn range. All the pages in the range
718 * are reserved so nobody should be touching them so we should be safe
719 */
720 memmap_init_range(nr_pages, nid, zone_idx(zone), start_pfn, 0,
721 MEMINIT_HOTPLUG, altmap, migratetype);
722
723 set_zone_contiguous(zone);
724}
725
726struct auto_movable_stats {
727 unsigned long kernel_early_pages;
728 unsigned long movable_pages;
729};
730
731static void auto_movable_stats_account_zone(struct auto_movable_stats *stats,
732 struct zone *zone)
733{
734 if (zone_idx(zone) == ZONE_MOVABLE) {
735 stats->movable_pages += zone->present_pages;
736 } else {
737 stats->kernel_early_pages += zone->present_early_pages;
738#ifdef CONFIG_CMA
739 /*
740 * CMA pages (never on hotplugged memory) behave like
741 * ZONE_MOVABLE.
742 */
743 stats->movable_pages += zone->cma_pages;
744 stats->kernel_early_pages -= zone->cma_pages;
745#endif /* CONFIG_CMA */
746 }
747}
748struct auto_movable_group_stats {
749 unsigned long movable_pages;
750 unsigned long req_kernel_early_pages;
751};
752
753static int auto_movable_stats_account_group(struct memory_group *group,
754 void *arg)
755{
756 const int ratio = READ_ONCE(auto_movable_ratio);
757 struct auto_movable_group_stats *stats = arg;
758 long pages;
759
760 /*
761 * We don't support modifying the config while the auto-movable online
762 * policy is already enabled. Just avoid the division by zero below.
763 */
764 if (!ratio)
765 return 0;
766
767 /*
768 * Calculate how many early kernel pages this group requires to
769 * satisfy the configured zone ratio.
770 */
771 pages = group->present_movable_pages * 100 / ratio;
772 pages -= group->present_kernel_pages;
773
774 if (pages > 0)
775 stats->req_kernel_early_pages += pages;
776 stats->movable_pages += group->present_movable_pages;
777 return 0;
778}
779
780static bool auto_movable_can_online_movable(int nid, struct memory_group *group,
781 unsigned long nr_pages)
782{
783 unsigned long kernel_early_pages, movable_pages;
784 struct auto_movable_group_stats group_stats = {};
785 struct auto_movable_stats stats = {};
786 pg_data_t *pgdat = NODE_DATA(nid);
787 struct zone *zone;
788 int i;
789
790 /* Walk all relevant zones and collect MOVABLE vs. KERNEL stats. */
791 if (nid == NUMA_NO_NODE) {
792 /* TODO: cache values */
793 for_each_populated_zone(zone)
794 auto_movable_stats_account_zone(&stats, zone);
795 } else {
796 for (i = 0; i < MAX_NR_ZONES; i++) {
797 zone = pgdat->node_zones + i;
798 if (populated_zone(zone))
799 auto_movable_stats_account_zone(&stats, zone);
800 }
801 }
802
803 kernel_early_pages = stats.kernel_early_pages;
804 movable_pages = stats.movable_pages;
805
806 /*
807 * Kernel memory inside dynamic memory group allows for more MOVABLE
808 * memory within the same group. Remove the effect of all but the
809 * current group from the stats.
810 */
811 walk_dynamic_memory_groups(nid, auto_movable_stats_account_group,
812 group, &group_stats);
813 if (kernel_early_pages <= group_stats.req_kernel_early_pages)
814 return false;
815 kernel_early_pages -= group_stats.req_kernel_early_pages;
816 movable_pages -= group_stats.movable_pages;
817
818 if (group && group->is_dynamic)
819 kernel_early_pages += group->present_kernel_pages;
820
821 /*
822 * Test if we could online the given number of pages to ZONE_MOVABLE
823 * and still stay in the configured ratio.
824 */
825 movable_pages += nr_pages;
826 return movable_pages <= (auto_movable_ratio * kernel_early_pages) / 100;
827}
828
829/*
830 * Returns a default kernel memory zone for the given pfn range.
831 * If no kernel zone covers this pfn range it will automatically go
832 * to the ZONE_NORMAL.
833 */
834static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn,
835 unsigned long nr_pages)
836{
837 struct pglist_data *pgdat = NODE_DATA(nid);
838 int zid;
839
840 for (zid = 0; zid < ZONE_NORMAL; zid++) {
841 struct zone *zone = &pgdat->node_zones[zid];
842
843 if (zone_intersects(zone, start_pfn, nr_pages))
844 return zone;
845 }
846
847 return &pgdat->node_zones[ZONE_NORMAL];
848}
849
850/*
851 * Determine to which zone to online memory dynamically based on user
852 * configuration and system stats. We care about the following ratio:
853 *
854 * MOVABLE : KERNEL
855 *
856 * Whereby MOVABLE is memory in ZONE_MOVABLE and KERNEL is memory in
857 * one of the kernel zones. CMA pages inside one of the kernel zones really
858 * behaves like ZONE_MOVABLE, so we treat them accordingly.
859 *
860 * We don't allow for hotplugged memory in a KERNEL zone to increase the
861 * amount of MOVABLE memory we can have, so we end up with:
862 *
863 * MOVABLE : KERNEL_EARLY
864 *
865 * Whereby KERNEL_EARLY is memory in one of the kernel zones, available sinze
866 * boot. We base our calculation on KERNEL_EARLY internally, because:
867 *
868 * a) Hotplugged memory in one of the kernel zones can sometimes still get
869 * hotunplugged, especially when hot(un)plugging individual memory blocks.
870 * There is no coordination across memory devices, therefore "automatic"
871 * hotunplugging, as implemented in hypervisors, could result in zone
872 * imbalances.
873 * b) Early/boot memory in one of the kernel zones can usually not get
874 * hotunplugged again (e.g., no firmware interface to unplug, fragmented
875 * with unmovable allocations). While there are corner cases where it might
876 * still work, it is barely relevant in practice.
877 *
878 * Exceptions are dynamic memory groups, which allow for more MOVABLE
879 * memory within the same memory group -- because in that case, there is
880 * coordination within the single memory device managed by a single driver.
881 *
882 * We rely on "present pages" instead of "managed pages", as the latter is
883 * highly unreliable and dynamic in virtualized environments, and does not
884 * consider boot time allocations. For example, memory ballooning adjusts the
885 * managed pages when inflating/deflating the balloon, and balloon compaction
886 * can even migrate inflated pages between zones.
887 *
888 * Using "present pages" is better but some things to keep in mind are:
889 *
890 * a) Some memblock allocations, such as for the crashkernel area, are
891 * effectively unused by the kernel, yet they account to "present pages".
892 * Fortunately, these allocations are comparatively small in relevant setups
893 * (e.g., fraction of system memory).
894 * b) Some hotplugged memory blocks in virtualized environments, esecially
895 * hotplugged by virtio-mem, look like they are completely present, however,
896 * only parts of the memory block are actually currently usable.
897 * "present pages" is an upper limit that can get reached at runtime. As
898 * we base our calculations on KERNEL_EARLY, this is not an issue.
899 */
900static struct zone *auto_movable_zone_for_pfn(int nid,
901 struct memory_group *group,
902 unsigned long pfn,
903 unsigned long nr_pages)
904{
905 unsigned long online_pages = 0, max_pages, end_pfn;
906 struct page *page;
907
908 if (!auto_movable_ratio)
909 goto kernel_zone;
910
911 if (group && !group->is_dynamic) {
912 max_pages = group->s.max_pages;
913 online_pages = group->present_movable_pages;
914
915 /* If anything is !MOVABLE online the rest !MOVABLE. */
916 if (group->present_kernel_pages)
917 goto kernel_zone;
918 } else if (!group || group->d.unit_pages == nr_pages) {
919 max_pages = nr_pages;
920 } else {
921 max_pages = group->d.unit_pages;
922 /*
923 * Take a look at all online sections in the current unit.
924 * We can safely assume that all pages within a section belong
925 * to the same zone, because dynamic memory groups only deal
926 * with hotplugged memory.
927 */
928 pfn = ALIGN_DOWN(pfn, group->d.unit_pages);
929 end_pfn = pfn + group->d.unit_pages;
930 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
931 page = pfn_to_online_page(pfn);
932 if (!page)
933 continue;
934 /* If anything is !MOVABLE online the rest !MOVABLE. */
935 if (!is_zone_movable_page(page))
936 goto kernel_zone;
937 online_pages += PAGES_PER_SECTION;
938 }
939 }
940
941 /*
942 * Online MOVABLE if we could *currently* online all remaining parts
943 * MOVABLE. We expect to (add+) online them immediately next, so if
944 * nobody interferes, all will be MOVABLE if possible.
945 */
946 nr_pages = max_pages - online_pages;
947 if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages))
948 goto kernel_zone;
949
950#ifdef CONFIG_NUMA
951 if (auto_movable_numa_aware &&
952 !auto_movable_can_online_movable(nid, group, nr_pages))
953 goto kernel_zone;
954#endif /* CONFIG_NUMA */
955
956 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
957kernel_zone:
958 return default_kernel_zone_for_pfn(nid, pfn, nr_pages);
959}
960
961static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn,
962 unsigned long nr_pages)
963{
964 struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn,
965 nr_pages);
966 struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
967 bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages);
968 bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages);
969
970 /*
971 * We inherit the existing zone in a simple case where zones do not
972 * overlap in the given range
973 */
974 if (in_kernel ^ in_movable)
975 return (in_kernel) ? kernel_zone : movable_zone;
976
977 /*
978 * If the range doesn't belong to any zone or two zones overlap in the
979 * given range then we use movable zone only if movable_node is
980 * enabled because we always online to a kernel zone by default.
981 */
982 return movable_node_enabled ? movable_zone : kernel_zone;
983}
984
985struct zone *zone_for_pfn_range(int online_type, int nid,
986 struct memory_group *group, unsigned long start_pfn,
987 unsigned long nr_pages)
988{
989 if (online_type == MMOP_ONLINE_KERNEL)
990 return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages);
991
992 if (online_type == MMOP_ONLINE_MOVABLE)
993 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
994
995 if (online_policy == ONLINE_POLICY_AUTO_MOVABLE)
996 return auto_movable_zone_for_pfn(nid, group, start_pfn, nr_pages);
997
998 return default_zone_for_pfn(nid, start_pfn, nr_pages);
999}
1000
1001/*
1002 * This function should only be called by memory_block_{online,offline},
1003 * and {online,offline}_pages.
1004 */
1005void adjust_present_page_count(struct page *page, struct memory_group *group,
1006 long nr_pages)
1007{
1008 struct zone *zone = page_zone(page);
1009 const bool movable = zone_idx(zone) == ZONE_MOVABLE;
1010
1011 /*
1012 * We only support onlining/offlining/adding/removing of complete
1013 * memory blocks; therefore, either all is either early or hotplugged.
1014 */
1015 if (early_section(__pfn_to_section(page_to_pfn(page))))
1016 zone->present_early_pages += nr_pages;
1017 zone->present_pages += nr_pages;
1018 zone->zone_pgdat->node_present_pages += nr_pages;
1019
1020 if (group && movable)
1021 group->present_movable_pages += nr_pages;
1022 else if (group && !movable)
1023 group->present_kernel_pages += nr_pages;
1024}
1025
1026int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages,
1027 struct zone *zone)
1028{
1029 unsigned long end_pfn = pfn + nr_pages;
1030 int ret, i;
1031
1032 ret = kasan_add_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages));
1033 if (ret)
1034 return ret;
1035
1036 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_UNMOVABLE);
1037
1038 for (i = 0; i < nr_pages; i++)
1039 SetPageVmemmapSelfHosted(pfn_to_page(pfn + i));
1040
1041 /*
1042 * It might be that the vmemmap_pages fully span sections. If that is
1043 * the case, mark those sections online here as otherwise they will be
1044 * left offline.
1045 */
1046 if (nr_pages >= PAGES_PER_SECTION)
1047 online_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION));
1048
1049 return ret;
1050}
1051
1052void mhp_deinit_memmap_on_memory(unsigned long pfn, unsigned long nr_pages)
1053{
1054 unsigned long end_pfn = pfn + nr_pages;
1055
1056 /*
1057 * It might be that the vmemmap_pages fully span sections. If that is
1058 * the case, mark those sections offline here as otherwise they will be
1059 * left online.
1060 */
1061 if (nr_pages >= PAGES_PER_SECTION)
1062 offline_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION));
1063
1064 /*
1065 * The pages associated with this vmemmap have been offlined, so
1066 * we can reset its state here.
1067 */
1068 remove_pfn_range_from_zone(page_zone(pfn_to_page(pfn)), pfn, nr_pages);
1069 kasan_remove_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages));
1070}
1071
1072int __ref online_pages(unsigned long pfn, unsigned long nr_pages,
1073 struct zone *zone, struct memory_group *group)
1074{
1075 unsigned long flags;
1076 int need_zonelists_rebuild = 0;
1077 const int nid = zone_to_nid(zone);
1078 int ret;
1079 struct memory_notify arg;
1080
1081 /*
1082 * {on,off}lining is constrained to full memory sections (or more
1083 * precisely to memory blocks from the user space POV).
1084 * memmap_on_memory is an exception because it reserves initial part
1085 * of the physical memory space for vmemmaps. That space is pageblock
1086 * aligned.
1087 */
1088 if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(pfn) ||
1089 !IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION)))
1090 return -EINVAL;
1091
1092 mem_hotplug_begin();
1093
1094 /* associate pfn range with the zone */
1095 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_ISOLATE);
1096
1097 arg.start_pfn = pfn;
1098 arg.nr_pages = nr_pages;
1099 node_states_check_changes_online(nr_pages, zone, &arg);
1100
1101 ret = memory_notify(MEM_GOING_ONLINE, &arg);
1102 ret = notifier_to_errno(ret);
1103 if (ret)
1104 goto failed_addition;
1105
1106 /*
1107 * Fixup the number of isolated pageblocks before marking the sections
1108 * onlining, such that undo_isolate_page_range() works correctly.
1109 */
1110 spin_lock_irqsave(&zone->lock, flags);
1111 zone->nr_isolate_pageblock += nr_pages / pageblock_nr_pages;
1112 spin_unlock_irqrestore(&zone->lock, flags);
1113
1114 /*
1115 * If this zone is not populated, then it is not in zonelist.
1116 * This means the page allocator ignores this zone.
1117 * So, zonelist must be updated after online.
1118 */
1119 if (!populated_zone(zone)) {
1120 need_zonelists_rebuild = 1;
1121 setup_zone_pageset(zone);
1122 }
1123
1124 online_pages_range(pfn, nr_pages);
1125 adjust_present_page_count(pfn_to_page(pfn), group, nr_pages);
1126
1127 node_states_set_node(nid, &arg);
1128 if (need_zonelists_rebuild)
1129 build_all_zonelists(NULL);
1130
1131 /* Basic onlining is complete, allow allocation of onlined pages. */
1132 undo_isolate_page_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE);
1133
1134 /*
1135 * Freshly onlined pages aren't shuffled (e.g., all pages are placed to
1136 * the tail of the freelist when undoing isolation). Shuffle the whole
1137 * zone to make sure the just onlined pages are properly distributed
1138 * across the whole freelist - to create an initial shuffle.
1139 */
1140 shuffle_zone(zone);
1141
1142 /* reinitialise watermarks and update pcp limits */
1143 init_per_zone_wmark_min();
1144
1145 kswapd_run(nid);
1146 kcompactd_run(nid);
1147
1148 writeback_set_ratelimit();
1149
1150 memory_notify(MEM_ONLINE, &arg);
1151 mem_hotplug_done();
1152 return 0;
1153
1154failed_addition:
1155 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
1156 (unsigned long long) pfn << PAGE_SHIFT,
1157 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
1158 memory_notify(MEM_CANCEL_ONLINE, &arg);
1159 remove_pfn_range_from_zone(zone, pfn, nr_pages);
1160 mem_hotplug_done();
1161 return ret;
1162}
1163
1164static void reset_node_present_pages(pg_data_t *pgdat)
1165{
1166 struct zone *z;
1167
1168 for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
1169 z->present_pages = 0;
1170
1171 pgdat->node_present_pages = 0;
1172}
1173
1174/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1175static pg_data_t __ref *hotadd_init_pgdat(int nid)
1176{
1177 struct pglist_data *pgdat;
1178
1179 /*
1180 * NODE_DATA is preallocated (free_area_init) but its internal
1181 * state is not allocated completely. Add missing pieces.
1182 * Completely offline nodes stay around and they just need
1183 * reintialization.
1184 */
1185 pgdat = NODE_DATA(nid);
1186
1187 /* init node's zones as empty zones, we don't have any present pages.*/
1188 free_area_init_core_hotplug(pgdat);
1189
1190 /*
1191 * The node we allocated has no zone fallback lists. For avoiding
1192 * to access not-initialized zonelist, build here.
1193 */
1194 build_all_zonelists(pgdat);
1195
1196 /*
1197 * When memory is hot-added, all the memory is in offline state. So
1198 * clear all zones' present_pages because they will be updated in
1199 * online_pages() and offline_pages().
1200 * TODO: should be in free_area_init_core_hotplug?
1201 */
1202 reset_node_managed_pages(pgdat);
1203 reset_node_present_pages(pgdat);
1204
1205 return pgdat;
1206}
1207
1208/*
1209 * __try_online_node - online a node if offlined
1210 * @nid: the node ID
1211 * @set_node_online: Whether we want to online the node
1212 * called by cpu_up() to online a node without onlined memory.
1213 *
1214 * Returns:
1215 * 1 -> a new node has been allocated
1216 * 0 -> the node is already online
1217 * -ENOMEM -> the node could not be allocated
1218 */
1219static int __try_online_node(int nid, bool set_node_online)
1220{
1221 pg_data_t *pgdat;
1222 int ret = 1;
1223
1224 if (node_online(nid))
1225 return 0;
1226
1227 pgdat = hotadd_init_pgdat(nid);
1228 if (!pgdat) {
1229 pr_err("Cannot online node %d due to NULL pgdat\n", nid);
1230 ret = -ENOMEM;
1231 goto out;
1232 }
1233
1234 if (set_node_online) {
1235 node_set_online(nid);
1236 ret = register_one_node(nid);
1237 BUG_ON(ret);
1238 }
1239out:
1240 return ret;
1241}
1242
1243/*
1244 * Users of this function always want to online/register the node
1245 */
1246int try_online_node(int nid)
1247{
1248 int ret;
1249
1250 mem_hotplug_begin();
1251 ret = __try_online_node(nid, true);
1252 mem_hotplug_done();
1253 return ret;
1254}
1255
1256static int check_hotplug_memory_range(u64 start, u64 size)
1257{
1258 /* memory range must be block size aligned */
1259 if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) ||
1260 !IS_ALIGNED(size, memory_block_size_bytes())) {
1261 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
1262 memory_block_size_bytes(), start, size);
1263 return -EINVAL;
1264 }
1265
1266 return 0;
1267}
1268
1269static int online_memory_block(struct memory_block *mem, void *arg)
1270{
1271 mem->online_type = mhp_default_online_type;
1272 return device_online(&mem->dev);
1273}
1274
1275bool mhp_supports_memmap_on_memory(unsigned long size)
1276{
1277 unsigned long nr_vmemmap_pages = size / PAGE_SIZE;
1278 unsigned long vmemmap_size = nr_vmemmap_pages * sizeof(struct page);
1279 unsigned long remaining_size = size - vmemmap_size;
1280
1281 /*
1282 * Besides having arch support and the feature enabled at runtime, we
1283 * need a few more assumptions to hold true:
1284 *
1285 * a) We span a single memory block: memory onlining/offlinin;g happens
1286 * in memory block granularity. We don't want the vmemmap of online
1287 * memory blocks to reside on offline memory blocks. In the future,
1288 * we might want to support variable-sized memory blocks to make the
1289 * feature more versatile.
1290 *
1291 * b) The vmemmap pages span complete PMDs: We don't want vmemmap code
1292 * to populate memory from the altmap for unrelated parts (i.e.,
1293 * other memory blocks)
1294 *
1295 * c) The vmemmap pages (and thereby the pages that will be exposed to
1296 * the buddy) have to cover full pageblocks: memory onlining/offlining
1297 * code requires applicable ranges to be page-aligned, for example, to
1298 * set the migratetypes properly.
1299 *
1300 * TODO: Although we have a check here to make sure that vmemmap pages
1301 * fully populate a PMD, it is not the right place to check for
1302 * this. A much better solution involves improving vmemmap code
1303 * to fallback to base pages when trying to populate vmemmap using
1304 * altmap as an alternative source of memory, and we do not exactly
1305 * populate a single PMD.
1306 */
1307 return mhp_memmap_on_memory() &&
1308 size == memory_block_size_bytes() &&
1309 IS_ALIGNED(vmemmap_size, PMD_SIZE) &&
1310 IS_ALIGNED(remaining_size, (pageblock_nr_pages << PAGE_SHIFT));
1311}
1312
1313/*
1314 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1315 * and online/offline operations (triggered e.g. by sysfs).
1316 *
1317 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
1318 */
1319int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
1320{
1321 struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
1322 enum memblock_flags memblock_flags = MEMBLOCK_NONE;
1323 struct vmem_altmap mhp_altmap = {};
1324 struct memory_group *group = NULL;
1325 u64 start, size;
1326 bool new_node = false;
1327 int ret;
1328
1329 start = res->start;
1330 size = resource_size(res);
1331
1332 ret = check_hotplug_memory_range(start, size);
1333 if (ret)
1334 return ret;
1335
1336 if (mhp_flags & MHP_NID_IS_MGID) {
1337 group = memory_group_find_by_id(nid);
1338 if (!group)
1339 return -EINVAL;
1340 nid = group->nid;
1341 }
1342
1343 if (!node_possible(nid)) {
1344 WARN(1, "node %d was absent from the node_possible_map\n", nid);
1345 return -EINVAL;
1346 }
1347
1348 mem_hotplug_begin();
1349
1350 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
1351 if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
1352 memblock_flags = MEMBLOCK_DRIVER_MANAGED;
1353 ret = memblock_add_node(start, size, nid, memblock_flags);
1354 if (ret)
1355 goto error_mem_hotplug_end;
1356 }
1357
1358 ret = __try_online_node(nid, false);
1359 if (ret < 0)
1360 goto error;
1361 new_node = ret;
1362
1363 /*
1364 * Self hosted memmap array
1365 */
1366 if (mhp_flags & MHP_MEMMAP_ON_MEMORY) {
1367 if (!mhp_supports_memmap_on_memory(size)) {
1368 ret = -EINVAL;
1369 goto error;
1370 }
1371 mhp_altmap.free = PHYS_PFN(size);
1372 mhp_altmap.base_pfn = PHYS_PFN(start);
1373 params.altmap = &mhp_altmap;
1374 }
1375
1376 /* call arch's memory hotadd */
1377 ret = arch_add_memory(nid, start, size, ¶ms);
1378 if (ret < 0)
1379 goto error;
1380
1381 /* create memory block devices after memory was added */
1382 ret = create_memory_block_devices(start, size, mhp_altmap.alloc,
1383 group);
1384 if (ret) {
1385 arch_remove_memory(start, size, NULL);
1386 goto error;
1387 }
1388
1389 if (new_node) {
1390 /* If sysfs file of new node can't be created, cpu on the node
1391 * can't be hot-added. There is no rollback way now.
1392 * So, check by BUG_ON() to catch it reluctantly..
1393 * We online node here. We can't roll back from here.
1394 */
1395 node_set_online(nid);
1396 ret = __register_one_node(nid);
1397 BUG_ON(ret);
1398 }
1399
1400 register_memory_blocks_under_node(nid, PFN_DOWN(start),
1401 PFN_UP(start + size - 1),
1402 MEMINIT_HOTPLUG);
1403
1404 /* create new memmap entry */
1405 if (!strcmp(res->name, "System RAM"))
1406 firmware_map_add_hotplug(start, start + size, "System RAM");
1407
1408 /* device_online() will take the lock when calling online_pages() */
1409 mem_hotplug_done();
1410
1411 /*
1412 * In case we're allowed to merge the resource, flag it and trigger
1413 * merging now that adding succeeded.
1414 */
1415 if (mhp_flags & MHP_MERGE_RESOURCE)
1416 merge_system_ram_resource(res);
1417
1418 /* online pages if requested */
1419 if (mhp_default_online_type != MMOP_OFFLINE)
1420 walk_memory_blocks(start, size, NULL, online_memory_block);
1421
1422 return ret;
1423error:
1424 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
1425 memblock_remove(start, size);
1426error_mem_hotplug_end:
1427 mem_hotplug_done();
1428 return ret;
1429}
1430
1431/* requires device_hotplug_lock, see add_memory_resource() */
1432int __ref __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
1433{
1434 struct resource *res;
1435 int ret;
1436
1437 res = register_memory_resource(start, size, "System RAM");
1438 if (IS_ERR(res))
1439 return PTR_ERR(res);
1440
1441 ret = add_memory_resource(nid, res, mhp_flags);
1442 if (ret < 0)
1443 release_memory_resource(res);
1444 return ret;
1445}
1446
1447int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
1448{
1449 int rc;
1450
1451 lock_device_hotplug();
1452 rc = __add_memory(nid, start, size, mhp_flags);
1453 unlock_device_hotplug();
1454
1455 return rc;
1456}
1457EXPORT_SYMBOL_GPL(add_memory);
1458
1459/*
1460 * Add special, driver-managed memory to the system as system RAM. Such
1461 * memory is not exposed via the raw firmware-provided memmap as system
1462 * RAM, instead, it is detected and added by a driver - during cold boot,
1463 * after a reboot, and after kexec.
1464 *
1465 * Reasons why this memory should not be used for the initial memmap of a
1466 * kexec kernel or for placing kexec images:
1467 * - The booting kernel is in charge of determining how this memory will be
1468 * used (e.g., use persistent memory as system RAM)
1469 * - Coordination with a hypervisor is required before this memory
1470 * can be used (e.g., inaccessible parts).
1471 *
1472 * For this memory, no entries in /sys/firmware/memmap ("raw firmware-provided
1473 * memory map") are created. Also, the created memory resource is flagged
1474 * with IORESOURCE_SYSRAM_DRIVER_MANAGED, so in-kernel users can special-case
1475 * this memory as well (esp., not place kexec images onto it).
1476 *
1477 * The resource_name (visible via /proc/iomem) has to have the format
1478 * "System RAM ($DRIVER)".
1479 */
1480int add_memory_driver_managed(int nid, u64 start, u64 size,
1481 const char *resource_name, mhp_t mhp_flags)
1482{
1483 struct resource *res;
1484 int rc;
1485
1486 if (!resource_name ||
1487 strstr(resource_name, "System RAM (") != resource_name ||
1488 resource_name[strlen(resource_name) - 1] != ')')
1489 return -EINVAL;
1490
1491 lock_device_hotplug();
1492
1493 res = register_memory_resource(start, size, resource_name);
1494 if (IS_ERR(res)) {
1495 rc = PTR_ERR(res);
1496 goto out_unlock;
1497 }
1498
1499 rc = add_memory_resource(nid, res, mhp_flags);
1500 if (rc < 0)
1501 release_memory_resource(res);
1502
1503out_unlock:
1504 unlock_device_hotplug();
1505 return rc;
1506}
1507EXPORT_SYMBOL_GPL(add_memory_driver_managed);
1508
1509/*
1510 * Platforms should define arch_get_mappable_range() that provides
1511 * maximum possible addressable physical memory range for which the
1512 * linear mapping could be created. The platform returned address
1513 * range must adhere to these following semantics.
1514 *
1515 * - range.start <= range.end
1516 * - Range includes both end points [range.start..range.end]
1517 *
1518 * There is also a fallback definition provided here, allowing the
1519 * entire possible physical address range in case any platform does
1520 * not define arch_get_mappable_range().
1521 */
1522struct range __weak arch_get_mappable_range(void)
1523{
1524 struct range mhp_range = {
1525 .start = 0UL,
1526 .end = -1ULL,
1527 };
1528 return mhp_range;
1529}
1530
1531struct range mhp_get_pluggable_range(bool need_mapping)
1532{
1533 const u64 max_phys = (1ULL << MAX_PHYSMEM_BITS) - 1;
1534 struct range mhp_range;
1535
1536 if (need_mapping) {
1537 mhp_range = arch_get_mappable_range();
1538 if (mhp_range.start > max_phys) {
1539 mhp_range.start = 0;
1540 mhp_range.end = 0;
1541 }
1542 mhp_range.end = min_t(u64, mhp_range.end, max_phys);
1543 } else {
1544 mhp_range.start = 0;
1545 mhp_range.end = max_phys;
1546 }
1547 return mhp_range;
1548}
1549EXPORT_SYMBOL_GPL(mhp_get_pluggable_range);
1550
1551bool mhp_range_allowed(u64 start, u64 size, bool need_mapping)
1552{
1553 struct range mhp_range = mhp_get_pluggable_range(need_mapping);
1554 u64 end = start + size;
1555
1556 if (start < end && start >= mhp_range.start && (end - 1) <= mhp_range.end)
1557 return true;
1558
1559 pr_warn("Hotplug memory [%#llx-%#llx] exceeds maximum addressable range [%#llx-%#llx]\n",
1560 start, end, mhp_range.start, mhp_range.end);
1561 return false;
1562}
1563
1564#ifdef CONFIG_MEMORY_HOTREMOVE
1565/*
1566 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
1567 * non-lru movable pages and hugepages). Will skip over most unmovable
1568 * pages (esp., pages that can be skipped when offlining), but bail out on
1569 * definitely unmovable pages.
1570 *
1571 * Returns:
1572 * 0 in case a movable page is found and movable_pfn was updated.
1573 * -ENOENT in case no movable page was found.
1574 * -EBUSY in case a definitely unmovable page was found.
1575 */
1576static int scan_movable_pages(unsigned long start, unsigned long end,
1577 unsigned long *movable_pfn)
1578{
1579 unsigned long pfn;
1580
1581 for (pfn = start; pfn < end; pfn++) {
1582 struct page *page, *head;
1583 unsigned long skip;
1584
1585 if (!pfn_valid(pfn))
1586 continue;
1587 page = pfn_to_page(pfn);
1588 if (PageLRU(page))
1589 goto found;
1590 if (__PageMovable(page))
1591 goto found;
1592
1593 /*
1594 * PageOffline() pages that are not marked __PageMovable() and
1595 * have a reference count > 0 (after MEM_GOING_OFFLINE) are
1596 * definitely unmovable. If their reference count would be 0,
1597 * they could at least be skipped when offlining memory.
1598 */
1599 if (PageOffline(page) && page_count(page))
1600 return -EBUSY;
1601
1602 if (!PageHuge(page))
1603 continue;
1604 head = compound_head(page);
1605 /*
1606 * This test is racy as we hold no reference or lock. The
1607 * hugetlb page could have been free'ed and head is no longer
1608 * a hugetlb page before the following check. In such unlikely
1609 * cases false positives and negatives are possible. Calling
1610 * code must deal with these scenarios.
1611 */
1612 if (HPageMigratable(head))
1613 goto found;
1614 skip = compound_nr(head) - (page - head);
1615 pfn += skip - 1;
1616 }
1617 return -ENOENT;
1618found:
1619 *movable_pfn = pfn;
1620 return 0;
1621}
1622
1623static int
1624do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1625{
1626 unsigned long pfn;
1627 struct page *page, *head;
1628 int ret = 0;
1629 LIST_HEAD(source);
1630 static DEFINE_RATELIMIT_STATE(migrate_rs, DEFAULT_RATELIMIT_INTERVAL,
1631 DEFAULT_RATELIMIT_BURST);
1632
1633 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1634 struct folio *folio;
1635
1636 if (!pfn_valid(pfn))
1637 continue;
1638 page = pfn_to_page(pfn);
1639 folio = page_folio(page);
1640 head = &folio->page;
1641
1642 if (PageHuge(page)) {
1643 pfn = page_to_pfn(head) + compound_nr(head) - 1;
1644 isolate_hugetlb(head, &source);
1645 continue;
1646 } else if (PageTransHuge(page))
1647 pfn = page_to_pfn(head) + thp_nr_pages(page) - 1;
1648
1649 /*
1650 * HWPoison pages have elevated reference counts so the migration would
1651 * fail on them. It also doesn't make any sense to migrate them in the
1652 * first place. Still try to unmap such a page in case it is still mapped
1653 * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep
1654 * the unmap as the catch all safety net).
1655 */
1656 if (PageHWPoison(page)) {
1657 if (WARN_ON(folio_test_lru(folio)))
1658 folio_isolate_lru(folio);
1659 if (folio_mapped(folio))
1660 try_to_unmap(folio, TTU_IGNORE_MLOCK);
1661 continue;
1662 }
1663
1664 if (!get_page_unless_zero(page))
1665 continue;
1666 /*
1667 * We can skip free pages. And we can deal with pages on
1668 * LRU and non-lru movable pages.
1669 */
1670 if (PageLRU(page))
1671 ret = isolate_lru_page(page);
1672 else
1673 ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE);
1674 if (!ret) { /* Success */
1675 list_add_tail(&page->lru, &source);
1676 if (!__PageMovable(page))
1677 inc_node_page_state(page, NR_ISOLATED_ANON +
1678 page_is_file_lru(page));
1679
1680 } else {
1681 if (__ratelimit(&migrate_rs)) {
1682 pr_warn("failed to isolate pfn %lx\n", pfn);
1683 dump_page(page, "isolation failed");
1684 }
1685 }
1686 put_page(page);
1687 }
1688 if (!list_empty(&source)) {
1689 nodemask_t nmask = node_states[N_MEMORY];
1690 struct migration_target_control mtc = {
1691 .nmask = &nmask,
1692 .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
1693 };
1694
1695 /*
1696 * We have checked that migration range is on a single zone so
1697 * we can use the nid of the first page to all the others.
1698 */
1699 mtc.nid = page_to_nid(list_first_entry(&source, struct page, lru));
1700
1701 /*
1702 * try to allocate from a different node but reuse this node
1703 * if there are no other online nodes to be used (e.g. we are
1704 * offlining a part of the only existing node)
1705 */
1706 node_clear(mtc.nid, nmask);
1707 if (nodes_empty(nmask))
1708 node_set(mtc.nid, nmask);
1709 ret = migrate_pages(&source, alloc_migration_target, NULL,
1710 (unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG, NULL);
1711 if (ret) {
1712 list_for_each_entry(page, &source, lru) {
1713 if (__ratelimit(&migrate_rs)) {
1714 pr_warn("migrating pfn %lx failed ret:%d\n",
1715 page_to_pfn(page), ret);
1716 dump_page(page, "migration failure");
1717 }
1718 }
1719 putback_movable_pages(&source);
1720 }
1721 }
1722
1723 return ret;
1724}
1725
1726static int __init cmdline_parse_movable_node(char *p)
1727{
1728 movable_node_enabled = true;
1729 return 0;
1730}
1731early_param("movable_node", cmdline_parse_movable_node);
1732
1733/* check which state of node_states will be changed when offline memory */
1734static void node_states_check_changes_offline(unsigned long nr_pages,
1735 struct zone *zone, struct memory_notify *arg)
1736{
1737 struct pglist_data *pgdat = zone->zone_pgdat;
1738 unsigned long present_pages = 0;
1739 enum zone_type zt;
1740
1741 arg->status_change_nid = NUMA_NO_NODE;
1742 arg->status_change_nid_normal = NUMA_NO_NODE;
1743
1744 /*
1745 * Check whether node_states[N_NORMAL_MEMORY] will be changed.
1746 * If the memory to be offline is within the range
1747 * [0..ZONE_NORMAL], and it is the last present memory there,
1748 * the zones in that range will become empty after the offlining,
1749 * thus we can determine that we need to clear the node from
1750 * node_states[N_NORMAL_MEMORY].
1751 */
1752 for (zt = 0; zt <= ZONE_NORMAL; zt++)
1753 present_pages += pgdat->node_zones[zt].present_pages;
1754 if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages)
1755 arg->status_change_nid_normal = zone_to_nid(zone);
1756
1757 /*
1758 * We have accounted the pages from [0..ZONE_NORMAL); ZONE_HIGHMEM
1759 * does not apply as we don't support 32bit.
1760 * Here we count the possible pages from ZONE_MOVABLE.
1761 * If after having accounted all the pages, we see that the nr_pages
1762 * to be offlined is over or equal to the accounted pages,
1763 * we know that the node will become empty, and so, we can clear
1764 * it for N_MEMORY as well.
1765 */
1766 present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages;
1767
1768 if (nr_pages >= present_pages)
1769 arg->status_change_nid = zone_to_nid(zone);
1770}
1771
1772static void node_states_clear_node(int node, struct memory_notify *arg)
1773{
1774 if (arg->status_change_nid_normal >= 0)
1775 node_clear_state(node, N_NORMAL_MEMORY);
1776
1777 if (arg->status_change_nid >= 0)
1778 node_clear_state(node, N_MEMORY);
1779}
1780
1781static int count_system_ram_pages_cb(unsigned long start_pfn,
1782 unsigned long nr_pages, void *data)
1783{
1784 unsigned long *nr_system_ram_pages = data;
1785
1786 *nr_system_ram_pages += nr_pages;
1787 return 0;
1788}
1789
1790int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages,
1791 struct zone *zone, struct memory_group *group)
1792{
1793 const unsigned long end_pfn = start_pfn + nr_pages;
1794 unsigned long pfn, system_ram_pages = 0;
1795 const int node = zone_to_nid(zone);
1796 unsigned long flags;
1797 struct memory_notify arg;
1798 char *reason;
1799 int ret;
1800
1801 /*
1802 * {on,off}lining is constrained to full memory sections (or more
1803 * precisely to memory blocks from the user space POV).
1804 * memmap_on_memory is an exception because it reserves initial part
1805 * of the physical memory space for vmemmaps. That space is pageblock
1806 * aligned.
1807 */
1808 if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(start_pfn) ||
1809 !IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION)))
1810 return -EINVAL;
1811
1812 mem_hotplug_begin();
1813
1814 /*
1815 * Don't allow to offline memory blocks that contain holes.
1816 * Consequently, memory blocks with holes can never get onlined
1817 * via the hotplug path - online_pages() - as hotplugged memory has
1818 * no holes. This way, we e.g., don't have to worry about marking
1819 * memory holes PG_reserved, don't need pfn_valid() checks, and can
1820 * avoid using walk_system_ram_range() later.
1821 */
1822 walk_system_ram_range(start_pfn, nr_pages, &system_ram_pages,
1823 count_system_ram_pages_cb);
1824 if (system_ram_pages != nr_pages) {
1825 ret = -EINVAL;
1826 reason = "memory holes";
1827 goto failed_removal;
1828 }
1829
1830 /*
1831 * We only support offlining of memory blocks managed by a single zone,
1832 * checked by calling code. This is just a sanity check that we might
1833 * want to remove in the future.
1834 */
1835 if (WARN_ON_ONCE(page_zone(pfn_to_page(start_pfn)) != zone ||
1836 page_zone(pfn_to_page(end_pfn - 1)) != zone)) {
1837 ret = -EINVAL;
1838 reason = "multizone range";
1839 goto failed_removal;
1840 }
1841
1842 /*
1843 * Disable pcplists so that page isolation cannot race with freeing
1844 * in a way that pages from isolated pageblock are left on pcplists.
1845 */
1846 zone_pcp_disable(zone);
1847 lru_cache_disable();
1848
1849 /* set above range as isolated */
1850 ret = start_isolate_page_range(start_pfn, end_pfn,
1851 MIGRATE_MOVABLE,
1852 MEMORY_OFFLINE | REPORT_FAILURE,
1853 GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL);
1854 if (ret) {
1855 reason = "failure to isolate range";
1856 goto failed_removal_pcplists_disabled;
1857 }
1858
1859 arg.start_pfn = start_pfn;
1860 arg.nr_pages = nr_pages;
1861 node_states_check_changes_offline(nr_pages, zone, &arg);
1862
1863 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1864 ret = notifier_to_errno(ret);
1865 if (ret) {
1866 reason = "notifier failure";
1867 goto failed_removal_isolated;
1868 }
1869
1870 do {
1871 pfn = start_pfn;
1872 do {
1873 if (signal_pending(current)) {
1874 ret = -EINTR;
1875 reason = "signal backoff";
1876 goto failed_removal_isolated;
1877 }
1878
1879 cond_resched();
1880
1881 ret = scan_movable_pages(pfn, end_pfn, &pfn);
1882 if (!ret) {
1883 /*
1884 * TODO: fatal migration failures should bail
1885 * out
1886 */
1887 do_migrate_range(pfn, end_pfn);
1888 }
1889 } while (!ret);
1890
1891 if (ret != -ENOENT) {
1892 reason = "unmovable page";
1893 goto failed_removal_isolated;
1894 }
1895
1896 /*
1897 * Dissolve free hugepages in the memory block before doing
1898 * offlining actually in order to make hugetlbfs's object
1899 * counting consistent.
1900 */
1901 ret = dissolve_free_huge_pages(start_pfn, end_pfn);
1902 if (ret) {
1903 reason = "failure to dissolve huge pages";
1904 goto failed_removal_isolated;
1905 }
1906
1907 ret = test_pages_isolated(start_pfn, end_pfn, MEMORY_OFFLINE);
1908
1909 } while (ret);
1910
1911 /* Mark all sections offline and remove free pages from the buddy. */
1912 __offline_isolated_pages(start_pfn, end_pfn);
1913 pr_debug("Offlined Pages %ld\n", nr_pages);
1914
1915 /*
1916 * The memory sections are marked offline, and the pageblock flags
1917 * effectively stale; nobody should be touching them. Fixup the number
1918 * of isolated pageblocks, memory onlining will properly revert this.
1919 */
1920 spin_lock_irqsave(&zone->lock, flags);
1921 zone->nr_isolate_pageblock -= nr_pages / pageblock_nr_pages;
1922 spin_unlock_irqrestore(&zone->lock, flags);
1923
1924 lru_cache_enable();
1925 zone_pcp_enable(zone);
1926
1927 /* removal success */
1928 adjust_managed_page_count(pfn_to_page(start_pfn), -nr_pages);
1929 adjust_present_page_count(pfn_to_page(start_pfn), group, -nr_pages);
1930
1931 /* reinitialise watermarks and update pcp limits */
1932 init_per_zone_wmark_min();
1933
1934 if (!populated_zone(zone)) {
1935 zone_pcp_reset(zone);
1936 build_all_zonelists(NULL);
1937 }
1938
1939 node_states_clear_node(node, &arg);
1940 if (arg.status_change_nid >= 0) {
1941 kcompactd_stop(node);
1942 kswapd_stop(node);
1943 }
1944
1945 writeback_set_ratelimit();
1946
1947 memory_notify(MEM_OFFLINE, &arg);
1948 remove_pfn_range_from_zone(zone, start_pfn, nr_pages);
1949 mem_hotplug_done();
1950 return 0;
1951
1952failed_removal_isolated:
1953 /* pushback to free area */
1954 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1955 memory_notify(MEM_CANCEL_OFFLINE, &arg);
1956failed_removal_pcplists_disabled:
1957 lru_cache_enable();
1958 zone_pcp_enable(zone);
1959failed_removal:
1960 pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n",
1961 (unsigned long long) start_pfn << PAGE_SHIFT,
1962 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1,
1963 reason);
1964 mem_hotplug_done();
1965 return ret;
1966}
1967
1968static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
1969{
1970 int *nid = arg;
1971
1972 *nid = mem->nid;
1973 if (unlikely(mem->state != MEM_OFFLINE)) {
1974 phys_addr_t beginpa, endpa;
1975
1976 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
1977 endpa = beginpa + memory_block_size_bytes() - 1;
1978 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
1979 &beginpa, &endpa);
1980
1981 return -EBUSY;
1982 }
1983 return 0;
1984}
1985
1986static int get_nr_vmemmap_pages_cb(struct memory_block *mem, void *arg)
1987{
1988 /*
1989 * If not set, continue with the next block.
1990 */
1991 return mem->nr_vmemmap_pages;
1992}
1993
1994static int check_cpu_on_node(int nid)
1995{
1996 int cpu;
1997
1998 for_each_present_cpu(cpu) {
1999 if (cpu_to_node(cpu) == nid)
2000 /*
2001 * the cpu on this node isn't removed, and we can't
2002 * offline this node.
2003 */
2004 return -EBUSY;
2005 }
2006
2007 return 0;
2008}
2009
2010static int check_no_memblock_for_node_cb(struct memory_block *mem, void *arg)
2011{
2012 int nid = *(int *)arg;
2013
2014 /*
2015 * If a memory block belongs to multiple nodes, the stored nid is not
2016 * reliable. However, such blocks are always online (e.g., cannot get
2017 * offlined) and, therefore, are still spanned by the node.
2018 */
2019 return mem->nid == nid ? -EEXIST : 0;
2020}
2021
2022/**
2023 * try_offline_node
2024 * @nid: the node ID
2025 *
2026 * Offline a node if all memory sections and cpus of the node are removed.
2027 *
2028 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2029 * and online/offline operations before this call.
2030 */
2031void try_offline_node(int nid)
2032{
2033 int rc;
2034
2035 /*
2036 * If the node still spans pages (especially ZONE_DEVICE), don't
2037 * offline it. A node spans memory after move_pfn_range_to_zone(),
2038 * e.g., after the memory block was onlined.
2039 */
2040 if (node_spanned_pages(nid))
2041 return;
2042
2043 /*
2044 * Especially offline memory blocks might not be spanned by the
2045 * node. They will get spanned by the node once they get onlined.
2046 * However, they link to the node in sysfs and can get onlined later.
2047 */
2048 rc = for_each_memory_block(&nid, check_no_memblock_for_node_cb);
2049 if (rc)
2050 return;
2051
2052 if (check_cpu_on_node(nid))
2053 return;
2054
2055 /*
2056 * all memory/cpu of this node are removed, we can offline this
2057 * node now.
2058 */
2059 node_set_offline(nid);
2060 unregister_one_node(nid);
2061}
2062EXPORT_SYMBOL(try_offline_node);
2063
2064static int __ref try_remove_memory(u64 start, u64 size)
2065{
2066 struct vmem_altmap mhp_altmap = {};
2067 struct vmem_altmap *altmap = NULL;
2068 unsigned long nr_vmemmap_pages;
2069 int rc = 0, nid = NUMA_NO_NODE;
2070
2071 BUG_ON(check_hotplug_memory_range(start, size));
2072
2073 /*
2074 * All memory blocks must be offlined before removing memory. Check
2075 * whether all memory blocks in question are offline and return error
2076 * if this is not the case.
2077 *
2078 * While at it, determine the nid. Note that if we'd have mixed nodes,
2079 * we'd only try to offline the last determined one -- which is good
2080 * enough for the cases we care about.
2081 */
2082 rc = walk_memory_blocks(start, size, &nid, check_memblock_offlined_cb);
2083 if (rc)
2084 return rc;
2085
2086 /*
2087 * We only support removing memory added with MHP_MEMMAP_ON_MEMORY in
2088 * the same granularity it was added - a single memory block.
2089 */
2090 if (mhp_memmap_on_memory()) {
2091 nr_vmemmap_pages = walk_memory_blocks(start, size, NULL,
2092 get_nr_vmemmap_pages_cb);
2093 if (nr_vmemmap_pages) {
2094 if (size != memory_block_size_bytes()) {
2095 pr_warn("Refuse to remove %#llx - %#llx,"
2096 "wrong granularity\n",
2097 start, start + size);
2098 return -EINVAL;
2099 }
2100
2101 /*
2102 * Let remove_pmd_table->free_hugepage_table do the
2103 * right thing if we used vmem_altmap when hot-adding
2104 * the range.
2105 */
2106 mhp_altmap.alloc = nr_vmemmap_pages;
2107 altmap = &mhp_altmap;
2108 }
2109 }
2110
2111 /* remove memmap entry */
2112 firmware_map_remove(start, start + size, "System RAM");
2113
2114 /*
2115 * Memory block device removal under the device_hotplug_lock is
2116 * a barrier against racing online attempts.
2117 */
2118 remove_memory_block_devices(start, size);
2119
2120 mem_hotplug_begin();
2121
2122 arch_remove_memory(start, size, altmap);
2123
2124 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
2125 memblock_phys_free(start, size);
2126 memblock_remove(start, size);
2127 }
2128
2129 release_mem_region_adjustable(start, size);
2130
2131 if (nid != NUMA_NO_NODE)
2132 try_offline_node(nid);
2133
2134 mem_hotplug_done();
2135 return 0;
2136}
2137
2138/**
2139 * __remove_memory - Remove memory if every memory block is offline
2140 * @start: physical address of the region to remove
2141 * @size: size of the region to remove
2142 *
2143 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2144 * and online/offline operations before this call, as required by
2145 * try_offline_node().
2146 */
2147void __remove_memory(u64 start, u64 size)
2148{
2149
2150 /*
2151 * trigger BUG() if some memory is not offlined prior to calling this
2152 * function
2153 */
2154 if (try_remove_memory(start, size))
2155 BUG();
2156}
2157
2158/*
2159 * Remove memory if every memory block is offline, otherwise return -EBUSY is
2160 * some memory is not offline
2161 */
2162int remove_memory(u64 start, u64 size)
2163{
2164 int rc;
2165
2166 lock_device_hotplug();
2167 rc = try_remove_memory(start, size);
2168 unlock_device_hotplug();
2169
2170 return rc;
2171}
2172EXPORT_SYMBOL_GPL(remove_memory);
2173
2174static int try_offline_memory_block(struct memory_block *mem, void *arg)
2175{
2176 uint8_t online_type = MMOP_ONLINE_KERNEL;
2177 uint8_t **online_types = arg;
2178 struct page *page;
2179 int rc;
2180
2181 /*
2182 * Sense the online_type via the zone of the memory block. Offlining
2183 * with multiple zones within one memory block will be rejected
2184 * by offlining code ... so we don't care about that.
2185 */
2186 page = pfn_to_online_page(section_nr_to_pfn(mem->start_section_nr));
2187 if (page && zone_idx(page_zone(page)) == ZONE_MOVABLE)
2188 online_type = MMOP_ONLINE_MOVABLE;
2189
2190 rc = device_offline(&mem->dev);
2191 /*
2192 * Default is MMOP_OFFLINE - change it only if offlining succeeded,
2193 * so try_reonline_memory_block() can do the right thing.
2194 */
2195 if (!rc)
2196 **online_types = online_type;
2197
2198 (*online_types)++;
2199 /* Ignore if already offline. */
2200 return rc < 0 ? rc : 0;
2201}
2202
2203static int try_reonline_memory_block(struct memory_block *mem, void *arg)
2204{
2205 uint8_t **online_types = arg;
2206 int rc;
2207
2208 if (**online_types != MMOP_OFFLINE) {
2209 mem->online_type = **online_types;
2210 rc = device_online(&mem->dev);
2211 if (rc < 0)
2212 pr_warn("%s: Failed to re-online memory: %d",
2213 __func__, rc);
2214 }
2215
2216 /* Continue processing all remaining memory blocks. */
2217 (*online_types)++;
2218 return 0;
2219}
2220
2221/*
2222 * Try to offline and remove memory. Might take a long time to finish in case
2223 * memory is still in use. Primarily useful for memory devices that logically
2224 * unplugged all memory (so it's no longer in use) and want to offline + remove
2225 * that memory.
2226 */
2227int offline_and_remove_memory(u64 start, u64 size)
2228{
2229 const unsigned long mb_count = size / memory_block_size_bytes();
2230 uint8_t *online_types, *tmp;
2231 int rc;
2232
2233 if (!IS_ALIGNED(start, memory_block_size_bytes()) ||
2234 !IS_ALIGNED(size, memory_block_size_bytes()) || !size)
2235 return -EINVAL;
2236
2237 /*
2238 * We'll remember the old online type of each memory block, so we can
2239 * try to revert whatever we did when offlining one memory block fails
2240 * after offlining some others succeeded.
2241 */
2242 online_types = kmalloc_array(mb_count, sizeof(*online_types),
2243 GFP_KERNEL);
2244 if (!online_types)
2245 return -ENOMEM;
2246 /*
2247 * Initialize all states to MMOP_OFFLINE, so when we abort processing in
2248 * try_offline_memory_block(), we'll skip all unprocessed blocks in
2249 * try_reonline_memory_block().
2250 */
2251 memset(online_types, MMOP_OFFLINE, mb_count);
2252
2253 lock_device_hotplug();
2254
2255 tmp = online_types;
2256 rc = walk_memory_blocks(start, size, &tmp, try_offline_memory_block);
2257
2258 /*
2259 * In case we succeeded to offline all memory, remove it.
2260 * This cannot fail as it cannot get onlined in the meantime.
2261 */
2262 if (!rc) {
2263 rc = try_remove_memory(start, size);
2264 if (rc)
2265 pr_err("%s: Failed to remove memory: %d", __func__, rc);
2266 }
2267
2268 /*
2269 * Rollback what we did. While memory onlining might theoretically fail
2270 * (nacked by a notifier), it barely ever happens.
2271 */
2272 if (rc) {
2273 tmp = online_types;
2274 walk_memory_blocks(start, size, &tmp,
2275 try_reonline_memory_block);
2276 }
2277 unlock_device_hotplug();
2278
2279 kfree(online_types);
2280 return rc;
2281}
2282EXPORT_SYMBOL_GPL(offline_and_remove_memory);
2283#endif /* CONFIG_MEMORY_HOTREMOVE */