Loading...
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/highmem.h>
25#include <linux/vmalloc.h>
26#include <linux/ioport.h>
27#include <linux/delay.h>
28#include <linux/migrate.h>
29#include <linux/page-isolation.h>
30#include <linux/pfn.h>
31#include <linux/suspend.h>
32#include <linux/mm_inline.h>
33#include <linux/firmware-map.h>
34#include <linux/stop_machine.h>
35#include <linux/hugetlb.h>
36#include <linux/memblock.h>
37#include <linux/compaction.h>
38#include <linux/rmap.h>
39
40#include <asm/tlbflush.h>
41
42#include "internal.h"
43#include "shuffle.h"
44
45/*
46 * online_page_callback contains pointer to current page onlining function.
47 * Initially it is generic_online_page(). If it is required it could be
48 * changed by calling set_online_page_callback() for callback registration
49 * and restore_online_page_callback() for generic callback restore.
50 */
51
52static void generic_online_page(struct page *page, unsigned int order);
53
54static online_page_callback_t online_page_callback = generic_online_page;
55static DEFINE_MUTEX(online_page_callback_lock);
56
57DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock);
58
59void get_online_mems(void)
60{
61 percpu_down_read(&mem_hotplug_lock);
62}
63
64void put_online_mems(void)
65{
66 percpu_up_read(&mem_hotplug_lock);
67}
68
69bool movable_node_enabled = false;
70
71#ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
72bool memhp_auto_online;
73#else
74bool memhp_auto_online = true;
75#endif
76EXPORT_SYMBOL_GPL(memhp_auto_online);
77
78static int __init setup_memhp_default_state(char *str)
79{
80 if (!strcmp(str, "online"))
81 memhp_auto_online = true;
82 else if (!strcmp(str, "offline"))
83 memhp_auto_online = false;
84
85 return 1;
86}
87__setup("memhp_default_state=", setup_memhp_default_state);
88
89void mem_hotplug_begin(void)
90{
91 cpus_read_lock();
92 percpu_down_write(&mem_hotplug_lock);
93}
94
95void mem_hotplug_done(void)
96{
97 percpu_up_write(&mem_hotplug_lock);
98 cpus_read_unlock();
99}
100
101u64 max_mem_size = U64_MAX;
102
103/* add this memory to iomem resource */
104static struct resource *register_memory_resource(u64 start, u64 size)
105{
106 struct resource *res;
107 unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
108 char *resource_name = "System RAM";
109
110 if (start + size > max_mem_size)
111 return ERR_PTR(-E2BIG);
112
113 /*
114 * Request ownership of the new memory range. This might be
115 * a child of an existing resource that was present but
116 * not marked as busy.
117 */
118 res = __request_region(&iomem_resource, start, size,
119 resource_name, flags);
120
121 if (!res) {
122 pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n",
123 start, start + size);
124 return ERR_PTR(-EEXIST);
125 }
126 return res;
127}
128
129static void release_memory_resource(struct resource *res)
130{
131 if (!res)
132 return;
133 release_resource(res);
134 kfree(res);
135}
136
137#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
138void get_page_bootmem(unsigned long info, struct page *page,
139 unsigned long type)
140{
141 page->freelist = (void *)type;
142 SetPagePrivate(page);
143 set_page_private(page, info);
144 page_ref_inc(page);
145}
146
147void put_page_bootmem(struct page *page)
148{
149 unsigned long type;
150
151 type = (unsigned long) page->freelist;
152 BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
153 type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
154
155 if (page_ref_dec_return(page) == 1) {
156 page->freelist = NULL;
157 ClearPagePrivate(page);
158 set_page_private(page, 0);
159 INIT_LIST_HEAD(&page->lru);
160 free_reserved_page(page);
161 }
162}
163
164#ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
165#ifndef CONFIG_SPARSEMEM_VMEMMAP
166static void register_page_bootmem_info_section(unsigned long start_pfn)
167{
168 unsigned long mapsize, section_nr, i;
169 struct mem_section *ms;
170 struct page *page, *memmap;
171 struct mem_section_usage *usage;
172
173 section_nr = pfn_to_section_nr(start_pfn);
174 ms = __nr_to_section(section_nr);
175
176 /* Get section's memmap address */
177 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
178
179 /*
180 * Get page for the memmap's phys address
181 * XXX: need more consideration for sparse_vmemmap...
182 */
183 page = virt_to_page(memmap);
184 mapsize = sizeof(struct page) * PAGES_PER_SECTION;
185 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
186
187 /* remember memmap's page */
188 for (i = 0; i < mapsize; i++, page++)
189 get_page_bootmem(section_nr, page, SECTION_INFO);
190
191 usage = ms->usage;
192 page = virt_to_page(usage);
193
194 mapsize = PAGE_ALIGN(mem_section_usage_size()) >> PAGE_SHIFT;
195
196 for (i = 0; i < mapsize; i++, page++)
197 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
198
199}
200#else /* CONFIG_SPARSEMEM_VMEMMAP */
201static void register_page_bootmem_info_section(unsigned long start_pfn)
202{
203 unsigned long mapsize, section_nr, i;
204 struct mem_section *ms;
205 struct page *page, *memmap;
206 struct mem_section_usage *usage;
207
208 section_nr = pfn_to_section_nr(start_pfn);
209 ms = __nr_to_section(section_nr);
210
211 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
212
213 register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
214
215 usage = ms->usage;
216 page = virt_to_page(usage);
217
218 mapsize = PAGE_ALIGN(mem_section_usage_size()) >> PAGE_SHIFT;
219
220 for (i = 0; i < mapsize; i++, page++)
221 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
222}
223#endif /* !CONFIG_SPARSEMEM_VMEMMAP */
224
225void __init register_page_bootmem_info_node(struct pglist_data *pgdat)
226{
227 unsigned long i, pfn, end_pfn, nr_pages;
228 int node = pgdat->node_id;
229 struct page *page;
230
231 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
232 page = virt_to_page(pgdat);
233
234 for (i = 0; i < nr_pages; i++, page++)
235 get_page_bootmem(node, page, NODE_INFO);
236
237 pfn = pgdat->node_start_pfn;
238 end_pfn = pgdat_end_pfn(pgdat);
239
240 /* register section info */
241 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
242 /*
243 * Some platforms can assign the same pfn to multiple nodes - on
244 * node0 as well as nodeN. To avoid registering a pfn against
245 * multiple nodes we check that this pfn does not already
246 * reside in some other nodes.
247 */
248 if (pfn_valid(pfn) && (early_pfn_to_nid(pfn) == node))
249 register_page_bootmem_info_section(pfn);
250 }
251}
252#endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
253
254static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
255 const char *reason)
256{
257 /*
258 * Disallow all operations smaller than a sub-section and only
259 * allow operations smaller than a section for
260 * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range()
261 * enforces a larger memory_block_size_bytes() granularity for
262 * memory that will be marked online, so this check should only
263 * fire for direct arch_{add,remove}_memory() users outside of
264 * add_memory_resource().
265 */
266 unsigned long min_align;
267
268 if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
269 min_align = PAGES_PER_SUBSECTION;
270 else
271 min_align = PAGES_PER_SECTION;
272 if (!IS_ALIGNED(pfn, min_align)
273 || !IS_ALIGNED(nr_pages, min_align)) {
274 WARN(1, "Misaligned __%s_pages start: %#lx end: #%lx\n",
275 reason, pfn, pfn + nr_pages - 1);
276 return -EINVAL;
277 }
278 return 0;
279}
280
281/*
282 * Reasonably generic function for adding memory. It is
283 * expected that archs that support memory hotplug will
284 * call this function after deciding the zone to which to
285 * add the new pages.
286 */
287int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
288 struct mhp_restrictions *restrictions)
289{
290 int err;
291 unsigned long nr, start_sec, end_sec;
292 struct vmem_altmap *altmap = restrictions->altmap;
293
294 if (altmap) {
295 /*
296 * Validate altmap is within bounds of the total request
297 */
298 if (altmap->base_pfn != pfn
299 || vmem_altmap_offset(altmap) > nr_pages) {
300 pr_warn_once("memory add fail, invalid altmap\n");
301 return -EINVAL;
302 }
303 altmap->alloc = 0;
304 }
305
306 err = check_pfn_span(pfn, nr_pages, "add");
307 if (err)
308 return err;
309
310 start_sec = pfn_to_section_nr(pfn);
311 end_sec = pfn_to_section_nr(pfn + nr_pages - 1);
312 for (nr = start_sec; nr <= end_sec; nr++) {
313 unsigned long pfns;
314
315 pfns = min(nr_pages, PAGES_PER_SECTION
316 - (pfn & ~PAGE_SECTION_MASK));
317 err = sparse_add_section(nid, pfn, pfns, altmap);
318 if (err)
319 break;
320 pfn += pfns;
321 nr_pages -= pfns;
322 cond_resched();
323 }
324 vmemmap_populate_print_last();
325 return err;
326}
327
328/* find the smallest valid pfn in the range [start_pfn, end_pfn) */
329static unsigned long find_smallest_section_pfn(int nid, struct zone *zone,
330 unsigned long start_pfn,
331 unsigned long end_pfn)
332{
333 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) {
334 if (unlikely(!pfn_to_online_page(start_pfn)))
335 continue;
336
337 if (unlikely(pfn_to_nid(start_pfn) != nid))
338 continue;
339
340 if (zone && zone != page_zone(pfn_to_page(start_pfn)))
341 continue;
342
343 return start_pfn;
344 }
345
346 return 0;
347}
348
349/* find the biggest valid pfn in the range [start_pfn, end_pfn). */
350static unsigned long find_biggest_section_pfn(int nid, struct zone *zone,
351 unsigned long start_pfn,
352 unsigned long end_pfn)
353{
354 unsigned long pfn;
355
356 /* pfn is the end pfn of a memory section. */
357 pfn = end_pfn - 1;
358 for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) {
359 if (unlikely(!pfn_to_online_page(pfn)))
360 continue;
361
362 if (unlikely(pfn_to_nid(pfn) != nid))
363 continue;
364
365 if (zone && zone != page_zone(pfn_to_page(pfn)))
366 continue;
367
368 return pfn;
369 }
370
371 return 0;
372}
373
374static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
375 unsigned long end_pfn)
376{
377 unsigned long zone_start_pfn = zone->zone_start_pfn;
378 unsigned long z = zone_end_pfn(zone); /* zone_end_pfn namespace clash */
379 unsigned long zone_end_pfn = z;
380 unsigned long pfn;
381 int nid = zone_to_nid(zone);
382
383 zone_span_writelock(zone);
384 if (zone_start_pfn == start_pfn) {
385 /*
386 * If the section is smallest section in the zone, it need
387 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
388 * In this case, we find second smallest valid mem_section
389 * for shrinking zone.
390 */
391 pfn = find_smallest_section_pfn(nid, zone, end_pfn,
392 zone_end_pfn);
393 if (pfn) {
394 zone->zone_start_pfn = pfn;
395 zone->spanned_pages = zone_end_pfn - pfn;
396 }
397 } else if (zone_end_pfn == end_pfn) {
398 /*
399 * If the section is biggest section in the zone, it need
400 * shrink zone->spanned_pages.
401 * In this case, we find second biggest valid mem_section for
402 * shrinking zone.
403 */
404 pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
405 start_pfn);
406 if (pfn)
407 zone->spanned_pages = pfn - zone_start_pfn + 1;
408 }
409
410 /*
411 * The section is not biggest or smallest mem_section in the zone, it
412 * only creates a hole in the zone. So in this case, we need not
413 * change the zone. But perhaps, the zone has only hole data. Thus
414 * it check the zone has only hole or not.
415 */
416 pfn = zone_start_pfn;
417 for (; pfn < zone_end_pfn; pfn += PAGES_PER_SUBSECTION) {
418 if (unlikely(!pfn_to_online_page(pfn)))
419 continue;
420
421 if (page_zone(pfn_to_page(pfn)) != zone)
422 continue;
423
424 /* Skip range to be removed */
425 if (pfn >= start_pfn && pfn < end_pfn)
426 continue;
427
428 /* If we find valid section, we have nothing to do */
429 zone_span_writeunlock(zone);
430 return;
431 }
432
433 /* The zone has no valid section */
434 zone->zone_start_pfn = 0;
435 zone->spanned_pages = 0;
436 zone_span_writeunlock(zone);
437}
438
439static void update_pgdat_span(struct pglist_data *pgdat)
440{
441 unsigned long node_start_pfn = 0, node_end_pfn = 0;
442 struct zone *zone;
443
444 for (zone = pgdat->node_zones;
445 zone < pgdat->node_zones + MAX_NR_ZONES; zone++) {
446 unsigned long zone_end_pfn = zone->zone_start_pfn +
447 zone->spanned_pages;
448
449 /* No need to lock the zones, they can't change. */
450 if (!zone->spanned_pages)
451 continue;
452 if (!node_end_pfn) {
453 node_start_pfn = zone->zone_start_pfn;
454 node_end_pfn = zone_end_pfn;
455 continue;
456 }
457
458 if (zone_end_pfn > node_end_pfn)
459 node_end_pfn = zone_end_pfn;
460 if (zone->zone_start_pfn < node_start_pfn)
461 node_start_pfn = zone->zone_start_pfn;
462 }
463
464 pgdat->node_start_pfn = node_start_pfn;
465 pgdat->node_spanned_pages = node_end_pfn - node_start_pfn;
466}
467
468static void __remove_zone(struct zone *zone, unsigned long start_pfn,
469 unsigned long nr_pages)
470{
471 struct pglist_data *pgdat = zone->zone_pgdat;
472 unsigned long flags;
473
474#ifdef CONFIG_ZONE_DEVICE
475 /*
476 * Zone shrinking code cannot properly deal with ZONE_DEVICE. So
477 * we will not try to shrink the zones - which is okay as
478 * set_zone_contiguous() cannot deal with ZONE_DEVICE either way.
479 */
480 if (zone_idx(zone) == ZONE_DEVICE)
481 return;
482#endif
483
484 pgdat_resize_lock(zone->zone_pgdat, &flags);
485 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
486 update_pgdat_span(pgdat);
487 pgdat_resize_unlock(zone->zone_pgdat, &flags);
488}
489
490static void __remove_section(struct zone *zone, unsigned long pfn,
491 unsigned long nr_pages, unsigned long map_offset,
492 struct vmem_altmap *altmap)
493{
494 struct mem_section *ms = __nr_to_section(pfn_to_section_nr(pfn));
495
496 if (WARN_ON_ONCE(!valid_section(ms)))
497 return;
498
499 __remove_zone(zone, pfn, nr_pages);
500 sparse_remove_section(ms, pfn, nr_pages, map_offset, altmap);
501}
502
503/**
504 * __remove_pages() - remove sections of pages from a zone
505 * @zone: zone from which pages need to be removed
506 * @pfn: starting pageframe (must be aligned to start of a section)
507 * @nr_pages: number of pages to remove (must be multiple of section size)
508 * @altmap: alternative device page map or %NULL if default memmap is used
509 *
510 * Generic helper function to remove section mappings and sysfs entries
511 * for the section of the memory we are removing. Caller needs to make
512 * sure that pages are marked reserved and zones are adjust properly by
513 * calling offline_pages().
514 */
515void __remove_pages(struct zone *zone, unsigned long pfn,
516 unsigned long nr_pages, struct vmem_altmap *altmap)
517{
518 unsigned long map_offset = 0;
519 unsigned long nr, start_sec, end_sec;
520
521 map_offset = vmem_altmap_offset(altmap);
522
523 clear_zone_contiguous(zone);
524
525 if (check_pfn_span(pfn, nr_pages, "remove"))
526 return;
527
528 start_sec = pfn_to_section_nr(pfn);
529 end_sec = pfn_to_section_nr(pfn + nr_pages - 1);
530 for (nr = start_sec; nr <= end_sec; nr++) {
531 unsigned long pfns;
532
533 cond_resched();
534 pfns = min(nr_pages, PAGES_PER_SECTION
535 - (pfn & ~PAGE_SECTION_MASK));
536 __remove_section(zone, pfn, pfns, map_offset, altmap);
537 pfn += pfns;
538 nr_pages -= pfns;
539 map_offset = 0;
540 }
541
542 set_zone_contiguous(zone);
543}
544
545int set_online_page_callback(online_page_callback_t callback)
546{
547 int rc = -EINVAL;
548
549 get_online_mems();
550 mutex_lock(&online_page_callback_lock);
551
552 if (online_page_callback == generic_online_page) {
553 online_page_callback = callback;
554 rc = 0;
555 }
556
557 mutex_unlock(&online_page_callback_lock);
558 put_online_mems();
559
560 return rc;
561}
562EXPORT_SYMBOL_GPL(set_online_page_callback);
563
564int restore_online_page_callback(online_page_callback_t callback)
565{
566 int rc = -EINVAL;
567
568 get_online_mems();
569 mutex_lock(&online_page_callback_lock);
570
571 if (online_page_callback == callback) {
572 online_page_callback = generic_online_page;
573 rc = 0;
574 }
575
576 mutex_unlock(&online_page_callback_lock);
577 put_online_mems();
578
579 return rc;
580}
581EXPORT_SYMBOL_GPL(restore_online_page_callback);
582
583void __online_page_set_limits(struct page *page)
584{
585}
586EXPORT_SYMBOL_GPL(__online_page_set_limits);
587
588void __online_page_increment_counters(struct page *page)
589{
590 adjust_managed_page_count(page, 1);
591}
592EXPORT_SYMBOL_GPL(__online_page_increment_counters);
593
594void __online_page_free(struct page *page)
595{
596 __free_reserved_page(page);
597}
598EXPORT_SYMBOL_GPL(__online_page_free);
599
600static void generic_online_page(struct page *page, unsigned int order)
601{
602 kernel_map_pages(page, 1 << order, 1);
603 __free_pages_core(page, order);
604 totalram_pages_add(1UL << order);
605#ifdef CONFIG_HIGHMEM
606 if (PageHighMem(page))
607 totalhigh_pages_add(1UL << order);
608#endif
609}
610
611static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
612 void *arg)
613{
614 const unsigned long end_pfn = start_pfn + nr_pages;
615 unsigned long pfn;
616 int order;
617
618 /*
619 * Online the pages. The callback might decide to keep some pages
620 * PG_reserved (to add them to the buddy later), but we still account
621 * them as being online/belonging to this zone ("present").
622 */
623 for (pfn = start_pfn; pfn < end_pfn; pfn += 1ul << order) {
624 order = min(MAX_ORDER - 1, get_order(PFN_PHYS(end_pfn - pfn)));
625 /* __free_pages_core() wants pfns to be aligned to the order */
626 if (WARN_ON_ONCE(!IS_ALIGNED(pfn, 1ul << order)))
627 order = 0;
628 (*online_page_callback)(pfn_to_page(pfn), order);
629 }
630
631 /* mark all involved sections as online */
632 online_mem_sections(start_pfn, end_pfn);
633
634 *(unsigned long *)arg += nr_pages;
635 return 0;
636}
637
638/* check which state of node_states will be changed when online memory */
639static void node_states_check_changes_online(unsigned long nr_pages,
640 struct zone *zone, struct memory_notify *arg)
641{
642 int nid = zone_to_nid(zone);
643
644 arg->status_change_nid = NUMA_NO_NODE;
645 arg->status_change_nid_normal = NUMA_NO_NODE;
646 arg->status_change_nid_high = NUMA_NO_NODE;
647
648 if (!node_state(nid, N_MEMORY))
649 arg->status_change_nid = nid;
650 if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY))
651 arg->status_change_nid_normal = nid;
652#ifdef CONFIG_HIGHMEM
653 if (zone_idx(zone) <= ZONE_HIGHMEM && !node_state(nid, N_HIGH_MEMORY))
654 arg->status_change_nid_high = nid;
655#endif
656}
657
658static void node_states_set_node(int node, struct memory_notify *arg)
659{
660 if (arg->status_change_nid_normal >= 0)
661 node_set_state(node, N_NORMAL_MEMORY);
662
663 if (arg->status_change_nid_high >= 0)
664 node_set_state(node, N_HIGH_MEMORY);
665
666 if (arg->status_change_nid >= 0)
667 node_set_state(node, N_MEMORY);
668}
669
670static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
671 unsigned long nr_pages)
672{
673 unsigned long old_end_pfn = zone_end_pfn(zone);
674
675 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
676 zone->zone_start_pfn = start_pfn;
677
678 zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn;
679}
680
681static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn,
682 unsigned long nr_pages)
683{
684 unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
685
686 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
687 pgdat->node_start_pfn = start_pfn;
688
689 pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn;
690
691}
692/*
693 * Associate the pfn range with the given zone, initializing the memmaps
694 * and resizing the pgdat/zone data to span the added pages. After this
695 * call, all affected pages are PG_reserved.
696 */
697void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
698 unsigned long nr_pages, struct vmem_altmap *altmap)
699{
700 struct pglist_data *pgdat = zone->zone_pgdat;
701 int nid = pgdat->node_id;
702 unsigned long flags;
703
704 clear_zone_contiguous(zone);
705
706 /* TODO Huh pgdat is irqsave while zone is not. It used to be like that before */
707 pgdat_resize_lock(pgdat, &flags);
708 zone_span_writelock(zone);
709 if (zone_is_empty(zone))
710 init_currently_empty_zone(zone, start_pfn, nr_pages);
711 resize_zone_range(zone, start_pfn, nr_pages);
712 zone_span_writeunlock(zone);
713 resize_pgdat_range(pgdat, start_pfn, nr_pages);
714 pgdat_resize_unlock(pgdat, &flags);
715
716 /*
717 * TODO now we have a visible range of pages which are not associated
718 * with their zone properly. Not nice but set_pfnblock_flags_mask
719 * expects the zone spans the pfn range. All the pages in the range
720 * are reserved so nobody should be touching them so we should be safe
721 */
722 memmap_init_zone(nr_pages, nid, zone_idx(zone), start_pfn,
723 MEMMAP_HOTPLUG, altmap);
724
725 set_zone_contiguous(zone);
726}
727
728/*
729 * Returns a default kernel memory zone for the given pfn range.
730 * If no kernel zone covers this pfn range it will automatically go
731 * to the ZONE_NORMAL.
732 */
733static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn,
734 unsigned long nr_pages)
735{
736 struct pglist_data *pgdat = NODE_DATA(nid);
737 int zid;
738
739 for (zid = 0; zid <= ZONE_NORMAL; zid++) {
740 struct zone *zone = &pgdat->node_zones[zid];
741
742 if (zone_intersects(zone, start_pfn, nr_pages))
743 return zone;
744 }
745
746 return &pgdat->node_zones[ZONE_NORMAL];
747}
748
749static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn,
750 unsigned long nr_pages)
751{
752 struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn,
753 nr_pages);
754 struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
755 bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages);
756 bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages);
757
758 /*
759 * We inherit the existing zone in a simple case where zones do not
760 * overlap in the given range
761 */
762 if (in_kernel ^ in_movable)
763 return (in_kernel) ? kernel_zone : movable_zone;
764
765 /*
766 * If the range doesn't belong to any zone or two zones overlap in the
767 * given range then we use movable zone only if movable_node is
768 * enabled because we always online to a kernel zone by default.
769 */
770 return movable_node_enabled ? movable_zone : kernel_zone;
771}
772
773struct zone * zone_for_pfn_range(int online_type, int nid, unsigned start_pfn,
774 unsigned long nr_pages)
775{
776 if (online_type == MMOP_ONLINE_KERNEL)
777 return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages);
778
779 if (online_type == MMOP_ONLINE_MOVABLE)
780 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
781
782 return default_zone_for_pfn(nid, start_pfn, nr_pages);
783}
784
785int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
786{
787 unsigned long flags;
788 unsigned long onlined_pages = 0;
789 struct zone *zone;
790 int need_zonelists_rebuild = 0;
791 int nid;
792 int ret;
793 struct memory_notify arg;
794 struct memory_block *mem;
795
796 mem_hotplug_begin();
797
798 /*
799 * We can't use pfn_to_nid() because nid might be stored in struct page
800 * which is not yet initialized. Instead, we find nid from memory block.
801 */
802 mem = find_memory_block(__pfn_to_section(pfn));
803 nid = mem->nid;
804 put_device(&mem->dev);
805
806 /* associate pfn range with the zone */
807 zone = zone_for_pfn_range(online_type, nid, pfn, nr_pages);
808 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL);
809
810 arg.start_pfn = pfn;
811 arg.nr_pages = nr_pages;
812 node_states_check_changes_online(nr_pages, zone, &arg);
813
814 ret = memory_notify(MEM_GOING_ONLINE, &arg);
815 ret = notifier_to_errno(ret);
816 if (ret)
817 goto failed_addition;
818
819 /*
820 * If this zone is not populated, then it is not in zonelist.
821 * This means the page allocator ignores this zone.
822 * So, zonelist must be updated after online.
823 */
824 if (!populated_zone(zone)) {
825 need_zonelists_rebuild = 1;
826 setup_zone_pageset(zone);
827 }
828
829 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
830 online_pages_range);
831 if (ret) {
832 /* not a single memory resource was applicable */
833 if (need_zonelists_rebuild)
834 zone_pcp_reset(zone);
835 goto failed_addition;
836 }
837
838 zone->present_pages += onlined_pages;
839
840 pgdat_resize_lock(zone->zone_pgdat, &flags);
841 zone->zone_pgdat->node_present_pages += onlined_pages;
842 pgdat_resize_unlock(zone->zone_pgdat, &flags);
843
844 shuffle_zone(zone);
845
846 node_states_set_node(nid, &arg);
847 if (need_zonelists_rebuild)
848 build_all_zonelists(NULL);
849 else
850 zone_pcp_update(zone);
851
852 init_per_zone_wmark_min();
853
854 kswapd_run(nid);
855 kcompactd_run(nid);
856
857 vm_total_pages = nr_free_pagecache_pages();
858
859 writeback_set_ratelimit();
860
861 memory_notify(MEM_ONLINE, &arg);
862 mem_hotplug_done();
863 return 0;
864
865failed_addition:
866 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
867 (unsigned long long) pfn << PAGE_SHIFT,
868 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
869 memory_notify(MEM_CANCEL_ONLINE, &arg);
870 mem_hotplug_done();
871 return ret;
872}
873#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
874
875static void reset_node_present_pages(pg_data_t *pgdat)
876{
877 struct zone *z;
878
879 for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
880 z->present_pages = 0;
881
882 pgdat->node_present_pages = 0;
883}
884
885/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
886static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
887{
888 struct pglist_data *pgdat;
889 unsigned long start_pfn = PFN_DOWN(start);
890
891 pgdat = NODE_DATA(nid);
892 if (!pgdat) {
893 pgdat = arch_alloc_nodedata(nid);
894 if (!pgdat)
895 return NULL;
896
897 pgdat->per_cpu_nodestats =
898 alloc_percpu(struct per_cpu_nodestat);
899 arch_refresh_nodedata(nid, pgdat);
900 } else {
901 int cpu;
902 /*
903 * Reset the nr_zones, order and classzone_idx before reuse.
904 * Note that kswapd will init kswapd_classzone_idx properly
905 * when it starts in the near future.
906 */
907 pgdat->nr_zones = 0;
908 pgdat->kswapd_order = 0;
909 pgdat->kswapd_classzone_idx = 0;
910 for_each_online_cpu(cpu) {
911 struct per_cpu_nodestat *p;
912
913 p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
914 memset(p, 0, sizeof(*p));
915 }
916 }
917
918 /* we can use NODE_DATA(nid) from here */
919
920 pgdat->node_id = nid;
921 pgdat->node_start_pfn = start_pfn;
922
923 /* init node's zones as empty zones, we don't have any present pages.*/
924 free_area_init_core_hotplug(nid);
925
926 /*
927 * The node we allocated has no zone fallback lists. For avoiding
928 * to access not-initialized zonelist, build here.
929 */
930 build_all_zonelists(pgdat);
931
932 /*
933 * When memory is hot-added, all the memory is in offline state. So
934 * clear all zones' present_pages because they will be updated in
935 * online_pages() and offline_pages().
936 */
937 reset_node_managed_pages(pgdat);
938 reset_node_present_pages(pgdat);
939
940 return pgdat;
941}
942
943static void rollback_node_hotadd(int nid)
944{
945 pg_data_t *pgdat = NODE_DATA(nid);
946
947 arch_refresh_nodedata(nid, NULL);
948 free_percpu(pgdat->per_cpu_nodestats);
949 arch_free_nodedata(pgdat);
950}
951
952
953/**
954 * try_online_node - online a node if offlined
955 * @nid: the node ID
956 * @start: start addr of the node
957 * @set_node_online: Whether we want to online the node
958 * called by cpu_up() to online a node without onlined memory.
959 *
960 * Returns:
961 * 1 -> a new node has been allocated
962 * 0 -> the node is already online
963 * -ENOMEM -> the node could not be allocated
964 */
965static int __try_online_node(int nid, u64 start, bool set_node_online)
966{
967 pg_data_t *pgdat;
968 int ret = 1;
969
970 if (node_online(nid))
971 return 0;
972
973 pgdat = hotadd_new_pgdat(nid, start);
974 if (!pgdat) {
975 pr_err("Cannot online node %d due to NULL pgdat\n", nid);
976 ret = -ENOMEM;
977 goto out;
978 }
979
980 if (set_node_online) {
981 node_set_online(nid);
982 ret = register_one_node(nid);
983 BUG_ON(ret);
984 }
985out:
986 return ret;
987}
988
989/*
990 * Users of this function always want to online/register the node
991 */
992int try_online_node(int nid)
993{
994 int ret;
995
996 mem_hotplug_begin();
997 ret = __try_online_node(nid, 0, true);
998 mem_hotplug_done();
999 return ret;
1000}
1001
1002static int check_hotplug_memory_range(u64 start, u64 size)
1003{
1004 /* memory range must be block size aligned */
1005 if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) ||
1006 !IS_ALIGNED(size, memory_block_size_bytes())) {
1007 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
1008 memory_block_size_bytes(), start, size);
1009 return -EINVAL;
1010 }
1011
1012 return 0;
1013}
1014
1015static int online_memory_block(struct memory_block *mem, void *arg)
1016{
1017 return device_online(&mem->dev);
1018}
1019
1020/*
1021 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1022 * and online/offline operations (triggered e.g. by sysfs).
1023 *
1024 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
1025 */
1026int __ref add_memory_resource(int nid, struct resource *res)
1027{
1028 struct mhp_restrictions restrictions = {};
1029 u64 start, size;
1030 bool new_node = false;
1031 int ret;
1032
1033 start = res->start;
1034 size = resource_size(res);
1035
1036 ret = check_hotplug_memory_range(start, size);
1037 if (ret)
1038 return ret;
1039
1040 mem_hotplug_begin();
1041
1042 /*
1043 * Add new range to memblock so that when hotadd_new_pgdat() is called
1044 * to allocate new pgdat, get_pfn_range_for_nid() will be able to find
1045 * this new range and calculate total pages correctly. The range will
1046 * be removed at hot-remove time.
1047 */
1048 memblock_add_node(start, size, nid);
1049
1050 ret = __try_online_node(nid, start, false);
1051 if (ret < 0)
1052 goto error;
1053 new_node = ret;
1054
1055 /* call arch's memory hotadd */
1056 ret = arch_add_memory(nid, start, size, &restrictions);
1057 if (ret < 0)
1058 goto error;
1059
1060 /* create memory block devices after memory was added */
1061 ret = create_memory_block_devices(start, size);
1062 if (ret) {
1063 arch_remove_memory(nid, start, size, NULL);
1064 goto error;
1065 }
1066
1067 if (new_node) {
1068 /* If sysfs file of new node can't be created, cpu on the node
1069 * can't be hot-added. There is no rollback way now.
1070 * So, check by BUG_ON() to catch it reluctantly..
1071 * We online node here. We can't roll back from here.
1072 */
1073 node_set_online(nid);
1074 ret = __register_one_node(nid);
1075 BUG_ON(ret);
1076 }
1077
1078 /* link memory sections under this node.*/
1079 ret = link_mem_sections(nid, PFN_DOWN(start), PFN_UP(start + size - 1));
1080 BUG_ON(ret);
1081
1082 /* create new memmap entry */
1083 firmware_map_add_hotplug(start, start + size, "System RAM");
1084
1085 /* device_online() will take the lock when calling online_pages() */
1086 mem_hotplug_done();
1087
1088 /* online pages if requested */
1089 if (memhp_auto_online)
1090 walk_memory_blocks(start, size, NULL, online_memory_block);
1091
1092 return ret;
1093error:
1094 /* rollback pgdat allocation and others */
1095 if (new_node)
1096 rollback_node_hotadd(nid);
1097 memblock_remove(start, size);
1098 mem_hotplug_done();
1099 return ret;
1100}
1101
1102/* requires device_hotplug_lock, see add_memory_resource() */
1103int __ref __add_memory(int nid, u64 start, u64 size)
1104{
1105 struct resource *res;
1106 int ret;
1107
1108 res = register_memory_resource(start, size);
1109 if (IS_ERR(res))
1110 return PTR_ERR(res);
1111
1112 ret = add_memory_resource(nid, res);
1113 if (ret < 0)
1114 release_memory_resource(res);
1115 return ret;
1116}
1117
1118int add_memory(int nid, u64 start, u64 size)
1119{
1120 int rc;
1121
1122 lock_device_hotplug();
1123 rc = __add_memory(nid, start, size);
1124 unlock_device_hotplug();
1125
1126 return rc;
1127}
1128EXPORT_SYMBOL_GPL(add_memory);
1129
1130#ifdef CONFIG_MEMORY_HOTREMOVE
1131/*
1132 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
1133 * set and the size of the free page is given by page_order(). Using this,
1134 * the function determines if the pageblock contains only free pages.
1135 * Due to buddy contraints, a free page at least the size of a pageblock will
1136 * be located at the start of the pageblock
1137 */
1138static inline int pageblock_free(struct page *page)
1139{
1140 return PageBuddy(page) && page_order(page) >= pageblock_order;
1141}
1142
1143/* Return the pfn of the start of the next active pageblock after a given pfn */
1144static unsigned long next_active_pageblock(unsigned long pfn)
1145{
1146 struct page *page = pfn_to_page(pfn);
1147
1148 /* Ensure the starting page is pageblock-aligned */
1149 BUG_ON(pfn & (pageblock_nr_pages - 1));
1150
1151 /* If the entire pageblock is free, move to the end of free page */
1152 if (pageblock_free(page)) {
1153 int order;
1154 /* be careful. we don't have locks, page_order can be changed.*/
1155 order = page_order(page);
1156 if ((order < MAX_ORDER) && (order >= pageblock_order))
1157 return pfn + (1 << order);
1158 }
1159
1160 return pfn + pageblock_nr_pages;
1161}
1162
1163static bool is_pageblock_removable_nolock(unsigned long pfn)
1164{
1165 struct page *page = pfn_to_page(pfn);
1166 struct zone *zone;
1167
1168 /*
1169 * We have to be careful here because we are iterating over memory
1170 * sections which are not zone aware so we might end up outside of
1171 * the zone but still within the section.
1172 * We have to take care about the node as well. If the node is offline
1173 * its NODE_DATA will be NULL - see page_zone.
1174 */
1175 if (!node_online(page_to_nid(page)))
1176 return false;
1177
1178 zone = page_zone(page);
1179 pfn = page_to_pfn(page);
1180 if (!zone_spans_pfn(zone, pfn))
1181 return false;
1182
1183 return !has_unmovable_pages(zone, page, 0, MIGRATE_MOVABLE, SKIP_HWPOISON);
1184}
1185
1186/* Checks if this range of memory is likely to be hot-removable. */
1187bool is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
1188{
1189 unsigned long end_pfn, pfn;
1190
1191 end_pfn = min(start_pfn + nr_pages,
1192 zone_end_pfn(page_zone(pfn_to_page(start_pfn))));
1193
1194 /* Check the starting page of each pageblock within the range */
1195 for (pfn = start_pfn; pfn < end_pfn; pfn = next_active_pageblock(pfn)) {
1196 if (!is_pageblock_removable_nolock(pfn))
1197 return false;
1198 cond_resched();
1199 }
1200
1201 /* All pageblocks in the memory block are likely to be hot-removable */
1202 return true;
1203}
1204
1205/*
1206 * Confirm all pages in a range [start, end) belong to the same zone.
1207 * When true, return its valid [start, end).
1208 */
1209int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn,
1210 unsigned long *valid_start, unsigned long *valid_end)
1211{
1212 unsigned long pfn, sec_end_pfn;
1213 unsigned long start, end;
1214 struct zone *zone = NULL;
1215 struct page *page;
1216 int i;
1217 for (pfn = start_pfn, sec_end_pfn = SECTION_ALIGN_UP(start_pfn + 1);
1218 pfn < end_pfn;
1219 pfn = sec_end_pfn, sec_end_pfn += PAGES_PER_SECTION) {
1220 /* Make sure the memory section is present first */
1221 if (!present_section_nr(pfn_to_section_nr(pfn)))
1222 continue;
1223 for (; pfn < sec_end_pfn && pfn < end_pfn;
1224 pfn += MAX_ORDER_NR_PAGES) {
1225 i = 0;
1226 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
1227 while ((i < MAX_ORDER_NR_PAGES) &&
1228 !pfn_valid_within(pfn + i))
1229 i++;
1230 if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn)
1231 continue;
1232 /* Check if we got outside of the zone */
1233 if (zone && !zone_spans_pfn(zone, pfn + i))
1234 return 0;
1235 page = pfn_to_page(pfn + i);
1236 if (zone && page_zone(page) != zone)
1237 return 0;
1238 if (!zone)
1239 start = pfn + i;
1240 zone = page_zone(page);
1241 end = pfn + MAX_ORDER_NR_PAGES;
1242 }
1243 }
1244
1245 if (zone) {
1246 *valid_start = start;
1247 *valid_end = min(end, end_pfn);
1248 return 1;
1249 } else {
1250 return 0;
1251 }
1252}
1253
1254/*
1255 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
1256 * non-lru movable pages and hugepages). We scan pfn because it's much
1257 * easier than scanning over linked list. This function returns the pfn
1258 * of the first found movable page if it's found, otherwise 0.
1259 */
1260static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
1261{
1262 unsigned long pfn;
1263
1264 for (pfn = start; pfn < end; pfn++) {
1265 struct page *page, *head;
1266 unsigned long skip;
1267
1268 if (!pfn_valid(pfn))
1269 continue;
1270 page = pfn_to_page(pfn);
1271 if (PageLRU(page))
1272 return pfn;
1273 if (__PageMovable(page))
1274 return pfn;
1275
1276 if (!PageHuge(page))
1277 continue;
1278 head = compound_head(page);
1279 if (page_huge_active(head))
1280 return pfn;
1281 skip = compound_nr(head) - (page - head);
1282 pfn += skip - 1;
1283 }
1284 return 0;
1285}
1286
1287static struct page *new_node_page(struct page *page, unsigned long private)
1288{
1289 int nid = page_to_nid(page);
1290 nodemask_t nmask = node_states[N_MEMORY];
1291
1292 /*
1293 * try to allocate from a different node but reuse this node if there
1294 * are no other online nodes to be used (e.g. we are offlining a part
1295 * of the only existing node)
1296 */
1297 node_clear(nid, nmask);
1298 if (nodes_empty(nmask))
1299 node_set(nid, nmask);
1300
1301 return new_page_nodemask(page, nid, &nmask);
1302}
1303
1304static int
1305do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1306{
1307 unsigned long pfn;
1308 struct page *page;
1309 int ret = 0;
1310 LIST_HEAD(source);
1311
1312 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1313 if (!pfn_valid(pfn))
1314 continue;
1315 page = pfn_to_page(pfn);
1316
1317 if (PageHuge(page)) {
1318 struct page *head = compound_head(page);
1319 pfn = page_to_pfn(head) + compound_nr(head) - 1;
1320 isolate_huge_page(head, &source);
1321 continue;
1322 } else if (PageTransHuge(page))
1323 pfn = page_to_pfn(compound_head(page))
1324 + hpage_nr_pages(page) - 1;
1325
1326 /*
1327 * HWPoison pages have elevated reference counts so the migration would
1328 * fail on them. It also doesn't make any sense to migrate them in the
1329 * first place. Still try to unmap such a page in case it is still mapped
1330 * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep
1331 * the unmap as the catch all safety net).
1332 */
1333 if (PageHWPoison(page)) {
1334 if (WARN_ON(PageLRU(page)))
1335 isolate_lru_page(page);
1336 if (page_mapped(page))
1337 try_to_unmap(page, TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS);
1338 continue;
1339 }
1340
1341 if (!get_page_unless_zero(page))
1342 continue;
1343 /*
1344 * We can skip free pages. And we can deal with pages on
1345 * LRU and non-lru movable pages.
1346 */
1347 if (PageLRU(page))
1348 ret = isolate_lru_page(page);
1349 else
1350 ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE);
1351 if (!ret) { /* Success */
1352 list_add_tail(&page->lru, &source);
1353 if (!__PageMovable(page))
1354 inc_node_page_state(page, NR_ISOLATED_ANON +
1355 page_is_file_cache(page));
1356
1357 } else {
1358 pr_warn("failed to isolate pfn %lx\n", pfn);
1359 dump_page(page, "isolation failed");
1360 }
1361 put_page(page);
1362 }
1363 if (!list_empty(&source)) {
1364 /* Allocate a new page from the nearest neighbor node */
1365 ret = migrate_pages(&source, new_node_page, NULL, 0,
1366 MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
1367 if (ret) {
1368 list_for_each_entry(page, &source, lru) {
1369 pr_warn("migrating pfn %lx failed ret:%d ",
1370 page_to_pfn(page), ret);
1371 dump_page(page, "migration failure");
1372 }
1373 putback_movable_pages(&source);
1374 }
1375 }
1376
1377 return ret;
1378}
1379
1380/*
1381 * remove from free_area[] and mark all as Reserved.
1382 */
1383static int
1384offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1385 void *data)
1386{
1387 unsigned long *offlined_pages = (unsigned long *)data;
1388
1389 *offlined_pages += __offline_isolated_pages(start, start + nr_pages);
1390 return 0;
1391}
1392
1393/*
1394 * Check all pages in range, recoreded as memory resource, are isolated.
1395 */
1396static int
1397check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1398 void *data)
1399{
1400 return test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
1401}
1402
1403static int __init cmdline_parse_movable_node(char *p)
1404{
1405#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
1406 movable_node_enabled = true;
1407#else
1408 pr_warn("movable_node parameter depends on CONFIG_HAVE_MEMBLOCK_NODE_MAP to work properly\n");
1409#endif
1410 return 0;
1411}
1412early_param("movable_node", cmdline_parse_movable_node);
1413
1414/* check which state of node_states will be changed when offline memory */
1415static void node_states_check_changes_offline(unsigned long nr_pages,
1416 struct zone *zone, struct memory_notify *arg)
1417{
1418 struct pglist_data *pgdat = zone->zone_pgdat;
1419 unsigned long present_pages = 0;
1420 enum zone_type zt;
1421
1422 arg->status_change_nid = NUMA_NO_NODE;
1423 arg->status_change_nid_normal = NUMA_NO_NODE;
1424 arg->status_change_nid_high = NUMA_NO_NODE;
1425
1426 /*
1427 * Check whether node_states[N_NORMAL_MEMORY] will be changed.
1428 * If the memory to be offline is within the range
1429 * [0..ZONE_NORMAL], and it is the last present memory there,
1430 * the zones in that range will become empty after the offlining,
1431 * thus we can determine that we need to clear the node from
1432 * node_states[N_NORMAL_MEMORY].
1433 */
1434 for (zt = 0; zt <= ZONE_NORMAL; zt++)
1435 present_pages += pgdat->node_zones[zt].present_pages;
1436 if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages)
1437 arg->status_change_nid_normal = zone_to_nid(zone);
1438
1439#ifdef CONFIG_HIGHMEM
1440 /*
1441 * node_states[N_HIGH_MEMORY] contains nodes which
1442 * have normal memory or high memory.
1443 * Here we add the present_pages belonging to ZONE_HIGHMEM.
1444 * If the zone is within the range of [0..ZONE_HIGHMEM), and
1445 * we determine that the zones in that range become empty,
1446 * we need to clear the node for N_HIGH_MEMORY.
1447 */
1448 present_pages += pgdat->node_zones[ZONE_HIGHMEM].present_pages;
1449 if (zone_idx(zone) <= ZONE_HIGHMEM && nr_pages >= present_pages)
1450 arg->status_change_nid_high = zone_to_nid(zone);
1451#endif
1452
1453 /*
1454 * We have accounted the pages from [0..ZONE_NORMAL), and
1455 * in case of CONFIG_HIGHMEM the pages from ZONE_HIGHMEM
1456 * as well.
1457 * Here we count the possible pages from ZONE_MOVABLE.
1458 * If after having accounted all the pages, we see that the nr_pages
1459 * to be offlined is over or equal to the accounted pages,
1460 * we know that the node will become empty, and so, we can clear
1461 * it for N_MEMORY as well.
1462 */
1463 present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages;
1464
1465 if (nr_pages >= present_pages)
1466 arg->status_change_nid = zone_to_nid(zone);
1467}
1468
1469static void node_states_clear_node(int node, struct memory_notify *arg)
1470{
1471 if (arg->status_change_nid_normal >= 0)
1472 node_clear_state(node, N_NORMAL_MEMORY);
1473
1474 if (arg->status_change_nid_high >= 0)
1475 node_clear_state(node, N_HIGH_MEMORY);
1476
1477 if (arg->status_change_nid >= 0)
1478 node_clear_state(node, N_MEMORY);
1479}
1480
1481static int __ref __offline_pages(unsigned long start_pfn,
1482 unsigned long end_pfn)
1483{
1484 unsigned long pfn, nr_pages;
1485 unsigned long offlined_pages = 0;
1486 int ret, node, nr_isolate_pageblock;
1487 unsigned long flags;
1488 unsigned long valid_start, valid_end;
1489 struct zone *zone;
1490 struct memory_notify arg;
1491 char *reason;
1492
1493 mem_hotplug_begin();
1494
1495 /* This makes hotplug much easier...and readable.
1496 we assume this for now. .*/
1497 if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start,
1498 &valid_end)) {
1499 ret = -EINVAL;
1500 reason = "multizone range";
1501 goto failed_removal;
1502 }
1503
1504 zone = page_zone(pfn_to_page(valid_start));
1505 node = zone_to_nid(zone);
1506 nr_pages = end_pfn - start_pfn;
1507
1508 /* set above range as isolated */
1509 ret = start_isolate_page_range(start_pfn, end_pfn,
1510 MIGRATE_MOVABLE,
1511 SKIP_HWPOISON | REPORT_FAILURE);
1512 if (ret < 0) {
1513 reason = "failure to isolate range";
1514 goto failed_removal;
1515 }
1516 nr_isolate_pageblock = ret;
1517
1518 arg.start_pfn = start_pfn;
1519 arg.nr_pages = nr_pages;
1520 node_states_check_changes_offline(nr_pages, zone, &arg);
1521
1522 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1523 ret = notifier_to_errno(ret);
1524 if (ret) {
1525 reason = "notifier failure";
1526 goto failed_removal_isolated;
1527 }
1528
1529 do {
1530 for (pfn = start_pfn; pfn;) {
1531 if (signal_pending(current)) {
1532 ret = -EINTR;
1533 reason = "signal backoff";
1534 goto failed_removal_isolated;
1535 }
1536
1537 cond_resched();
1538 lru_add_drain_all();
1539
1540 pfn = scan_movable_pages(pfn, end_pfn);
1541 if (pfn) {
1542 /*
1543 * TODO: fatal migration failures should bail
1544 * out
1545 */
1546 do_migrate_range(pfn, end_pfn);
1547 }
1548 }
1549
1550 /*
1551 * Dissolve free hugepages in the memory block before doing
1552 * offlining actually in order to make hugetlbfs's object
1553 * counting consistent.
1554 */
1555 ret = dissolve_free_huge_pages(start_pfn, end_pfn);
1556 if (ret) {
1557 reason = "failure to dissolve huge pages";
1558 goto failed_removal_isolated;
1559 }
1560 /* check again */
1561 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn,
1562 NULL, check_pages_isolated_cb);
1563 } while (ret);
1564
1565 /* Ok, all of our target is isolated.
1566 We cannot do rollback at this point. */
1567 walk_system_ram_range(start_pfn, end_pfn - start_pfn,
1568 &offlined_pages, offline_isolated_pages_cb);
1569 pr_info("Offlined Pages %ld\n", offlined_pages);
1570 /*
1571 * Onlining will reset pagetype flags and makes migrate type
1572 * MOVABLE, so just need to decrease the number of isolated
1573 * pageblocks zone counter here.
1574 */
1575 spin_lock_irqsave(&zone->lock, flags);
1576 zone->nr_isolate_pageblock -= nr_isolate_pageblock;
1577 spin_unlock_irqrestore(&zone->lock, flags);
1578
1579 /* removal success */
1580 adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages);
1581 zone->present_pages -= offlined_pages;
1582
1583 pgdat_resize_lock(zone->zone_pgdat, &flags);
1584 zone->zone_pgdat->node_present_pages -= offlined_pages;
1585 pgdat_resize_unlock(zone->zone_pgdat, &flags);
1586
1587 init_per_zone_wmark_min();
1588
1589 if (!populated_zone(zone)) {
1590 zone_pcp_reset(zone);
1591 build_all_zonelists(NULL);
1592 } else
1593 zone_pcp_update(zone);
1594
1595 node_states_clear_node(node, &arg);
1596 if (arg.status_change_nid >= 0) {
1597 kswapd_stop(node);
1598 kcompactd_stop(node);
1599 }
1600
1601 vm_total_pages = nr_free_pagecache_pages();
1602 writeback_set_ratelimit();
1603
1604 memory_notify(MEM_OFFLINE, &arg);
1605 mem_hotplug_done();
1606 return 0;
1607
1608failed_removal_isolated:
1609 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1610 memory_notify(MEM_CANCEL_OFFLINE, &arg);
1611failed_removal:
1612 pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n",
1613 (unsigned long long) start_pfn << PAGE_SHIFT,
1614 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1,
1615 reason);
1616 /* pushback to free area */
1617 mem_hotplug_done();
1618 return ret;
1619}
1620
1621int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1622{
1623 return __offline_pages(start_pfn, start_pfn + nr_pages);
1624}
1625
1626static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
1627{
1628 int ret = !is_memblock_offlined(mem);
1629
1630 if (unlikely(ret)) {
1631 phys_addr_t beginpa, endpa;
1632
1633 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
1634 endpa = beginpa + memory_block_size_bytes() - 1;
1635 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
1636 &beginpa, &endpa);
1637
1638 return -EBUSY;
1639 }
1640 return 0;
1641}
1642
1643static int check_cpu_on_node(pg_data_t *pgdat)
1644{
1645 int cpu;
1646
1647 for_each_present_cpu(cpu) {
1648 if (cpu_to_node(cpu) == pgdat->node_id)
1649 /*
1650 * the cpu on this node isn't removed, and we can't
1651 * offline this node.
1652 */
1653 return -EBUSY;
1654 }
1655
1656 return 0;
1657}
1658
1659static int check_no_memblock_for_node_cb(struct memory_block *mem, void *arg)
1660{
1661 int nid = *(int *)arg;
1662
1663 /*
1664 * If a memory block belongs to multiple nodes, the stored nid is not
1665 * reliable. However, such blocks are always online (e.g., cannot get
1666 * offlined) and, therefore, are still spanned by the node.
1667 */
1668 return mem->nid == nid ? -EEXIST : 0;
1669}
1670
1671/**
1672 * try_offline_node
1673 * @nid: the node ID
1674 *
1675 * Offline a node if all memory sections and cpus of the node are removed.
1676 *
1677 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1678 * and online/offline operations before this call.
1679 */
1680void try_offline_node(int nid)
1681{
1682 pg_data_t *pgdat = NODE_DATA(nid);
1683 int rc;
1684
1685 /*
1686 * If the node still spans pages (especially ZONE_DEVICE), don't
1687 * offline it. A node spans memory after move_pfn_range_to_zone(),
1688 * e.g., after the memory block was onlined.
1689 */
1690 if (pgdat->node_spanned_pages)
1691 return;
1692
1693 /*
1694 * Especially offline memory blocks might not be spanned by the
1695 * node. They will get spanned by the node once they get onlined.
1696 * However, they link to the node in sysfs and can get onlined later.
1697 */
1698 rc = for_each_memory_block(&nid, check_no_memblock_for_node_cb);
1699 if (rc)
1700 return;
1701
1702 if (check_cpu_on_node(pgdat))
1703 return;
1704
1705 /*
1706 * all memory/cpu of this node are removed, we can offline this
1707 * node now.
1708 */
1709 node_set_offline(nid);
1710 unregister_one_node(nid);
1711}
1712EXPORT_SYMBOL(try_offline_node);
1713
1714static void __release_memory_resource(resource_size_t start,
1715 resource_size_t size)
1716{
1717 int ret;
1718
1719 /*
1720 * When removing memory in the same granularity as it was added,
1721 * this function never fails. It might only fail if resources
1722 * have to be adjusted or split. We'll ignore the error, as
1723 * removing of memory cannot fail.
1724 */
1725 ret = release_mem_region_adjustable(&iomem_resource, start, size);
1726 if (ret) {
1727 resource_size_t endres = start + size - 1;
1728
1729 pr_warn("Unable to release resource <%pa-%pa> (%d)\n",
1730 &start, &endres, ret);
1731 }
1732}
1733
1734static int __ref try_remove_memory(int nid, u64 start, u64 size)
1735{
1736 int rc = 0;
1737
1738 BUG_ON(check_hotplug_memory_range(start, size));
1739
1740 mem_hotplug_begin();
1741
1742 /*
1743 * All memory blocks must be offlined before removing memory. Check
1744 * whether all memory blocks in question are offline and return error
1745 * if this is not the case.
1746 */
1747 rc = walk_memory_blocks(start, size, NULL, check_memblock_offlined_cb);
1748 if (rc)
1749 goto done;
1750
1751 /* remove memmap entry */
1752 firmware_map_remove(start, start + size, "System RAM");
1753 memblock_free(start, size);
1754 memblock_remove(start, size);
1755
1756 /* remove memory block devices before removing memory */
1757 remove_memory_block_devices(start, size);
1758
1759 arch_remove_memory(nid, start, size, NULL);
1760 __release_memory_resource(start, size);
1761
1762 try_offline_node(nid);
1763
1764done:
1765 mem_hotplug_done();
1766 return rc;
1767}
1768
1769/**
1770 * remove_memory
1771 * @nid: the node ID
1772 * @start: physical address of the region to remove
1773 * @size: size of the region to remove
1774 *
1775 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1776 * and online/offline operations before this call, as required by
1777 * try_offline_node().
1778 */
1779void __remove_memory(int nid, u64 start, u64 size)
1780{
1781
1782 /*
1783 * trigger BUG() if some memory is not offlined prior to calling this
1784 * function
1785 */
1786 if (try_remove_memory(nid, start, size))
1787 BUG();
1788}
1789
1790/*
1791 * Remove memory if every memory block is offline, otherwise return -EBUSY is
1792 * some memory is not offline
1793 */
1794int remove_memory(int nid, u64 start, u64 size)
1795{
1796 int rc;
1797
1798 lock_device_hotplug();
1799 rc = try_remove_memory(nid, start, size);
1800 unlock_device_hotplug();
1801
1802 return rc;
1803}
1804EXPORT_SYMBOL_GPL(remove_memory);
1805#endif /* CONFIG_MEMORY_HOTREMOVE */
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/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/memremap.h>
22#include <linux/memory_hotplug.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#include <linux/stop_machine.h>
33#include <linux/hugetlb.h>
34#include <linux/memblock.h>
35#include <linux/compaction.h>
36#include <linux/rmap.h>
37#include <linux/module.h>
38
39#include <asm/tlbflush.h>
40
41#include "internal.h"
42#include "shuffle.h"
43
44enum {
45 MEMMAP_ON_MEMORY_DISABLE = 0,
46 MEMMAP_ON_MEMORY_ENABLE,
47 MEMMAP_ON_MEMORY_FORCE,
48};
49
50static int memmap_mode __read_mostly = MEMMAP_ON_MEMORY_DISABLE;
51
52static inline unsigned long memory_block_memmap_size(void)
53{
54 return PHYS_PFN(memory_block_size_bytes()) * sizeof(struct page);
55}
56
57static inline unsigned long memory_block_memmap_on_memory_pages(void)
58{
59 unsigned long nr_pages = PFN_UP(memory_block_memmap_size());
60
61 /*
62 * In "forced" memmap_on_memory mode, we add extra pages to align the
63 * vmemmap size to cover full pageblocks. That way, we can add memory
64 * even if the vmemmap size is not properly aligned, however, we might waste
65 * memory.
66 */
67 if (memmap_mode == MEMMAP_ON_MEMORY_FORCE)
68 return pageblock_align(nr_pages);
69 return nr_pages;
70}
71
72#ifdef CONFIG_MHP_MEMMAP_ON_MEMORY
73/*
74 * memory_hotplug.memmap_on_memory parameter
75 */
76static int set_memmap_mode(const char *val, const struct kernel_param *kp)
77{
78 int ret, mode;
79 bool enabled;
80
81 if (sysfs_streq(val, "force") || sysfs_streq(val, "FORCE")) {
82 mode = MEMMAP_ON_MEMORY_FORCE;
83 } else {
84 ret = kstrtobool(val, &enabled);
85 if (ret < 0)
86 return ret;
87 if (enabled)
88 mode = MEMMAP_ON_MEMORY_ENABLE;
89 else
90 mode = MEMMAP_ON_MEMORY_DISABLE;
91 }
92 *((int *)kp->arg) = mode;
93 if (mode == MEMMAP_ON_MEMORY_FORCE) {
94 unsigned long memmap_pages = memory_block_memmap_on_memory_pages();
95
96 pr_info_once("Memory hotplug will waste %ld pages in each memory block\n",
97 memmap_pages - PFN_UP(memory_block_memmap_size()));
98 }
99 return 0;
100}
101
102static int get_memmap_mode(char *buffer, const struct kernel_param *kp)
103{
104 int mode = *((int *)kp->arg);
105
106 if (mode == MEMMAP_ON_MEMORY_FORCE)
107 return sprintf(buffer, "force\n");
108 return sprintf(buffer, "%c\n", mode ? 'Y' : 'N');
109}
110
111static const struct kernel_param_ops memmap_mode_ops = {
112 .set = set_memmap_mode,
113 .get = get_memmap_mode,
114};
115module_param_cb(memmap_on_memory, &memmap_mode_ops, &memmap_mode, 0444);
116MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug\n"
117 "With value \"force\" it could result in memory wastage due "
118 "to memmap size limitations (Y/N/force)");
119
120static inline bool mhp_memmap_on_memory(void)
121{
122 return memmap_mode != MEMMAP_ON_MEMORY_DISABLE;
123}
124#else
125static inline bool mhp_memmap_on_memory(void)
126{
127 return false;
128}
129#endif
130
131enum {
132 ONLINE_POLICY_CONTIG_ZONES = 0,
133 ONLINE_POLICY_AUTO_MOVABLE,
134};
135
136static const char * const online_policy_to_str[] = {
137 [ONLINE_POLICY_CONTIG_ZONES] = "contig-zones",
138 [ONLINE_POLICY_AUTO_MOVABLE] = "auto-movable",
139};
140
141static int set_online_policy(const char *val, const struct kernel_param *kp)
142{
143 int ret = sysfs_match_string(online_policy_to_str, val);
144
145 if (ret < 0)
146 return ret;
147 *((int *)kp->arg) = ret;
148 return 0;
149}
150
151static int get_online_policy(char *buffer, const struct kernel_param *kp)
152{
153 return sprintf(buffer, "%s\n", online_policy_to_str[*((int *)kp->arg)]);
154}
155
156/*
157 * memory_hotplug.online_policy: configure online behavior when onlining without
158 * specifying a zone (MMOP_ONLINE)
159 *
160 * "contig-zones": keep zone contiguous
161 * "auto-movable": online memory to ZONE_MOVABLE if the configuration
162 * (auto_movable_ratio, auto_movable_numa_aware) allows for it
163 */
164static int online_policy __read_mostly = ONLINE_POLICY_CONTIG_ZONES;
165static const struct kernel_param_ops online_policy_ops = {
166 .set = set_online_policy,
167 .get = get_online_policy,
168};
169module_param_cb(online_policy, &online_policy_ops, &online_policy, 0644);
170MODULE_PARM_DESC(online_policy,
171 "Set the online policy (\"contig-zones\", \"auto-movable\") "
172 "Default: \"contig-zones\"");
173
174/*
175 * memory_hotplug.auto_movable_ratio: specify maximum MOVABLE:KERNEL ratio
176 *
177 * The ratio represent an upper limit and the kernel might decide to not
178 * online some memory to ZONE_MOVABLE -- e.g., because hotplugged KERNEL memory
179 * doesn't allow for more MOVABLE memory.
180 */
181static unsigned int auto_movable_ratio __read_mostly = 301;
182module_param(auto_movable_ratio, uint, 0644);
183MODULE_PARM_DESC(auto_movable_ratio,
184 "Set the maximum ratio of MOVABLE:KERNEL memory in the system "
185 "in percent for \"auto-movable\" online policy. Default: 301");
186
187/*
188 * memory_hotplug.auto_movable_numa_aware: consider numa node stats
189 */
190#ifdef CONFIG_NUMA
191static bool auto_movable_numa_aware __read_mostly = true;
192module_param(auto_movable_numa_aware, bool, 0644);
193MODULE_PARM_DESC(auto_movable_numa_aware,
194 "Consider numa node stats in addition to global stats in "
195 "\"auto-movable\" online policy. Default: true");
196#endif /* CONFIG_NUMA */
197
198/*
199 * online_page_callback contains pointer to current page onlining function.
200 * Initially it is generic_online_page(). If it is required it could be
201 * changed by calling set_online_page_callback() for callback registration
202 * and restore_online_page_callback() for generic callback restore.
203 */
204
205static online_page_callback_t online_page_callback = generic_online_page;
206static DEFINE_MUTEX(online_page_callback_lock);
207
208DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock);
209
210void get_online_mems(void)
211{
212 percpu_down_read(&mem_hotplug_lock);
213}
214
215void put_online_mems(void)
216{
217 percpu_up_read(&mem_hotplug_lock);
218}
219
220bool movable_node_enabled = false;
221
222#ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
223int mhp_default_online_type = MMOP_OFFLINE;
224#else
225int mhp_default_online_type = MMOP_ONLINE;
226#endif
227
228static int __init setup_memhp_default_state(char *str)
229{
230 const int online_type = mhp_online_type_from_str(str);
231
232 if (online_type >= 0)
233 mhp_default_online_type = online_type;
234
235 return 1;
236}
237__setup("memhp_default_state=", setup_memhp_default_state);
238
239void mem_hotplug_begin(void)
240{
241 cpus_read_lock();
242 percpu_down_write(&mem_hotplug_lock);
243}
244
245void mem_hotplug_done(void)
246{
247 percpu_up_write(&mem_hotplug_lock);
248 cpus_read_unlock();
249}
250
251u64 max_mem_size = U64_MAX;
252
253/* add this memory to iomem resource */
254static struct resource *register_memory_resource(u64 start, u64 size,
255 const char *resource_name)
256{
257 struct resource *res;
258 unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
259
260 if (strcmp(resource_name, "System RAM"))
261 flags |= IORESOURCE_SYSRAM_DRIVER_MANAGED;
262
263 if (!mhp_range_allowed(start, size, true))
264 return ERR_PTR(-E2BIG);
265
266 /*
267 * Make sure value parsed from 'mem=' only restricts memory adding
268 * while booting, so that memory hotplug won't be impacted. Please
269 * refer to document of 'mem=' in kernel-parameters.txt for more
270 * details.
271 */
272 if (start + size > max_mem_size && system_state < SYSTEM_RUNNING)
273 return ERR_PTR(-E2BIG);
274
275 /*
276 * Request ownership of the new memory range. This might be
277 * a child of an existing resource that was present but
278 * not marked as busy.
279 */
280 res = __request_region(&iomem_resource, start, size,
281 resource_name, flags);
282
283 if (!res) {
284 pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n",
285 start, start + size);
286 return ERR_PTR(-EEXIST);
287 }
288 return res;
289}
290
291static void release_memory_resource(struct resource *res)
292{
293 if (!res)
294 return;
295 release_resource(res);
296 kfree(res);
297}
298
299static int check_pfn_span(unsigned long pfn, unsigned long nr_pages)
300{
301 /*
302 * Disallow all operations smaller than a sub-section and only
303 * allow operations smaller than a section for
304 * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range()
305 * enforces a larger memory_block_size_bytes() granularity for
306 * memory that will be marked online, so this check should only
307 * fire for direct arch_{add,remove}_memory() users outside of
308 * add_memory_resource().
309 */
310 unsigned long min_align;
311
312 if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
313 min_align = PAGES_PER_SUBSECTION;
314 else
315 min_align = PAGES_PER_SECTION;
316 if (!IS_ALIGNED(pfn | nr_pages, min_align))
317 return -EINVAL;
318 return 0;
319}
320
321/*
322 * Return page for the valid pfn only if the page is online. All pfn
323 * walkers which rely on the fully initialized page->flags and others
324 * should use this rather than pfn_valid && pfn_to_page
325 */
326struct page *pfn_to_online_page(unsigned long pfn)
327{
328 unsigned long nr = pfn_to_section_nr(pfn);
329 struct dev_pagemap *pgmap;
330 struct mem_section *ms;
331
332 if (nr >= NR_MEM_SECTIONS)
333 return NULL;
334
335 ms = __nr_to_section(nr);
336 if (!online_section(ms))
337 return NULL;
338
339 /*
340 * Save some code text when online_section() +
341 * pfn_section_valid() are sufficient.
342 */
343 if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) && !pfn_valid(pfn))
344 return NULL;
345
346 if (!pfn_section_valid(ms, pfn))
347 return NULL;
348
349 if (!online_device_section(ms))
350 return pfn_to_page(pfn);
351
352 /*
353 * Slowpath: when ZONE_DEVICE collides with
354 * ZONE_{NORMAL,MOVABLE} within the same section some pfns in
355 * the section may be 'offline' but 'valid'. Only
356 * get_dev_pagemap() can determine sub-section online status.
357 */
358 pgmap = get_dev_pagemap(pfn, NULL);
359 put_dev_pagemap(pgmap);
360
361 /* The presence of a pgmap indicates ZONE_DEVICE offline pfn */
362 if (pgmap)
363 return NULL;
364
365 return pfn_to_page(pfn);
366}
367EXPORT_SYMBOL_GPL(pfn_to_online_page);
368
369int __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
370 struct mhp_params *params)
371{
372 const unsigned long end_pfn = pfn + nr_pages;
373 unsigned long cur_nr_pages;
374 int err;
375 struct vmem_altmap *altmap = params->altmap;
376
377 if (WARN_ON_ONCE(!pgprot_val(params->pgprot)))
378 return -EINVAL;
379
380 VM_BUG_ON(!mhp_range_allowed(PFN_PHYS(pfn), nr_pages * PAGE_SIZE, false));
381
382 if (altmap) {
383 /*
384 * Validate altmap is within bounds of the total request
385 */
386 if (altmap->base_pfn != pfn
387 || vmem_altmap_offset(altmap) > nr_pages) {
388 pr_warn_once("memory add fail, invalid altmap\n");
389 return -EINVAL;
390 }
391 altmap->alloc = 0;
392 }
393
394 if (check_pfn_span(pfn, nr_pages)) {
395 WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__, pfn, pfn + nr_pages - 1);
396 return -EINVAL;
397 }
398
399 for (; pfn < end_pfn; pfn += cur_nr_pages) {
400 /* Select all remaining pages up to the next section boundary */
401 cur_nr_pages = min(end_pfn - pfn,
402 SECTION_ALIGN_UP(pfn + 1) - pfn);
403 err = sparse_add_section(nid, pfn, cur_nr_pages, altmap,
404 params->pgmap);
405 if (err)
406 break;
407 cond_resched();
408 }
409 vmemmap_populate_print_last();
410 return err;
411}
412
413/* find the smallest valid pfn in the range [start_pfn, end_pfn) */
414static unsigned long find_smallest_section_pfn(int nid, struct zone *zone,
415 unsigned long start_pfn,
416 unsigned long end_pfn)
417{
418 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) {
419 if (unlikely(!pfn_to_online_page(start_pfn)))
420 continue;
421
422 if (unlikely(pfn_to_nid(start_pfn) != nid))
423 continue;
424
425 if (zone != page_zone(pfn_to_page(start_pfn)))
426 continue;
427
428 return start_pfn;
429 }
430
431 return 0;
432}
433
434/* find the biggest valid pfn in the range [start_pfn, end_pfn). */
435static unsigned long find_biggest_section_pfn(int nid, struct zone *zone,
436 unsigned long start_pfn,
437 unsigned long end_pfn)
438{
439 unsigned long pfn;
440
441 /* pfn is the end pfn of a memory section. */
442 pfn = end_pfn - 1;
443 for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) {
444 if (unlikely(!pfn_to_online_page(pfn)))
445 continue;
446
447 if (unlikely(pfn_to_nid(pfn) != nid))
448 continue;
449
450 if (zone != page_zone(pfn_to_page(pfn)))
451 continue;
452
453 return pfn;
454 }
455
456 return 0;
457}
458
459static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
460 unsigned long end_pfn)
461{
462 unsigned long pfn;
463 int nid = zone_to_nid(zone);
464
465 if (zone->zone_start_pfn == start_pfn) {
466 /*
467 * If the section is smallest section in the zone, it need
468 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
469 * In this case, we find second smallest valid mem_section
470 * for shrinking zone.
471 */
472 pfn = find_smallest_section_pfn(nid, zone, end_pfn,
473 zone_end_pfn(zone));
474 if (pfn) {
475 zone->spanned_pages = zone_end_pfn(zone) - pfn;
476 zone->zone_start_pfn = pfn;
477 } else {
478 zone->zone_start_pfn = 0;
479 zone->spanned_pages = 0;
480 }
481 } else if (zone_end_pfn(zone) == end_pfn) {
482 /*
483 * If the section is biggest section in the zone, it need
484 * shrink zone->spanned_pages.
485 * In this case, we find second biggest valid mem_section for
486 * shrinking zone.
487 */
488 pfn = find_biggest_section_pfn(nid, zone, zone->zone_start_pfn,
489 start_pfn);
490 if (pfn)
491 zone->spanned_pages = pfn - zone->zone_start_pfn + 1;
492 else {
493 zone->zone_start_pfn = 0;
494 zone->spanned_pages = 0;
495 }
496 }
497}
498
499static void update_pgdat_span(struct pglist_data *pgdat)
500{
501 unsigned long node_start_pfn = 0, node_end_pfn = 0;
502 struct zone *zone;
503
504 for (zone = pgdat->node_zones;
505 zone < pgdat->node_zones + MAX_NR_ZONES; zone++) {
506 unsigned long end_pfn = zone_end_pfn(zone);
507
508 /* No need to lock the zones, they can't change. */
509 if (!zone->spanned_pages)
510 continue;
511 if (!node_end_pfn) {
512 node_start_pfn = zone->zone_start_pfn;
513 node_end_pfn = end_pfn;
514 continue;
515 }
516
517 if (end_pfn > node_end_pfn)
518 node_end_pfn = end_pfn;
519 if (zone->zone_start_pfn < node_start_pfn)
520 node_start_pfn = zone->zone_start_pfn;
521 }
522
523 pgdat->node_start_pfn = node_start_pfn;
524 pgdat->node_spanned_pages = node_end_pfn - node_start_pfn;
525}
526
527void remove_pfn_range_from_zone(struct zone *zone,
528 unsigned long start_pfn,
529 unsigned long nr_pages)
530{
531 const unsigned long end_pfn = start_pfn + nr_pages;
532 struct pglist_data *pgdat = zone->zone_pgdat;
533 unsigned long pfn, cur_nr_pages;
534
535 /* Poison struct pages because they are now uninitialized again. */
536 for (pfn = start_pfn; pfn < end_pfn; pfn += cur_nr_pages) {
537 cond_resched();
538
539 /* Select all remaining pages up to the next section boundary */
540 cur_nr_pages =
541 min(end_pfn - pfn, SECTION_ALIGN_UP(pfn + 1) - pfn);
542 page_init_poison(pfn_to_page(pfn),
543 sizeof(struct page) * cur_nr_pages);
544 }
545
546 /*
547 * Zone shrinking code cannot properly deal with ZONE_DEVICE. So
548 * we will not try to shrink the zones - which is okay as
549 * set_zone_contiguous() cannot deal with ZONE_DEVICE either way.
550 */
551 if (zone_is_zone_device(zone))
552 return;
553
554 clear_zone_contiguous(zone);
555
556 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
557 update_pgdat_span(pgdat);
558
559 set_zone_contiguous(zone);
560}
561
562/**
563 * __remove_pages() - remove sections of pages
564 * @pfn: starting pageframe (must be aligned to start of a section)
565 * @nr_pages: number of pages to remove (must be multiple of section size)
566 * @altmap: alternative device page map or %NULL if default memmap is used
567 *
568 * Generic helper function to remove section mappings and sysfs entries
569 * for the section of the memory we are removing. Caller needs to make
570 * sure that pages are marked reserved and zones are adjust properly by
571 * calling offline_pages().
572 */
573void __remove_pages(unsigned long pfn, unsigned long nr_pages,
574 struct vmem_altmap *altmap)
575{
576 const unsigned long end_pfn = pfn + nr_pages;
577 unsigned long cur_nr_pages;
578
579 if (check_pfn_span(pfn, nr_pages)) {
580 WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__, pfn, pfn + nr_pages - 1);
581 return;
582 }
583
584 for (; pfn < end_pfn; pfn += cur_nr_pages) {
585 cond_resched();
586 /* Select all remaining pages up to the next section boundary */
587 cur_nr_pages = min(end_pfn - pfn,
588 SECTION_ALIGN_UP(pfn + 1) - pfn);
589 sparse_remove_section(pfn, cur_nr_pages, altmap);
590 }
591}
592
593int set_online_page_callback(online_page_callback_t callback)
594{
595 int rc = -EINVAL;
596
597 get_online_mems();
598 mutex_lock(&online_page_callback_lock);
599
600 if (online_page_callback == generic_online_page) {
601 online_page_callback = callback;
602 rc = 0;
603 }
604
605 mutex_unlock(&online_page_callback_lock);
606 put_online_mems();
607
608 return rc;
609}
610EXPORT_SYMBOL_GPL(set_online_page_callback);
611
612int restore_online_page_callback(online_page_callback_t callback)
613{
614 int rc = -EINVAL;
615
616 get_online_mems();
617 mutex_lock(&online_page_callback_lock);
618
619 if (online_page_callback == callback) {
620 online_page_callback = generic_online_page;
621 rc = 0;
622 }
623
624 mutex_unlock(&online_page_callback_lock);
625 put_online_mems();
626
627 return rc;
628}
629EXPORT_SYMBOL_GPL(restore_online_page_callback);
630
631/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
632void generic_online_page(struct page *page, unsigned int order)
633{
634 __free_pages_core(page, order, MEMINIT_HOTPLUG);
635}
636EXPORT_SYMBOL_GPL(generic_online_page);
637
638static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages)
639{
640 const unsigned long end_pfn = start_pfn + nr_pages;
641 unsigned long pfn;
642
643 /*
644 * Online the pages in MAX_PAGE_ORDER aligned chunks. The callback might
645 * decide to not expose all pages to the buddy (e.g., expose them
646 * later). We account all pages as being online and belonging to this
647 * zone ("present").
648 * When using memmap_on_memory, the range might not be aligned to
649 * MAX_ORDER_NR_PAGES - 1, but pageblock aligned. __ffs() will detect
650 * this and the first chunk to online will be pageblock_nr_pages.
651 */
652 for (pfn = start_pfn; pfn < end_pfn;) {
653 int order;
654
655 /*
656 * Free to online pages in the largest chunks alignment allows.
657 *
658 * __ffs() behaviour is undefined for 0. start == 0 is
659 * MAX_PAGE_ORDER-aligned, Set order to MAX_PAGE_ORDER for
660 * the case.
661 */
662 if (pfn)
663 order = min_t(int, MAX_PAGE_ORDER, __ffs(pfn));
664 else
665 order = MAX_PAGE_ORDER;
666
667 (*online_page_callback)(pfn_to_page(pfn), order);
668 pfn += (1UL << order);
669 }
670
671 /* mark all involved sections as online */
672 online_mem_sections(start_pfn, end_pfn);
673}
674
675/* check which state of node_states will be changed when online memory */
676static void node_states_check_changes_online(unsigned long nr_pages,
677 struct zone *zone, struct memory_notify *arg)
678{
679 int nid = zone_to_nid(zone);
680
681 arg->status_change_nid = NUMA_NO_NODE;
682 arg->status_change_nid_normal = NUMA_NO_NODE;
683
684 if (!node_state(nid, N_MEMORY))
685 arg->status_change_nid = nid;
686 if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY))
687 arg->status_change_nid_normal = nid;
688}
689
690static void node_states_set_node(int node, struct memory_notify *arg)
691{
692 if (arg->status_change_nid_normal >= 0)
693 node_set_state(node, N_NORMAL_MEMORY);
694
695 if (arg->status_change_nid >= 0)
696 node_set_state(node, N_MEMORY);
697}
698
699static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
700 unsigned long nr_pages)
701{
702 unsigned long old_end_pfn = zone_end_pfn(zone);
703
704 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
705 zone->zone_start_pfn = start_pfn;
706
707 zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn;
708}
709
710static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn,
711 unsigned long nr_pages)
712{
713 unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
714
715 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
716 pgdat->node_start_pfn = start_pfn;
717
718 pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn;
719
720}
721
722#ifdef CONFIG_ZONE_DEVICE
723static void section_taint_zone_device(unsigned long pfn)
724{
725 struct mem_section *ms = __pfn_to_section(pfn);
726
727 ms->section_mem_map |= SECTION_TAINT_ZONE_DEVICE;
728}
729#else
730static inline void section_taint_zone_device(unsigned long pfn)
731{
732}
733#endif
734
735/*
736 * Associate the pfn range with the given zone, initializing the memmaps
737 * and resizing the pgdat/zone data to span the added pages. After this
738 * call, all affected pages are PageOffline().
739 *
740 * All aligned pageblocks are initialized to the specified migratetype
741 * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related
742 * zone stats (e.g., nr_isolate_pageblock) are touched.
743 */
744void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
745 unsigned long nr_pages,
746 struct vmem_altmap *altmap, int migratetype)
747{
748 struct pglist_data *pgdat = zone->zone_pgdat;
749 int nid = pgdat->node_id;
750
751 clear_zone_contiguous(zone);
752
753 if (zone_is_empty(zone))
754 init_currently_empty_zone(zone, start_pfn, nr_pages);
755 resize_zone_range(zone, start_pfn, nr_pages);
756 resize_pgdat_range(pgdat, start_pfn, nr_pages);
757
758 /*
759 * Subsection population requires care in pfn_to_online_page().
760 * Set the taint to enable the slow path detection of
761 * ZONE_DEVICE pages in an otherwise ZONE_{NORMAL,MOVABLE}
762 * section.
763 */
764 if (zone_is_zone_device(zone)) {
765 if (!IS_ALIGNED(start_pfn, PAGES_PER_SECTION))
766 section_taint_zone_device(start_pfn);
767 if (!IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION))
768 section_taint_zone_device(start_pfn + nr_pages);
769 }
770
771 /*
772 * TODO now we have a visible range of pages which are not associated
773 * with their zone properly. Not nice but set_pfnblock_flags_mask
774 * expects the zone spans the pfn range. All the pages in the range
775 * are reserved so nobody should be touching them so we should be safe
776 */
777 memmap_init_range(nr_pages, nid, zone_idx(zone), start_pfn, 0,
778 MEMINIT_HOTPLUG, altmap, migratetype);
779
780 set_zone_contiguous(zone);
781}
782
783struct auto_movable_stats {
784 unsigned long kernel_early_pages;
785 unsigned long movable_pages;
786};
787
788static void auto_movable_stats_account_zone(struct auto_movable_stats *stats,
789 struct zone *zone)
790{
791 if (zone_idx(zone) == ZONE_MOVABLE) {
792 stats->movable_pages += zone->present_pages;
793 } else {
794 stats->kernel_early_pages += zone->present_early_pages;
795#ifdef CONFIG_CMA
796 /*
797 * CMA pages (never on hotplugged memory) behave like
798 * ZONE_MOVABLE.
799 */
800 stats->movable_pages += zone->cma_pages;
801 stats->kernel_early_pages -= zone->cma_pages;
802#endif /* CONFIG_CMA */
803 }
804}
805struct auto_movable_group_stats {
806 unsigned long movable_pages;
807 unsigned long req_kernel_early_pages;
808};
809
810static int auto_movable_stats_account_group(struct memory_group *group,
811 void *arg)
812{
813 const int ratio = READ_ONCE(auto_movable_ratio);
814 struct auto_movable_group_stats *stats = arg;
815 long pages;
816
817 /*
818 * We don't support modifying the config while the auto-movable online
819 * policy is already enabled. Just avoid the division by zero below.
820 */
821 if (!ratio)
822 return 0;
823
824 /*
825 * Calculate how many early kernel pages this group requires to
826 * satisfy the configured zone ratio.
827 */
828 pages = group->present_movable_pages * 100 / ratio;
829 pages -= group->present_kernel_pages;
830
831 if (pages > 0)
832 stats->req_kernel_early_pages += pages;
833 stats->movable_pages += group->present_movable_pages;
834 return 0;
835}
836
837static bool auto_movable_can_online_movable(int nid, struct memory_group *group,
838 unsigned long nr_pages)
839{
840 unsigned long kernel_early_pages, movable_pages;
841 struct auto_movable_group_stats group_stats = {};
842 struct auto_movable_stats stats = {};
843 struct zone *zone;
844 int i;
845
846 /* Walk all relevant zones and collect MOVABLE vs. KERNEL stats. */
847 if (nid == NUMA_NO_NODE) {
848 /* TODO: cache values */
849 for_each_populated_zone(zone)
850 auto_movable_stats_account_zone(&stats, zone);
851 } else {
852 for (i = 0; i < MAX_NR_ZONES; i++) {
853 pg_data_t *pgdat = NODE_DATA(nid);
854
855 zone = pgdat->node_zones + i;
856 if (populated_zone(zone))
857 auto_movable_stats_account_zone(&stats, zone);
858 }
859 }
860
861 kernel_early_pages = stats.kernel_early_pages;
862 movable_pages = stats.movable_pages;
863
864 /*
865 * Kernel memory inside dynamic memory group allows for more MOVABLE
866 * memory within the same group. Remove the effect of all but the
867 * current group from the stats.
868 */
869 walk_dynamic_memory_groups(nid, auto_movable_stats_account_group,
870 group, &group_stats);
871 if (kernel_early_pages <= group_stats.req_kernel_early_pages)
872 return false;
873 kernel_early_pages -= group_stats.req_kernel_early_pages;
874 movable_pages -= group_stats.movable_pages;
875
876 if (group && group->is_dynamic)
877 kernel_early_pages += group->present_kernel_pages;
878
879 /*
880 * Test if we could online the given number of pages to ZONE_MOVABLE
881 * and still stay in the configured ratio.
882 */
883 movable_pages += nr_pages;
884 return movable_pages <= (auto_movable_ratio * kernel_early_pages) / 100;
885}
886
887/*
888 * Returns a default kernel memory zone for the given pfn range.
889 * If no kernel zone covers this pfn range it will automatically go
890 * to the ZONE_NORMAL.
891 */
892static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn,
893 unsigned long nr_pages)
894{
895 struct pglist_data *pgdat = NODE_DATA(nid);
896 int zid;
897
898 for (zid = 0; zid < ZONE_NORMAL; zid++) {
899 struct zone *zone = &pgdat->node_zones[zid];
900
901 if (zone_intersects(zone, start_pfn, nr_pages))
902 return zone;
903 }
904
905 return &pgdat->node_zones[ZONE_NORMAL];
906}
907
908/*
909 * Determine to which zone to online memory dynamically based on user
910 * configuration and system stats. We care about the following ratio:
911 *
912 * MOVABLE : KERNEL
913 *
914 * Whereby MOVABLE is memory in ZONE_MOVABLE and KERNEL is memory in
915 * one of the kernel zones. CMA pages inside one of the kernel zones really
916 * behaves like ZONE_MOVABLE, so we treat them accordingly.
917 *
918 * We don't allow for hotplugged memory in a KERNEL zone to increase the
919 * amount of MOVABLE memory we can have, so we end up with:
920 *
921 * MOVABLE : KERNEL_EARLY
922 *
923 * Whereby KERNEL_EARLY is memory in one of the kernel zones, available sinze
924 * boot. We base our calculation on KERNEL_EARLY internally, because:
925 *
926 * a) Hotplugged memory in one of the kernel zones can sometimes still get
927 * hotunplugged, especially when hot(un)plugging individual memory blocks.
928 * There is no coordination across memory devices, therefore "automatic"
929 * hotunplugging, as implemented in hypervisors, could result in zone
930 * imbalances.
931 * b) Early/boot memory in one of the kernel zones can usually not get
932 * hotunplugged again (e.g., no firmware interface to unplug, fragmented
933 * with unmovable allocations). While there are corner cases where it might
934 * still work, it is barely relevant in practice.
935 *
936 * Exceptions are dynamic memory groups, which allow for more MOVABLE
937 * memory within the same memory group -- because in that case, there is
938 * coordination within the single memory device managed by a single driver.
939 *
940 * We rely on "present pages" instead of "managed pages", as the latter is
941 * highly unreliable and dynamic in virtualized environments, and does not
942 * consider boot time allocations. For example, memory ballooning adjusts the
943 * managed pages when inflating/deflating the balloon, and balloon compaction
944 * can even migrate inflated pages between zones.
945 *
946 * Using "present pages" is better but some things to keep in mind are:
947 *
948 * a) Some memblock allocations, such as for the crashkernel area, are
949 * effectively unused by the kernel, yet they account to "present pages".
950 * Fortunately, these allocations are comparatively small in relevant setups
951 * (e.g., fraction of system memory).
952 * b) Some hotplugged memory blocks in virtualized environments, esecially
953 * hotplugged by virtio-mem, look like they are completely present, however,
954 * only parts of the memory block are actually currently usable.
955 * "present pages" is an upper limit that can get reached at runtime. As
956 * we base our calculations on KERNEL_EARLY, this is not an issue.
957 */
958static struct zone *auto_movable_zone_for_pfn(int nid,
959 struct memory_group *group,
960 unsigned long pfn,
961 unsigned long nr_pages)
962{
963 unsigned long online_pages = 0, max_pages, end_pfn;
964 struct page *page;
965
966 if (!auto_movable_ratio)
967 goto kernel_zone;
968
969 if (group && !group->is_dynamic) {
970 max_pages = group->s.max_pages;
971 online_pages = group->present_movable_pages;
972
973 /* If anything is !MOVABLE online the rest !MOVABLE. */
974 if (group->present_kernel_pages)
975 goto kernel_zone;
976 } else if (!group || group->d.unit_pages == nr_pages) {
977 max_pages = nr_pages;
978 } else {
979 max_pages = group->d.unit_pages;
980 /*
981 * Take a look at all online sections in the current unit.
982 * We can safely assume that all pages within a section belong
983 * to the same zone, because dynamic memory groups only deal
984 * with hotplugged memory.
985 */
986 pfn = ALIGN_DOWN(pfn, group->d.unit_pages);
987 end_pfn = pfn + group->d.unit_pages;
988 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
989 page = pfn_to_online_page(pfn);
990 if (!page)
991 continue;
992 /* If anything is !MOVABLE online the rest !MOVABLE. */
993 if (!is_zone_movable_page(page))
994 goto kernel_zone;
995 online_pages += PAGES_PER_SECTION;
996 }
997 }
998
999 /*
1000 * Online MOVABLE if we could *currently* online all remaining parts
1001 * MOVABLE. We expect to (add+) online them immediately next, so if
1002 * nobody interferes, all will be MOVABLE if possible.
1003 */
1004 nr_pages = max_pages - online_pages;
1005 if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages))
1006 goto kernel_zone;
1007
1008#ifdef CONFIG_NUMA
1009 if (auto_movable_numa_aware &&
1010 !auto_movable_can_online_movable(nid, group, nr_pages))
1011 goto kernel_zone;
1012#endif /* CONFIG_NUMA */
1013
1014 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
1015kernel_zone:
1016 return default_kernel_zone_for_pfn(nid, pfn, nr_pages);
1017}
1018
1019static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn,
1020 unsigned long nr_pages)
1021{
1022 struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn,
1023 nr_pages);
1024 struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
1025 bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages);
1026 bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages);
1027
1028 /*
1029 * We inherit the existing zone in a simple case where zones do not
1030 * overlap in the given range
1031 */
1032 if (in_kernel ^ in_movable)
1033 return (in_kernel) ? kernel_zone : movable_zone;
1034
1035 /*
1036 * If the range doesn't belong to any zone or two zones overlap in the
1037 * given range then we use movable zone only if movable_node is
1038 * enabled because we always online to a kernel zone by default.
1039 */
1040 return movable_node_enabled ? movable_zone : kernel_zone;
1041}
1042
1043struct zone *zone_for_pfn_range(int online_type, int nid,
1044 struct memory_group *group, unsigned long start_pfn,
1045 unsigned long nr_pages)
1046{
1047 if (online_type == MMOP_ONLINE_KERNEL)
1048 return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages);
1049
1050 if (online_type == MMOP_ONLINE_MOVABLE)
1051 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
1052
1053 if (online_policy == ONLINE_POLICY_AUTO_MOVABLE)
1054 return auto_movable_zone_for_pfn(nid, group, start_pfn, nr_pages);
1055
1056 return default_zone_for_pfn(nid, start_pfn, nr_pages);
1057}
1058
1059/*
1060 * This function should only be called by memory_block_{online,offline},
1061 * and {online,offline}_pages.
1062 */
1063void adjust_present_page_count(struct page *page, struct memory_group *group,
1064 long nr_pages)
1065{
1066 struct zone *zone = page_zone(page);
1067 const bool movable = zone_idx(zone) == ZONE_MOVABLE;
1068
1069 /*
1070 * We only support onlining/offlining/adding/removing of complete
1071 * memory blocks; therefore, either all is either early or hotplugged.
1072 */
1073 if (early_section(__pfn_to_section(page_to_pfn(page))))
1074 zone->present_early_pages += nr_pages;
1075 zone->present_pages += nr_pages;
1076 zone->zone_pgdat->node_present_pages += nr_pages;
1077
1078 if (group && movable)
1079 group->present_movable_pages += nr_pages;
1080 else if (group && !movable)
1081 group->present_kernel_pages += nr_pages;
1082}
1083
1084int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages,
1085 struct zone *zone, bool mhp_off_inaccessible)
1086{
1087 unsigned long end_pfn = pfn + nr_pages;
1088 int ret, i;
1089
1090 ret = kasan_add_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages));
1091 if (ret)
1092 return ret;
1093
1094 /*
1095 * Memory block is accessible at this stage and hence poison the struct
1096 * pages now. If the memory block is accessible during memory hotplug
1097 * addition phase, then page poisining is already performed in
1098 * sparse_add_section().
1099 */
1100 if (mhp_off_inaccessible)
1101 page_init_poison(pfn_to_page(pfn), sizeof(struct page) * nr_pages);
1102
1103 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_UNMOVABLE);
1104
1105 for (i = 0; i < nr_pages; i++) {
1106 struct page *page = pfn_to_page(pfn + i);
1107
1108 __ClearPageOffline(page);
1109 SetPageVmemmapSelfHosted(page);
1110 }
1111
1112 /*
1113 * It might be that the vmemmap_pages fully span sections. If that is
1114 * the case, mark those sections online here as otherwise they will be
1115 * left offline.
1116 */
1117 if (nr_pages >= PAGES_PER_SECTION)
1118 online_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION));
1119
1120 return ret;
1121}
1122
1123void mhp_deinit_memmap_on_memory(unsigned long pfn, unsigned long nr_pages)
1124{
1125 unsigned long end_pfn = pfn + nr_pages;
1126
1127 /*
1128 * It might be that the vmemmap_pages fully span sections. If that is
1129 * the case, mark those sections offline here as otherwise they will be
1130 * left online.
1131 */
1132 if (nr_pages >= PAGES_PER_SECTION)
1133 offline_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION));
1134
1135 /*
1136 * The pages associated with this vmemmap have been offlined, so
1137 * we can reset its state here.
1138 */
1139 remove_pfn_range_from_zone(page_zone(pfn_to_page(pfn)), pfn, nr_pages);
1140 kasan_remove_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages));
1141}
1142
1143/*
1144 * Must be called with mem_hotplug_lock in write mode.
1145 */
1146int online_pages(unsigned long pfn, unsigned long nr_pages,
1147 struct zone *zone, struct memory_group *group)
1148{
1149 unsigned long flags;
1150 int need_zonelists_rebuild = 0;
1151 const int nid = zone_to_nid(zone);
1152 int ret;
1153 struct memory_notify arg;
1154
1155 /*
1156 * {on,off}lining is constrained to full memory sections (or more
1157 * precisely to memory blocks from the user space POV).
1158 * memmap_on_memory is an exception because it reserves initial part
1159 * of the physical memory space for vmemmaps. That space is pageblock
1160 * aligned.
1161 */
1162 if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(pfn) ||
1163 !IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION)))
1164 return -EINVAL;
1165
1166
1167 /* associate pfn range with the zone */
1168 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_ISOLATE);
1169
1170 arg.start_pfn = pfn;
1171 arg.nr_pages = nr_pages;
1172 node_states_check_changes_online(nr_pages, zone, &arg);
1173
1174 ret = memory_notify(MEM_GOING_ONLINE, &arg);
1175 ret = notifier_to_errno(ret);
1176 if (ret)
1177 goto failed_addition;
1178
1179 /*
1180 * Fixup the number of isolated pageblocks before marking the sections
1181 * onlining, such that undo_isolate_page_range() works correctly.
1182 */
1183 spin_lock_irqsave(&zone->lock, flags);
1184 zone->nr_isolate_pageblock += nr_pages / pageblock_nr_pages;
1185 spin_unlock_irqrestore(&zone->lock, flags);
1186
1187 /*
1188 * If this zone is not populated, then it is not in zonelist.
1189 * This means the page allocator ignores this zone.
1190 * So, zonelist must be updated after online.
1191 */
1192 if (!populated_zone(zone)) {
1193 need_zonelists_rebuild = 1;
1194 setup_zone_pageset(zone);
1195 }
1196
1197 online_pages_range(pfn, nr_pages);
1198 adjust_present_page_count(pfn_to_page(pfn), group, nr_pages);
1199
1200 node_states_set_node(nid, &arg);
1201 if (need_zonelists_rebuild)
1202 build_all_zonelists(NULL);
1203
1204 /* Basic onlining is complete, allow allocation of onlined pages. */
1205 undo_isolate_page_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE);
1206
1207 /*
1208 * Freshly onlined pages aren't shuffled (e.g., all pages are placed to
1209 * the tail of the freelist when undoing isolation). Shuffle the whole
1210 * zone to make sure the just onlined pages are properly distributed
1211 * across the whole freelist - to create an initial shuffle.
1212 */
1213 shuffle_zone(zone);
1214
1215 /* reinitialise watermarks and update pcp limits */
1216 init_per_zone_wmark_min();
1217
1218 kswapd_run(nid);
1219 kcompactd_run(nid);
1220
1221 writeback_set_ratelimit();
1222
1223 memory_notify(MEM_ONLINE, &arg);
1224 return 0;
1225
1226failed_addition:
1227 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
1228 (unsigned long long) pfn << PAGE_SHIFT,
1229 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
1230 memory_notify(MEM_CANCEL_ONLINE, &arg);
1231 remove_pfn_range_from_zone(zone, pfn, nr_pages);
1232 return ret;
1233}
1234
1235/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1236static pg_data_t *hotadd_init_pgdat(int nid)
1237{
1238 struct pglist_data *pgdat;
1239
1240 /*
1241 * NODE_DATA is preallocated (free_area_init) but its internal
1242 * state is not allocated completely. Add missing pieces.
1243 * Completely offline nodes stay around and they just need
1244 * reintialization.
1245 */
1246 pgdat = NODE_DATA(nid);
1247
1248 /* init node's zones as empty zones, we don't have any present pages.*/
1249 free_area_init_core_hotplug(pgdat);
1250
1251 /*
1252 * The node we allocated has no zone fallback lists. For avoiding
1253 * to access not-initialized zonelist, build here.
1254 */
1255 build_all_zonelists(pgdat);
1256
1257 return pgdat;
1258}
1259
1260/*
1261 * __try_online_node - online a node if offlined
1262 * @nid: the node ID
1263 * @set_node_online: Whether we want to online the node
1264 * called by cpu_up() to online a node without onlined memory.
1265 *
1266 * Returns:
1267 * 1 -> a new node has been allocated
1268 * 0 -> the node is already online
1269 * -ENOMEM -> the node could not be allocated
1270 */
1271static int __try_online_node(int nid, bool set_node_online)
1272{
1273 pg_data_t *pgdat;
1274 int ret = 1;
1275
1276 if (node_online(nid))
1277 return 0;
1278
1279 pgdat = hotadd_init_pgdat(nid);
1280 if (!pgdat) {
1281 pr_err("Cannot online node %d due to NULL pgdat\n", nid);
1282 ret = -ENOMEM;
1283 goto out;
1284 }
1285
1286 if (set_node_online) {
1287 node_set_online(nid);
1288 ret = register_one_node(nid);
1289 BUG_ON(ret);
1290 }
1291out:
1292 return ret;
1293}
1294
1295/*
1296 * Users of this function always want to online/register the node
1297 */
1298int try_online_node(int nid)
1299{
1300 int ret;
1301
1302 mem_hotplug_begin();
1303 ret = __try_online_node(nid, true);
1304 mem_hotplug_done();
1305 return ret;
1306}
1307
1308static int check_hotplug_memory_range(u64 start, u64 size)
1309{
1310 /* memory range must be block size aligned */
1311 if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) ||
1312 !IS_ALIGNED(size, memory_block_size_bytes())) {
1313 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
1314 memory_block_size_bytes(), start, size);
1315 return -EINVAL;
1316 }
1317
1318 return 0;
1319}
1320
1321static int online_memory_block(struct memory_block *mem, void *arg)
1322{
1323 mem->online_type = mhp_default_online_type;
1324 return device_online(&mem->dev);
1325}
1326
1327#ifndef arch_supports_memmap_on_memory
1328static inline bool arch_supports_memmap_on_memory(unsigned long vmemmap_size)
1329{
1330 /*
1331 * As default, we want the vmemmap to span a complete PMD such that we
1332 * can map the vmemmap using a single PMD if supported by the
1333 * architecture.
1334 */
1335 return IS_ALIGNED(vmemmap_size, PMD_SIZE);
1336}
1337#endif
1338
1339bool mhp_supports_memmap_on_memory(void)
1340{
1341 unsigned long vmemmap_size = memory_block_memmap_size();
1342 unsigned long memmap_pages = memory_block_memmap_on_memory_pages();
1343
1344 /*
1345 * Besides having arch support and the feature enabled at runtime, we
1346 * need a few more assumptions to hold true:
1347 *
1348 * a) The vmemmap pages span complete PMDs: We don't want vmemmap code
1349 * to populate memory from the altmap for unrelated parts (i.e.,
1350 * other memory blocks)
1351 *
1352 * b) The vmemmap pages (and thereby the pages that will be exposed to
1353 * the buddy) have to cover full pageblocks: memory onlining/offlining
1354 * code requires applicable ranges to be page-aligned, for example, to
1355 * set the migratetypes properly.
1356 *
1357 * TODO: Although we have a check here to make sure that vmemmap pages
1358 * fully populate a PMD, it is not the right place to check for
1359 * this. A much better solution involves improving vmemmap code
1360 * to fallback to base pages when trying to populate vmemmap using
1361 * altmap as an alternative source of memory, and we do not exactly
1362 * populate a single PMD.
1363 */
1364 if (!mhp_memmap_on_memory())
1365 return false;
1366
1367 /*
1368 * Make sure the vmemmap allocation is fully contained
1369 * so that we always allocate vmemmap memory from altmap area.
1370 */
1371 if (!IS_ALIGNED(vmemmap_size, PAGE_SIZE))
1372 return false;
1373
1374 /*
1375 * start pfn should be pageblock_nr_pages aligned for correctly
1376 * setting migrate types
1377 */
1378 if (!pageblock_aligned(memmap_pages))
1379 return false;
1380
1381 if (memmap_pages == PHYS_PFN(memory_block_size_bytes()))
1382 /* No effective hotplugged memory doesn't make sense. */
1383 return false;
1384
1385 return arch_supports_memmap_on_memory(vmemmap_size);
1386}
1387EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory);
1388
1389static void remove_memory_blocks_and_altmaps(u64 start, u64 size)
1390{
1391 unsigned long memblock_size = memory_block_size_bytes();
1392 u64 cur_start;
1393
1394 /*
1395 * For memmap_on_memory, the altmaps were added on a per-memblock
1396 * basis; we have to process each individual memory block.
1397 */
1398 for (cur_start = start; cur_start < start + size;
1399 cur_start += memblock_size) {
1400 struct vmem_altmap *altmap = NULL;
1401 struct memory_block *mem;
1402
1403 mem = find_memory_block(pfn_to_section_nr(PFN_DOWN(cur_start)));
1404 if (WARN_ON_ONCE(!mem))
1405 continue;
1406
1407 altmap = mem->altmap;
1408 mem->altmap = NULL;
1409
1410 remove_memory_block_devices(cur_start, memblock_size);
1411
1412 arch_remove_memory(cur_start, memblock_size, altmap);
1413
1414 /* Verify that all vmemmap pages have actually been freed. */
1415 WARN(altmap->alloc, "Altmap not fully unmapped");
1416 kfree(altmap);
1417 }
1418}
1419
1420static int create_altmaps_and_memory_blocks(int nid, struct memory_group *group,
1421 u64 start, u64 size, mhp_t mhp_flags)
1422{
1423 unsigned long memblock_size = memory_block_size_bytes();
1424 u64 cur_start;
1425 int ret;
1426
1427 for (cur_start = start; cur_start < start + size;
1428 cur_start += memblock_size) {
1429 struct mhp_params params = { .pgprot =
1430 pgprot_mhp(PAGE_KERNEL) };
1431 struct vmem_altmap mhp_altmap = {
1432 .base_pfn = PHYS_PFN(cur_start),
1433 .end_pfn = PHYS_PFN(cur_start + memblock_size - 1),
1434 };
1435
1436 mhp_altmap.free = memory_block_memmap_on_memory_pages();
1437 if (mhp_flags & MHP_OFFLINE_INACCESSIBLE)
1438 mhp_altmap.inaccessible = true;
1439 params.altmap = kmemdup(&mhp_altmap, sizeof(struct vmem_altmap),
1440 GFP_KERNEL);
1441 if (!params.altmap) {
1442 ret = -ENOMEM;
1443 goto out;
1444 }
1445
1446 /* call arch's memory hotadd */
1447 ret = arch_add_memory(nid, cur_start, memblock_size, ¶ms);
1448 if (ret < 0) {
1449 kfree(params.altmap);
1450 goto out;
1451 }
1452
1453 /* create memory block devices after memory was added */
1454 ret = create_memory_block_devices(cur_start, memblock_size,
1455 params.altmap, group);
1456 if (ret) {
1457 arch_remove_memory(cur_start, memblock_size, NULL);
1458 kfree(params.altmap);
1459 goto out;
1460 }
1461 }
1462
1463 return 0;
1464out:
1465 if (ret && cur_start != start)
1466 remove_memory_blocks_and_altmaps(start, cur_start - start);
1467 return ret;
1468}
1469
1470/*
1471 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1472 * and online/offline operations (triggered e.g. by sysfs).
1473 *
1474 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
1475 */
1476int add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
1477{
1478 struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
1479 enum memblock_flags memblock_flags = MEMBLOCK_NONE;
1480 struct memory_group *group = NULL;
1481 u64 start, size;
1482 bool new_node = false;
1483 int ret;
1484
1485 start = res->start;
1486 size = resource_size(res);
1487
1488 ret = check_hotplug_memory_range(start, size);
1489 if (ret)
1490 return ret;
1491
1492 if (mhp_flags & MHP_NID_IS_MGID) {
1493 group = memory_group_find_by_id(nid);
1494 if (!group)
1495 return -EINVAL;
1496 nid = group->nid;
1497 }
1498
1499 if (!node_possible(nid)) {
1500 WARN(1, "node %d was absent from the node_possible_map\n", nid);
1501 return -EINVAL;
1502 }
1503
1504 mem_hotplug_begin();
1505
1506 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
1507 if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
1508 memblock_flags = MEMBLOCK_DRIVER_MANAGED;
1509 ret = memblock_add_node(start, size, nid, memblock_flags);
1510 if (ret)
1511 goto error_mem_hotplug_end;
1512 }
1513
1514 ret = __try_online_node(nid, false);
1515 if (ret < 0)
1516 goto error;
1517 new_node = ret;
1518
1519 /*
1520 * Self hosted memmap array
1521 */
1522 if ((mhp_flags & MHP_MEMMAP_ON_MEMORY) &&
1523 mhp_supports_memmap_on_memory()) {
1524 ret = create_altmaps_and_memory_blocks(nid, group, start, size, mhp_flags);
1525 if (ret)
1526 goto error;
1527 } else {
1528 ret = arch_add_memory(nid, start, size, ¶ms);
1529 if (ret < 0)
1530 goto error;
1531
1532 /* create memory block devices after memory was added */
1533 ret = create_memory_block_devices(start, size, NULL, group);
1534 if (ret) {
1535 arch_remove_memory(start, size, params.altmap);
1536 goto error;
1537 }
1538 }
1539
1540 if (new_node) {
1541 /* If sysfs file of new node can't be created, cpu on the node
1542 * can't be hot-added. There is no rollback way now.
1543 * So, check by BUG_ON() to catch it reluctantly..
1544 * We online node here. We can't roll back from here.
1545 */
1546 node_set_online(nid);
1547 ret = __register_one_node(nid);
1548 BUG_ON(ret);
1549 }
1550
1551 register_memory_blocks_under_node(nid, PFN_DOWN(start),
1552 PFN_UP(start + size - 1),
1553 MEMINIT_HOTPLUG);
1554
1555 /* create new memmap entry */
1556 if (!strcmp(res->name, "System RAM"))
1557 firmware_map_add_hotplug(start, start + size, "System RAM");
1558
1559 /* device_online() will take the lock when calling online_pages() */
1560 mem_hotplug_done();
1561
1562 /*
1563 * In case we're allowed to merge the resource, flag it and trigger
1564 * merging now that adding succeeded.
1565 */
1566 if (mhp_flags & MHP_MERGE_RESOURCE)
1567 merge_system_ram_resource(res);
1568
1569 /* online pages if requested */
1570 if (mhp_default_online_type != MMOP_OFFLINE)
1571 walk_memory_blocks(start, size, NULL, online_memory_block);
1572
1573 return ret;
1574error:
1575 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
1576 memblock_remove(start, size);
1577error_mem_hotplug_end:
1578 mem_hotplug_done();
1579 return ret;
1580}
1581
1582/* requires device_hotplug_lock, see add_memory_resource() */
1583int __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
1584{
1585 struct resource *res;
1586 int ret;
1587
1588 res = register_memory_resource(start, size, "System RAM");
1589 if (IS_ERR(res))
1590 return PTR_ERR(res);
1591
1592 ret = add_memory_resource(nid, res, mhp_flags);
1593 if (ret < 0)
1594 release_memory_resource(res);
1595 return ret;
1596}
1597
1598int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
1599{
1600 int rc;
1601
1602 lock_device_hotplug();
1603 rc = __add_memory(nid, start, size, mhp_flags);
1604 unlock_device_hotplug();
1605
1606 return rc;
1607}
1608EXPORT_SYMBOL_GPL(add_memory);
1609
1610/*
1611 * Add special, driver-managed memory to the system as system RAM. Such
1612 * memory is not exposed via the raw firmware-provided memmap as system
1613 * RAM, instead, it is detected and added by a driver - during cold boot,
1614 * after a reboot, and after kexec.
1615 *
1616 * Reasons why this memory should not be used for the initial memmap of a
1617 * kexec kernel or for placing kexec images:
1618 * - The booting kernel is in charge of determining how this memory will be
1619 * used (e.g., use persistent memory as system RAM)
1620 * - Coordination with a hypervisor is required before this memory
1621 * can be used (e.g., inaccessible parts).
1622 *
1623 * For this memory, no entries in /sys/firmware/memmap ("raw firmware-provided
1624 * memory map") are created. Also, the created memory resource is flagged
1625 * with IORESOURCE_SYSRAM_DRIVER_MANAGED, so in-kernel users can special-case
1626 * this memory as well (esp., not place kexec images onto it).
1627 *
1628 * The resource_name (visible via /proc/iomem) has to have the format
1629 * "System RAM ($DRIVER)".
1630 */
1631int add_memory_driver_managed(int nid, u64 start, u64 size,
1632 const char *resource_name, mhp_t mhp_flags)
1633{
1634 struct resource *res;
1635 int rc;
1636
1637 if (!resource_name ||
1638 strstr(resource_name, "System RAM (") != resource_name ||
1639 resource_name[strlen(resource_name) - 1] != ')')
1640 return -EINVAL;
1641
1642 lock_device_hotplug();
1643
1644 res = register_memory_resource(start, size, resource_name);
1645 if (IS_ERR(res)) {
1646 rc = PTR_ERR(res);
1647 goto out_unlock;
1648 }
1649
1650 rc = add_memory_resource(nid, res, mhp_flags);
1651 if (rc < 0)
1652 release_memory_resource(res);
1653
1654out_unlock:
1655 unlock_device_hotplug();
1656 return rc;
1657}
1658EXPORT_SYMBOL_GPL(add_memory_driver_managed);
1659
1660/*
1661 * Platforms should define arch_get_mappable_range() that provides
1662 * maximum possible addressable physical memory range for which the
1663 * linear mapping could be created. The platform returned address
1664 * range must adhere to these following semantics.
1665 *
1666 * - range.start <= range.end
1667 * - Range includes both end points [range.start..range.end]
1668 *
1669 * There is also a fallback definition provided here, allowing the
1670 * entire possible physical address range in case any platform does
1671 * not define arch_get_mappable_range().
1672 */
1673struct range __weak arch_get_mappable_range(void)
1674{
1675 struct range mhp_range = {
1676 .start = 0UL,
1677 .end = -1ULL,
1678 };
1679 return mhp_range;
1680}
1681
1682struct range mhp_get_pluggable_range(bool need_mapping)
1683{
1684 const u64 max_phys = DIRECT_MAP_PHYSMEM_END;
1685 struct range mhp_range;
1686
1687 if (need_mapping) {
1688 mhp_range = arch_get_mappable_range();
1689 if (mhp_range.start > max_phys) {
1690 mhp_range.start = 0;
1691 mhp_range.end = 0;
1692 }
1693 mhp_range.end = min_t(u64, mhp_range.end, max_phys);
1694 } else {
1695 mhp_range.start = 0;
1696 mhp_range.end = max_phys;
1697 }
1698 return mhp_range;
1699}
1700EXPORT_SYMBOL_GPL(mhp_get_pluggable_range);
1701
1702bool mhp_range_allowed(u64 start, u64 size, bool need_mapping)
1703{
1704 struct range mhp_range = mhp_get_pluggable_range(need_mapping);
1705 u64 end = start + size;
1706
1707 if (start < end && start >= mhp_range.start && (end - 1) <= mhp_range.end)
1708 return true;
1709
1710 pr_warn("Hotplug memory [%#llx-%#llx] exceeds maximum addressable range [%#llx-%#llx]\n",
1711 start, end, mhp_range.start, mhp_range.end);
1712 return false;
1713}
1714
1715#ifdef CONFIG_MEMORY_HOTREMOVE
1716/*
1717 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
1718 * non-lru movable pages and hugepages). Will skip over most unmovable
1719 * pages (esp., pages that can be skipped when offlining), but bail out on
1720 * definitely unmovable pages.
1721 *
1722 * Returns:
1723 * 0 in case a movable page is found and movable_pfn was updated.
1724 * -ENOENT in case no movable page was found.
1725 * -EBUSY in case a definitely unmovable page was found.
1726 */
1727static int scan_movable_pages(unsigned long start, unsigned long end,
1728 unsigned long *movable_pfn)
1729{
1730 unsigned long pfn;
1731
1732 for (pfn = start; pfn < end; pfn++) {
1733 struct page *page;
1734 struct folio *folio;
1735
1736 if (!pfn_valid(pfn))
1737 continue;
1738 page = pfn_to_page(pfn);
1739 if (PageLRU(page))
1740 goto found;
1741 if (__PageMovable(page))
1742 goto found;
1743
1744 /*
1745 * PageOffline() pages that are not marked __PageMovable() and
1746 * have a reference count > 0 (after MEM_GOING_OFFLINE) are
1747 * definitely unmovable. If their reference count would be 0,
1748 * they could at least be skipped when offlining memory.
1749 */
1750 if (PageOffline(page) && page_count(page))
1751 return -EBUSY;
1752
1753 if (!PageHuge(page))
1754 continue;
1755 folio = page_folio(page);
1756 /*
1757 * This test is racy as we hold no reference or lock. The
1758 * hugetlb page could have been free'ed and head is no longer
1759 * a hugetlb page before the following check. In such unlikely
1760 * cases false positives and negatives are possible. Calling
1761 * code must deal with these scenarios.
1762 */
1763 if (folio_test_hugetlb_migratable(folio))
1764 goto found;
1765 pfn |= folio_nr_pages(folio) - 1;
1766 }
1767 return -ENOENT;
1768found:
1769 *movable_pfn = pfn;
1770 return 0;
1771}
1772
1773static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1774{
1775 struct folio *folio;
1776 unsigned long pfn;
1777 LIST_HEAD(source);
1778 static DEFINE_RATELIMIT_STATE(migrate_rs, DEFAULT_RATELIMIT_INTERVAL,
1779 DEFAULT_RATELIMIT_BURST);
1780
1781 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1782 struct page *page;
1783
1784 if (!pfn_valid(pfn))
1785 continue;
1786 page = pfn_to_page(pfn);
1787 folio = page_folio(page);
1788
1789 /*
1790 * No reference or lock is held on the folio, so it might
1791 * be modified concurrently (e.g. split). As such,
1792 * folio_nr_pages() may read garbage. This is fine as the outer
1793 * loop will revisit the split folio later.
1794 */
1795 if (folio_test_large(folio))
1796 pfn = folio_pfn(folio) + folio_nr_pages(folio) - 1;
1797
1798 if (!folio_try_get(folio))
1799 continue;
1800
1801 if (unlikely(page_folio(page) != folio))
1802 goto put_folio;
1803
1804 if (folio_test_hwpoison(folio) ||
1805 (folio_test_large(folio) && folio_test_has_hwpoisoned(folio))) {
1806 if (WARN_ON(folio_test_lru(folio)))
1807 folio_isolate_lru(folio);
1808 if (folio_mapped(folio)) {
1809 folio_lock(folio);
1810 unmap_poisoned_folio(folio, pfn, false);
1811 folio_unlock(folio);
1812 }
1813
1814 goto put_folio;
1815 }
1816
1817 if (!isolate_folio_to_list(folio, &source)) {
1818 if (__ratelimit(&migrate_rs)) {
1819 pr_warn("failed to isolate pfn %lx\n",
1820 page_to_pfn(page));
1821 dump_page(page, "isolation failed");
1822 }
1823 }
1824put_folio:
1825 folio_put(folio);
1826 }
1827 if (!list_empty(&source)) {
1828 nodemask_t nmask = node_states[N_MEMORY];
1829 struct migration_target_control mtc = {
1830 .nmask = &nmask,
1831 .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
1832 .reason = MR_MEMORY_HOTPLUG,
1833 };
1834 int ret;
1835
1836 /*
1837 * We have checked that migration range is on a single zone so
1838 * we can use the nid of the first page to all the others.
1839 */
1840 mtc.nid = folio_nid(list_first_entry(&source, struct folio, lru));
1841
1842 /*
1843 * try to allocate from a different node but reuse this node
1844 * if there are no other online nodes to be used (e.g. we are
1845 * offlining a part of the only existing node)
1846 */
1847 node_clear(mtc.nid, nmask);
1848 if (nodes_empty(nmask))
1849 node_set(mtc.nid, nmask);
1850 ret = migrate_pages(&source, alloc_migration_target, NULL,
1851 (unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG, NULL);
1852 if (ret) {
1853 list_for_each_entry(folio, &source, lru) {
1854 if (__ratelimit(&migrate_rs)) {
1855 pr_warn("migrating pfn %lx failed ret:%d\n",
1856 folio_pfn(folio), ret);
1857 dump_page(&folio->page,
1858 "migration failure");
1859 }
1860 }
1861 putback_movable_pages(&source);
1862 }
1863 }
1864}
1865
1866static int __init cmdline_parse_movable_node(char *p)
1867{
1868 movable_node_enabled = true;
1869 return 0;
1870}
1871early_param("movable_node", cmdline_parse_movable_node);
1872
1873/* check which state of node_states will be changed when offline memory */
1874static void node_states_check_changes_offline(unsigned long nr_pages,
1875 struct zone *zone, struct memory_notify *arg)
1876{
1877 struct pglist_data *pgdat = zone->zone_pgdat;
1878 unsigned long present_pages = 0;
1879 enum zone_type zt;
1880
1881 arg->status_change_nid = NUMA_NO_NODE;
1882 arg->status_change_nid_normal = NUMA_NO_NODE;
1883
1884 /*
1885 * Check whether node_states[N_NORMAL_MEMORY] will be changed.
1886 * If the memory to be offline is within the range
1887 * [0..ZONE_NORMAL], and it is the last present memory there,
1888 * the zones in that range will become empty after the offlining,
1889 * thus we can determine that we need to clear the node from
1890 * node_states[N_NORMAL_MEMORY].
1891 */
1892 for (zt = 0; zt <= ZONE_NORMAL; zt++)
1893 present_pages += pgdat->node_zones[zt].present_pages;
1894 if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages)
1895 arg->status_change_nid_normal = zone_to_nid(zone);
1896
1897 /*
1898 * We have accounted the pages from [0..ZONE_NORMAL); ZONE_HIGHMEM
1899 * does not apply as we don't support 32bit.
1900 * Here we count the possible pages from ZONE_MOVABLE.
1901 * If after having accounted all the pages, we see that the nr_pages
1902 * to be offlined is over or equal to the accounted pages,
1903 * we know that the node will become empty, and so, we can clear
1904 * it for N_MEMORY as well.
1905 */
1906 present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages;
1907
1908 if (nr_pages >= present_pages)
1909 arg->status_change_nid = zone_to_nid(zone);
1910}
1911
1912static void node_states_clear_node(int node, struct memory_notify *arg)
1913{
1914 if (arg->status_change_nid_normal >= 0)
1915 node_clear_state(node, N_NORMAL_MEMORY);
1916
1917 if (arg->status_change_nid >= 0)
1918 node_clear_state(node, N_MEMORY);
1919}
1920
1921static int count_system_ram_pages_cb(unsigned long start_pfn,
1922 unsigned long nr_pages, void *data)
1923{
1924 unsigned long *nr_system_ram_pages = data;
1925
1926 *nr_system_ram_pages += nr_pages;
1927 return 0;
1928}
1929
1930/*
1931 * Must be called with mem_hotplug_lock in write mode.
1932 */
1933int offline_pages(unsigned long start_pfn, unsigned long nr_pages,
1934 struct zone *zone, struct memory_group *group)
1935{
1936 const unsigned long end_pfn = start_pfn + nr_pages;
1937 unsigned long pfn, managed_pages, system_ram_pages = 0;
1938 const int node = zone_to_nid(zone);
1939 unsigned long flags;
1940 struct memory_notify arg;
1941 char *reason;
1942 int ret;
1943
1944 /*
1945 * {on,off}lining is constrained to full memory sections (or more
1946 * precisely to memory blocks from the user space POV).
1947 * memmap_on_memory is an exception because it reserves initial part
1948 * of the physical memory space for vmemmaps. That space is pageblock
1949 * aligned.
1950 */
1951 if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(start_pfn) ||
1952 !IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION)))
1953 return -EINVAL;
1954
1955 /*
1956 * Don't allow to offline memory blocks that contain holes.
1957 * Consequently, memory blocks with holes can never get onlined
1958 * via the hotplug path - online_pages() - as hotplugged memory has
1959 * no holes. This way, we don't have to worry about memory holes,
1960 * don't need pfn_valid() checks, and can avoid using
1961 * walk_system_ram_range() later.
1962 */
1963 walk_system_ram_range(start_pfn, nr_pages, &system_ram_pages,
1964 count_system_ram_pages_cb);
1965 if (system_ram_pages != nr_pages) {
1966 ret = -EINVAL;
1967 reason = "memory holes";
1968 goto failed_removal;
1969 }
1970
1971 /*
1972 * We only support offlining of memory blocks managed by a single zone,
1973 * checked by calling code. This is just a sanity check that we might
1974 * want to remove in the future.
1975 */
1976 if (WARN_ON_ONCE(page_zone(pfn_to_page(start_pfn)) != zone ||
1977 page_zone(pfn_to_page(end_pfn - 1)) != zone)) {
1978 ret = -EINVAL;
1979 reason = "multizone range";
1980 goto failed_removal;
1981 }
1982
1983 /*
1984 * Disable pcplists so that page isolation cannot race with freeing
1985 * in a way that pages from isolated pageblock are left on pcplists.
1986 */
1987 zone_pcp_disable(zone);
1988 lru_cache_disable();
1989
1990 /* set above range as isolated */
1991 ret = start_isolate_page_range(start_pfn, end_pfn,
1992 MIGRATE_MOVABLE,
1993 MEMORY_OFFLINE | REPORT_FAILURE,
1994 GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL);
1995 if (ret) {
1996 reason = "failure to isolate range";
1997 goto failed_removal_pcplists_disabled;
1998 }
1999
2000 arg.start_pfn = start_pfn;
2001 arg.nr_pages = nr_pages;
2002 node_states_check_changes_offline(nr_pages, zone, &arg);
2003
2004 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
2005 ret = notifier_to_errno(ret);
2006 if (ret) {
2007 reason = "notifier failure";
2008 goto failed_removal_isolated;
2009 }
2010
2011 do {
2012 pfn = start_pfn;
2013 do {
2014 /*
2015 * Historically we always checked for any signal and
2016 * can't limit it to fatal signals without eventually
2017 * breaking user space.
2018 */
2019 if (signal_pending(current)) {
2020 ret = -EINTR;
2021 reason = "signal backoff";
2022 goto failed_removal_isolated;
2023 }
2024
2025 cond_resched();
2026
2027 ret = scan_movable_pages(pfn, end_pfn, &pfn);
2028 if (!ret) {
2029 /*
2030 * TODO: fatal migration failures should bail
2031 * out
2032 */
2033 do_migrate_range(pfn, end_pfn);
2034 }
2035 } while (!ret);
2036
2037 if (ret != -ENOENT) {
2038 reason = "unmovable page";
2039 goto failed_removal_isolated;
2040 }
2041
2042 /*
2043 * Dissolve free hugetlb folios in the memory block before doing
2044 * offlining actually in order to make hugetlbfs's object
2045 * counting consistent.
2046 */
2047 ret = dissolve_free_hugetlb_folios(start_pfn, end_pfn);
2048 if (ret) {
2049 reason = "failure to dissolve huge pages";
2050 goto failed_removal_isolated;
2051 }
2052
2053 ret = test_pages_isolated(start_pfn, end_pfn, MEMORY_OFFLINE);
2054
2055 } while (ret);
2056
2057 /* Mark all sections offline and remove free pages from the buddy. */
2058 managed_pages = __offline_isolated_pages(start_pfn, end_pfn);
2059 pr_debug("Offlined Pages %ld\n", nr_pages);
2060
2061 /*
2062 * The memory sections are marked offline, and the pageblock flags
2063 * effectively stale; nobody should be touching them. Fixup the number
2064 * of isolated pageblocks, memory onlining will properly revert this.
2065 */
2066 spin_lock_irqsave(&zone->lock, flags);
2067 zone->nr_isolate_pageblock -= nr_pages / pageblock_nr_pages;
2068 spin_unlock_irqrestore(&zone->lock, flags);
2069
2070 lru_cache_enable();
2071 zone_pcp_enable(zone);
2072
2073 /* removal success */
2074 adjust_managed_page_count(pfn_to_page(start_pfn), -managed_pages);
2075 adjust_present_page_count(pfn_to_page(start_pfn), group, -nr_pages);
2076
2077 /* reinitialise watermarks and update pcp limits */
2078 init_per_zone_wmark_min();
2079
2080 /*
2081 * Make sure to mark the node as memory-less before rebuilding the zone
2082 * list. Otherwise this node would still appear in the fallback lists.
2083 */
2084 node_states_clear_node(node, &arg);
2085 if (!populated_zone(zone)) {
2086 zone_pcp_reset(zone);
2087 build_all_zonelists(NULL);
2088 }
2089
2090 if (arg.status_change_nid >= 0) {
2091 kcompactd_stop(node);
2092 kswapd_stop(node);
2093 }
2094
2095 writeback_set_ratelimit();
2096
2097 memory_notify(MEM_OFFLINE, &arg);
2098 remove_pfn_range_from_zone(zone, start_pfn, nr_pages);
2099 return 0;
2100
2101failed_removal_isolated:
2102 /* pushback to free area */
2103 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
2104 memory_notify(MEM_CANCEL_OFFLINE, &arg);
2105failed_removal_pcplists_disabled:
2106 lru_cache_enable();
2107 zone_pcp_enable(zone);
2108failed_removal:
2109 pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n",
2110 (unsigned long long) start_pfn << PAGE_SHIFT,
2111 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1,
2112 reason);
2113 return ret;
2114}
2115
2116static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
2117{
2118 int *nid = arg;
2119
2120 *nid = mem->nid;
2121 if (unlikely(mem->state != MEM_OFFLINE)) {
2122 phys_addr_t beginpa, endpa;
2123
2124 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
2125 endpa = beginpa + memory_block_size_bytes() - 1;
2126 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
2127 &beginpa, &endpa);
2128
2129 return -EBUSY;
2130 }
2131 return 0;
2132}
2133
2134static int count_memory_range_altmaps_cb(struct memory_block *mem, void *arg)
2135{
2136 u64 *num_altmaps = (u64 *)arg;
2137
2138 if (mem->altmap)
2139 *num_altmaps += 1;
2140
2141 return 0;
2142}
2143
2144static int check_cpu_on_node(int nid)
2145{
2146 int cpu;
2147
2148 for_each_present_cpu(cpu) {
2149 if (cpu_to_node(cpu) == nid)
2150 /*
2151 * the cpu on this node isn't removed, and we can't
2152 * offline this node.
2153 */
2154 return -EBUSY;
2155 }
2156
2157 return 0;
2158}
2159
2160static int check_no_memblock_for_node_cb(struct memory_block *mem, void *arg)
2161{
2162 int nid = *(int *)arg;
2163
2164 /*
2165 * If a memory block belongs to multiple nodes, the stored nid is not
2166 * reliable. However, such blocks are always online (e.g., cannot get
2167 * offlined) and, therefore, are still spanned by the node.
2168 */
2169 return mem->nid == nid ? -EEXIST : 0;
2170}
2171
2172/**
2173 * try_offline_node
2174 * @nid: the node ID
2175 *
2176 * Offline a node if all memory sections and cpus of the node are removed.
2177 *
2178 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2179 * and online/offline operations before this call.
2180 */
2181void try_offline_node(int nid)
2182{
2183 int rc;
2184
2185 /*
2186 * If the node still spans pages (especially ZONE_DEVICE), don't
2187 * offline it. A node spans memory after move_pfn_range_to_zone(),
2188 * e.g., after the memory block was onlined.
2189 */
2190 if (node_spanned_pages(nid))
2191 return;
2192
2193 /*
2194 * Especially offline memory blocks might not be spanned by the
2195 * node. They will get spanned by the node once they get onlined.
2196 * However, they link to the node in sysfs and can get onlined later.
2197 */
2198 rc = for_each_memory_block(&nid, check_no_memblock_for_node_cb);
2199 if (rc)
2200 return;
2201
2202 if (check_cpu_on_node(nid))
2203 return;
2204
2205 /*
2206 * all memory/cpu of this node are removed, we can offline this
2207 * node now.
2208 */
2209 node_set_offline(nid);
2210 unregister_one_node(nid);
2211}
2212EXPORT_SYMBOL(try_offline_node);
2213
2214static int memory_blocks_have_altmaps(u64 start, u64 size)
2215{
2216 u64 num_memblocks = size / memory_block_size_bytes();
2217 u64 num_altmaps = 0;
2218
2219 if (!mhp_memmap_on_memory())
2220 return 0;
2221
2222 walk_memory_blocks(start, size, &num_altmaps,
2223 count_memory_range_altmaps_cb);
2224
2225 if (num_altmaps == 0)
2226 return 0;
2227
2228 if (WARN_ON_ONCE(num_memblocks != num_altmaps))
2229 return -EINVAL;
2230
2231 return 1;
2232}
2233
2234static int try_remove_memory(u64 start, u64 size)
2235{
2236 int rc, nid = NUMA_NO_NODE;
2237
2238 BUG_ON(check_hotplug_memory_range(start, size));
2239
2240 /*
2241 * All memory blocks must be offlined before removing memory. Check
2242 * whether all memory blocks in question are offline and return error
2243 * if this is not the case.
2244 *
2245 * While at it, determine the nid. Note that if we'd have mixed nodes,
2246 * we'd only try to offline the last determined one -- which is good
2247 * enough for the cases we care about.
2248 */
2249 rc = walk_memory_blocks(start, size, &nid, check_memblock_offlined_cb);
2250 if (rc)
2251 return rc;
2252
2253 /* remove memmap entry */
2254 firmware_map_remove(start, start + size, "System RAM");
2255
2256 mem_hotplug_begin();
2257
2258 rc = memory_blocks_have_altmaps(start, size);
2259 if (rc < 0) {
2260 mem_hotplug_done();
2261 return rc;
2262 } else if (!rc) {
2263 /*
2264 * Memory block device removal under the device_hotplug_lock is
2265 * a barrier against racing online attempts.
2266 * No altmaps present, do the removal directly
2267 */
2268 remove_memory_block_devices(start, size);
2269 arch_remove_memory(start, size, NULL);
2270 } else {
2271 /* all memblocks in the range have altmaps */
2272 remove_memory_blocks_and_altmaps(start, size);
2273 }
2274
2275 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
2276 memblock_remove(start, size);
2277
2278 release_mem_region_adjustable(start, size);
2279
2280 if (nid != NUMA_NO_NODE)
2281 try_offline_node(nid);
2282
2283 mem_hotplug_done();
2284 return 0;
2285}
2286
2287/**
2288 * __remove_memory - Remove memory if every memory block is offline
2289 * @start: physical address of the region to remove
2290 * @size: size of the region to remove
2291 *
2292 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2293 * and online/offline operations before this call, as required by
2294 * try_offline_node().
2295 */
2296void __remove_memory(u64 start, u64 size)
2297{
2298
2299 /*
2300 * trigger BUG() if some memory is not offlined prior to calling this
2301 * function
2302 */
2303 if (try_remove_memory(start, size))
2304 BUG();
2305}
2306
2307/*
2308 * Remove memory if every memory block is offline, otherwise return -EBUSY is
2309 * some memory is not offline
2310 */
2311int remove_memory(u64 start, u64 size)
2312{
2313 int rc;
2314
2315 lock_device_hotplug();
2316 rc = try_remove_memory(start, size);
2317 unlock_device_hotplug();
2318
2319 return rc;
2320}
2321EXPORT_SYMBOL_GPL(remove_memory);
2322
2323static int try_offline_memory_block(struct memory_block *mem, void *arg)
2324{
2325 uint8_t online_type = MMOP_ONLINE_KERNEL;
2326 uint8_t **online_types = arg;
2327 struct page *page;
2328 int rc;
2329
2330 /*
2331 * Sense the online_type via the zone of the memory block. Offlining
2332 * with multiple zones within one memory block will be rejected
2333 * by offlining code ... so we don't care about that.
2334 */
2335 page = pfn_to_online_page(section_nr_to_pfn(mem->start_section_nr));
2336 if (page && zone_idx(page_zone(page)) == ZONE_MOVABLE)
2337 online_type = MMOP_ONLINE_MOVABLE;
2338
2339 rc = device_offline(&mem->dev);
2340 /*
2341 * Default is MMOP_OFFLINE - change it only if offlining succeeded,
2342 * so try_reonline_memory_block() can do the right thing.
2343 */
2344 if (!rc)
2345 **online_types = online_type;
2346
2347 (*online_types)++;
2348 /* Ignore if already offline. */
2349 return rc < 0 ? rc : 0;
2350}
2351
2352static int try_reonline_memory_block(struct memory_block *mem, void *arg)
2353{
2354 uint8_t **online_types = arg;
2355 int rc;
2356
2357 if (**online_types != MMOP_OFFLINE) {
2358 mem->online_type = **online_types;
2359 rc = device_online(&mem->dev);
2360 if (rc < 0)
2361 pr_warn("%s: Failed to re-online memory: %d",
2362 __func__, rc);
2363 }
2364
2365 /* Continue processing all remaining memory blocks. */
2366 (*online_types)++;
2367 return 0;
2368}
2369
2370/*
2371 * Try to offline and remove memory. Might take a long time to finish in case
2372 * memory is still in use. Primarily useful for memory devices that logically
2373 * unplugged all memory (so it's no longer in use) and want to offline + remove
2374 * that memory.
2375 */
2376int offline_and_remove_memory(u64 start, u64 size)
2377{
2378 const unsigned long mb_count = size / memory_block_size_bytes();
2379 uint8_t *online_types, *tmp;
2380 int rc;
2381
2382 if (!IS_ALIGNED(start, memory_block_size_bytes()) ||
2383 !IS_ALIGNED(size, memory_block_size_bytes()) || !size)
2384 return -EINVAL;
2385
2386 /*
2387 * We'll remember the old online type of each memory block, so we can
2388 * try to revert whatever we did when offlining one memory block fails
2389 * after offlining some others succeeded.
2390 */
2391 online_types = kmalloc_array(mb_count, sizeof(*online_types),
2392 GFP_KERNEL);
2393 if (!online_types)
2394 return -ENOMEM;
2395 /*
2396 * Initialize all states to MMOP_OFFLINE, so when we abort processing in
2397 * try_offline_memory_block(), we'll skip all unprocessed blocks in
2398 * try_reonline_memory_block().
2399 */
2400 memset(online_types, MMOP_OFFLINE, mb_count);
2401
2402 lock_device_hotplug();
2403
2404 tmp = online_types;
2405 rc = walk_memory_blocks(start, size, &tmp, try_offline_memory_block);
2406
2407 /*
2408 * In case we succeeded to offline all memory, remove it.
2409 * This cannot fail as it cannot get onlined in the meantime.
2410 */
2411 if (!rc) {
2412 rc = try_remove_memory(start, size);
2413 if (rc)
2414 pr_err("%s: Failed to remove memory: %d", __func__, rc);
2415 }
2416
2417 /*
2418 * Rollback what we did. While memory onlining might theoretically fail
2419 * (nacked by a notifier), it barely ever happens.
2420 */
2421 if (rc) {
2422 tmp = online_types;
2423 walk_memory_blocks(start, size, &tmp,
2424 try_reonline_memory_block);
2425 }
2426 unlock_device_hotplug();
2427
2428 kfree(online_types);
2429 return rc;
2430}
2431EXPORT_SYMBOL_GPL(offline_and_remove_memory);
2432#endif /* CONFIG_MEMORY_HOTREMOVE */