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1/*
2 * linux/mm/memory_hotplug.c
3 *
4 * Copyright (C)
5 */
6
7#include <linux/stddef.h>
8#include <linux/mm.h>
9#include <linux/swap.h>
10#include <linux/interrupt.h>
11#include <linux/pagemap.h>
12#include <linux/compiler.h>
13#include <linux/export.h>
14#include <linux/pagevec.h>
15#include <linux/writeback.h>
16#include <linux/slab.h>
17#include <linux/sysctl.h>
18#include <linux/cpu.h>
19#include <linux/memory.h>
20#include <linux/memory_hotplug.h>
21#include <linux/highmem.h>
22#include <linux/vmalloc.h>
23#include <linux/ioport.h>
24#include <linux/delay.h>
25#include <linux/migrate.h>
26#include <linux/page-isolation.h>
27#include <linux/pfn.h>
28#include <linux/suspend.h>
29#include <linux/mm_inline.h>
30#include <linux/firmware-map.h>
31#include <linux/stop_machine.h>
32#include <linux/hugetlb.h>
33#include <linux/memblock.h>
34
35#include <asm/tlbflush.h>
36
37#include "internal.h"
38
39/*
40 * online_page_callback contains pointer to current page onlining function.
41 * Initially it is generic_online_page(). If it is required it could be
42 * changed by calling set_online_page_callback() for callback registration
43 * and restore_online_page_callback() for generic callback restore.
44 */
45
46static void generic_online_page(struct page *page);
47
48static online_page_callback_t online_page_callback = generic_online_page;
49
50DEFINE_MUTEX(mem_hotplug_mutex);
51
52void lock_memory_hotplug(void)
53{
54 mutex_lock(&mem_hotplug_mutex);
55}
56
57void unlock_memory_hotplug(void)
58{
59 mutex_unlock(&mem_hotplug_mutex);
60}
61
62
63/* add this memory to iomem resource */
64static struct resource *register_memory_resource(u64 start, u64 size)
65{
66 struct resource *res;
67 res = kzalloc(sizeof(struct resource), GFP_KERNEL);
68 BUG_ON(!res);
69
70 res->name = "System RAM";
71 res->start = start;
72 res->end = start + size - 1;
73 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
74 if (request_resource(&iomem_resource, res) < 0) {
75 pr_debug("System RAM resource %pR cannot be added\n", res);
76 kfree(res);
77 res = NULL;
78 }
79 return res;
80}
81
82static void release_memory_resource(struct resource *res)
83{
84 if (!res)
85 return;
86 release_resource(res);
87 kfree(res);
88 return;
89}
90
91#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
92void get_page_bootmem(unsigned long info, struct page *page,
93 unsigned long type)
94{
95 page->lru.next = (struct list_head *) type;
96 SetPagePrivate(page);
97 set_page_private(page, info);
98 atomic_inc(&page->_count);
99}
100
101void put_page_bootmem(struct page *page)
102{
103 unsigned long type;
104
105 type = (unsigned long) page->lru.next;
106 BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
107 type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
108
109 if (atomic_dec_return(&page->_count) == 1) {
110 ClearPagePrivate(page);
111 set_page_private(page, 0);
112 INIT_LIST_HEAD(&page->lru);
113 free_reserved_page(page);
114 }
115}
116
117#ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
118#ifndef CONFIG_SPARSEMEM_VMEMMAP
119static void register_page_bootmem_info_section(unsigned long start_pfn)
120{
121 unsigned long *usemap, mapsize, section_nr, i;
122 struct mem_section *ms;
123 struct page *page, *memmap;
124
125 section_nr = pfn_to_section_nr(start_pfn);
126 ms = __nr_to_section(section_nr);
127
128 /* Get section's memmap address */
129 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
130
131 /*
132 * Get page for the memmap's phys address
133 * XXX: need more consideration for sparse_vmemmap...
134 */
135 page = virt_to_page(memmap);
136 mapsize = sizeof(struct page) * PAGES_PER_SECTION;
137 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
138
139 /* remember memmap's page */
140 for (i = 0; i < mapsize; i++, page++)
141 get_page_bootmem(section_nr, page, SECTION_INFO);
142
143 usemap = __nr_to_section(section_nr)->pageblock_flags;
144 page = virt_to_page(usemap);
145
146 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
147
148 for (i = 0; i < mapsize; i++, page++)
149 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
150
151}
152#else /* CONFIG_SPARSEMEM_VMEMMAP */
153static void register_page_bootmem_info_section(unsigned long start_pfn)
154{
155 unsigned long *usemap, mapsize, section_nr, i;
156 struct mem_section *ms;
157 struct page *page, *memmap;
158
159 if (!pfn_valid(start_pfn))
160 return;
161
162 section_nr = pfn_to_section_nr(start_pfn);
163 ms = __nr_to_section(section_nr);
164
165 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
166
167 register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
168
169 usemap = __nr_to_section(section_nr)->pageblock_flags;
170 page = virt_to_page(usemap);
171
172 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
173
174 for (i = 0; i < mapsize; i++, page++)
175 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
176}
177#endif /* !CONFIG_SPARSEMEM_VMEMMAP */
178
179void register_page_bootmem_info_node(struct pglist_data *pgdat)
180{
181 unsigned long i, pfn, end_pfn, nr_pages;
182 int node = pgdat->node_id;
183 struct page *page;
184 struct zone *zone;
185
186 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
187 page = virt_to_page(pgdat);
188
189 for (i = 0; i < nr_pages; i++, page++)
190 get_page_bootmem(node, page, NODE_INFO);
191
192 zone = &pgdat->node_zones[0];
193 for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
194 if (zone_is_initialized(zone)) {
195 nr_pages = zone->wait_table_hash_nr_entries
196 * sizeof(wait_queue_head_t);
197 nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
198 page = virt_to_page(zone->wait_table);
199
200 for (i = 0; i < nr_pages; i++, page++)
201 get_page_bootmem(node, page, NODE_INFO);
202 }
203 }
204
205 pfn = pgdat->node_start_pfn;
206 end_pfn = pgdat_end_pfn(pgdat);
207
208 /* register section info */
209 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
210 /*
211 * Some platforms can assign the same pfn to multiple nodes - on
212 * node0 as well as nodeN. To avoid registering a pfn against
213 * multiple nodes we check that this pfn does not already
214 * reside in some other nodes.
215 */
216 if (pfn_valid(pfn) && (pfn_to_nid(pfn) == node))
217 register_page_bootmem_info_section(pfn);
218 }
219}
220#endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
221
222static void grow_zone_span(struct zone *zone, unsigned long start_pfn,
223 unsigned long end_pfn)
224{
225 unsigned long old_zone_end_pfn;
226
227 zone_span_writelock(zone);
228
229 old_zone_end_pfn = zone_end_pfn(zone);
230 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
231 zone->zone_start_pfn = start_pfn;
232
233 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
234 zone->zone_start_pfn;
235
236 zone_span_writeunlock(zone);
237}
238
239static void resize_zone(struct zone *zone, unsigned long start_pfn,
240 unsigned long end_pfn)
241{
242 zone_span_writelock(zone);
243
244 if (end_pfn - start_pfn) {
245 zone->zone_start_pfn = start_pfn;
246 zone->spanned_pages = end_pfn - start_pfn;
247 } else {
248 /*
249 * make it consist as free_area_init_core(),
250 * if spanned_pages = 0, then keep start_pfn = 0
251 */
252 zone->zone_start_pfn = 0;
253 zone->spanned_pages = 0;
254 }
255
256 zone_span_writeunlock(zone);
257}
258
259static void fix_zone_id(struct zone *zone, unsigned long start_pfn,
260 unsigned long end_pfn)
261{
262 enum zone_type zid = zone_idx(zone);
263 int nid = zone->zone_pgdat->node_id;
264 unsigned long pfn;
265
266 for (pfn = start_pfn; pfn < end_pfn; pfn++)
267 set_page_links(pfn_to_page(pfn), zid, nid, pfn);
268}
269
270/* Can fail with -ENOMEM from allocating a wait table with vmalloc() or
271 * alloc_bootmem_node_nopanic()/memblock_virt_alloc_node_nopanic() */
272static int __ref ensure_zone_is_initialized(struct zone *zone,
273 unsigned long start_pfn, unsigned long num_pages)
274{
275 if (!zone_is_initialized(zone))
276 return init_currently_empty_zone(zone, start_pfn, num_pages,
277 MEMMAP_HOTPLUG);
278 return 0;
279}
280
281static int __meminit move_pfn_range_left(struct zone *z1, struct zone *z2,
282 unsigned long start_pfn, unsigned long end_pfn)
283{
284 int ret;
285 unsigned long flags;
286 unsigned long z1_start_pfn;
287
288 ret = ensure_zone_is_initialized(z1, start_pfn, end_pfn - start_pfn);
289 if (ret)
290 return ret;
291
292 pgdat_resize_lock(z1->zone_pgdat, &flags);
293
294 /* can't move pfns which are higher than @z2 */
295 if (end_pfn > zone_end_pfn(z2))
296 goto out_fail;
297 /* the move out part must be at the left most of @z2 */
298 if (start_pfn > z2->zone_start_pfn)
299 goto out_fail;
300 /* must included/overlap */
301 if (end_pfn <= z2->zone_start_pfn)
302 goto out_fail;
303
304 /* use start_pfn for z1's start_pfn if z1 is empty */
305 if (!zone_is_empty(z1))
306 z1_start_pfn = z1->zone_start_pfn;
307 else
308 z1_start_pfn = start_pfn;
309
310 resize_zone(z1, z1_start_pfn, end_pfn);
311 resize_zone(z2, end_pfn, zone_end_pfn(z2));
312
313 pgdat_resize_unlock(z1->zone_pgdat, &flags);
314
315 fix_zone_id(z1, start_pfn, end_pfn);
316
317 return 0;
318out_fail:
319 pgdat_resize_unlock(z1->zone_pgdat, &flags);
320 return -1;
321}
322
323static int __meminit move_pfn_range_right(struct zone *z1, struct zone *z2,
324 unsigned long start_pfn, unsigned long end_pfn)
325{
326 int ret;
327 unsigned long flags;
328 unsigned long z2_end_pfn;
329
330 ret = ensure_zone_is_initialized(z2, start_pfn, end_pfn - start_pfn);
331 if (ret)
332 return ret;
333
334 pgdat_resize_lock(z1->zone_pgdat, &flags);
335
336 /* can't move pfns which are lower than @z1 */
337 if (z1->zone_start_pfn > start_pfn)
338 goto out_fail;
339 /* the move out part mast at the right most of @z1 */
340 if (zone_end_pfn(z1) > end_pfn)
341 goto out_fail;
342 /* must included/overlap */
343 if (start_pfn >= zone_end_pfn(z1))
344 goto out_fail;
345
346 /* use end_pfn for z2's end_pfn if z2 is empty */
347 if (!zone_is_empty(z2))
348 z2_end_pfn = zone_end_pfn(z2);
349 else
350 z2_end_pfn = end_pfn;
351
352 resize_zone(z1, z1->zone_start_pfn, start_pfn);
353 resize_zone(z2, start_pfn, z2_end_pfn);
354
355 pgdat_resize_unlock(z1->zone_pgdat, &flags);
356
357 fix_zone_id(z2, start_pfn, end_pfn);
358
359 return 0;
360out_fail:
361 pgdat_resize_unlock(z1->zone_pgdat, &flags);
362 return -1;
363}
364
365static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
366 unsigned long end_pfn)
367{
368 unsigned long old_pgdat_end_pfn = pgdat_end_pfn(pgdat);
369
370 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
371 pgdat->node_start_pfn = start_pfn;
372
373 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
374 pgdat->node_start_pfn;
375}
376
377static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
378{
379 struct pglist_data *pgdat = zone->zone_pgdat;
380 int nr_pages = PAGES_PER_SECTION;
381 int nid = pgdat->node_id;
382 int zone_type;
383 unsigned long flags;
384 int ret;
385
386 zone_type = zone - pgdat->node_zones;
387 ret = ensure_zone_is_initialized(zone, phys_start_pfn, nr_pages);
388 if (ret)
389 return ret;
390
391 pgdat_resize_lock(zone->zone_pgdat, &flags);
392 grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
393 grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
394 phys_start_pfn + nr_pages);
395 pgdat_resize_unlock(zone->zone_pgdat, &flags);
396 memmap_init_zone(nr_pages, nid, zone_type,
397 phys_start_pfn, MEMMAP_HOTPLUG);
398 return 0;
399}
400
401static int __meminit __add_section(int nid, struct zone *zone,
402 unsigned long phys_start_pfn)
403{
404 int ret;
405
406 if (pfn_valid(phys_start_pfn))
407 return -EEXIST;
408
409 ret = sparse_add_one_section(zone, phys_start_pfn);
410
411 if (ret < 0)
412 return ret;
413
414 ret = __add_zone(zone, phys_start_pfn);
415
416 if (ret < 0)
417 return ret;
418
419 return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
420}
421
422/*
423 * Reasonably generic function for adding memory. It is
424 * expected that archs that support memory hotplug will
425 * call this function after deciding the zone to which to
426 * add the new pages.
427 */
428int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
429 unsigned long nr_pages)
430{
431 unsigned long i;
432 int err = 0;
433 int start_sec, end_sec;
434 /* during initialize mem_map, align hot-added range to section */
435 start_sec = pfn_to_section_nr(phys_start_pfn);
436 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
437
438 for (i = start_sec; i <= end_sec; i++) {
439 err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);
440
441 /*
442 * EEXIST is finally dealt with by ioresource collision
443 * check. see add_memory() => register_memory_resource()
444 * Warning will be printed if there is collision.
445 */
446 if (err && (err != -EEXIST))
447 break;
448 err = 0;
449 }
450
451 return err;
452}
453EXPORT_SYMBOL_GPL(__add_pages);
454
455#ifdef CONFIG_MEMORY_HOTREMOVE
456/* find the smallest valid pfn in the range [start_pfn, end_pfn) */
457static int find_smallest_section_pfn(int nid, struct zone *zone,
458 unsigned long start_pfn,
459 unsigned long end_pfn)
460{
461 struct mem_section *ms;
462
463 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) {
464 ms = __pfn_to_section(start_pfn);
465
466 if (unlikely(!valid_section(ms)))
467 continue;
468
469 if (unlikely(pfn_to_nid(start_pfn) != nid))
470 continue;
471
472 if (zone && zone != page_zone(pfn_to_page(start_pfn)))
473 continue;
474
475 return start_pfn;
476 }
477
478 return 0;
479}
480
481/* find the biggest valid pfn in the range [start_pfn, end_pfn). */
482static int find_biggest_section_pfn(int nid, struct zone *zone,
483 unsigned long start_pfn,
484 unsigned long end_pfn)
485{
486 struct mem_section *ms;
487 unsigned long pfn;
488
489 /* pfn is the end pfn of a memory section. */
490 pfn = end_pfn - 1;
491 for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) {
492 ms = __pfn_to_section(pfn);
493
494 if (unlikely(!valid_section(ms)))
495 continue;
496
497 if (unlikely(pfn_to_nid(pfn) != nid))
498 continue;
499
500 if (zone && zone != page_zone(pfn_to_page(pfn)))
501 continue;
502
503 return pfn;
504 }
505
506 return 0;
507}
508
509static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
510 unsigned long end_pfn)
511{
512 unsigned long zone_start_pfn = zone->zone_start_pfn;
513 unsigned long z = zone_end_pfn(zone); /* zone_end_pfn namespace clash */
514 unsigned long zone_end_pfn = z;
515 unsigned long pfn;
516 struct mem_section *ms;
517 int nid = zone_to_nid(zone);
518
519 zone_span_writelock(zone);
520 if (zone_start_pfn == start_pfn) {
521 /*
522 * If the section is smallest section in the zone, it need
523 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
524 * In this case, we find second smallest valid mem_section
525 * for shrinking zone.
526 */
527 pfn = find_smallest_section_pfn(nid, zone, end_pfn,
528 zone_end_pfn);
529 if (pfn) {
530 zone->zone_start_pfn = pfn;
531 zone->spanned_pages = zone_end_pfn - pfn;
532 }
533 } else if (zone_end_pfn == end_pfn) {
534 /*
535 * If the section is biggest section in the zone, it need
536 * shrink zone->spanned_pages.
537 * In this case, we find second biggest valid mem_section for
538 * shrinking zone.
539 */
540 pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
541 start_pfn);
542 if (pfn)
543 zone->spanned_pages = pfn - zone_start_pfn + 1;
544 }
545
546 /*
547 * The section is not biggest or smallest mem_section in the zone, it
548 * only creates a hole in the zone. So in this case, we need not
549 * change the zone. But perhaps, the zone has only hole data. Thus
550 * it check the zone has only hole or not.
551 */
552 pfn = zone_start_pfn;
553 for (; pfn < zone_end_pfn; pfn += PAGES_PER_SECTION) {
554 ms = __pfn_to_section(pfn);
555
556 if (unlikely(!valid_section(ms)))
557 continue;
558
559 if (page_zone(pfn_to_page(pfn)) != zone)
560 continue;
561
562 /* If the section is current section, it continues the loop */
563 if (start_pfn == pfn)
564 continue;
565
566 /* If we find valid section, we have nothing to do */
567 zone_span_writeunlock(zone);
568 return;
569 }
570
571 /* The zone has no valid section */
572 zone->zone_start_pfn = 0;
573 zone->spanned_pages = 0;
574 zone_span_writeunlock(zone);
575}
576
577static void shrink_pgdat_span(struct pglist_data *pgdat,
578 unsigned long start_pfn, unsigned long end_pfn)
579{
580 unsigned long pgdat_start_pfn = pgdat->node_start_pfn;
581 unsigned long p = pgdat_end_pfn(pgdat); /* pgdat_end_pfn namespace clash */
582 unsigned long pgdat_end_pfn = p;
583 unsigned long pfn;
584 struct mem_section *ms;
585 int nid = pgdat->node_id;
586
587 if (pgdat_start_pfn == start_pfn) {
588 /*
589 * If the section is smallest section in the pgdat, it need
590 * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages.
591 * In this case, we find second smallest valid mem_section
592 * for shrinking zone.
593 */
594 pfn = find_smallest_section_pfn(nid, NULL, end_pfn,
595 pgdat_end_pfn);
596 if (pfn) {
597 pgdat->node_start_pfn = pfn;
598 pgdat->node_spanned_pages = pgdat_end_pfn - pfn;
599 }
600 } else if (pgdat_end_pfn == end_pfn) {
601 /*
602 * If the section is biggest section in the pgdat, it need
603 * shrink pgdat->node_spanned_pages.
604 * In this case, we find second biggest valid mem_section for
605 * shrinking zone.
606 */
607 pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn,
608 start_pfn);
609 if (pfn)
610 pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1;
611 }
612
613 /*
614 * If the section is not biggest or smallest mem_section in the pgdat,
615 * it only creates a hole in the pgdat. So in this case, we need not
616 * change the pgdat.
617 * But perhaps, the pgdat has only hole data. Thus it check the pgdat
618 * has only hole or not.
619 */
620 pfn = pgdat_start_pfn;
621 for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) {
622 ms = __pfn_to_section(pfn);
623
624 if (unlikely(!valid_section(ms)))
625 continue;
626
627 if (pfn_to_nid(pfn) != nid)
628 continue;
629
630 /* If the section is current section, it continues the loop */
631 if (start_pfn == pfn)
632 continue;
633
634 /* If we find valid section, we have nothing to do */
635 return;
636 }
637
638 /* The pgdat has no valid section */
639 pgdat->node_start_pfn = 0;
640 pgdat->node_spanned_pages = 0;
641}
642
643static void __remove_zone(struct zone *zone, unsigned long start_pfn)
644{
645 struct pglist_data *pgdat = zone->zone_pgdat;
646 int nr_pages = PAGES_PER_SECTION;
647 int zone_type;
648 unsigned long flags;
649
650 zone_type = zone - pgdat->node_zones;
651
652 pgdat_resize_lock(zone->zone_pgdat, &flags);
653 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
654 shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages);
655 pgdat_resize_unlock(zone->zone_pgdat, &flags);
656}
657
658static int __remove_section(struct zone *zone, struct mem_section *ms)
659{
660 unsigned long start_pfn;
661 int scn_nr;
662 int ret = -EINVAL;
663
664 if (!valid_section(ms))
665 return ret;
666
667 ret = unregister_memory_section(ms);
668 if (ret)
669 return ret;
670
671 scn_nr = __section_nr(ms);
672 start_pfn = section_nr_to_pfn(scn_nr);
673 __remove_zone(zone, start_pfn);
674
675 sparse_remove_one_section(zone, ms);
676 return 0;
677}
678
679/**
680 * __remove_pages() - remove sections of pages from a zone
681 * @zone: zone from which pages need to be removed
682 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
683 * @nr_pages: number of pages to remove (must be multiple of section size)
684 *
685 * Generic helper function to remove section mappings and sysfs entries
686 * for the section of the memory we are removing. Caller needs to make
687 * sure that pages are marked reserved and zones are adjust properly by
688 * calling offline_pages().
689 */
690int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
691 unsigned long nr_pages)
692{
693 unsigned long i;
694 int sections_to_remove;
695 resource_size_t start, size;
696 int ret = 0;
697
698 /*
699 * We can only remove entire sections
700 */
701 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
702 BUG_ON(nr_pages % PAGES_PER_SECTION);
703
704 start = phys_start_pfn << PAGE_SHIFT;
705 size = nr_pages * PAGE_SIZE;
706 ret = release_mem_region_adjustable(&iomem_resource, start, size);
707 if (ret) {
708 resource_size_t endres = start + size - 1;
709
710 pr_warn("Unable to release resource <%pa-%pa> (%d)\n",
711 &start, &endres, ret);
712 }
713
714 sections_to_remove = nr_pages / PAGES_PER_SECTION;
715 for (i = 0; i < sections_to_remove; i++) {
716 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
717 ret = __remove_section(zone, __pfn_to_section(pfn));
718 if (ret)
719 break;
720 }
721 return ret;
722}
723EXPORT_SYMBOL_GPL(__remove_pages);
724#endif /* CONFIG_MEMORY_HOTREMOVE */
725
726int set_online_page_callback(online_page_callback_t callback)
727{
728 int rc = -EINVAL;
729
730 lock_memory_hotplug();
731
732 if (online_page_callback == generic_online_page) {
733 online_page_callback = callback;
734 rc = 0;
735 }
736
737 unlock_memory_hotplug();
738
739 return rc;
740}
741EXPORT_SYMBOL_GPL(set_online_page_callback);
742
743int restore_online_page_callback(online_page_callback_t callback)
744{
745 int rc = -EINVAL;
746
747 lock_memory_hotplug();
748
749 if (online_page_callback == callback) {
750 online_page_callback = generic_online_page;
751 rc = 0;
752 }
753
754 unlock_memory_hotplug();
755
756 return rc;
757}
758EXPORT_SYMBOL_GPL(restore_online_page_callback);
759
760void __online_page_set_limits(struct page *page)
761{
762}
763EXPORT_SYMBOL_GPL(__online_page_set_limits);
764
765void __online_page_increment_counters(struct page *page)
766{
767 adjust_managed_page_count(page, 1);
768}
769EXPORT_SYMBOL_GPL(__online_page_increment_counters);
770
771void __online_page_free(struct page *page)
772{
773 __free_reserved_page(page);
774}
775EXPORT_SYMBOL_GPL(__online_page_free);
776
777static void generic_online_page(struct page *page)
778{
779 __online_page_set_limits(page);
780 __online_page_increment_counters(page);
781 __online_page_free(page);
782}
783
784static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
785 void *arg)
786{
787 unsigned long i;
788 unsigned long onlined_pages = *(unsigned long *)arg;
789 struct page *page;
790 if (PageReserved(pfn_to_page(start_pfn)))
791 for (i = 0; i < nr_pages; i++) {
792 page = pfn_to_page(start_pfn + i);
793 (*online_page_callback)(page);
794 onlined_pages++;
795 }
796 *(unsigned long *)arg = onlined_pages;
797 return 0;
798}
799
800#ifdef CONFIG_MOVABLE_NODE
801/*
802 * When CONFIG_MOVABLE_NODE, we permit onlining of a node which doesn't have
803 * normal memory.
804 */
805static bool can_online_high_movable(struct zone *zone)
806{
807 return true;
808}
809#else /* CONFIG_MOVABLE_NODE */
810/* ensure every online node has NORMAL memory */
811static bool can_online_high_movable(struct zone *zone)
812{
813 return node_state(zone_to_nid(zone), N_NORMAL_MEMORY);
814}
815#endif /* CONFIG_MOVABLE_NODE */
816
817/* check which state of node_states will be changed when online memory */
818static void node_states_check_changes_online(unsigned long nr_pages,
819 struct zone *zone, struct memory_notify *arg)
820{
821 int nid = zone_to_nid(zone);
822 enum zone_type zone_last = ZONE_NORMAL;
823
824 /*
825 * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
826 * contains nodes which have zones of 0...ZONE_NORMAL,
827 * set zone_last to ZONE_NORMAL.
828 *
829 * If we don't have HIGHMEM nor movable node,
830 * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
831 * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
832 */
833 if (N_MEMORY == N_NORMAL_MEMORY)
834 zone_last = ZONE_MOVABLE;
835
836 /*
837 * if the memory to be online is in a zone of 0...zone_last, and
838 * the zones of 0...zone_last don't have memory before online, we will
839 * need to set the node to node_states[N_NORMAL_MEMORY] after
840 * the memory is online.
841 */
842 if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY))
843 arg->status_change_nid_normal = nid;
844 else
845 arg->status_change_nid_normal = -1;
846
847#ifdef CONFIG_HIGHMEM
848 /*
849 * If we have movable node, node_states[N_HIGH_MEMORY]
850 * contains nodes which have zones of 0...ZONE_HIGHMEM,
851 * set zone_last to ZONE_HIGHMEM.
852 *
853 * If we don't have movable node, node_states[N_NORMAL_MEMORY]
854 * contains nodes which have zones of 0...ZONE_MOVABLE,
855 * set zone_last to ZONE_MOVABLE.
856 */
857 zone_last = ZONE_HIGHMEM;
858 if (N_MEMORY == N_HIGH_MEMORY)
859 zone_last = ZONE_MOVABLE;
860
861 if (zone_idx(zone) <= zone_last && !node_state(nid, N_HIGH_MEMORY))
862 arg->status_change_nid_high = nid;
863 else
864 arg->status_change_nid_high = -1;
865#else
866 arg->status_change_nid_high = arg->status_change_nid_normal;
867#endif
868
869 /*
870 * if the node don't have memory befor online, we will need to
871 * set the node to node_states[N_MEMORY] after the memory
872 * is online.
873 */
874 if (!node_state(nid, N_MEMORY))
875 arg->status_change_nid = nid;
876 else
877 arg->status_change_nid = -1;
878}
879
880static void node_states_set_node(int node, struct memory_notify *arg)
881{
882 if (arg->status_change_nid_normal >= 0)
883 node_set_state(node, N_NORMAL_MEMORY);
884
885 if (arg->status_change_nid_high >= 0)
886 node_set_state(node, N_HIGH_MEMORY);
887
888 node_set_state(node, N_MEMORY);
889}
890
891
892int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
893{
894 unsigned long flags;
895 unsigned long onlined_pages = 0;
896 struct zone *zone;
897 int need_zonelists_rebuild = 0;
898 int nid;
899 int ret;
900 struct memory_notify arg;
901
902 lock_memory_hotplug();
903 /*
904 * This doesn't need a lock to do pfn_to_page().
905 * The section can't be removed here because of the
906 * memory_block->state_mutex.
907 */
908 zone = page_zone(pfn_to_page(pfn));
909
910 if ((zone_idx(zone) > ZONE_NORMAL || online_type == ONLINE_MOVABLE) &&
911 !can_online_high_movable(zone)) {
912 unlock_memory_hotplug();
913 return -EINVAL;
914 }
915
916 if (online_type == ONLINE_KERNEL && zone_idx(zone) == ZONE_MOVABLE) {
917 if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages)) {
918 unlock_memory_hotplug();
919 return -EINVAL;
920 }
921 }
922 if (online_type == ONLINE_MOVABLE && zone_idx(zone) == ZONE_MOVABLE - 1) {
923 if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages)) {
924 unlock_memory_hotplug();
925 return -EINVAL;
926 }
927 }
928
929 /* Previous code may changed the zone of the pfn range */
930 zone = page_zone(pfn_to_page(pfn));
931
932 arg.start_pfn = pfn;
933 arg.nr_pages = nr_pages;
934 node_states_check_changes_online(nr_pages, zone, &arg);
935
936 nid = pfn_to_nid(pfn);
937
938 ret = memory_notify(MEM_GOING_ONLINE, &arg);
939 ret = notifier_to_errno(ret);
940 if (ret) {
941 memory_notify(MEM_CANCEL_ONLINE, &arg);
942 unlock_memory_hotplug();
943 return ret;
944 }
945 /*
946 * If this zone is not populated, then it is not in zonelist.
947 * This means the page allocator ignores this zone.
948 * So, zonelist must be updated after online.
949 */
950 mutex_lock(&zonelists_mutex);
951 if (!populated_zone(zone)) {
952 need_zonelists_rebuild = 1;
953 build_all_zonelists(NULL, zone);
954 }
955
956 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
957 online_pages_range);
958 if (ret) {
959 if (need_zonelists_rebuild)
960 zone_pcp_reset(zone);
961 mutex_unlock(&zonelists_mutex);
962 printk(KERN_DEBUG "online_pages [mem %#010llx-%#010llx] failed\n",
963 (unsigned long long) pfn << PAGE_SHIFT,
964 (((unsigned long long) pfn + nr_pages)
965 << PAGE_SHIFT) - 1);
966 memory_notify(MEM_CANCEL_ONLINE, &arg);
967 unlock_memory_hotplug();
968 return ret;
969 }
970
971 zone->present_pages += onlined_pages;
972
973 pgdat_resize_lock(zone->zone_pgdat, &flags);
974 zone->zone_pgdat->node_present_pages += onlined_pages;
975 pgdat_resize_unlock(zone->zone_pgdat, &flags);
976
977 if (onlined_pages) {
978 node_states_set_node(zone_to_nid(zone), &arg);
979 if (need_zonelists_rebuild)
980 build_all_zonelists(NULL, NULL);
981 else
982 zone_pcp_update(zone);
983 }
984
985 mutex_unlock(&zonelists_mutex);
986
987 init_per_zone_wmark_min();
988
989 if (onlined_pages)
990 kswapd_run(zone_to_nid(zone));
991
992 vm_total_pages = nr_free_pagecache_pages();
993
994 writeback_set_ratelimit();
995
996 if (onlined_pages)
997 memory_notify(MEM_ONLINE, &arg);
998 unlock_memory_hotplug();
999
1000 return 0;
1001}
1002#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
1003
1004/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1005static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
1006{
1007 struct pglist_data *pgdat;
1008 unsigned long zones_size[MAX_NR_ZONES] = {0};
1009 unsigned long zholes_size[MAX_NR_ZONES] = {0};
1010 unsigned long start_pfn = start >> PAGE_SHIFT;
1011
1012 pgdat = NODE_DATA(nid);
1013 if (!pgdat) {
1014 pgdat = arch_alloc_nodedata(nid);
1015 if (!pgdat)
1016 return NULL;
1017
1018 arch_refresh_nodedata(nid, pgdat);
1019 }
1020
1021 /* we can use NODE_DATA(nid) from here */
1022
1023 /* init node's zones as empty zones, we don't have any present pages.*/
1024 free_area_init_node(nid, zones_size, start_pfn, zholes_size);
1025
1026 /*
1027 * The node we allocated has no zone fallback lists. For avoiding
1028 * to access not-initialized zonelist, build here.
1029 */
1030 mutex_lock(&zonelists_mutex);
1031 build_all_zonelists(pgdat, NULL);
1032 mutex_unlock(&zonelists_mutex);
1033
1034 return pgdat;
1035}
1036
1037static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
1038{
1039 arch_refresh_nodedata(nid, NULL);
1040 arch_free_nodedata(pgdat);
1041 return;
1042}
1043
1044
1045/**
1046 * try_online_node - online a node if offlined
1047 *
1048 * called by cpu_up() to online a node without onlined memory.
1049 */
1050int try_online_node(int nid)
1051{
1052 pg_data_t *pgdat;
1053 int ret;
1054
1055 if (node_online(nid))
1056 return 0;
1057
1058 lock_memory_hotplug();
1059 pgdat = hotadd_new_pgdat(nid, 0);
1060 if (!pgdat) {
1061 pr_err("Cannot online node %d due to NULL pgdat\n", nid);
1062 ret = -ENOMEM;
1063 goto out;
1064 }
1065 node_set_online(nid);
1066 ret = register_one_node(nid);
1067 BUG_ON(ret);
1068
1069 if (pgdat->node_zonelists->_zonerefs->zone == NULL) {
1070 mutex_lock(&zonelists_mutex);
1071 build_all_zonelists(NULL, NULL);
1072 mutex_unlock(&zonelists_mutex);
1073 }
1074
1075out:
1076 unlock_memory_hotplug();
1077 return ret;
1078}
1079
1080static int check_hotplug_memory_range(u64 start, u64 size)
1081{
1082 u64 start_pfn = start >> PAGE_SHIFT;
1083 u64 nr_pages = size >> PAGE_SHIFT;
1084
1085 /* Memory range must be aligned with section */
1086 if ((start_pfn & ~PAGE_SECTION_MASK) ||
1087 (nr_pages % PAGES_PER_SECTION) || (!nr_pages)) {
1088 pr_err("Section-unaligned hotplug range: start 0x%llx, size 0x%llx\n",
1089 (unsigned long long)start,
1090 (unsigned long long)size);
1091 return -EINVAL;
1092 }
1093
1094 return 0;
1095}
1096
1097/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1098int __ref add_memory(int nid, u64 start, u64 size)
1099{
1100 pg_data_t *pgdat = NULL;
1101 bool new_pgdat;
1102 bool new_node;
1103 struct resource *res;
1104 int ret;
1105
1106 ret = check_hotplug_memory_range(start, size);
1107 if (ret)
1108 return ret;
1109
1110 res = register_memory_resource(start, size);
1111 ret = -EEXIST;
1112 if (!res)
1113 return ret;
1114
1115 { /* Stupid hack to suppress address-never-null warning */
1116 void *p = NODE_DATA(nid);
1117 new_pgdat = !p;
1118 }
1119
1120 lock_memory_hotplug();
1121
1122 new_node = !node_online(nid);
1123 if (new_node) {
1124 pgdat = hotadd_new_pgdat(nid, start);
1125 ret = -ENOMEM;
1126 if (!pgdat)
1127 goto error;
1128 }
1129
1130 /* call arch's memory hotadd */
1131 ret = arch_add_memory(nid, start, size);
1132
1133 if (ret < 0)
1134 goto error;
1135
1136 /* we online node here. we can't roll back from here. */
1137 node_set_online(nid);
1138
1139 if (new_node) {
1140 ret = register_one_node(nid);
1141 /*
1142 * If sysfs file of new node can't create, cpu on the node
1143 * can't be hot-added. There is no rollback way now.
1144 * So, check by BUG_ON() to catch it reluctantly..
1145 */
1146 BUG_ON(ret);
1147 }
1148
1149 /* create new memmap entry */
1150 firmware_map_add_hotplug(start, start + size, "System RAM");
1151
1152 goto out;
1153
1154error:
1155 /* rollback pgdat allocation and others */
1156 if (new_pgdat)
1157 rollback_node_hotadd(nid, pgdat);
1158 release_memory_resource(res);
1159
1160out:
1161 unlock_memory_hotplug();
1162 return ret;
1163}
1164EXPORT_SYMBOL_GPL(add_memory);
1165
1166#ifdef CONFIG_MEMORY_HOTREMOVE
1167/*
1168 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
1169 * set and the size of the free page is given by page_order(). Using this,
1170 * the function determines if the pageblock contains only free pages.
1171 * Due to buddy contraints, a free page at least the size of a pageblock will
1172 * be located at the start of the pageblock
1173 */
1174static inline int pageblock_free(struct page *page)
1175{
1176 return PageBuddy(page) && page_order(page) >= pageblock_order;
1177}
1178
1179/* Return the start of the next active pageblock after a given page */
1180static struct page *next_active_pageblock(struct page *page)
1181{
1182 /* Ensure the starting page is pageblock-aligned */
1183 BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
1184
1185 /* If the entire pageblock is free, move to the end of free page */
1186 if (pageblock_free(page)) {
1187 int order;
1188 /* be careful. we don't have locks, page_order can be changed.*/
1189 order = page_order(page);
1190 if ((order < MAX_ORDER) && (order >= pageblock_order))
1191 return page + (1 << order);
1192 }
1193
1194 return page + pageblock_nr_pages;
1195}
1196
1197/* Checks if this range of memory is likely to be hot-removable. */
1198int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
1199{
1200 struct page *page = pfn_to_page(start_pfn);
1201 struct page *end_page = page + nr_pages;
1202
1203 /* Check the starting page of each pageblock within the range */
1204 for (; page < end_page; page = next_active_pageblock(page)) {
1205 if (!is_pageblock_removable_nolock(page))
1206 return 0;
1207 cond_resched();
1208 }
1209
1210 /* All pageblocks in the memory block are likely to be hot-removable */
1211 return 1;
1212}
1213
1214/*
1215 * Confirm all pages in a range [start, end) is belongs to the same zone.
1216 */
1217static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
1218{
1219 unsigned long pfn;
1220 struct zone *zone = NULL;
1221 struct page *page;
1222 int i;
1223 for (pfn = start_pfn;
1224 pfn < end_pfn;
1225 pfn += MAX_ORDER_NR_PAGES) {
1226 i = 0;
1227 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
1228 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
1229 i++;
1230 if (i == MAX_ORDER_NR_PAGES)
1231 continue;
1232 page = pfn_to_page(pfn + i);
1233 if (zone && page_zone(page) != zone)
1234 return 0;
1235 zone = page_zone(page);
1236 }
1237 return 1;
1238}
1239
1240/*
1241 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages
1242 * and hugepages). We scan pfn because it's much easier than scanning over
1243 * linked list. This function returns the pfn of the first found movable
1244 * page if it's found, otherwise 0.
1245 */
1246static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
1247{
1248 unsigned long pfn;
1249 struct page *page;
1250 for (pfn = start; pfn < end; pfn++) {
1251 if (pfn_valid(pfn)) {
1252 page = pfn_to_page(pfn);
1253 if (PageLRU(page))
1254 return pfn;
1255 if (PageHuge(page)) {
1256 if (is_hugepage_active(page))
1257 return pfn;
1258 else
1259 pfn = round_up(pfn + 1,
1260 1 << compound_order(page)) - 1;
1261 }
1262 }
1263 }
1264 return 0;
1265}
1266
1267#define NR_OFFLINE_AT_ONCE_PAGES (256)
1268static int
1269do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1270{
1271 unsigned long pfn;
1272 struct page *page;
1273 int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
1274 int not_managed = 0;
1275 int ret = 0;
1276 LIST_HEAD(source);
1277
1278 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
1279 if (!pfn_valid(pfn))
1280 continue;
1281 page = pfn_to_page(pfn);
1282
1283 if (PageHuge(page)) {
1284 struct page *head = compound_head(page);
1285 pfn = page_to_pfn(head) + (1<<compound_order(head)) - 1;
1286 if (compound_order(head) > PFN_SECTION_SHIFT) {
1287 ret = -EBUSY;
1288 break;
1289 }
1290 if (isolate_huge_page(page, &source))
1291 move_pages -= 1 << compound_order(head);
1292 continue;
1293 }
1294
1295 if (!get_page_unless_zero(page))
1296 continue;
1297 /*
1298 * We can skip free pages. And we can only deal with pages on
1299 * LRU.
1300 */
1301 ret = isolate_lru_page(page);
1302 if (!ret) { /* Success */
1303 put_page(page);
1304 list_add_tail(&page->lru, &source);
1305 move_pages--;
1306 inc_zone_page_state(page, NR_ISOLATED_ANON +
1307 page_is_file_cache(page));
1308
1309 } else {
1310#ifdef CONFIG_DEBUG_VM
1311 printk(KERN_ALERT "removing pfn %lx from LRU failed\n",
1312 pfn);
1313 dump_page(page, "failed to remove from LRU");
1314#endif
1315 put_page(page);
1316 /* Because we don't have big zone->lock. we should
1317 check this again here. */
1318 if (page_count(page)) {
1319 not_managed++;
1320 ret = -EBUSY;
1321 break;
1322 }
1323 }
1324 }
1325 if (!list_empty(&source)) {
1326 if (not_managed) {
1327 putback_movable_pages(&source);
1328 goto out;
1329 }
1330
1331 /*
1332 * alloc_migrate_target should be improooooved!!
1333 * migrate_pages returns # of failed pages.
1334 */
1335 ret = migrate_pages(&source, alloc_migrate_target, 0,
1336 MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
1337 if (ret)
1338 putback_movable_pages(&source);
1339 }
1340out:
1341 return ret;
1342}
1343
1344/*
1345 * remove from free_area[] and mark all as Reserved.
1346 */
1347static int
1348offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1349 void *data)
1350{
1351 __offline_isolated_pages(start, start + nr_pages);
1352 return 0;
1353}
1354
1355static void
1356offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
1357{
1358 walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
1359 offline_isolated_pages_cb);
1360}
1361
1362/*
1363 * Check all pages in range, recoreded as memory resource, are isolated.
1364 */
1365static int
1366check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1367 void *data)
1368{
1369 int ret;
1370 long offlined = *(long *)data;
1371 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
1372 offlined = nr_pages;
1373 if (!ret)
1374 *(long *)data += offlined;
1375 return ret;
1376}
1377
1378static long
1379check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
1380{
1381 long offlined = 0;
1382 int ret;
1383
1384 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
1385 check_pages_isolated_cb);
1386 if (ret < 0)
1387 offlined = (long)ret;
1388 return offlined;
1389}
1390
1391#ifdef CONFIG_MOVABLE_NODE
1392/*
1393 * When CONFIG_MOVABLE_NODE, we permit offlining of a node which doesn't have
1394 * normal memory.
1395 */
1396static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1397{
1398 return true;
1399}
1400#else /* CONFIG_MOVABLE_NODE */
1401/* ensure the node has NORMAL memory if it is still online */
1402static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1403{
1404 struct pglist_data *pgdat = zone->zone_pgdat;
1405 unsigned long present_pages = 0;
1406 enum zone_type zt;
1407
1408 for (zt = 0; zt <= ZONE_NORMAL; zt++)
1409 present_pages += pgdat->node_zones[zt].present_pages;
1410
1411 if (present_pages > nr_pages)
1412 return true;
1413
1414 present_pages = 0;
1415 for (; zt <= ZONE_MOVABLE; zt++)
1416 present_pages += pgdat->node_zones[zt].present_pages;
1417
1418 /*
1419 * we can't offline the last normal memory until all
1420 * higher memory is offlined.
1421 */
1422 return present_pages == 0;
1423}
1424#endif /* CONFIG_MOVABLE_NODE */
1425
1426static int __init cmdline_parse_movable_node(char *p)
1427{
1428#ifdef CONFIG_MOVABLE_NODE
1429 /*
1430 * Memory used by the kernel cannot be hot-removed because Linux
1431 * cannot migrate the kernel pages. When memory hotplug is
1432 * enabled, we should prevent memblock from allocating memory
1433 * for the kernel.
1434 *
1435 * ACPI SRAT records all hotpluggable memory ranges. But before
1436 * SRAT is parsed, we don't know about it.
1437 *
1438 * The kernel image is loaded into memory at very early time. We
1439 * cannot prevent this anyway. So on NUMA system, we set any
1440 * node the kernel resides in as un-hotpluggable.
1441 *
1442 * Since on modern servers, one node could have double-digit
1443 * gigabytes memory, we can assume the memory around the kernel
1444 * image is also un-hotpluggable. So before SRAT is parsed, just
1445 * allocate memory near the kernel image to try the best to keep
1446 * the kernel away from hotpluggable memory.
1447 */
1448 memblock_set_bottom_up(true);
1449 movable_node_enabled = true;
1450#else
1451 pr_warn("movable_node option not supported\n");
1452#endif
1453 return 0;
1454}
1455early_param("movable_node", cmdline_parse_movable_node);
1456
1457/* check which state of node_states will be changed when offline memory */
1458static void node_states_check_changes_offline(unsigned long nr_pages,
1459 struct zone *zone, struct memory_notify *arg)
1460{
1461 struct pglist_data *pgdat = zone->zone_pgdat;
1462 unsigned long present_pages = 0;
1463 enum zone_type zt, zone_last = ZONE_NORMAL;
1464
1465 /*
1466 * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
1467 * contains nodes which have zones of 0...ZONE_NORMAL,
1468 * set zone_last to ZONE_NORMAL.
1469 *
1470 * If we don't have HIGHMEM nor movable node,
1471 * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
1472 * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
1473 */
1474 if (N_MEMORY == N_NORMAL_MEMORY)
1475 zone_last = ZONE_MOVABLE;
1476
1477 /*
1478 * check whether node_states[N_NORMAL_MEMORY] will be changed.
1479 * If the memory to be offline is in a zone of 0...zone_last,
1480 * and it is the last present memory, 0...zone_last will
1481 * become empty after offline , thus we can determind we will
1482 * need to clear the node from node_states[N_NORMAL_MEMORY].
1483 */
1484 for (zt = 0; zt <= zone_last; zt++)
1485 present_pages += pgdat->node_zones[zt].present_pages;
1486 if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1487 arg->status_change_nid_normal = zone_to_nid(zone);
1488 else
1489 arg->status_change_nid_normal = -1;
1490
1491#ifdef CONFIG_HIGHMEM
1492 /*
1493 * If we have movable node, node_states[N_HIGH_MEMORY]
1494 * contains nodes which have zones of 0...ZONE_HIGHMEM,
1495 * set zone_last to ZONE_HIGHMEM.
1496 *
1497 * If we don't have movable node, node_states[N_NORMAL_MEMORY]
1498 * contains nodes which have zones of 0...ZONE_MOVABLE,
1499 * set zone_last to ZONE_MOVABLE.
1500 */
1501 zone_last = ZONE_HIGHMEM;
1502 if (N_MEMORY == N_HIGH_MEMORY)
1503 zone_last = ZONE_MOVABLE;
1504
1505 for (; zt <= zone_last; zt++)
1506 present_pages += pgdat->node_zones[zt].present_pages;
1507 if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1508 arg->status_change_nid_high = zone_to_nid(zone);
1509 else
1510 arg->status_change_nid_high = -1;
1511#else
1512 arg->status_change_nid_high = arg->status_change_nid_normal;
1513#endif
1514
1515 /*
1516 * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE
1517 */
1518 zone_last = ZONE_MOVABLE;
1519
1520 /*
1521 * check whether node_states[N_HIGH_MEMORY] will be changed
1522 * If we try to offline the last present @nr_pages from the node,
1523 * we can determind we will need to clear the node from
1524 * node_states[N_HIGH_MEMORY].
1525 */
1526 for (; zt <= zone_last; zt++)
1527 present_pages += pgdat->node_zones[zt].present_pages;
1528 if (nr_pages >= present_pages)
1529 arg->status_change_nid = zone_to_nid(zone);
1530 else
1531 arg->status_change_nid = -1;
1532}
1533
1534static void node_states_clear_node(int node, struct memory_notify *arg)
1535{
1536 if (arg->status_change_nid_normal >= 0)
1537 node_clear_state(node, N_NORMAL_MEMORY);
1538
1539 if ((N_MEMORY != N_NORMAL_MEMORY) &&
1540 (arg->status_change_nid_high >= 0))
1541 node_clear_state(node, N_HIGH_MEMORY);
1542
1543 if ((N_MEMORY != N_HIGH_MEMORY) &&
1544 (arg->status_change_nid >= 0))
1545 node_clear_state(node, N_MEMORY);
1546}
1547
1548static int __ref __offline_pages(unsigned long start_pfn,
1549 unsigned long end_pfn, unsigned long timeout)
1550{
1551 unsigned long pfn, nr_pages, expire;
1552 long offlined_pages;
1553 int ret, drain, retry_max, node;
1554 unsigned long flags;
1555 struct zone *zone;
1556 struct memory_notify arg;
1557
1558 /* at least, alignment against pageblock is necessary */
1559 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
1560 return -EINVAL;
1561 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
1562 return -EINVAL;
1563 /* This makes hotplug much easier...and readable.
1564 we assume this for now. .*/
1565 if (!test_pages_in_a_zone(start_pfn, end_pfn))
1566 return -EINVAL;
1567
1568 lock_memory_hotplug();
1569
1570 zone = page_zone(pfn_to_page(start_pfn));
1571 node = zone_to_nid(zone);
1572 nr_pages = end_pfn - start_pfn;
1573
1574 ret = -EINVAL;
1575 if (zone_idx(zone) <= ZONE_NORMAL && !can_offline_normal(zone, nr_pages))
1576 goto out;
1577
1578 /* set above range as isolated */
1579 ret = start_isolate_page_range(start_pfn, end_pfn,
1580 MIGRATE_MOVABLE, true);
1581 if (ret)
1582 goto out;
1583
1584 arg.start_pfn = start_pfn;
1585 arg.nr_pages = nr_pages;
1586 node_states_check_changes_offline(nr_pages, zone, &arg);
1587
1588 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1589 ret = notifier_to_errno(ret);
1590 if (ret)
1591 goto failed_removal;
1592
1593 pfn = start_pfn;
1594 expire = jiffies + timeout;
1595 drain = 0;
1596 retry_max = 5;
1597repeat:
1598 /* start memory hot removal */
1599 ret = -EAGAIN;
1600 if (time_after(jiffies, expire))
1601 goto failed_removal;
1602 ret = -EINTR;
1603 if (signal_pending(current))
1604 goto failed_removal;
1605 ret = 0;
1606 if (drain) {
1607 lru_add_drain_all();
1608 cond_resched();
1609 drain_all_pages();
1610 }
1611
1612 pfn = scan_movable_pages(start_pfn, end_pfn);
1613 if (pfn) { /* We have movable pages */
1614 ret = do_migrate_range(pfn, end_pfn);
1615 if (!ret) {
1616 drain = 1;
1617 goto repeat;
1618 } else {
1619 if (ret < 0)
1620 if (--retry_max == 0)
1621 goto failed_removal;
1622 yield();
1623 drain = 1;
1624 goto repeat;
1625 }
1626 }
1627 /* drain all zone's lru pagevec, this is asynchronous... */
1628 lru_add_drain_all();
1629 yield();
1630 /* drain pcp pages, this is synchronous. */
1631 drain_all_pages();
1632 /*
1633 * dissolve free hugepages in the memory block before doing offlining
1634 * actually in order to make hugetlbfs's object counting consistent.
1635 */
1636 dissolve_free_huge_pages(start_pfn, end_pfn);
1637 /* check again */
1638 offlined_pages = check_pages_isolated(start_pfn, end_pfn);
1639 if (offlined_pages < 0) {
1640 ret = -EBUSY;
1641 goto failed_removal;
1642 }
1643 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
1644 /* Ok, all of our target is isolated.
1645 We cannot do rollback at this point. */
1646 offline_isolated_pages(start_pfn, end_pfn);
1647 /* reset pagetype flags and makes migrate type to be MOVABLE */
1648 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1649 /* removal success */
1650 adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages);
1651 zone->present_pages -= offlined_pages;
1652
1653 pgdat_resize_lock(zone->zone_pgdat, &flags);
1654 zone->zone_pgdat->node_present_pages -= offlined_pages;
1655 pgdat_resize_unlock(zone->zone_pgdat, &flags);
1656
1657 init_per_zone_wmark_min();
1658
1659 if (!populated_zone(zone)) {
1660 zone_pcp_reset(zone);
1661 mutex_lock(&zonelists_mutex);
1662 build_all_zonelists(NULL, NULL);
1663 mutex_unlock(&zonelists_mutex);
1664 } else
1665 zone_pcp_update(zone);
1666
1667 node_states_clear_node(node, &arg);
1668 if (arg.status_change_nid >= 0)
1669 kswapd_stop(node);
1670
1671 vm_total_pages = nr_free_pagecache_pages();
1672 writeback_set_ratelimit();
1673
1674 memory_notify(MEM_OFFLINE, &arg);
1675 unlock_memory_hotplug();
1676 return 0;
1677
1678failed_removal:
1679 printk(KERN_INFO "memory offlining [mem %#010llx-%#010llx] failed\n",
1680 (unsigned long long) start_pfn << PAGE_SHIFT,
1681 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
1682 memory_notify(MEM_CANCEL_OFFLINE, &arg);
1683 /* pushback to free area */
1684 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1685
1686out:
1687 unlock_memory_hotplug();
1688 return ret;
1689}
1690
1691int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1692{
1693 return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);
1694}
1695#endif /* CONFIG_MEMORY_HOTREMOVE */
1696
1697/**
1698 * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn)
1699 * @start_pfn: start pfn of the memory range
1700 * @end_pfn: end pfn of the memory range
1701 * @arg: argument passed to func
1702 * @func: callback for each memory section walked
1703 *
1704 * This function walks through all present mem sections in range
1705 * [start_pfn, end_pfn) and call func on each mem section.
1706 *
1707 * Returns the return value of func.
1708 */
1709int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
1710 void *arg, int (*func)(struct memory_block *, void *))
1711{
1712 struct memory_block *mem = NULL;
1713 struct mem_section *section;
1714 unsigned long pfn, section_nr;
1715 int ret;
1716
1717 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1718 section_nr = pfn_to_section_nr(pfn);
1719 if (!present_section_nr(section_nr))
1720 continue;
1721
1722 section = __nr_to_section(section_nr);
1723 /* same memblock? */
1724 if (mem)
1725 if ((section_nr >= mem->start_section_nr) &&
1726 (section_nr <= mem->end_section_nr))
1727 continue;
1728
1729 mem = find_memory_block_hinted(section, mem);
1730 if (!mem)
1731 continue;
1732
1733 ret = func(mem, arg);
1734 if (ret) {
1735 kobject_put(&mem->dev.kobj);
1736 return ret;
1737 }
1738 }
1739
1740 if (mem)
1741 kobject_put(&mem->dev.kobj);
1742
1743 return 0;
1744}
1745
1746#ifdef CONFIG_MEMORY_HOTREMOVE
1747static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
1748{
1749 int ret = !is_memblock_offlined(mem);
1750
1751 if (unlikely(ret)) {
1752 phys_addr_t beginpa, endpa;
1753
1754 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
1755 endpa = PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1;
1756 pr_warn("removing memory fails, because memory "
1757 "[%pa-%pa] is onlined\n",
1758 &beginpa, &endpa);
1759 }
1760
1761 return ret;
1762}
1763
1764static int check_cpu_on_node(pg_data_t *pgdat)
1765{
1766 int cpu;
1767
1768 for_each_present_cpu(cpu) {
1769 if (cpu_to_node(cpu) == pgdat->node_id)
1770 /*
1771 * the cpu on this node isn't removed, and we can't
1772 * offline this node.
1773 */
1774 return -EBUSY;
1775 }
1776
1777 return 0;
1778}
1779
1780static void unmap_cpu_on_node(pg_data_t *pgdat)
1781{
1782#ifdef CONFIG_ACPI_NUMA
1783 int cpu;
1784
1785 for_each_possible_cpu(cpu)
1786 if (cpu_to_node(cpu) == pgdat->node_id)
1787 numa_clear_node(cpu);
1788#endif
1789}
1790
1791static int check_and_unmap_cpu_on_node(pg_data_t *pgdat)
1792{
1793 int ret;
1794
1795 ret = check_cpu_on_node(pgdat);
1796 if (ret)
1797 return ret;
1798
1799 /*
1800 * the node will be offlined when we come here, so we can clear
1801 * the cpu_to_node() now.
1802 */
1803
1804 unmap_cpu_on_node(pgdat);
1805 return 0;
1806}
1807
1808/**
1809 * try_offline_node
1810 *
1811 * Offline a node if all memory sections and cpus of the node are removed.
1812 *
1813 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1814 * and online/offline operations before this call.
1815 */
1816void try_offline_node(int nid)
1817{
1818 pg_data_t *pgdat = NODE_DATA(nid);
1819 unsigned long start_pfn = pgdat->node_start_pfn;
1820 unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
1821 unsigned long pfn;
1822 struct page *pgdat_page = virt_to_page(pgdat);
1823 int i;
1824
1825 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1826 unsigned long section_nr = pfn_to_section_nr(pfn);
1827
1828 if (!present_section_nr(section_nr))
1829 continue;
1830
1831 if (pfn_to_nid(pfn) != nid)
1832 continue;
1833
1834 /*
1835 * some memory sections of this node are not removed, and we
1836 * can't offline node now.
1837 */
1838 return;
1839 }
1840
1841 if (check_and_unmap_cpu_on_node(pgdat))
1842 return;
1843
1844 /*
1845 * all memory/cpu of this node are removed, we can offline this
1846 * node now.
1847 */
1848 node_set_offline(nid);
1849 unregister_one_node(nid);
1850
1851 if (!PageSlab(pgdat_page) && !PageCompound(pgdat_page))
1852 /* node data is allocated from boot memory */
1853 return;
1854
1855 /* free waittable in each zone */
1856 for (i = 0; i < MAX_NR_ZONES; i++) {
1857 struct zone *zone = pgdat->node_zones + i;
1858
1859 /*
1860 * wait_table may be allocated from boot memory,
1861 * here only free if it's allocated by vmalloc.
1862 */
1863 if (is_vmalloc_addr(zone->wait_table))
1864 vfree(zone->wait_table);
1865 }
1866
1867 /*
1868 * Since there is no way to guarentee the address of pgdat/zone is not
1869 * on stack of any kernel threads or used by other kernel objects
1870 * without reference counting or other symchronizing method, do not
1871 * reset node_data and free pgdat here. Just reset it to 0 and reuse
1872 * the memory when the node is online again.
1873 */
1874 memset(pgdat, 0, sizeof(*pgdat));
1875}
1876EXPORT_SYMBOL(try_offline_node);
1877
1878/**
1879 * remove_memory
1880 *
1881 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1882 * and online/offline operations before this call, as required by
1883 * try_offline_node().
1884 */
1885void __ref remove_memory(int nid, u64 start, u64 size)
1886{
1887 int ret;
1888
1889 BUG_ON(check_hotplug_memory_range(start, size));
1890
1891 lock_memory_hotplug();
1892
1893 /*
1894 * All memory blocks must be offlined before removing memory. Check
1895 * whether all memory blocks in question are offline and trigger a BUG()
1896 * if this is not the case.
1897 */
1898 ret = walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1), NULL,
1899 check_memblock_offlined_cb);
1900 if (ret) {
1901 unlock_memory_hotplug();
1902 BUG();
1903 }
1904
1905 /* remove memmap entry */
1906 firmware_map_remove(start, start + size, "System RAM");
1907
1908 arch_remove_memory(start, size);
1909
1910 try_offline_node(nid);
1911
1912 unlock_memory_hotplug();
1913}
1914EXPORT_SYMBOL_GPL(remove_memory);
1915#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/pagevec.h>
17#include <linux/writeback.h>
18#include <linux/slab.h>
19#include <linux/sysctl.h>
20#include <linux/cpu.h>
21#include <linux/memory.h>
22#include <linux/memremap.h>
23#include <linux/memory_hotplug.h>
24#include <linux/vmalloc.h>
25#include <linux/ioport.h>
26#include <linux/delay.h>
27#include <linux/migrate.h>
28#include <linux/page-isolation.h>
29#include <linux/pfn.h>
30#include <linux/suspend.h>
31#include <linux/mm_inline.h>
32#include <linux/firmware-map.h>
33#include <linux/stop_machine.h>
34#include <linux/hugetlb.h>
35#include <linux/memblock.h>
36#include <linux/compaction.h>
37#include <linux/rmap.h>
38#include <linux/module.h>
39
40#include <asm/tlbflush.h>
41
42#include "internal.h"
43#include "shuffle.h"
44
45#ifdef CONFIG_MHP_MEMMAP_ON_MEMORY
46/*
47 * memory_hotplug.memmap_on_memory parameter
48 */
49static bool memmap_on_memory __ro_after_init;
50module_param(memmap_on_memory, bool, 0444);
51MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug");
52
53static inline bool mhp_memmap_on_memory(void)
54{
55 return memmap_on_memory;
56}
57#else
58static inline bool mhp_memmap_on_memory(void)
59{
60 return false;
61}
62#endif
63
64enum {
65 ONLINE_POLICY_CONTIG_ZONES = 0,
66 ONLINE_POLICY_AUTO_MOVABLE,
67};
68
69static const char * const online_policy_to_str[] = {
70 [ONLINE_POLICY_CONTIG_ZONES] = "contig-zones",
71 [ONLINE_POLICY_AUTO_MOVABLE] = "auto-movable",
72};
73
74static int set_online_policy(const char *val, const struct kernel_param *kp)
75{
76 int ret = sysfs_match_string(online_policy_to_str, val);
77
78 if (ret < 0)
79 return ret;
80 *((int *)kp->arg) = ret;
81 return 0;
82}
83
84static int get_online_policy(char *buffer, const struct kernel_param *kp)
85{
86 return sprintf(buffer, "%s\n", online_policy_to_str[*((int *)kp->arg)]);
87}
88
89/*
90 * memory_hotplug.online_policy: configure online behavior when onlining without
91 * specifying a zone (MMOP_ONLINE)
92 *
93 * "contig-zones": keep zone contiguous
94 * "auto-movable": online memory to ZONE_MOVABLE if the configuration
95 * (auto_movable_ratio, auto_movable_numa_aware) allows for it
96 */
97static int online_policy __read_mostly = ONLINE_POLICY_CONTIG_ZONES;
98static const struct kernel_param_ops online_policy_ops = {
99 .set = set_online_policy,
100 .get = get_online_policy,
101};
102module_param_cb(online_policy, &online_policy_ops, &online_policy, 0644);
103MODULE_PARM_DESC(online_policy,
104 "Set the online policy (\"contig-zones\", \"auto-movable\") "
105 "Default: \"contig-zones\"");
106
107/*
108 * memory_hotplug.auto_movable_ratio: specify maximum MOVABLE:KERNEL ratio
109 *
110 * The ratio represent an upper limit and the kernel might decide to not
111 * online some memory to ZONE_MOVABLE -- e.g., because hotplugged KERNEL memory
112 * doesn't allow for more MOVABLE memory.
113 */
114static unsigned int auto_movable_ratio __read_mostly = 301;
115module_param(auto_movable_ratio, uint, 0644);
116MODULE_PARM_DESC(auto_movable_ratio,
117 "Set the maximum ratio of MOVABLE:KERNEL memory in the system "
118 "in percent for \"auto-movable\" online policy. Default: 301");
119
120/*
121 * memory_hotplug.auto_movable_numa_aware: consider numa node stats
122 */
123#ifdef CONFIG_NUMA
124static bool auto_movable_numa_aware __read_mostly = true;
125module_param(auto_movable_numa_aware, bool, 0644);
126MODULE_PARM_DESC(auto_movable_numa_aware,
127 "Consider numa node stats in addition to global stats in "
128 "\"auto-movable\" online policy. Default: true");
129#endif /* CONFIG_NUMA */
130
131/*
132 * online_page_callback contains pointer to current page onlining function.
133 * Initially it is generic_online_page(). If it is required it could be
134 * changed by calling set_online_page_callback() for callback registration
135 * and restore_online_page_callback() for generic callback restore.
136 */
137
138static online_page_callback_t online_page_callback = generic_online_page;
139static DEFINE_MUTEX(online_page_callback_lock);
140
141DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock);
142
143void get_online_mems(void)
144{
145 percpu_down_read(&mem_hotplug_lock);
146}
147
148void put_online_mems(void)
149{
150 percpu_up_read(&mem_hotplug_lock);
151}
152
153bool movable_node_enabled = false;
154
155#ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
156int mhp_default_online_type = MMOP_OFFLINE;
157#else
158int mhp_default_online_type = MMOP_ONLINE;
159#endif
160
161static int __init setup_memhp_default_state(char *str)
162{
163 const int online_type = mhp_online_type_from_str(str);
164
165 if (online_type >= 0)
166 mhp_default_online_type = online_type;
167
168 return 1;
169}
170__setup("memhp_default_state=", setup_memhp_default_state);
171
172void mem_hotplug_begin(void)
173{
174 cpus_read_lock();
175 percpu_down_write(&mem_hotplug_lock);
176}
177
178void mem_hotplug_done(void)
179{
180 percpu_up_write(&mem_hotplug_lock);
181 cpus_read_unlock();
182}
183
184u64 max_mem_size = U64_MAX;
185
186/* add this memory to iomem resource */
187static struct resource *register_memory_resource(u64 start, u64 size,
188 const char *resource_name)
189{
190 struct resource *res;
191 unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
192
193 if (strcmp(resource_name, "System RAM"))
194 flags |= IORESOURCE_SYSRAM_DRIVER_MANAGED;
195
196 if (!mhp_range_allowed(start, size, true))
197 return ERR_PTR(-E2BIG);
198
199 /*
200 * Make sure value parsed from 'mem=' only restricts memory adding
201 * while booting, so that memory hotplug won't be impacted. Please
202 * refer to document of 'mem=' in kernel-parameters.txt for more
203 * details.
204 */
205 if (start + size > max_mem_size && system_state < SYSTEM_RUNNING)
206 return ERR_PTR(-E2BIG);
207
208 /*
209 * Request ownership of the new memory range. This might be
210 * a child of an existing resource that was present but
211 * not marked as busy.
212 */
213 res = __request_region(&iomem_resource, start, size,
214 resource_name, flags);
215
216 if (!res) {
217 pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n",
218 start, start + size);
219 return ERR_PTR(-EEXIST);
220 }
221 return res;
222}
223
224static void release_memory_resource(struct resource *res)
225{
226 if (!res)
227 return;
228 release_resource(res);
229 kfree(res);
230}
231
232static int check_pfn_span(unsigned long pfn, unsigned long nr_pages)
233{
234 /*
235 * Disallow all operations smaller than a sub-section and only
236 * allow operations smaller than a section for
237 * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range()
238 * enforces a larger memory_block_size_bytes() granularity for
239 * memory that will be marked online, so this check should only
240 * fire for direct arch_{add,remove}_memory() users outside of
241 * add_memory_resource().
242 */
243 unsigned long min_align;
244
245 if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
246 min_align = PAGES_PER_SUBSECTION;
247 else
248 min_align = PAGES_PER_SECTION;
249 if (!IS_ALIGNED(pfn | nr_pages, min_align))
250 return -EINVAL;
251 return 0;
252}
253
254/*
255 * Return page for the valid pfn only if the page is online. All pfn
256 * walkers which rely on the fully initialized page->flags and others
257 * should use this rather than pfn_valid && pfn_to_page
258 */
259struct page *pfn_to_online_page(unsigned long pfn)
260{
261 unsigned long nr = pfn_to_section_nr(pfn);
262 struct dev_pagemap *pgmap;
263 struct mem_section *ms;
264
265 if (nr >= NR_MEM_SECTIONS)
266 return NULL;
267
268 ms = __nr_to_section(nr);
269 if (!online_section(ms))
270 return NULL;
271
272 /*
273 * Save some code text when online_section() +
274 * pfn_section_valid() are sufficient.
275 */
276 if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) && !pfn_valid(pfn))
277 return NULL;
278
279 if (!pfn_section_valid(ms, pfn))
280 return NULL;
281
282 if (!online_device_section(ms))
283 return pfn_to_page(pfn);
284
285 /*
286 * Slowpath: when ZONE_DEVICE collides with
287 * ZONE_{NORMAL,MOVABLE} within the same section some pfns in
288 * the section may be 'offline' but 'valid'. Only
289 * get_dev_pagemap() can determine sub-section online status.
290 */
291 pgmap = get_dev_pagemap(pfn, NULL);
292 put_dev_pagemap(pgmap);
293
294 /* The presence of a pgmap indicates ZONE_DEVICE offline pfn */
295 if (pgmap)
296 return NULL;
297
298 return pfn_to_page(pfn);
299}
300EXPORT_SYMBOL_GPL(pfn_to_online_page);
301
302int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
303 struct mhp_params *params)
304{
305 const unsigned long end_pfn = pfn + nr_pages;
306 unsigned long cur_nr_pages;
307 int err;
308 struct vmem_altmap *altmap = params->altmap;
309
310 if (WARN_ON_ONCE(!pgprot_val(params->pgprot)))
311 return -EINVAL;
312
313 VM_BUG_ON(!mhp_range_allowed(PFN_PHYS(pfn), nr_pages * PAGE_SIZE, false));
314
315 if (altmap) {
316 /*
317 * Validate altmap is within bounds of the total request
318 */
319 if (altmap->base_pfn != pfn
320 || vmem_altmap_offset(altmap) > nr_pages) {
321 pr_warn_once("memory add fail, invalid altmap\n");
322 return -EINVAL;
323 }
324 altmap->alloc = 0;
325 }
326
327 if (check_pfn_span(pfn, nr_pages)) {
328 WARN(1, "Misaligned %s start: %#lx end: #%lx\n", __func__, pfn, pfn + nr_pages - 1);
329 return -EINVAL;
330 }
331
332 for (; pfn < end_pfn; pfn += cur_nr_pages) {
333 /* Select all remaining pages up to the next section boundary */
334 cur_nr_pages = min(end_pfn - pfn,
335 SECTION_ALIGN_UP(pfn + 1) - pfn);
336 err = sparse_add_section(nid, pfn, cur_nr_pages, altmap,
337 params->pgmap);
338 if (err)
339 break;
340 cond_resched();
341 }
342 vmemmap_populate_print_last();
343 return err;
344}
345
346/* find the smallest valid pfn in the range [start_pfn, end_pfn) */
347static unsigned long find_smallest_section_pfn(int nid, struct zone *zone,
348 unsigned long start_pfn,
349 unsigned long end_pfn)
350{
351 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) {
352 if (unlikely(!pfn_to_online_page(start_pfn)))
353 continue;
354
355 if (unlikely(pfn_to_nid(start_pfn) != nid))
356 continue;
357
358 if (zone != page_zone(pfn_to_page(start_pfn)))
359 continue;
360
361 return start_pfn;
362 }
363
364 return 0;
365}
366
367/* find the biggest valid pfn in the range [start_pfn, end_pfn). */
368static unsigned long find_biggest_section_pfn(int nid, struct zone *zone,
369 unsigned long start_pfn,
370 unsigned long end_pfn)
371{
372 unsigned long pfn;
373
374 /* pfn is the end pfn of a memory section. */
375 pfn = end_pfn - 1;
376 for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) {
377 if (unlikely(!pfn_to_online_page(pfn)))
378 continue;
379
380 if (unlikely(pfn_to_nid(pfn) != nid))
381 continue;
382
383 if (zone != page_zone(pfn_to_page(pfn)))
384 continue;
385
386 return pfn;
387 }
388
389 return 0;
390}
391
392static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
393 unsigned long end_pfn)
394{
395 unsigned long pfn;
396 int nid = zone_to_nid(zone);
397
398 if (zone->zone_start_pfn == start_pfn) {
399 /*
400 * If the section is smallest section in the zone, it need
401 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
402 * In this case, we find second smallest valid mem_section
403 * for shrinking zone.
404 */
405 pfn = find_smallest_section_pfn(nid, zone, end_pfn,
406 zone_end_pfn(zone));
407 if (pfn) {
408 zone->spanned_pages = zone_end_pfn(zone) - pfn;
409 zone->zone_start_pfn = pfn;
410 } else {
411 zone->zone_start_pfn = 0;
412 zone->spanned_pages = 0;
413 }
414 } else if (zone_end_pfn(zone) == end_pfn) {
415 /*
416 * If the section is biggest section in the zone, it need
417 * shrink zone->spanned_pages.
418 * In this case, we find second biggest valid mem_section for
419 * shrinking zone.
420 */
421 pfn = find_biggest_section_pfn(nid, zone, zone->zone_start_pfn,
422 start_pfn);
423 if (pfn)
424 zone->spanned_pages = pfn - zone->zone_start_pfn + 1;
425 else {
426 zone->zone_start_pfn = 0;
427 zone->spanned_pages = 0;
428 }
429 }
430}
431
432static void update_pgdat_span(struct pglist_data *pgdat)
433{
434 unsigned long node_start_pfn = 0, node_end_pfn = 0;
435 struct zone *zone;
436
437 for (zone = pgdat->node_zones;
438 zone < pgdat->node_zones + MAX_NR_ZONES; zone++) {
439 unsigned long end_pfn = zone_end_pfn(zone);
440
441 /* No need to lock the zones, they can't change. */
442 if (!zone->spanned_pages)
443 continue;
444 if (!node_end_pfn) {
445 node_start_pfn = zone->zone_start_pfn;
446 node_end_pfn = end_pfn;
447 continue;
448 }
449
450 if (end_pfn > node_end_pfn)
451 node_end_pfn = end_pfn;
452 if (zone->zone_start_pfn < node_start_pfn)
453 node_start_pfn = zone->zone_start_pfn;
454 }
455
456 pgdat->node_start_pfn = node_start_pfn;
457 pgdat->node_spanned_pages = node_end_pfn - node_start_pfn;
458}
459
460void __ref remove_pfn_range_from_zone(struct zone *zone,
461 unsigned long start_pfn,
462 unsigned long nr_pages)
463{
464 const unsigned long end_pfn = start_pfn + nr_pages;
465 struct pglist_data *pgdat = zone->zone_pgdat;
466 unsigned long pfn, cur_nr_pages;
467
468 /* Poison struct pages because they are now uninitialized again. */
469 for (pfn = start_pfn; pfn < end_pfn; pfn += cur_nr_pages) {
470 cond_resched();
471
472 /* Select all remaining pages up to the next section boundary */
473 cur_nr_pages =
474 min(end_pfn - pfn, SECTION_ALIGN_UP(pfn + 1) - pfn);
475 page_init_poison(pfn_to_page(pfn),
476 sizeof(struct page) * cur_nr_pages);
477 }
478
479 /*
480 * Zone shrinking code cannot properly deal with ZONE_DEVICE. So
481 * we will not try to shrink the zones - which is okay as
482 * set_zone_contiguous() cannot deal with ZONE_DEVICE either way.
483 */
484 if (zone_is_zone_device(zone))
485 return;
486
487 clear_zone_contiguous(zone);
488
489 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
490 update_pgdat_span(pgdat);
491
492 set_zone_contiguous(zone);
493}
494
495static void __remove_section(unsigned long pfn, unsigned long nr_pages,
496 unsigned long map_offset,
497 struct vmem_altmap *altmap)
498{
499 struct mem_section *ms = __pfn_to_section(pfn);
500
501 if (WARN_ON_ONCE(!valid_section(ms)))
502 return;
503
504 sparse_remove_section(ms, pfn, nr_pages, map_offset, altmap);
505}
506
507/**
508 * __remove_pages() - remove sections of pages
509 * @pfn: starting pageframe (must be aligned to start of a section)
510 * @nr_pages: number of pages to remove (must be multiple of section size)
511 * @altmap: alternative device page map or %NULL if default memmap is used
512 *
513 * Generic helper function to remove section mappings and sysfs entries
514 * for the section of the memory we are removing. Caller needs to make
515 * sure that pages are marked reserved and zones are adjust properly by
516 * calling offline_pages().
517 */
518void __remove_pages(unsigned long pfn, unsigned long nr_pages,
519 struct vmem_altmap *altmap)
520{
521 const unsigned long end_pfn = pfn + nr_pages;
522 unsigned long cur_nr_pages;
523 unsigned long map_offset = 0;
524
525 map_offset = vmem_altmap_offset(altmap);
526
527 if (check_pfn_span(pfn, nr_pages)) {
528 WARN(1, "Misaligned %s start: %#lx end: #%lx\n", __func__, pfn, pfn + nr_pages - 1);
529 return;
530 }
531
532 for (; pfn < end_pfn; pfn += cur_nr_pages) {
533 cond_resched();
534 /* Select all remaining pages up to the next section boundary */
535 cur_nr_pages = min(end_pfn - pfn,
536 SECTION_ALIGN_UP(pfn + 1) - pfn);
537 __remove_section(pfn, cur_nr_pages, map_offset, altmap);
538 map_offset = 0;
539 }
540}
541
542int set_online_page_callback(online_page_callback_t callback)
543{
544 int rc = -EINVAL;
545
546 get_online_mems();
547 mutex_lock(&online_page_callback_lock);
548
549 if (online_page_callback == generic_online_page) {
550 online_page_callback = callback;
551 rc = 0;
552 }
553
554 mutex_unlock(&online_page_callback_lock);
555 put_online_mems();
556
557 return rc;
558}
559EXPORT_SYMBOL_GPL(set_online_page_callback);
560
561int restore_online_page_callback(online_page_callback_t callback)
562{
563 int rc = -EINVAL;
564
565 get_online_mems();
566 mutex_lock(&online_page_callback_lock);
567
568 if (online_page_callback == callback) {
569 online_page_callback = generic_online_page;
570 rc = 0;
571 }
572
573 mutex_unlock(&online_page_callback_lock);
574 put_online_mems();
575
576 return rc;
577}
578EXPORT_SYMBOL_GPL(restore_online_page_callback);
579
580void generic_online_page(struct page *page, unsigned int order)
581{
582 /*
583 * Freeing the page with debug_pagealloc enabled will try to unmap it,
584 * so we should map it first. This is better than introducing a special
585 * case in page freeing fast path.
586 */
587 debug_pagealloc_map_pages(page, 1 << order);
588 __free_pages_core(page, order);
589 totalram_pages_add(1UL << order);
590}
591EXPORT_SYMBOL_GPL(generic_online_page);
592
593static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages)
594{
595 const unsigned long end_pfn = start_pfn + nr_pages;
596 unsigned long pfn;
597
598 /*
599 * Online the pages in MAX_ORDER - 1 aligned chunks. The callback might
600 * decide to not expose all pages to the buddy (e.g., expose them
601 * later). We account all pages as being online and belonging to this
602 * zone ("present").
603 * When using memmap_on_memory, the range might not be aligned to
604 * MAX_ORDER_NR_PAGES - 1, but pageblock aligned. __ffs() will detect
605 * this and the first chunk to online will be pageblock_nr_pages.
606 */
607 for (pfn = start_pfn; pfn < end_pfn;) {
608 int order = min(MAX_ORDER - 1UL, __ffs(pfn));
609
610 (*online_page_callback)(pfn_to_page(pfn), order);
611 pfn += (1UL << order);
612 }
613
614 /* mark all involved sections as online */
615 online_mem_sections(start_pfn, end_pfn);
616}
617
618/* check which state of node_states will be changed when online memory */
619static void node_states_check_changes_online(unsigned long nr_pages,
620 struct zone *zone, struct memory_notify *arg)
621{
622 int nid = zone_to_nid(zone);
623
624 arg->status_change_nid = NUMA_NO_NODE;
625 arg->status_change_nid_normal = NUMA_NO_NODE;
626
627 if (!node_state(nid, N_MEMORY))
628 arg->status_change_nid = nid;
629 if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY))
630 arg->status_change_nid_normal = nid;
631}
632
633static void node_states_set_node(int node, struct memory_notify *arg)
634{
635 if (arg->status_change_nid_normal >= 0)
636 node_set_state(node, N_NORMAL_MEMORY);
637
638 if (arg->status_change_nid >= 0)
639 node_set_state(node, N_MEMORY);
640}
641
642static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
643 unsigned long nr_pages)
644{
645 unsigned long old_end_pfn = zone_end_pfn(zone);
646
647 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
648 zone->zone_start_pfn = start_pfn;
649
650 zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn;
651}
652
653static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn,
654 unsigned long nr_pages)
655{
656 unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
657
658 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
659 pgdat->node_start_pfn = start_pfn;
660
661 pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn;
662
663}
664
665#ifdef CONFIG_ZONE_DEVICE
666static void section_taint_zone_device(unsigned long pfn)
667{
668 struct mem_section *ms = __pfn_to_section(pfn);
669
670 ms->section_mem_map |= SECTION_TAINT_ZONE_DEVICE;
671}
672#else
673static inline void section_taint_zone_device(unsigned long pfn)
674{
675}
676#endif
677
678/*
679 * Associate the pfn range with the given zone, initializing the memmaps
680 * and resizing the pgdat/zone data to span the added pages. After this
681 * call, all affected pages are PG_reserved.
682 *
683 * All aligned pageblocks are initialized to the specified migratetype
684 * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related
685 * zone stats (e.g., nr_isolate_pageblock) are touched.
686 */
687void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
688 unsigned long nr_pages,
689 struct vmem_altmap *altmap, int migratetype)
690{
691 struct pglist_data *pgdat = zone->zone_pgdat;
692 int nid = pgdat->node_id;
693
694 clear_zone_contiguous(zone);
695
696 if (zone_is_empty(zone))
697 init_currently_empty_zone(zone, start_pfn, nr_pages);
698 resize_zone_range(zone, start_pfn, nr_pages);
699 resize_pgdat_range(pgdat, start_pfn, nr_pages);
700
701 /*
702 * Subsection population requires care in pfn_to_online_page().
703 * Set the taint to enable the slow path detection of
704 * ZONE_DEVICE pages in an otherwise ZONE_{NORMAL,MOVABLE}
705 * section.
706 */
707 if (zone_is_zone_device(zone)) {
708 if (!IS_ALIGNED(start_pfn, PAGES_PER_SECTION))
709 section_taint_zone_device(start_pfn);
710 if (!IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION))
711 section_taint_zone_device(start_pfn + nr_pages);
712 }
713
714 /*
715 * TODO now we have a visible range of pages which are not associated
716 * with their zone properly. Not nice but set_pfnblock_flags_mask
717 * expects the zone spans the pfn range. All the pages in the range
718 * are reserved so nobody should be touching them so we should be safe
719 */
720 memmap_init_range(nr_pages, nid, zone_idx(zone), start_pfn, 0,
721 MEMINIT_HOTPLUG, altmap, migratetype);
722
723 set_zone_contiguous(zone);
724}
725
726struct auto_movable_stats {
727 unsigned long kernel_early_pages;
728 unsigned long movable_pages;
729};
730
731static void auto_movable_stats_account_zone(struct auto_movable_stats *stats,
732 struct zone *zone)
733{
734 if (zone_idx(zone) == ZONE_MOVABLE) {
735 stats->movable_pages += zone->present_pages;
736 } else {
737 stats->kernel_early_pages += zone->present_early_pages;
738#ifdef CONFIG_CMA
739 /*
740 * CMA pages (never on hotplugged memory) behave like
741 * ZONE_MOVABLE.
742 */
743 stats->movable_pages += zone->cma_pages;
744 stats->kernel_early_pages -= zone->cma_pages;
745#endif /* CONFIG_CMA */
746 }
747}
748struct auto_movable_group_stats {
749 unsigned long movable_pages;
750 unsigned long req_kernel_early_pages;
751};
752
753static int auto_movable_stats_account_group(struct memory_group *group,
754 void *arg)
755{
756 const int ratio = READ_ONCE(auto_movable_ratio);
757 struct auto_movable_group_stats *stats = arg;
758 long pages;
759
760 /*
761 * We don't support modifying the config while the auto-movable online
762 * policy is already enabled. Just avoid the division by zero below.
763 */
764 if (!ratio)
765 return 0;
766
767 /*
768 * Calculate how many early kernel pages this group requires to
769 * satisfy the configured zone ratio.
770 */
771 pages = group->present_movable_pages * 100 / ratio;
772 pages -= group->present_kernel_pages;
773
774 if (pages > 0)
775 stats->req_kernel_early_pages += pages;
776 stats->movable_pages += group->present_movable_pages;
777 return 0;
778}
779
780static bool auto_movable_can_online_movable(int nid, struct memory_group *group,
781 unsigned long nr_pages)
782{
783 unsigned long kernel_early_pages, movable_pages;
784 struct auto_movable_group_stats group_stats = {};
785 struct auto_movable_stats stats = {};
786 pg_data_t *pgdat = NODE_DATA(nid);
787 struct zone *zone;
788 int i;
789
790 /* Walk all relevant zones and collect MOVABLE vs. KERNEL stats. */
791 if (nid == NUMA_NO_NODE) {
792 /* TODO: cache values */
793 for_each_populated_zone(zone)
794 auto_movable_stats_account_zone(&stats, zone);
795 } else {
796 for (i = 0; i < MAX_NR_ZONES; i++) {
797 zone = pgdat->node_zones + i;
798 if (populated_zone(zone))
799 auto_movable_stats_account_zone(&stats, zone);
800 }
801 }
802
803 kernel_early_pages = stats.kernel_early_pages;
804 movable_pages = stats.movable_pages;
805
806 /*
807 * Kernel memory inside dynamic memory group allows for more MOVABLE
808 * memory within the same group. Remove the effect of all but the
809 * current group from the stats.
810 */
811 walk_dynamic_memory_groups(nid, auto_movable_stats_account_group,
812 group, &group_stats);
813 if (kernel_early_pages <= group_stats.req_kernel_early_pages)
814 return false;
815 kernel_early_pages -= group_stats.req_kernel_early_pages;
816 movable_pages -= group_stats.movable_pages;
817
818 if (group && group->is_dynamic)
819 kernel_early_pages += group->present_kernel_pages;
820
821 /*
822 * Test if we could online the given number of pages to ZONE_MOVABLE
823 * and still stay in the configured ratio.
824 */
825 movable_pages += nr_pages;
826 return movable_pages <= (auto_movable_ratio * kernel_early_pages) / 100;
827}
828
829/*
830 * Returns a default kernel memory zone for the given pfn range.
831 * If no kernel zone covers this pfn range it will automatically go
832 * to the ZONE_NORMAL.
833 */
834static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn,
835 unsigned long nr_pages)
836{
837 struct pglist_data *pgdat = NODE_DATA(nid);
838 int zid;
839
840 for (zid = 0; zid < ZONE_NORMAL; zid++) {
841 struct zone *zone = &pgdat->node_zones[zid];
842
843 if (zone_intersects(zone, start_pfn, nr_pages))
844 return zone;
845 }
846
847 return &pgdat->node_zones[ZONE_NORMAL];
848}
849
850/*
851 * Determine to which zone to online memory dynamically based on user
852 * configuration and system stats. We care about the following ratio:
853 *
854 * MOVABLE : KERNEL
855 *
856 * Whereby MOVABLE is memory in ZONE_MOVABLE and KERNEL is memory in
857 * one of the kernel zones. CMA pages inside one of the kernel zones really
858 * behaves like ZONE_MOVABLE, so we treat them accordingly.
859 *
860 * We don't allow for hotplugged memory in a KERNEL zone to increase the
861 * amount of MOVABLE memory we can have, so we end up with:
862 *
863 * MOVABLE : KERNEL_EARLY
864 *
865 * Whereby KERNEL_EARLY is memory in one of the kernel zones, available sinze
866 * boot. We base our calculation on KERNEL_EARLY internally, because:
867 *
868 * a) Hotplugged memory in one of the kernel zones can sometimes still get
869 * hotunplugged, especially when hot(un)plugging individual memory blocks.
870 * There is no coordination across memory devices, therefore "automatic"
871 * hotunplugging, as implemented in hypervisors, could result in zone
872 * imbalances.
873 * b) Early/boot memory in one of the kernel zones can usually not get
874 * hotunplugged again (e.g., no firmware interface to unplug, fragmented
875 * with unmovable allocations). While there are corner cases where it might
876 * still work, it is barely relevant in practice.
877 *
878 * Exceptions are dynamic memory groups, which allow for more MOVABLE
879 * memory within the same memory group -- because in that case, there is
880 * coordination within the single memory device managed by a single driver.
881 *
882 * We rely on "present pages" instead of "managed pages", as the latter is
883 * highly unreliable and dynamic in virtualized environments, and does not
884 * consider boot time allocations. For example, memory ballooning adjusts the
885 * managed pages when inflating/deflating the balloon, and balloon compaction
886 * can even migrate inflated pages between zones.
887 *
888 * Using "present pages" is better but some things to keep in mind are:
889 *
890 * a) Some memblock allocations, such as for the crashkernel area, are
891 * effectively unused by the kernel, yet they account to "present pages".
892 * Fortunately, these allocations are comparatively small in relevant setups
893 * (e.g., fraction of system memory).
894 * b) Some hotplugged memory blocks in virtualized environments, esecially
895 * hotplugged by virtio-mem, look like they are completely present, however,
896 * only parts of the memory block are actually currently usable.
897 * "present pages" is an upper limit that can get reached at runtime. As
898 * we base our calculations on KERNEL_EARLY, this is not an issue.
899 */
900static struct zone *auto_movable_zone_for_pfn(int nid,
901 struct memory_group *group,
902 unsigned long pfn,
903 unsigned long nr_pages)
904{
905 unsigned long online_pages = 0, max_pages, end_pfn;
906 struct page *page;
907
908 if (!auto_movable_ratio)
909 goto kernel_zone;
910
911 if (group && !group->is_dynamic) {
912 max_pages = group->s.max_pages;
913 online_pages = group->present_movable_pages;
914
915 /* If anything is !MOVABLE online the rest !MOVABLE. */
916 if (group->present_kernel_pages)
917 goto kernel_zone;
918 } else if (!group || group->d.unit_pages == nr_pages) {
919 max_pages = nr_pages;
920 } else {
921 max_pages = group->d.unit_pages;
922 /*
923 * Take a look at all online sections in the current unit.
924 * We can safely assume that all pages within a section belong
925 * to the same zone, because dynamic memory groups only deal
926 * with hotplugged memory.
927 */
928 pfn = ALIGN_DOWN(pfn, group->d.unit_pages);
929 end_pfn = pfn + group->d.unit_pages;
930 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
931 page = pfn_to_online_page(pfn);
932 if (!page)
933 continue;
934 /* If anything is !MOVABLE online the rest !MOVABLE. */
935 if (!is_zone_movable_page(page))
936 goto kernel_zone;
937 online_pages += PAGES_PER_SECTION;
938 }
939 }
940
941 /*
942 * Online MOVABLE if we could *currently* online all remaining parts
943 * MOVABLE. We expect to (add+) online them immediately next, so if
944 * nobody interferes, all will be MOVABLE if possible.
945 */
946 nr_pages = max_pages - online_pages;
947 if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages))
948 goto kernel_zone;
949
950#ifdef CONFIG_NUMA
951 if (auto_movable_numa_aware &&
952 !auto_movable_can_online_movable(nid, group, nr_pages))
953 goto kernel_zone;
954#endif /* CONFIG_NUMA */
955
956 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
957kernel_zone:
958 return default_kernel_zone_for_pfn(nid, pfn, nr_pages);
959}
960
961static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn,
962 unsigned long nr_pages)
963{
964 struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn,
965 nr_pages);
966 struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
967 bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages);
968 bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages);
969
970 /*
971 * We inherit the existing zone in a simple case where zones do not
972 * overlap in the given range
973 */
974 if (in_kernel ^ in_movable)
975 return (in_kernel) ? kernel_zone : movable_zone;
976
977 /*
978 * If the range doesn't belong to any zone or two zones overlap in the
979 * given range then we use movable zone only if movable_node is
980 * enabled because we always online to a kernel zone by default.
981 */
982 return movable_node_enabled ? movable_zone : kernel_zone;
983}
984
985struct zone *zone_for_pfn_range(int online_type, int nid,
986 struct memory_group *group, unsigned long start_pfn,
987 unsigned long nr_pages)
988{
989 if (online_type == MMOP_ONLINE_KERNEL)
990 return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages);
991
992 if (online_type == MMOP_ONLINE_MOVABLE)
993 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
994
995 if (online_policy == ONLINE_POLICY_AUTO_MOVABLE)
996 return auto_movable_zone_for_pfn(nid, group, start_pfn, nr_pages);
997
998 return default_zone_for_pfn(nid, start_pfn, nr_pages);
999}
1000
1001/*
1002 * This function should only be called by memory_block_{online,offline},
1003 * and {online,offline}_pages.
1004 */
1005void adjust_present_page_count(struct page *page, struct memory_group *group,
1006 long nr_pages)
1007{
1008 struct zone *zone = page_zone(page);
1009 const bool movable = zone_idx(zone) == ZONE_MOVABLE;
1010
1011 /*
1012 * We only support onlining/offlining/adding/removing of complete
1013 * memory blocks; therefore, either all is either early or hotplugged.
1014 */
1015 if (early_section(__pfn_to_section(page_to_pfn(page))))
1016 zone->present_early_pages += nr_pages;
1017 zone->present_pages += nr_pages;
1018 zone->zone_pgdat->node_present_pages += nr_pages;
1019
1020 if (group && movable)
1021 group->present_movable_pages += nr_pages;
1022 else if (group && !movable)
1023 group->present_kernel_pages += nr_pages;
1024}
1025
1026int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages,
1027 struct zone *zone)
1028{
1029 unsigned long end_pfn = pfn + nr_pages;
1030 int ret, i;
1031
1032 ret = kasan_add_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages));
1033 if (ret)
1034 return ret;
1035
1036 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_UNMOVABLE);
1037
1038 for (i = 0; i < nr_pages; i++)
1039 SetPageVmemmapSelfHosted(pfn_to_page(pfn + i));
1040
1041 /*
1042 * It might be that the vmemmap_pages fully span sections. If that is
1043 * the case, mark those sections online here as otherwise they will be
1044 * left offline.
1045 */
1046 if (nr_pages >= PAGES_PER_SECTION)
1047 online_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION));
1048
1049 return ret;
1050}
1051
1052void mhp_deinit_memmap_on_memory(unsigned long pfn, unsigned long nr_pages)
1053{
1054 unsigned long end_pfn = pfn + nr_pages;
1055
1056 /*
1057 * It might be that the vmemmap_pages fully span sections. If that is
1058 * the case, mark those sections offline here as otherwise they will be
1059 * left online.
1060 */
1061 if (nr_pages >= PAGES_PER_SECTION)
1062 offline_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION));
1063
1064 /*
1065 * The pages associated with this vmemmap have been offlined, so
1066 * we can reset its state here.
1067 */
1068 remove_pfn_range_from_zone(page_zone(pfn_to_page(pfn)), pfn, nr_pages);
1069 kasan_remove_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages));
1070}
1071
1072int __ref online_pages(unsigned long pfn, unsigned long nr_pages,
1073 struct zone *zone, struct memory_group *group)
1074{
1075 unsigned long flags;
1076 int need_zonelists_rebuild = 0;
1077 const int nid = zone_to_nid(zone);
1078 int ret;
1079 struct memory_notify arg;
1080
1081 /*
1082 * {on,off}lining is constrained to full memory sections (or more
1083 * precisely to memory blocks from the user space POV).
1084 * memmap_on_memory is an exception because it reserves initial part
1085 * of the physical memory space for vmemmaps. That space is pageblock
1086 * aligned.
1087 */
1088 if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(pfn) ||
1089 !IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION)))
1090 return -EINVAL;
1091
1092 mem_hotplug_begin();
1093
1094 /* associate pfn range with the zone */
1095 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_ISOLATE);
1096
1097 arg.start_pfn = pfn;
1098 arg.nr_pages = nr_pages;
1099 node_states_check_changes_online(nr_pages, zone, &arg);
1100
1101 ret = memory_notify(MEM_GOING_ONLINE, &arg);
1102 ret = notifier_to_errno(ret);
1103 if (ret)
1104 goto failed_addition;
1105
1106 /*
1107 * Fixup the number of isolated pageblocks before marking the sections
1108 * onlining, such that undo_isolate_page_range() works correctly.
1109 */
1110 spin_lock_irqsave(&zone->lock, flags);
1111 zone->nr_isolate_pageblock += nr_pages / pageblock_nr_pages;
1112 spin_unlock_irqrestore(&zone->lock, flags);
1113
1114 /*
1115 * If this zone is not populated, then it is not in zonelist.
1116 * This means the page allocator ignores this zone.
1117 * So, zonelist must be updated after online.
1118 */
1119 if (!populated_zone(zone)) {
1120 need_zonelists_rebuild = 1;
1121 setup_zone_pageset(zone);
1122 }
1123
1124 online_pages_range(pfn, nr_pages);
1125 adjust_present_page_count(pfn_to_page(pfn), group, nr_pages);
1126
1127 node_states_set_node(nid, &arg);
1128 if (need_zonelists_rebuild)
1129 build_all_zonelists(NULL);
1130
1131 /* Basic onlining is complete, allow allocation of onlined pages. */
1132 undo_isolate_page_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE);
1133
1134 /*
1135 * Freshly onlined pages aren't shuffled (e.g., all pages are placed to
1136 * the tail of the freelist when undoing isolation). Shuffle the whole
1137 * zone to make sure the just onlined pages are properly distributed
1138 * across the whole freelist - to create an initial shuffle.
1139 */
1140 shuffle_zone(zone);
1141
1142 /* reinitialise watermarks and update pcp limits */
1143 init_per_zone_wmark_min();
1144
1145 kswapd_run(nid);
1146 kcompactd_run(nid);
1147
1148 writeback_set_ratelimit();
1149
1150 memory_notify(MEM_ONLINE, &arg);
1151 mem_hotplug_done();
1152 return 0;
1153
1154failed_addition:
1155 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
1156 (unsigned long long) pfn << PAGE_SHIFT,
1157 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
1158 memory_notify(MEM_CANCEL_ONLINE, &arg);
1159 remove_pfn_range_from_zone(zone, pfn, nr_pages);
1160 mem_hotplug_done();
1161 return ret;
1162}
1163
1164static void reset_node_present_pages(pg_data_t *pgdat)
1165{
1166 struct zone *z;
1167
1168 for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
1169 z->present_pages = 0;
1170
1171 pgdat->node_present_pages = 0;
1172}
1173
1174/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1175static pg_data_t __ref *hotadd_init_pgdat(int nid)
1176{
1177 struct pglist_data *pgdat;
1178
1179 /*
1180 * NODE_DATA is preallocated (free_area_init) but its internal
1181 * state is not allocated completely. Add missing pieces.
1182 * Completely offline nodes stay around and they just need
1183 * reintialization.
1184 */
1185 pgdat = NODE_DATA(nid);
1186
1187 /* init node's zones as empty zones, we don't have any present pages.*/
1188 free_area_init_core_hotplug(pgdat);
1189
1190 /*
1191 * The node we allocated has no zone fallback lists. For avoiding
1192 * to access not-initialized zonelist, build here.
1193 */
1194 build_all_zonelists(pgdat);
1195
1196 /*
1197 * When memory is hot-added, all the memory is in offline state. So
1198 * clear all zones' present_pages because they will be updated in
1199 * online_pages() and offline_pages().
1200 * TODO: should be in free_area_init_core_hotplug?
1201 */
1202 reset_node_managed_pages(pgdat);
1203 reset_node_present_pages(pgdat);
1204
1205 return pgdat;
1206}
1207
1208/*
1209 * __try_online_node - online a node if offlined
1210 * @nid: the node ID
1211 * @set_node_online: Whether we want to online the node
1212 * called by cpu_up() to online a node without onlined memory.
1213 *
1214 * Returns:
1215 * 1 -> a new node has been allocated
1216 * 0 -> the node is already online
1217 * -ENOMEM -> the node could not be allocated
1218 */
1219static int __try_online_node(int nid, bool set_node_online)
1220{
1221 pg_data_t *pgdat;
1222 int ret = 1;
1223
1224 if (node_online(nid))
1225 return 0;
1226
1227 pgdat = hotadd_init_pgdat(nid);
1228 if (!pgdat) {
1229 pr_err("Cannot online node %d due to NULL pgdat\n", nid);
1230 ret = -ENOMEM;
1231 goto out;
1232 }
1233
1234 if (set_node_online) {
1235 node_set_online(nid);
1236 ret = register_one_node(nid);
1237 BUG_ON(ret);
1238 }
1239out:
1240 return ret;
1241}
1242
1243/*
1244 * Users of this function always want to online/register the node
1245 */
1246int try_online_node(int nid)
1247{
1248 int ret;
1249
1250 mem_hotplug_begin();
1251 ret = __try_online_node(nid, true);
1252 mem_hotplug_done();
1253 return ret;
1254}
1255
1256static int check_hotplug_memory_range(u64 start, u64 size)
1257{
1258 /* memory range must be block size aligned */
1259 if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) ||
1260 !IS_ALIGNED(size, memory_block_size_bytes())) {
1261 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
1262 memory_block_size_bytes(), start, size);
1263 return -EINVAL;
1264 }
1265
1266 return 0;
1267}
1268
1269static int online_memory_block(struct memory_block *mem, void *arg)
1270{
1271 mem->online_type = mhp_default_online_type;
1272 return device_online(&mem->dev);
1273}
1274
1275bool mhp_supports_memmap_on_memory(unsigned long size)
1276{
1277 unsigned long nr_vmemmap_pages = size / PAGE_SIZE;
1278 unsigned long vmemmap_size = nr_vmemmap_pages * sizeof(struct page);
1279 unsigned long remaining_size = size - vmemmap_size;
1280
1281 /*
1282 * Besides having arch support and the feature enabled at runtime, we
1283 * need a few more assumptions to hold true:
1284 *
1285 * a) We span a single memory block: memory onlining/offlinin;g happens
1286 * in memory block granularity. We don't want the vmemmap of online
1287 * memory blocks to reside on offline memory blocks. In the future,
1288 * we might want to support variable-sized memory blocks to make the
1289 * feature more versatile.
1290 *
1291 * b) The vmemmap pages span complete PMDs: We don't want vmemmap code
1292 * to populate memory from the altmap for unrelated parts (i.e.,
1293 * other memory blocks)
1294 *
1295 * c) The vmemmap pages (and thereby the pages that will be exposed to
1296 * the buddy) have to cover full pageblocks: memory onlining/offlining
1297 * code requires applicable ranges to be page-aligned, for example, to
1298 * set the migratetypes properly.
1299 *
1300 * TODO: Although we have a check here to make sure that vmemmap pages
1301 * fully populate a PMD, it is not the right place to check for
1302 * this. A much better solution involves improving vmemmap code
1303 * to fallback to base pages when trying to populate vmemmap using
1304 * altmap as an alternative source of memory, and we do not exactly
1305 * populate a single PMD.
1306 */
1307 return mhp_memmap_on_memory() &&
1308 size == memory_block_size_bytes() &&
1309 IS_ALIGNED(vmemmap_size, PMD_SIZE) &&
1310 IS_ALIGNED(remaining_size, (pageblock_nr_pages << PAGE_SHIFT));
1311}
1312
1313/*
1314 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1315 * and online/offline operations (triggered e.g. by sysfs).
1316 *
1317 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
1318 */
1319int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
1320{
1321 struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
1322 enum memblock_flags memblock_flags = MEMBLOCK_NONE;
1323 struct vmem_altmap mhp_altmap = {};
1324 struct memory_group *group = NULL;
1325 u64 start, size;
1326 bool new_node = false;
1327 int ret;
1328
1329 start = res->start;
1330 size = resource_size(res);
1331
1332 ret = check_hotplug_memory_range(start, size);
1333 if (ret)
1334 return ret;
1335
1336 if (mhp_flags & MHP_NID_IS_MGID) {
1337 group = memory_group_find_by_id(nid);
1338 if (!group)
1339 return -EINVAL;
1340 nid = group->nid;
1341 }
1342
1343 if (!node_possible(nid)) {
1344 WARN(1, "node %d was absent from the node_possible_map\n", nid);
1345 return -EINVAL;
1346 }
1347
1348 mem_hotplug_begin();
1349
1350 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
1351 if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
1352 memblock_flags = MEMBLOCK_DRIVER_MANAGED;
1353 ret = memblock_add_node(start, size, nid, memblock_flags);
1354 if (ret)
1355 goto error_mem_hotplug_end;
1356 }
1357
1358 ret = __try_online_node(nid, false);
1359 if (ret < 0)
1360 goto error;
1361 new_node = ret;
1362
1363 /*
1364 * Self hosted memmap array
1365 */
1366 if (mhp_flags & MHP_MEMMAP_ON_MEMORY) {
1367 if (!mhp_supports_memmap_on_memory(size)) {
1368 ret = -EINVAL;
1369 goto error;
1370 }
1371 mhp_altmap.free = PHYS_PFN(size);
1372 mhp_altmap.base_pfn = PHYS_PFN(start);
1373 params.altmap = &mhp_altmap;
1374 }
1375
1376 /* call arch's memory hotadd */
1377 ret = arch_add_memory(nid, start, size, ¶ms);
1378 if (ret < 0)
1379 goto error;
1380
1381 /* create memory block devices after memory was added */
1382 ret = create_memory_block_devices(start, size, mhp_altmap.alloc,
1383 group);
1384 if (ret) {
1385 arch_remove_memory(start, size, NULL);
1386 goto error;
1387 }
1388
1389 if (new_node) {
1390 /* If sysfs file of new node can't be created, cpu on the node
1391 * can't be hot-added. There is no rollback way now.
1392 * So, check by BUG_ON() to catch it reluctantly..
1393 * We online node here. We can't roll back from here.
1394 */
1395 node_set_online(nid);
1396 ret = __register_one_node(nid);
1397 BUG_ON(ret);
1398 }
1399
1400 register_memory_blocks_under_node(nid, PFN_DOWN(start),
1401 PFN_UP(start + size - 1),
1402 MEMINIT_HOTPLUG);
1403
1404 /* create new memmap entry */
1405 if (!strcmp(res->name, "System RAM"))
1406 firmware_map_add_hotplug(start, start + size, "System RAM");
1407
1408 /* device_online() will take the lock when calling online_pages() */
1409 mem_hotplug_done();
1410
1411 /*
1412 * In case we're allowed to merge the resource, flag it and trigger
1413 * merging now that adding succeeded.
1414 */
1415 if (mhp_flags & MHP_MERGE_RESOURCE)
1416 merge_system_ram_resource(res);
1417
1418 /* online pages if requested */
1419 if (mhp_default_online_type != MMOP_OFFLINE)
1420 walk_memory_blocks(start, size, NULL, online_memory_block);
1421
1422 return ret;
1423error:
1424 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
1425 memblock_remove(start, size);
1426error_mem_hotplug_end:
1427 mem_hotplug_done();
1428 return ret;
1429}
1430
1431/* requires device_hotplug_lock, see add_memory_resource() */
1432int __ref __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
1433{
1434 struct resource *res;
1435 int ret;
1436
1437 res = register_memory_resource(start, size, "System RAM");
1438 if (IS_ERR(res))
1439 return PTR_ERR(res);
1440
1441 ret = add_memory_resource(nid, res, mhp_flags);
1442 if (ret < 0)
1443 release_memory_resource(res);
1444 return ret;
1445}
1446
1447int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
1448{
1449 int rc;
1450
1451 lock_device_hotplug();
1452 rc = __add_memory(nid, start, size, mhp_flags);
1453 unlock_device_hotplug();
1454
1455 return rc;
1456}
1457EXPORT_SYMBOL_GPL(add_memory);
1458
1459/*
1460 * Add special, driver-managed memory to the system as system RAM. Such
1461 * memory is not exposed via the raw firmware-provided memmap as system
1462 * RAM, instead, it is detected and added by a driver - during cold boot,
1463 * after a reboot, and after kexec.
1464 *
1465 * Reasons why this memory should not be used for the initial memmap of a
1466 * kexec kernel or for placing kexec images:
1467 * - The booting kernel is in charge of determining how this memory will be
1468 * used (e.g., use persistent memory as system RAM)
1469 * - Coordination with a hypervisor is required before this memory
1470 * can be used (e.g., inaccessible parts).
1471 *
1472 * For this memory, no entries in /sys/firmware/memmap ("raw firmware-provided
1473 * memory map") are created. Also, the created memory resource is flagged
1474 * with IORESOURCE_SYSRAM_DRIVER_MANAGED, so in-kernel users can special-case
1475 * this memory as well (esp., not place kexec images onto it).
1476 *
1477 * The resource_name (visible via /proc/iomem) has to have the format
1478 * "System RAM ($DRIVER)".
1479 */
1480int add_memory_driver_managed(int nid, u64 start, u64 size,
1481 const char *resource_name, mhp_t mhp_flags)
1482{
1483 struct resource *res;
1484 int rc;
1485
1486 if (!resource_name ||
1487 strstr(resource_name, "System RAM (") != resource_name ||
1488 resource_name[strlen(resource_name) - 1] != ')')
1489 return -EINVAL;
1490
1491 lock_device_hotplug();
1492
1493 res = register_memory_resource(start, size, resource_name);
1494 if (IS_ERR(res)) {
1495 rc = PTR_ERR(res);
1496 goto out_unlock;
1497 }
1498
1499 rc = add_memory_resource(nid, res, mhp_flags);
1500 if (rc < 0)
1501 release_memory_resource(res);
1502
1503out_unlock:
1504 unlock_device_hotplug();
1505 return rc;
1506}
1507EXPORT_SYMBOL_GPL(add_memory_driver_managed);
1508
1509/*
1510 * Platforms should define arch_get_mappable_range() that provides
1511 * maximum possible addressable physical memory range for which the
1512 * linear mapping could be created. The platform returned address
1513 * range must adhere to these following semantics.
1514 *
1515 * - range.start <= range.end
1516 * - Range includes both end points [range.start..range.end]
1517 *
1518 * There is also a fallback definition provided here, allowing the
1519 * entire possible physical address range in case any platform does
1520 * not define arch_get_mappable_range().
1521 */
1522struct range __weak arch_get_mappable_range(void)
1523{
1524 struct range mhp_range = {
1525 .start = 0UL,
1526 .end = -1ULL,
1527 };
1528 return mhp_range;
1529}
1530
1531struct range mhp_get_pluggable_range(bool need_mapping)
1532{
1533 const u64 max_phys = (1ULL << MAX_PHYSMEM_BITS) - 1;
1534 struct range mhp_range;
1535
1536 if (need_mapping) {
1537 mhp_range = arch_get_mappable_range();
1538 if (mhp_range.start > max_phys) {
1539 mhp_range.start = 0;
1540 mhp_range.end = 0;
1541 }
1542 mhp_range.end = min_t(u64, mhp_range.end, max_phys);
1543 } else {
1544 mhp_range.start = 0;
1545 mhp_range.end = max_phys;
1546 }
1547 return mhp_range;
1548}
1549EXPORT_SYMBOL_GPL(mhp_get_pluggable_range);
1550
1551bool mhp_range_allowed(u64 start, u64 size, bool need_mapping)
1552{
1553 struct range mhp_range = mhp_get_pluggable_range(need_mapping);
1554 u64 end = start + size;
1555
1556 if (start < end && start >= mhp_range.start && (end - 1) <= mhp_range.end)
1557 return true;
1558
1559 pr_warn("Hotplug memory [%#llx-%#llx] exceeds maximum addressable range [%#llx-%#llx]\n",
1560 start, end, mhp_range.start, mhp_range.end);
1561 return false;
1562}
1563
1564#ifdef CONFIG_MEMORY_HOTREMOVE
1565/*
1566 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
1567 * non-lru movable pages and hugepages). Will skip over most unmovable
1568 * pages (esp., pages that can be skipped when offlining), but bail out on
1569 * definitely unmovable pages.
1570 *
1571 * Returns:
1572 * 0 in case a movable page is found and movable_pfn was updated.
1573 * -ENOENT in case no movable page was found.
1574 * -EBUSY in case a definitely unmovable page was found.
1575 */
1576static int scan_movable_pages(unsigned long start, unsigned long end,
1577 unsigned long *movable_pfn)
1578{
1579 unsigned long pfn;
1580
1581 for (pfn = start; pfn < end; pfn++) {
1582 struct page *page, *head;
1583 unsigned long skip;
1584
1585 if (!pfn_valid(pfn))
1586 continue;
1587 page = pfn_to_page(pfn);
1588 if (PageLRU(page))
1589 goto found;
1590 if (__PageMovable(page))
1591 goto found;
1592
1593 /*
1594 * PageOffline() pages that are not marked __PageMovable() and
1595 * have a reference count > 0 (after MEM_GOING_OFFLINE) are
1596 * definitely unmovable. If their reference count would be 0,
1597 * they could at least be skipped when offlining memory.
1598 */
1599 if (PageOffline(page) && page_count(page))
1600 return -EBUSY;
1601
1602 if (!PageHuge(page))
1603 continue;
1604 head = compound_head(page);
1605 /*
1606 * This test is racy as we hold no reference or lock. The
1607 * hugetlb page could have been free'ed and head is no longer
1608 * a hugetlb page before the following check. In such unlikely
1609 * cases false positives and negatives are possible. Calling
1610 * code must deal with these scenarios.
1611 */
1612 if (HPageMigratable(head))
1613 goto found;
1614 skip = compound_nr(head) - (page - head);
1615 pfn += skip - 1;
1616 }
1617 return -ENOENT;
1618found:
1619 *movable_pfn = pfn;
1620 return 0;
1621}
1622
1623static int
1624do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1625{
1626 unsigned long pfn;
1627 struct page *page, *head;
1628 int ret = 0;
1629 LIST_HEAD(source);
1630 static DEFINE_RATELIMIT_STATE(migrate_rs, DEFAULT_RATELIMIT_INTERVAL,
1631 DEFAULT_RATELIMIT_BURST);
1632
1633 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1634 struct folio *folio;
1635
1636 if (!pfn_valid(pfn))
1637 continue;
1638 page = pfn_to_page(pfn);
1639 folio = page_folio(page);
1640 head = &folio->page;
1641
1642 if (PageHuge(page)) {
1643 pfn = page_to_pfn(head) + compound_nr(head) - 1;
1644 isolate_hugetlb(head, &source);
1645 continue;
1646 } else if (PageTransHuge(page))
1647 pfn = page_to_pfn(head) + thp_nr_pages(page) - 1;
1648
1649 /*
1650 * HWPoison pages have elevated reference counts so the migration would
1651 * fail on them. It also doesn't make any sense to migrate them in the
1652 * first place. Still try to unmap such a page in case it is still mapped
1653 * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep
1654 * the unmap as the catch all safety net).
1655 */
1656 if (PageHWPoison(page)) {
1657 if (WARN_ON(folio_test_lru(folio)))
1658 folio_isolate_lru(folio);
1659 if (folio_mapped(folio))
1660 try_to_unmap(folio, TTU_IGNORE_MLOCK);
1661 continue;
1662 }
1663
1664 if (!get_page_unless_zero(page))
1665 continue;
1666 /*
1667 * We can skip free pages. And we can deal with pages on
1668 * LRU and non-lru movable pages.
1669 */
1670 if (PageLRU(page))
1671 ret = isolate_lru_page(page);
1672 else
1673 ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE);
1674 if (!ret) { /* Success */
1675 list_add_tail(&page->lru, &source);
1676 if (!__PageMovable(page))
1677 inc_node_page_state(page, NR_ISOLATED_ANON +
1678 page_is_file_lru(page));
1679
1680 } else {
1681 if (__ratelimit(&migrate_rs)) {
1682 pr_warn("failed to isolate pfn %lx\n", pfn);
1683 dump_page(page, "isolation failed");
1684 }
1685 }
1686 put_page(page);
1687 }
1688 if (!list_empty(&source)) {
1689 nodemask_t nmask = node_states[N_MEMORY];
1690 struct migration_target_control mtc = {
1691 .nmask = &nmask,
1692 .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
1693 };
1694
1695 /*
1696 * We have checked that migration range is on a single zone so
1697 * we can use the nid of the first page to all the others.
1698 */
1699 mtc.nid = page_to_nid(list_first_entry(&source, struct page, lru));
1700
1701 /*
1702 * try to allocate from a different node but reuse this node
1703 * if there are no other online nodes to be used (e.g. we are
1704 * offlining a part of the only existing node)
1705 */
1706 node_clear(mtc.nid, nmask);
1707 if (nodes_empty(nmask))
1708 node_set(mtc.nid, nmask);
1709 ret = migrate_pages(&source, alloc_migration_target, NULL,
1710 (unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG, NULL);
1711 if (ret) {
1712 list_for_each_entry(page, &source, lru) {
1713 if (__ratelimit(&migrate_rs)) {
1714 pr_warn("migrating pfn %lx failed ret:%d\n",
1715 page_to_pfn(page), ret);
1716 dump_page(page, "migration failure");
1717 }
1718 }
1719 putback_movable_pages(&source);
1720 }
1721 }
1722
1723 return ret;
1724}
1725
1726static int __init cmdline_parse_movable_node(char *p)
1727{
1728 movable_node_enabled = true;
1729 return 0;
1730}
1731early_param("movable_node", cmdline_parse_movable_node);
1732
1733/* check which state of node_states will be changed when offline memory */
1734static void node_states_check_changes_offline(unsigned long nr_pages,
1735 struct zone *zone, struct memory_notify *arg)
1736{
1737 struct pglist_data *pgdat = zone->zone_pgdat;
1738 unsigned long present_pages = 0;
1739 enum zone_type zt;
1740
1741 arg->status_change_nid = NUMA_NO_NODE;
1742 arg->status_change_nid_normal = NUMA_NO_NODE;
1743
1744 /*
1745 * Check whether node_states[N_NORMAL_MEMORY] will be changed.
1746 * If the memory to be offline is within the range
1747 * [0..ZONE_NORMAL], and it is the last present memory there,
1748 * the zones in that range will become empty after the offlining,
1749 * thus we can determine that we need to clear the node from
1750 * node_states[N_NORMAL_MEMORY].
1751 */
1752 for (zt = 0; zt <= ZONE_NORMAL; zt++)
1753 present_pages += pgdat->node_zones[zt].present_pages;
1754 if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages)
1755 arg->status_change_nid_normal = zone_to_nid(zone);
1756
1757 /*
1758 * We have accounted the pages from [0..ZONE_NORMAL); ZONE_HIGHMEM
1759 * does not apply as we don't support 32bit.
1760 * Here we count the possible pages from ZONE_MOVABLE.
1761 * If after having accounted all the pages, we see that the nr_pages
1762 * to be offlined is over or equal to the accounted pages,
1763 * we know that the node will become empty, and so, we can clear
1764 * it for N_MEMORY as well.
1765 */
1766 present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages;
1767
1768 if (nr_pages >= present_pages)
1769 arg->status_change_nid = zone_to_nid(zone);
1770}
1771
1772static void node_states_clear_node(int node, struct memory_notify *arg)
1773{
1774 if (arg->status_change_nid_normal >= 0)
1775 node_clear_state(node, N_NORMAL_MEMORY);
1776
1777 if (arg->status_change_nid >= 0)
1778 node_clear_state(node, N_MEMORY);
1779}
1780
1781static int count_system_ram_pages_cb(unsigned long start_pfn,
1782 unsigned long nr_pages, void *data)
1783{
1784 unsigned long *nr_system_ram_pages = data;
1785
1786 *nr_system_ram_pages += nr_pages;
1787 return 0;
1788}
1789
1790int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages,
1791 struct zone *zone, struct memory_group *group)
1792{
1793 const unsigned long end_pfn = start_pfn + nr_pages;
1794 unsigned long pfn, system_ram_pages = 0;
1795 const int node = zone_to_nid(zone);
1796 unsigned long flags;
1797 struct memory_notify arg;
1798 char *reason;
1799 int ret;
1800
1801 /*
1802 * {on,off}lining is constrained to full memory sections (or more
1803 * precisely to memory blocks from the user space POV).
1804 * memmap_on_memory is an exception because it reserves initial part
1805 * of the physical memory space for vmemmaps. That space is pageblock
1806 * aligned.
1807 */
1808 if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(start_pfn) ||
1809 !IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION)))
1810 return -EINVAL;
1811
1812 mem_hotplug_begin();
1813
1814 /*
1815 * Don't allow to offline memory blocks that contain holes.
1816 * Consequently, memory blocks with holes can never get onlined
1817 * via the hotplug path - online_pages() - as hotplugged memory has
1818 * no holes. This way, we e.g., don't have to worry about marking
1819 * memory holes PG_reserved, don't need pfn_valid() checks, and can
1820 * avoid using walk_system_ram_range() later.
1821 */
1822 walk_system_ram_range(start_pfn, nr_pages, &system_ram_pages,
1823 count_system_ram_pages_cb);
1824 if (system_ram_pages != nr_pages) {
1825 ret = -EINVAL;
1826 reason = "memory holes";
1827 goto failed_removal;
1828 }
1829
1830 /*
1831 * We only support offlining of memory blocks managed by a single zone,
1832 * checked by calling code. This is just a sanity check that we might
1833 * want to remove in the future.
1834 */
1835 if (WARN_ON_ONCE(page_zone(pfn_to_page(start_pfn)) != zone ||
1836 page_zone(pfn_to_page(end_pfn - 1)) != zone)) {
1837 ret = -EINVAL;
1838 reason = "multizone range";
1839 goto failed_removal;
1840 }
1841
1842 /*
1843 * Disable pcplists so that page isolation cannot race with freeing
1844 * in a way that pages from isolated pageblock are left on pcplists.
1845 */
1846 zone_pcp_disable(zone);
1847 lru_cache_disable();
1848
1849 /* set above range as isolated */
1850 ret = start_isolate_page_range(start_pfn, end_pfn,
1851 MIGRATE_MOVABLE,
1852 MEMORY_OFFLINE | REPORT_FAILURE,
1853 GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL);
1854 if (ret) {
1855 reason = "failure to isolate range";
1856 goto failed_removal_pcplists_disabled;
1857 }
1858
1859 arg.start_pfn = start_pfn;
1860 arg.nr_pages = nr_pages;
1861 node_states_check_changes_offline(nr_pages, zone, &arg);
1862
1863 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1864 ret = notifier_to_errno(ret);
1865 if (ret) {
1866 reason = "notifier failure";
1867 goto failed_removal_isolated;
1868 }
1869
1870 do {
1871 pfn = start_pfn;
1872 do {
1873 if (signal_pending(current)) {
1874 ret = -EINTR;
1875 reason = "signal backoff";
1876 goto failed_removal_isolated;
1877 }
1878
1879 cond_resched();
1880
1881 ret = scan_movable_pages(pfn, end_pfn, &pfn);
1882 if (!ret) {
1883 /*
1884 * TODO: fatal migration failures should bail
1885 * out
1886 */
1887 do_migrate_range(pfn, end_pfn);
1888 }
1889 } while (!ret);
1890
1891 if (ret != -ENOENT) {
1892 reason = "unmovable page";
1893 goto failed_removal_isolated;
1894 }
1895
1896 /*
1897 * Dissolve free hugepages in the memory block before doing
1898 * offlining actually in order to make hugetlbfs's object
1899 * counting consistent.
1900 */
1901 ret = dissolve_free_huge_pages(start_pfn, end_pfn);
1902 if (ret) {
1903 reason = "failure to dissolve huge pages";
1904 goto failed_removal_isolated;
1905 }
1906
1907 ret = test_pages_isolated(start_pfn, end_pfn, MEMORY_OFFLINE);
1908
1909 } while (ret);
1910
1911 /* Mark all sections offline and remove free pages from the buddy. */
1912 __offline_isolated_pages(start_pfn, end_pfn);
1913 pr_debug("Offlined Pages %ld\n", nr_pages);
1914
1915 /*
1916 * The memory sections are marked offline, and the pageblock flags
1917 * effectively stale; nobody should be touching them. Fixup the number
1918 * of isolated pageblocks, memory onlining will properly revert this.
1919 */
1920 spin_lock_irqsave(&zone->lock, flags);
1921 zone->nr_isolate_pageblock -= nr_pages / pageblock_nr_pages;
1922 spin_unlock_irqrestore(&zone->lock, flags);
1923
1924 lru_cache_enable();
1925 zone_pcp_enable(zone);
1926
1927 /* removal success */
1928 adjust_managed_page_count(pfn_to_page(start_pfn), -nr_pages);
1929 adjust_present_page_count(pfn_to_page(start_pfn), group, -nr_pages);
1930
1931 /* reinitialise watermarks and update pcp limits */
1932 init_per_zone_wmark_min();
1933
1934 if (!populated_zone(zone)) {
1935 zone_pcp_reset(zone);
1936 build_all_zonelists(NULL);
1937 }
1938
1939 node_states_clear_node(node, &arg);
1940 if (arg.status_change_nid >= 0) {
1941 kcompactd_stop(node);
1942 kswapd_stop(node);
1943 }
1944
1945 writeback_set_ratelimit();
1946
1947 memory_notify(MEM_OFFLINE, &arg);
1948 remove_pfn_range_from_zone(zone, start_pfn, nr_pages);
1949 mem_hotplug_done();
1950 return 0;
1951
1952failed_removal_isolated:
1953 /* pushback to free area */
1954 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1955 memory_notify(MEM_CANCEL_OFFLINE, &arg);
1956failed_removal_pcplists_disabled:
1957 lru_cache_enable();
1958 zone_pcp_enable(zone);
1959failed_removal:
1960 pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n",
1961 (unsigned long long) start_pfn << PAGE_SHIFT,
1962 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1,
1963 reason);
1964 mem_hotplug_done();
1965 return ret;
1966}
1967
1968static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
1969{
1970 int *nid = arg;
1971
1972 *nid = mem->nid;
1973 if (unlikely(mem->state != MEM_OFFLINE)) {
1974 phys_addr_t beginpa, endpa;
1975
1976 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
1977 endpa = beginpa + memory_block_size_bytes() - 1;
1978 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
1979 &beginpa, &endpa);
1980
1981 return -EBUSY;
1982 }
1983 return 0;
1984}
1985
1986static int get_nr_vmemmap_pages_cb(struct memory_block *mem, void *arg)
1987{
1988 /*
1989 * If not set, continue with the next block.
1990 */
1991 return mem->nr_vmemmap_pages;
1992}
1993
1994static int check_cpu_on_node(int nid)
1995{
1996 int cpu;
1997
1998 for_each_present_cpu(cpu) {
1999 if (cpu_to_node(cpu) == nid)
2000 /*
2001 * the cpu on this node isn't removed, and we can't
2002 * offline this node.
2003 */
2004 return -EBUSY;
2005 }
2006
2007 return 0;
2008}
2009
2010static int check_no_memblock_for_node_cb(struct memory_block *mem, void *arg)
2011{
2012 int nid = *(int *)arg;
2013
2014 /*
2015 * If a memory block belongs to multiple nodes, the stored nid is not
2016 * reliable. However, such blocks are always online (e.g., cannot get
2017 * offlined) and, therefore, are still spanned by the node.
2018 */
2019 return mem->nid == nid ? -EEXIST : 0;
2020}
2021
2022/**
2023 * try_offline_node
2024 * @nid: the node ID
2025 *
2026 * Offline a node if all memory sections and cpus of the node are removed.
2027 *
2028 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2029 * and online/offline operations before this call.
2030 */
2031void try_offline_node(int nid)
2032{
2033 int rc;
2034
2035 /*
2036 * If the node still spans pages (especially ZONE_DEVICE), don't
2037 * offline it. A node spans memory after move_pfn_range_to_zone(),
2038 * e.g., after the memory block was onlined.
2039 */
2040 if (node_spanned_pages(nid))
2041 return;
2042
2043 /*
2044 * Especially offline memory blocks might not be spanned by the
2045 * node. They will get spanned by the node once they get onlined.
2046 * However, they link to the node in sysfs and can get onlined later.
2047 */
2048 rc = for_each_memory_block(&nid, check_no_memblock_for_node_cb);
2049 if (rc)
2050 return;
2051
2052 if (check_cpu_on_node(nid))
2053 return;
2054
2055 /*
2056 * all memory/cpu of this node are removed, we can offline this
2057 * node now.
2058 */
2059 node_set_offline(nid);
2060 unregister_one_node(nid);
2061}
2062EXPORT_SYMBOL(try_offline_node);
2063
2064static int __ref try_remove_memory(u64 start, u64 size)
2065{
2066 struct vmem_altmap mhp_altmap = {};
2067 struct vmem_altmap *altmap = NULL;
2068 unsigned long nr_vmemmap_pages;
2069 int rc = 0, nid = NUMA_NO_NODE;
2070
2071 BUG_ON(check_hotplug_memory_range(start, size));
2072
2073 /*
2074 * All memory blocks must be offlined before removing memory. Check
2075 * whether all memory blocks in question are offline and return error
2076 * if this is not the case.
2077 *
2078 * While at it, determine the nid. Note that if we'd have mixed nodes,
2079 * we'd only try to offline the last determined one -- which is good
2080 * enough for the cases we care about.
2081 */
2082 rc = walk_memory_blocks(start, size, &nid, check_memblock_offlined_cb);
2083 if (rc)
2084 return rc;
2085
2086 /*
2087 * We only support removing memory added with MHP_MEMMAP_ON_MEMORY in
2088 * the same granularity it was added - a single memory block.
2089 */
2090 if (mhp_memmap_on_memory()) {
2091 nr_vmemmap_pages = walk_memory_blocks(start, size, NULL,
2092 get_nr_vmemmap_pages_cb);
2093 if (nr_vmemmap_pages) {
2094 if (size != memory_block_size_bytes()) {
2095 pr_warn("Refuse to remove %#llx - %#llx,"
2096 "wrong granularity\n",
2097 start, start + size);
2098 return -EINVAL;
2099 }
2100
2101 /*
2102 * Let remove_pmd_table->free_hugepage_table do the
2103 * right thing if we used vmem_altmap when hot-adding
2104 * the range.
2105 */
2106 mhp_altmap.alloc = nr_vmemmap_pages;
2107 altmap = &mhp_altmap;
2108 }
2109 }
2110
2111 /* remove memmap entry */
2112 firmware_map_remove(start, start + size, "System RAM");
2113
2114 /*
2115 * Memory block device removal under the device_hotplug_lock is
2116 * a barrier against racing online attempts.
2117 */
2118 remove_memory_block_devices(start, size);
2119
2120 mem_hotplug_begin();
2121
2122 arch_remove_memory(start, size, altmap);
2123
2124 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
2125 memblock_phys_free(start, size);
2126 memblock_remove(start, size);
2127 }
2128
2129 release_mem_region_adjustable(start, size);
2130
2131 if (nid != NUMA_NO_NODE)
2132 try_offline_node(nid);
2133
2134 mem_hotplug_done();
2135 return 0;
2136}
2137
2138/**
2139 * __remove_memory - Remove memory if every memory block is offline
2140 * @start: physical address of the region to remove
2141 * @size: size of the region to remove
2142 *
2143 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2144 * and online/offline operations before this call, as required by
2145 * try_offline_node().
2146 */
2147void __remove_memory(u64 start, u64 size)
2148{
2149
2150 /*
2151 * trigger BUG() if some memory is not offlined prior to calling this
2152 * function
2153 */
2154 if (try_remove_memory(start, size))
2155 BUG();
2156}
2157
2158/*
2159 * Remove memory if every memory block is offline, otherwise return -EBUSY is
2160 * some memory is not offline
2161 */
2162int remove_memory(u64 start, u64 size)
2163{
2164 int rc;
2165
2166 lock_device_hotplug();
2167 rc = try_remove_memory(start, size);
2168 unlock_device_hotplug();
2169
2170 return rc;
2171}
2172EXPORT_SYMBOL_GPL(remove_memory);
2173
2174static int try_offline_memory_block(struct memory_block *mem, void *arg)
2175{
2176 uint8_t online_type = MMOP_ONLINE_KERNEL;
2177 uint8_t **online_types = arg;
2178 struct page *page;
2179 int rc;
2180
2181 /*
2182 * Sense the online_type via the zone of the memory block. Offlining
2183 * with multiple zones within one memory block will be rejected
2184 * by offlining code ... so we don't care about that.
2185 */
2186 page = pfn_to_online_page(section_nr_to_pfn(mem->start_section_nr));
2187 if (page && zone_idx(page_zone(page)) == ZONE_MOVABLE)
2188 online_type = MMOP_ONLINE_MOVABLE;
2189
2190 rc = device_offline(&mem->dev);
2191 /*
2192 * Default is MMOP_OFFLINE - change it only if offlining succeeded,
2193 * so try_reonline_memory_block() can do the right thing.
2194 */
2195 if (!rc)
2196 **online_types = online_type;
2197
2198 (*online_types)++;
2199 /* Ignore if already offline. */
2200 return rc < 0 ? rc : 0;
2201}
2202
2203static int try_reonline_memory_block(struct memory_block *mem, void *arg)
2204{
2205 uint8_t **online_types = arg;
2206 int rc;
2207
2208 if (**online_types != MMOP_OFFLINE) {
2209 mem->online_type = **online_types;
2210 rc = device_online(&mem->dev);
2211 if (rc < 0)
2212 pr_warn("%s: Failed to re-online memory: %d",
2213 __func__, rc);
2214 }
2215
2216 /* Continue processing all remaining memory blocks. */
2217 (*online_types)++;
2218 return 0;
2219}
2220
2221/*
2222 * Try to offline and remove memory. Might take a long time to finish in case
2223 * memory is still in use. Primarily useful for memory devices that logically
2224 * unplugged all memory (so it's no longer in use) and want to offline + remove
2225 * that memory.
2226 */
2227int offline_and_remove_memory(u64 start, u64 size)
2228{
2229 const unsigned long mb_count = size / memory_block_size_bytes();
2230 uint8_t *online_types, *tmp;
2231 int rc;
2232
2233 if (!IS_ALIGNED(start, memory_block_size_bytes()) ||
2234 !IS_ALIGNED(size, memory_block_size_bytes()) || !size)
2235 return -EINVAL;
2236
2237 /*
2238 * We'll remember the old online type of each memory block, so we can
2239 * try to revert whatever we did when offlining one memory block fails
2240 * after offlining some others succeeded.
2241 */
2242 online_types = kmalloc_array(mb_count, sizeof(*online_types),
2243 GFP_KERNEL);
2244 if (!online_types)
2245 return -ENOMEM;
2246 /*
2247 * Initialize all states to MMOP_OFFLINE, so when we abort processing in
2248 * try_offline_memory_block(), we'll skip all unprocessed blocks in
2249 * try_reonline_memory_block().
2250 */
2251 memset(online_types, MMOP_OFFLINE, mb_count);
2252
2253 lock_device_hotplug();
2254
2255 tmp = online_types;
2256 rc = walk_memory_blocks(start, size, &tmp, try_offline_memory_block);
2257
2258 /*
2259 * In case we succeeded to offline all memory, remove it.
2260 * This cannot fail as it cannot get onlined in the meantime.
2261 */
2262 if (!rc) {
2263 rc = try_remove_memory(start, size);
2264 if (rc)
2265 pr_err("%s: Failed to remove memory: %d", __func__, rc);
2266 }
2267
2268 /*
2269 * Rollback what we did. While memory onlining might theoretically fail
2270 * (nacked by a notifier), it barely ever happens.
2271 */
2272 if (rc) {
2273 tmp = online_types;
2274 walk_memory_blocks(start, size, &tmp,
2275 try_reonline_memory_block);
2276 }
2277 unlock_device_hotplug();
2278
2279 kfree(online_types);
2280 return rc;
2281}
2282EXPORT_SYMBOL_GPL(offline_and_remove_memory);
2283#endif /* CONFIG_MEMORY_HOTREMOVE */