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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/writeback.h>
17#include <linux/slab.h>
18#include <linux/sysctl.h>
19#include <linux/cpu.h>
20#include <linux/memory.h>
21#include <linux/memremap.h>
22#include <linux/memory_hotplug.h>
23#include <linux/vmalloc.h>
24#include <linux/ioport.h>
25#include <linux/delay.h>
26#include <linux/migrate.h>
27#include <linux/page-isolation.h>
28#include <linux/pfn.h>
29#include <linux/suspend.h>
30#include <linux/mm_inline.h>
31#include <linux/firmware-map.h>
32#include <linux/stop_machine.h>
33#include <linux/hugetlb.h>
34#include <linux/memblock.h>
35#include <linux/compaction.h>
36#include <linux/rmap.h>
37#include <linux/module.h>
38
39#include <asm/tlbflush.h>
40
41#include "internal.h"
42#include "shuffle.h"
43
44enum {
45 MEMMAP_ON_MEMORY_DISABLE = 0,
46 MEMMAP_ON_MEMORY_ENABLE,
47 MEMMAP_ON_MEMORY_FORCE,
48};
49
50static int memmap_mode __read_mostly = MEMMAP_ON_MEMORY_DISABLE;
51
52static inline unsigned long memory_block_memmap_size(void)
53{
54 return PHYS_PFN(memory_block_size_bytes()) * sizeof(struct page);
55}
56
57static inline unsigned long memory_block_memmap_on_memory_pages(void)
58{
59 unsigned long nr_pages = PFN_UP(memory_block_memmap_size());
60
61 /*
62 * In "forced" memmap_on_memory mode, we add extra pages to align the
63 * vmemmap size to cover full pageblocks. That way, we can add memory
64 * even if the vmemmap size is not properly aligned, however, we might waste
65 * memory.
66 */
67 if (memmap_mode == MEMMAP_ON_MEMORY_FORCE)
68 return pageblock_align(nr_pages);
69 return nr_pages;
70}
71
72#ifdef CONFIG_MHP_MEMMAP_ON_MEMORY
73/*
74 * memory_hotplug.memmap_on_memory parameter
75 */
76static int set_memmap_mode(const char *val, const struct kernel_param *kp)
77{
78 int ret, mode;
79 bool enabled;
80
81 if (sysfs_streq(val, "force") || sysfs_streq(val, "FORCE")) {
82 mode = MEMMAP_ON_MEMORY_FORCE;
83 } else {
84 ret = kstrtobool(val, &enabled);
85 if (ret < 0)
86 return ret;
87 if (enabled)
88 mode = MEMMAP_ON_MEMORY_ENABLE;
89 else
90 mode = MEMMAP_ON_MEMORY_DISABLE;
91 }
92 *((int *)kp->arg) = mode;
93 if (mode == MEMMAP_ON_MEMORY_FORCE) {
94 unsigned long memmap_pages = memory_block_memmap_on_memory_pages();
95
96 pr_info_once("Memory hotplug will waste %ld pages in each memory block\n",
97 memmap_pages - PFN_UP(memory_block_memmap_size()));
98 }
99 return 0;
100}
101
102static int get_memmap_mode(char *buffer, const struct kernel_param *kp)
103{
104 int mode = *((int *)kp->arg);
105
106 if (mode == MEMMAP_ON_MEMORY_FORCE)
107 return sprintf(buffer, "force\n");
108 return sprintf(buffer, "%c\n", mode ? 'Y' : 'N');
109}
110
111static const struct kernel_param_ops memmap_mode_ops = {
112 .set = set_memmap_mode,
113 .get = get_memmap_mode,
114};
115module_param_cb(memmap_on_memory, &memmap_mode_ops, &memmap_mode, 0444);
116MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug\n"
117 "With value \"force\" it could result in memory wastage due "
118 "to memmap size limitations (Y/N/force)");
119
120static inline bool mhp_memmap_on_memory(void)
121{
122 return memmap_mode != MEMMAP_ON_MEMORY_DISABLE;
123}
124#else
125static inline bool mhp_memmap_on_memory(void)
126{
127 return false;
128}
129#endif
130
131enum {
132 ONLINE_POLICY_CONTIG_ZONES = 0,
133 ONLINE_POLICY_AUTO_MOVABLE,
134};
135
136static const char * const online_policy_to_str[] = {
137 [ONLINE_POLICY_CONTIG_ZONES] = "contig-zones",
138 [ONLINE_POLICY_AUTO_MOVABLE] = "auto-movable",
139};
140
141static int set_online_policy(const char *val, const struct kernel_param *kp)
142{
143 int ret = sysfs_match_string(online_policy_to_str, val);
144
145 if (ret < 0)
146 return ret;
147 *((int *)kp->arg) = ret;
148 return 0;
149}
150
151static int get_online_policy(char *buffer, const struct kernel_param *kp)
152{
153 return sprintf(buffer, "%s\n", online_policy_to_str[*((int *)kp->arg)]);
154}
155
156/*
157 * memory_hotplug.online_policy: configure online behavior when onlining without
158 * specifying a zone (MMOP_ONLINE)
159 *
160 * "contig-zones": keep zone contiguous
161 * "auto-movable": online memory to ZONE_MOVABLE if the configuration
162 * (auto_movable_ratio, auto_movable_numa_aware) allows for it
163 */
164static int online_policy __read_mostly = ONLINE_POLICY_CONTIG_ZONES;
165static const struct kernel_param_ops online_policy_ops = {
166 .set = set_online_policy,
167 .get = get_online_policy,
168};
169module_param_cb(online_policy, &online_policy_ops, &online_policy, 0644);
170MODULE_PARM_DESC(online_policy,
171 "Set the online policy (\"contig-zones\", \"auto-movable\") "
172 "Default: \"contig-zones\"");
173
174/*
175 * memory_hotplug.auto_movable_ratio: specify maximum MOVABLE:KERNEL ratio
176 *
177 * The ratio represent an upper limit and the kernel might decide to not
178 * online some memory to ZONE_MOVABLE -- e.g., because hotplugged KERNEL memory
179 * doesn't allow for more MOVABLE memory.
180 */
181static unsigned int auto_movable_ratio __read_mostly = 301;
182module_param(auto_movable_ratio, uint, 0644);
183MODULE_PARM_DESC(auto_movable_ratio,
184 "Set the maximum ratio of MOVABLE:KERNEL memory in the system "
185 "in percent for \"auto-movable\" online policy. Default: 301");
186
187/*
188 * memory_hotplug.auto_movable_numa_aware: consider numa node stats
189 */
190#ifdef CONFIG_NUMA
191static bool auto_movable_numa_aware __read_mostly = true;
192module_param(auto_movable_numa_aware, bool, 0644);
193MODULE_PARM_DESC(auto_movable_numa_aware,
194 "Consider numa node stats in addition to global stats in "
195 "\"auto-movable\" online policy. Default: true");
196#endif /* CONFIG_NUMA */
197
198/*
199 * online_page_callback contains pointer to current page onlining function.
200 * Initially it is generic_online_page(). If it is required it could be
201 * changed by calling set_online_page_callback() for callback registration
202 * and restore_online_page_callback() for generic callback restore.
203 */
204
205static online_page_callback_t online_page_callback = generic_online_page;
206static DEFINE_MUTEX(online_page_callback_lock);
207
208DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock);
209
210void get_online_mems(void)
211{
212 percpu_down_read(&mem_hotplug_lock);
213}
214
215void put_online_mems(void)
216{
217 percpu_up_read(&mem_hotplug_lock);
218}
219
220bool movable_node_enabled = false;
221
222#ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
223int mhp_default_online_type = MMOP_OFFLINE;
224#else
225int mhp_default_online_type = MMOP_ONLINE;
226#endif
227
228static int __init setup_memhp_default_state(char *str)
229{
230 const int online_type = mhp_online_type_from_str(str);
231
232 if (online_type >= 0)
233 mhp_default_online_type = online_type;
234
235 return 1;
236}
237__setup("memhp_default_state=", setup_memhp_default_state);
238
239void mem_hotplug_begin(void)
240{
241 cpus_read_lock();
242 percpu_down_write(&mem_hotplug_lock);
243}
244
245void mem_hotplug_done(void)
246{
247 percpu_up_write(&mem_hotplug_lock);
248 cpus_read_unlock();
249}
250
251u64 max_mem_size = U64_MAX;
252
253/* add this memory to iomem resource */
254static struct resource *register_memory_resource(u64 start, u64 size,
255 const char *resource_name)
256{
257 struct resource *res;
258 unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
259
260 if (strcmp(resource_name, "System RAM"))
261 flags |= IORESOURCE_SYSRAM_DRIVER_MANAGED;
262
263 if (!mhp_range_allowed(start, size, true))
264 return ERR_PTR(-E2BIG);
265
266 /*
267 * Make sure value parsed from 'mem=' only restricts memory adding
268 * while booting, so that memory hotplug won't be impacted. Please
269 * refer to document of 'mem=' in kernel-parameters.txt for more
270 * details.
271 */
272 if (start + size > max_mem_size && system_state < SYSTEM_RUNNING)
273 return ERR_PTR(-E2BIG);
274
275 /*
276 * Request ownership of the new memory range. This might be
277 * a child of an existing resource that was present but
278 * not marked as busy.
279 */
280 res = __request_region(&iomem_resource, start, size,
281 resource_name, flags);
282
283 if (!res) {
284 pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n",
285 start, start + size);
286 return ERR_PTR(-EEXIST);
287 }
288 return res;
289}
290
291static void release_memory_resource(struct resource *res)
292{
293 if (!res)
294 return;
295 release_resource(res);
296 kfree(res);
297}
298
299static int check_pfn_span(unsigned long pfn, unsigned long nr_pages)
300{
301 /*
302 * Disallow all operations smaller than a sub-section and only
303 * allow operations smaller than a section for
304 * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range()
305 * enforces a larger memory_block_size_bytes() granularity for
306 * memory that will be marked online, so this check should only
307 * fire for direct arch_{add,remove}_memory() users outside of
308 * add_memory_resource().
309 */
310 unsigned long min_align;
311
312 if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
313 min_align = PAGES_PER_SUBSECTION;
314 else
315 min_align = PAGES_PER_SECTION;
316 if (!IS_ALIGNED(pfn | nr_pages, min_align))
317 return -EINVAL;
318 return 0;
319}
320
321/*
322 * Return page for the valid pfn only if the page is online. All pfn
323 * walkers which rely on the fully initialized page->flags and others
324 * should use this rather than pfn_valid && pfn_to_page
325 */
326struct page *pfn_to_online_page(unsigned long pfn)
327{
328 unsigned long nr = pfn_to_section_nr(pfn);
329 struct dev_pagemap *pgmap;
330 struct mem_section *ms;
331
332 if (nr >= NR_MEM_SECTIONS)
333 return NULL;
334
335 ms = __nr_to_section(nr);
336 if (!online_section(ms))
337 return NULL;
338
339 /*
340 * Save some code text when online_section() +
341 * pfn_section_valid() are sufficient.
342 */
343 if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) && !pfn_valid(pfn))
344 return NULL;
345
346 if (!pfn_section_valid(ms, pfn))
347 return NULL;
348
349 if (!online_device_section(ms))
350 return pfn_to_page(pfn);
351
352 /*
353 * Slowpath: when ZONE_DEVICE collides with
354 * ZONE_{NORMAL,MOVABLE} within the same section some pfns in
355 * the section may be 'offline' but 'valid'. Only
356 * get_dev_pagemap() can determine sub-section online status.
357 */
358 pgmap = get_dev_pagemap(pfn, NULL);
359 put_dev_pagemap(pgmap);
360
361 /* The presence of a pgmap indicates ZONE_DEVICE offline pfn */
362 if (pgmap)
363 return NULL;
364
365 return pfn_to_page(pfn);
366}
367EXPORT_SYMBOL_GPL(pfn_to_online_page);
368
369int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
370 struct mhp_params *params)
371{
372 const unsigned long end_pfn = pfn + nr_pages;
373 unsigned long cur_nr_pages;
374 int err;
375 struct vmem_altmap *altmap = params->altmap;
376
377 if (WARN_ON_ONCE(!pgprot_val(params->pgprot)))
378 return -EINVAL;
379
380 VM_BUG_ON(!mhp_range_allowed(PFN_PHYS(pfn), nr_pages * PAGE_SIZE, false));
381
382 if (altmap) {
383 /*
384 * Validate altmap is within bounds of the total request
385 */
386 if (altmap->base_pfn != pfn
387 || vmem_altmap_offset(altmap) > nr_pages) {
388 pr_warn_once("memory add fail, invalid altmap\n");
389 return -EINVAL;
390 }
391 altmap->alloc = 0;
392 }
393
394 if (check_pfn_span(pfn, nr_pages)) {
395 WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__, pfn, pfn + nr_pages - 1);
396 return -EINVAL;
397 }
398
399 for (; pfn < end_pfn; pfn += cur_nr_pages) {
400 /* Select all remaining pages up to the next section boundary */
401 cur_nr_pages = min(end_pfn - pfn,
402 SECTION_ALIGN_UP(pfn + 1) - pfn);
403 err = sparse_add_section(nid, pfn, cur_nr_pages, altmap,
404 params->pgmap);
405 if (err)
406 break;
407 cond_resched();
408 }
409 vmemmap_populate_print_last();
410 return err;
411}
412
413/* find the smallest valid pfn in the range [start_pfn, end_pfn) */
414static unsigned long find_smallest_section_pfn(int nid, struct zone *zone,
415 unsigned long start_pfn,
416 unsigned long end_pfn)
417{
418 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) {
419 if (unlikely(!pfn_to_online_page(start_pfn)))
420 continue;
421
422 if (unlikely(pfn_to_nid(start_pfn) != nid))
423 continue;
424
425 if (zone != page_zone(pfn_to_page(start_pfn)))
426 continue;
427
428 return start_pfn;
429 }
430
431 return 0;
432}
433
434/* find the biggest valid pfn in the range [start_pfn, end_pfn). */
435static unsigned long find_biggest_section_pfn(int nid, struct zone *zone,
436 unsigned long start_pfn,
437 unsigned long end_pfn)
438{
439 unsigned long pfn;
440
441 /* pfn is the end pfn of a memory section. */
442 pfn = end_pfn - 1;
443 for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) {
444 if (unlikely(!pfn_to_online_page(pfn)))
445 continue;
446
447 if (unlikely(pfn_to_nid(pfn) != nid))
448 continue;
449
450 if (zone != page_zone(pfn_to_page(pfn)))
451 continue;
452
453 return pfn;
454 }
455
456 return 0;
457}
458
459static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
460 unsigned long end_pfn)
461{
462 unsigned long pfn;
463 int nid = zone_to_nid(zone);
464
465 if (zone->zone_start_pfn == start_pfn) {
466 /*
467 * If the section is smallest section in the zone, it need
468 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
469 * In this case, we find second smallest valid mem_section
470 * for shrinking zone.
471 */
472 pfn = find_smallest_section_pfn(nid, zone, end_pfn,
473 zone_end_pfn(zone));
474 if (pfn) {
475 zone->spanned_pages = zone_end_pfn(zone) - pfn;
476 zone->zone_start_pfn = pfn;
477 } else {
478 zone->zone_start_pfn = 0;
479 zone->spanned_pages = 0;
480 }
481 } else if (zone_end_pfn(zone) == end_pfn) {
482 /*
483 * If the section is biggest section in the zone, it need
484 * shrink zone->spanned_pages.
485 * In this case, we find second biggest valid mem_section for
486 * shrinking zone.
487 */
488 pfn = find_biggest_section_pfn(nid, zone, zone->zone_start_pfn,
489 start_pfn);
490 if (pfn)
491 zone->spanned_pages = pfn - zone->zone_start_pfn + 1;
492 else {
493 zone->zone_start_pfn = 0;
494 zone->spanned_pages = 0;
495 }
496 }
497}
498
499static void update_pgdat_span(struct pglist_data *pgdat)
500{
501 unsigned long node_start_pfn = 0, node_end_pfn = 0;
502 struct zone *zone;
503
504 for (zone = pgdat->node_zones;
505 zone < pgdat->node_zones + MAX_NR_ZONES; zone++) {
506 unsigned long end_pfn = zone_end_pfn(zone);
507
508 /* No need to lock the zones, they can't change. */
509 if (!zone->spanned_pages)
510 continue;
511 if (!node_end_pfn) {
512 node_start_pfn = zone->zone_start_pfn;
513 node_end_pfn = end_pfn;
514 continue;
515 }
516
517 if (end_pfn > node_end_pfn)
518 node_end_pfn = end_pfn;
519 if (zone->zone_start_pfn < node_start_pfn)
520 node_start_pfn = zone->zone_start_pfn;
521 }
522
523 pgdat->node_start_pfn = node_start_pfn;
524 pgdat->node_spanned_pages = node_end_pfn - node_start_pfn;
525}
526
527void __ref remove_pfn_range_from_zone(struct zone *zone,
528 unsigned long start_pfn,
529 unsigned long nr_pages)
530{
531 const unsigned long end_pfn = start_pfn + nr_pages;
532 struct pglist_data *pgdat = zone->zone_pgdat;
533 unsigned long pfn, cur_nr_pages;
534
535 /* Poison struct pages because they are now uninitialized again. */
536 for (pfn = start_pfn; pfn < end_pfn; pfn += cur_nr_pages) {
537 cond_resched();
538
539 /* Select all remaining pages up to the next section boundary */
540 cur_nr_pages =
541 min(end_pfn - pfn, SECTION_ALIGN_UP(pfn + 1) - pfn);
542 page_init_poison(pfn_to_page(pfn),
543 sizeof(struct page) * cur_nr_pages);
544 }
545
546 /*
547 * Zone shrinking code cannot properly deal with ZONE_DEVICE. So
548 * we will not try to shrink the zones - which is okay as
549 * set_zone_contiguous() cannot deal with ZONE_DEVICE either way.
550 */
551 if (zone_is_zone_device(zone))
552 return;
553
554 clear_zone_contiguous(zone);
555
556 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
557 update_pgdat_span(pgdat);
558
559 set_zone_contiguous(zone);
560}
561
562/**
563 * __remove_pages() - remove sections of pages
564 * @pfn: starting pageframe (must be aligned to start of a section)
565 * @nr_pages: number of pages to remove (must be multiple of section size)
566 * @altmap: alternative device page map or %NULL if default memmap is used
567 *
568 * Generic helper function to remove section mappings and sysfs entries
569 * for the section of the memory we are removing. Caller needs to make
570 * sure that pages are marked reserved and zones are adjust properly by
571 * calling offline_pages().
572 */
573void __remove_pages(unsigned long pfn, unsigned long nr_pages,
574 struct vmem_altmap *altmap)
575{
576 const unsigned long end_pfn = pfn + nr_pages;
577 unsigned long cur_nr_pages;
578
579 if (check_pfn_span(pfn, nr_pages)) {
580 WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__, pfn, pfn + nr_pages - 1);
581 return;
582 }
583
584 for (; pfn < end_pfn; pfn += cur_nr_pages) {
585 cond_resched();
586 /* Select all remaining pages up to the next section boundary */
587 cur_nr_pages = min(end_pfn - pfn,
588 SECTION_ALIGN_UP(pfn + 1) - pfn);
589 sparse_remove_section(pfn, cur_nr_pages, altmap);
590 }
591}
592
593int set_online_page_callback(online_page_callback_t callback)
594{
595 int rc = -EINVAL;
596
597 get_online_mems();
598 mutex_lock(&online_page_callback_lock);
599
600 if (online_page_callback == generic_online_page) {
601 online_page_callback = callback;
602 rc = 0;
603 }
604
605 mutex_unlock(&online_page_callback_lock);
606 put_online_mems();
607
608 return rc;
609}
610EXPORT_SYMBOL_GPL(set_online_page_callback);
611
612int restore_online_page_callback(online_page_callback_t callback)
613{
614 int rc = -EINVAL;
615
616 get_online_mems();
617 mutex_lock(&online_page_callback_lock);
618
619 if (online_page_callback == callback) {
620 online_page_callback = generic_online_page;
621 rc = 0;
622 }
623
624 mutex_unlock(&online_page_callback_lock);
625 put_online_mems();
626
627 return rc;
628}
629EXPORT_SYMBOL_GPL(restore_online_page_callback);
630
631void generic_online_page(struct page *page, unsigned int order)
632{
633 /*
634 * Freeing the page with debug_pagealloc enabled will try to unmap it,
635 * so we should map it first. This is better than introducing a special
636 * case in page freeing fast path.
637 */
638 debug_pagealloc_map_pages(page, 1 << order);
639 __free_pages_core(page, order);
640 totalram_pages_add(1UL << order);
641}
642EXPORT_SYMBOL_GPL(generic_online_page);
643
644static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages)
645{
646 const unsigned long end_pfn = start_pfn + nr_pages;
647 unsigned long pfn;
648
649 /*
650 * Online the pages in MAX_PAGE_ORDER aligned chunks. The callback might
651 * decide to not expose all pages to the buddy (e.g., expose them
652 * later). We account all pages as being online and belonging to this
653 * zone ("present").
654 * When using memmap_on_memory, the range might not be aligned to
655 * MAX_ORDER_NR_PAGES - 1, but pageblock aligned. __ffs() will detect
656 * this and the first chunk to online will be pageblock_nr_pages.
657 */
658 for (pfn = start_pfn; pfn < end_pfn;) {
659 int order;
660
661 /*
662 * Free to online pages in the largest chunks alignment allows.
663 *
664 * __ffs() behaviour is undefined for 0. start == 0 is
665 * MAX_PAGE_ORDER-aligned, Set order to MAX_PAGE_ORDER for
666 * the case.
667 */
668 if (pfn)
669 order = min_t(int, MAX_PAGE_ORDER, __ffs(pfn));
670 else
671 order = MAX_PAGE_ORDER;
672
673 (*online_page_callback)(pfn_to_page(pfn), order);
674 pfn += (1UL << order);
675 }
676
677 /* mark all involved sections as online */
678 online_mem_sections(start_pfn, end_pfn);
679}
680
681/* check which state of node_states will be changed when online memory */
682static void node_states_check_changes_online(unsigned long nr_pages,
683 struct zone *zone, struct memory_notify *arg)
684{
685 int nid = zone_to_nid(zone);
686
687 arg->status_change_nid = NUMA_NO_NODE;
688 arg->status_change_nid_normal = NUMA_NO_NODE;
689
690 if (!node_state(nid, N_MEMORY))
691 arg->status_change_nid = nid;
692 if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY))
693 arg->status_change_nid_normal = nid;
694}
695
696static void node_states_set_node(int node, struct memory_notify *arg)
697{
698 if (arg->status_change_nid_normal >= 0)
699 node_set_state(node, N_NORMAL_MEMORY);
700
701 if (arg->status_change_nid >= 0)
702 node_set_state(node, N_MEMORY);
703}
704
705static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
706 unsigned long nr_pages)
707{
708 unsigned long old_end_pfn = zone_end_pfn(zone);
709
710 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
711 zone->zone_start_pfn = start_pfn;
712
713 zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn;
714}
715
716static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn,
717 unsigned long nr_pages)
718{
719 unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
720
721 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
722 pgdat->node_start_pfn = start_pfn;
723
724 pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn;
725
726}
727
728#ifdef CONFIG_ZONE_DEVICE
729static void section_taint_zone_device(unsigned long pfn)
730{
731 struct mem_section *ms = __pfn_to_section(pfn);
732
733 ms->section_mem_map |= SECTION_TAINT_ZONE_DEVICE;
734}
735#else
736static inline void section_taint_zone_device(unsigned long pfn)
737{
738}
739#endif
740
741/*
742 * Associate the pfn range with the given zone, initializing the memmaps
743 * and resizing the pgdat/zone data to span the added pages. After this
744 * call, all affected pages are PG_reserved.
745 *
746 * All aligned pageblocks are initialized to the specified migratetype
747 * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related
748 * zone stats (e.g., nr_isolate_pageblock) are touched.
749 */
750void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
751 unsigned long nr_pages,
752 struct vmem_altmap *altmap, int migratetype)
753{
754 struct pglist_data *pgdat = zone->zone_pgdat;
755 int nid = pgdat->node_id;
756
757 clear_zone_contiguous(zone);
758
759 if (zone_is_empty(zone))
760 init_currently_empty_zone(zone, start_pfn, nr_pages);
761 resize_zone_range(zone, start_pfn, nr_pages);
762 resize_pgdat_range(pgdat, start_pfn, nr_pages);
763
764 /*
765 * Subsection population requires care in pfn_to_online_page().
766 * Set the taint to enable the slow path detection of
767 * ZONE_DEVICE pages in an otherwise ZONE_{NORMAL,MOVABLE}
768 * section.
769 */
770 if (zone_is_zone_device(zone)) {
771 if (!IS_ALIGNED(start_pfn, PAGES_PER_SECTION))
772 section_taint_zone_device(start_pfn);
773 if (!IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION))
774 section_taint_zone_device(start_pfn + nr_pages);
775 }
776
777 /*
778 * TODO now we have a visible range of pages which are not associated
779 * with their zone properly. Not nice but set_pfnblock_flags_mask
780 * expects the zone spans the pfn range. All the pages in the range
781 * are reserved so nobody should be touching them so we should be safe
782 */
783 memmap_init_range(nr_pages, nid, zone_idx(zone), start_pfn, 0,
784 MEMINIT_HOTPLUG, altmap, migratetype);
785
786 set_zone_contiguous(zone);
787}
788
789struct auto_movable_stats {
790 unsigned long kernel_early_pages;
791 unsigned long movable_pages;
792};
793
794static void auto_movable_stats_account_zone(struct auto_movable_stats *stats,
795 struct zone *zone)
796{
797 if (zone_idx(zone) == ZONE_MOVABLE) {
798 stats->movable_pages += zone->present_pages;
799 } else {
800 stats->kernel_early_pages += zone->present_early_pages;
801#ifdef CONFIG_CMA
802 /*
803 * CMA pages (never on hotplugged memory) behave like
804 * ZONE_MOVABLE.
805 */
806 stats->movable_pages += zone->cma_pages;
807 stats->kernel_early_pages -= zone->cma_pages;
808#endif /* CONFIG_CMA */
809 }
810}
811struct auto_movable_group_stats {
812 unsigned long movable_pages;
813 unsigned long req_kernel_early_pages;
814};
815
816static int auto_movable_stats_account_group(struct memory_group *group,
817 void *arg)
818{
819 const int ratio = READ_ONCE(auto_movable_ratio);
820 struct auto_movable_group_stats *stats = arg;
821 long pages;
822
823 /*
824 * We don't support modifying the config while the auto-movable online
825 * policy is already enabled. Just avoid the division by zero below.
826 */
827 if (!ratio)
828 return 0;
829
830 /*
831 * Calculate how many early kernel pages this group requires to
832 * satisfy the configured zone ratio.
833 */
834 pages = group->present_movable_pages * 100 / ratio;
835 pages -= group->present_kernel_pages;
836
837 if (pages > 0)
838 stats->req_kernel_early_pages += pages;
839 stats->movable_pages += group->present_movable_pages;
840 return 0;
841}
842
843static bool auto_movable_can_online_movable(int nid, struct memory_group *group,
844 unsigned long nr_pages)
845{
846 unsigned long kernel_early_pages, movable_pages;
847 struct auto_movable_group_stats group_stats = {};
848 struct auto_movable_stats stats = {};
849 pg_data_t *pgdat = NODE_DATA(nid);
850 struct zone *zone;
851 int i;
852
853 /* Walk all relevant zones and collect MOVABLE vs. KERNEL stats. */
854 if (nid == NUMA_NO_NODE) {
855 /* TODO: cache values */
856 for_each_populated_zone(zone)
857 auto_movable_stats_account_zone(&stats, zone);
858 } else {
859 for (i = 0; i < MAX_NR_ZONES; i++) {
860 zone = pgdat->node_zones + i;
861 if (populated_zone(zone))
862 auto_movable_stats_account_zone(&stats, zone);
863 }
864 }
865
866 kernel_early_pages = stats.kernel_early_pages;
867 movable_pages = stats.movable_pages;
868
869 /*
870 * Kernel memory inside dynamic memory group allows for more MOVABLE
871 * memory within the same group. Remove the effect of all but the
872 * current group from the stats.
873 */
874 walk_dynamic_memory_groups(nid, auto_movable_stats_account_group,
875 group, &group_stats);
876 if (kernel_early_pages <= group_stats.req_kernel_early_pages)
877 return false;
878 kernel_early_pages -= group_stats.req_kernel_early_pages;
879 movable_pages -= group_stats.movable_pages;
880
881 if (group && group->is_dynamic)
882 kernel_early_pages += group->present_kernel_pages;
883
884 /*
885 * Test if we could online the given number of pages to ZONE_MOVABLE
886 * and still stay in the configured ratio.
887 */
888 movable_pages += nr_pages;
889 return movable_pages <= (auto_movable_ratio * kernel_early_pages) / 100;
890}
891
892/*
893 * Returns a default kernel memory zone for the given pfn range.
894 * If no kernel zone covers this pfn range it will automatically go
895 * to the ZONE_NORMAL.
896 */
897static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn,
898 unsigned long nr_pages)
899{
900 struct pglist_data *pgdat = NODE_DATA(nid);
901 int zid;
902
903 for (zid = 0; zid < ZONE_NORMAL; zid++) {
904 struct zone *zone = &pgdat->node_zones[zid];
905
906 if (zone_intersects(zone, start_pfn, nr_pages))
907 return zone;
908 }
909
910 return &pgdat->node_zones[ZONE_NORMAL];
911}
912
913/*
914 * Determine to which zone to online memory dynamically based on user
915 * configuration and system stats. We care about the following ratio:
916 *
917 * MOVABLE : KERNEL
918 *
919 * Whereby MOVABLE is memory in ZONE_MOVABLE and KERNEL is memory in
920 * one of the kernel zones. CMA pages inside one of the kernel zones really
921 * behaves like ZONE_MOVABLE, so we treat them accordingly.
922 *
923 * We don't allow for hotplugged memory in a KERNEL zone to increase the
924 * amount of MOVABLE memory we can have, so we end up with:
925 *
926 * MOVABLE : KERNEL_EARLY
927 *
928 * Whereby KERNEL_EARLY is memory in one of the kernel zones, available sinze
929 * boot. We base our calculation on KERNEL_EARLY internally, because:
930 *
931 * a) Hotplugged memory in one of the kernel zones can sometimes still get
932 * hotunplugged, especially when hot(un)plugging individual memory blocks.
933 * There is no coordination across memory devices, therefore "automatic"
934 * hotunplugging, as implemented in hypervisors, could result in zone
935 * imbalances.
936 * b) Early/boot memory in one of the kernel zones can usually not get
937 * hotunplugged again (e.g., no firmware interface to unplug, fragmented
938 * with unmovable allocations). While there are corner cases where it might
939 * still work, it is barely relevant in practice.
940 *
941 * Exceptions are dynamic memory groups, which allow for more MOVABLE
942 * memory within the same memory group -- because in that case, there is
943 * coordination within the single memory device managed by a single driver.
944 *
945 * We rely on "present pages" instead of "managed pages", as the latter is
946 * highly unreliable and dynamic in virtualized environments, and does not
947 * consider boot time allocations. For example, memory ballooning adjusts the
948 * managed pages when inflating/deflating the balloon, and balloon compaction
949 * can even migrate inflated pages between zones.
950 *
951 * Using "present pages" is better but some things to keep in mind are:
952 *
953 * a) Some memblock allocations, such as for the crashkernel area, are
954 * effectively unused by the kernel, yet they account to "present pages".
955 * Fortunately, these allocations are comparatively small in relevant setups
956 * (e.g., fraction of system memory).
957 * b) Some hotplugged memory blocks in virtualized environments, esecially
958 * hotplugged by virtio-mem, look like they are completely present, however,
959 * only parts of the memory block are actually currently usable.
960 * "present pages" is an upper limit that can get reached at runtime. As
961 * we base our calculations on KERNEL_EARLY, this is not an issue.
962 */
963static struct zone *auto_movable_zone_for_pfn(int nid,
964 struct memory_group *group,
965 unsigned long pfn,
966 unsigned long nr_pages)
967{
968 unsigned long online_pages = 0, max_pages, end_pfn;
969 struct page *page;
970
971 if (!auto_movable_ratio)
972 goto kernel_zone;
973
974 if (group && !group->is_dynamic) {
975 max_pages = group->s.max_pages;
976 online_pages = group->present_movable_pages;
977
978 /* If anything is !MOVABLE online the rest !MOVABLE. */
979 if (group->present_kernel_pages)
980 goto kernel_zone;
981 } else if (!group || group->d.unit_pages == nr_pages) {
982 max_pages = nr_pages;
983 } else {
984 max_pages = group->d.unit_pages;
985 /*
986 * Take a look at all online sections in the current unit.
987 * We can safely assume that all pages within a section belong
988 * to the same zone, because dynamic memory groups only deal
989 * with hotplugged memory.
990 */
991 pfn = ALIGN_DOWN(pfn, group->d.unit_pages);
992 end_pfn = pfn + group->d.unit_pages;
993 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
994 page = pfn_to_online_page(pfn);
995 if (!page)
996 continue;
997 /* If anything is !MOVABLE online the rest !MOVABLE. */
998 if (!is_zone_movable_page(page))
999 goto kernel_zone;
1000 online_pages += PAGES_PER_SECTION;
1001 }
1002 }
1003
1004 /*
1005 * Online MOVABLE if we could *currently* online all remaining parts
1006 * MOVABLE. We expect to (add+) online them immediately next, so if
1007 * nobody interferes, all will be MOVABLE if possible.
1008 */
1009 nr_pages = max_pages - online_pages;
1010 if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages))
1011 goto kernel_zone;
1012
1013#ifdef CONFIG_NUMA
1014 if (auto_movable_numa_aware &&
1015 !auto_movable_can_online_movable(nid, group, nr_pages))
1016 goto kernel_zone;
1017#endif /* CONFIG_NUMA */
1018
1019 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
1020kernel_zone:
1021 return default_kernel_zone_for_pfn(nid, pfn, nr_pages);
1022}
1023
1024static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn,
1025 unsigned long nr_pages)
1026{
1027 struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn,
1028 nr_pages);
1029 struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
1030 bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages);
1031 bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages);
1032
1033 /*
1034 * We inherit the existing zone in a simple case where zones do not
1035 * overlap in the given range
1036 */
1037 if (in_kernel ^ in_movable)
1038 return (in_kernel) ? kernel_zone : movable_zone;
1039
1040 /*
1041 * If the range doesn't belong to any zone or two zones overlap in the
1042 * given range then we use movable zone only if movable_node is
1043 * enabled because we always online to a kernel zone by default.
1044 */
1045 return movable_node_enabled ? movable_zone : kernel_zone;
1046}
1047
1048struct zone *zone_for_pfn_range(int online_type, int nid,
1049 struct memory_group *group, unsigned long start_pfn,
1050 unsigned long nr_pages)
1051{
1052 if (online_type == MMOP_ONLINE_KERNEL)
1053 return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages);
1054
1055 if (online_type == MMOP_ONLINE_MOVABLE)
1056 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
1057
1058 if (online_policy == ONLINE_POLICY_AUTO_MOVABLE)
1059 return auto_movable_zone_for_pfn(nid, group, start_pfn, nr_pages);
1060
1061 return default_zone_for_pfn(nid, start_pfn, nr_pages);
1062}
1063
1064/*
1065 * This function should only be called by memory_block_{online,offline},
1066 * and {online,offline}_pages.
1067 */
1068void adjust_present_page_count(struct page *page, struct memory_group *group,
1069 long nr_pages)
1070{
1071 struct zone *zone = page_zone(page);
1072 const bool movable = zone_idx(zone) == ZONE_MOVABLE;
1073
1074 /*
1075 * We only support onlining/offlining/adding/removing of complete
1076 * memory blocks; therefore, either all is either early or hotplugged.
1077 */
1078 if (early_section(__pfn_to_section(page_to_pfn(page))))
1079 zone->present_early_pages += nr_pages;
1080 zone->present_pages += nr_pages;
1081 zone->zone_pgdat->node_present_pages += nr_pages;
1082
1083 if (group && movable)
1084 group->present_movable_pages += nr_pages;
1085 else if (group && !movable)
1086 group->present_kernel_pages += nr_pages;
1087}
1088
1089int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages,
1090 struct zone *zone, bool mhp_off_inaccessible)
1091{
1092 unsigned long end_pfn = pfn + nr_pages;
1093 int ret, i;
1094
1095 ret = kasan_add_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages));
1096 if (ret)
1097 return ret;
1098
1099 /*
1100 * Memory block is accessible at this stage and hence poison the struct
1101 * pages now. If the memory block is accessible during memory hotplug
1102 * addition phase, then page poisining is already performed in
1103 * sparse_add_section().
1104 */
1105 if (mhp_off_inaccessible)
1106 page_init_poison(pfn_to_page(pfn), sizeof(struct page) * nr_pages);
1107
1108 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_UNMOVABLE);
1109
1110 for (i = 0; i < nr_pages; i++)
1111 SetPageVmemmapSelfHosted(pfn_to_page(pfn + i));
1112
1113 /*
1114 * It might be that the vmemmap_pages fully span sections. If that is
1115 * the case, mark those sections online here as otherwise they will be
1116 * left offline.
1117 */
1118 if (nr_pages >= PAGES_PER_SECTION)
1119 online_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION));
1120
1121 return ret;
1122}
1123
1124void mhp_deinit_memmap_on_memory(unsigned long pfn, unsigned long nr_pages)
1125{
1126 unsigned long end_pfn = pfn + nr_pages;
1127
1128 /*
1129 * It might be that the vmemmap_pages fully span sections. If that is
1130 * the case, mark those sections offline here as otherwise they will be
1131 * left online.
1132 */
1133 if (nr_pages >= PAGES_PER_SECTION)
1134 offline_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION));
1135
1136 /*
1137 * The pages associated with this vmemmap have been offlined, so
1138 * we can reset its state here.
1139 */
1140 remove_pfn_range_from_zone(page_zone(pfn_to_page(pfn)), pfn, nr_pages);
1141 kasan_remove_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages));
1142}
1143
1144/*
1145 * Must be called with mem_hotplug_lock in write mode.
1146 */
1147int __ref online_pages(unsigned long pfn, unsigned long nr_pages,
1148 struct zone *zone, struct memory_group *group)
1149{
1150 unsigned long flags;
1151 int need_zonelists_rebuild = 0;
1152 const int nid = zone_to_nid(zone);
1153 int ret;
1154 struct memory_notify arg;
1155
1156 /*
1157 * {on,off}lining is constrained to full memory sections (or more
1158 * precisely to memory blocks from the user space POV).
1159 * memmap_on_memory is an exception because it reserves initial part
1160 * of the physical memory space for vmemmaps. That space is pageblock
1161 * aligned.
1162 */
1163 if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(pfn) ||
1164 !IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION)))
1165 return -EINVAL;
1166
1167
1168 /* associate pfn range with the zone */
1169 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_ISOLATE);
1170
1171 arg.start_pfn = pfn;
1172 arg.nr_pages = nr_pages;
1173 node_states_check_changes_online(nr_pages, zone, &arg);
1174
1175 ret = memory_notify(MEM_GOING_ONLINE, &arg);
1176 ret = notifier_to_errno(ret);
1177 if (ret)
1178 goto failed_addition;
1179
1180 /*
1181 * Fixup the number of isolated pageblocks before marking the sections
1182 * onlining, such that undo_isolate_page_range() works correctly.
1183 */
1184 spin_lock_irqsave(&zone->lock, flags);
1185 zone->nr_isolate_pageblock += nr_pages / pageblock_nr_pages;
1186 spin_unlock_irqrestore(&zone->lock, flags);
1187
1188 /*
1189 * If this zone is not populated, then it is not in zonelist.
1190 * This means the page allocator ignores this zone.
1191 * So, zonelist must be updated after online.
1192 */
1193 if (!populated_zone(zone)) {
1194 need_zonelists_rebuild = 1;
1195 setup_zone_pageset(zone);
1196 }
1197
1198 online_pages_range(pfn, nr_pages);
1199 adjust_present_page_count(pfn_to_page(pfn), group, nr_pages);
1200
1201 node_states_set_node(nid, &arg);
1202 if (need_zonelists_rebuild)
1203 build_all_zonelists(NULL);
1204
1205 /* Basic onlining is complete, allow allocation of onlined pages. */
1206 undo_isolate_page_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE);
1207
1208 /*
1209 * Freshly onlined pages aren't shuffled (e.g., all pages are placed to
1210 * the tail of the freelist when undoing isolation). Shuffle the whole
1211 * zone to make sure the just onlined pages are properly distributed
1212 * across the whole freelist - to create an initial shuffle.
1213 */
1214 shuffle_zone(zone);
1215
1216 /* reinitialise watermarks and update pcp limits */
1217 init_per_zone_wmark_min();
1218
1219 kswapd_run(nid);
1220 kcompactd_run(nid);
1221
1222 writeback_set_ratelimit();
1223
1224 memory_notify(MEM_ONLINE, &arg);
1225 return 0;
1226
1227failed_addition:
1228 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
1229 (unsigned long long) pfn << PAGE_SHIFT,
1230 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
1231 memory_notify(MEM_CANCEL_ONLINE, &arg);
1232 remove_pfn_range_from_zone(zone, pfn, nr_pages);
1233 return ret;
1234}
1235
1236/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1237static pg_data_t __ref *hotadd_init_pgdat(int nid)
1238{
1239 struct pglist_data *pgdat;
1240
1241 /*
1242 * NODE_DATA is preallocated (free_area_init) but its internal
1243 * state is not allocated completely. Add missing pieces.
1244 * Completely offline nodes stay around and they just need
1245 * reintialization.
1246 */
1247 pgdat = NODE_DATA(nid);
1248
1249 /* init node's zones as empty zones, we don't have any present pages.*/
1250 free_area_init_core_hotplug(pgdat);
1251
1252 /*
1253 * The node we allocated has no zone fallback lists. For avoiding
1254 * to access not-initialized zonelist, build here.
1255 */
1256 build_all_zonelists(pgdat);
1257
1258 return pgdat;
1259}
1260
1261/*
1262 * __try_online_node - online a node if offlined
1263 * @nid: the node ID
1264 * @set_node_online: Whether we want to online the node
1265 * called by cpu_up() to online a node without onlined memory.
1266 *
1267 * Returns:
1268 * 1 -> a new node has been allocated
1269 * 0 -> the node is already online
1270 * -ENOMEM -> the node could not be allocated
1271 */
1272static int __try_online_node(int nid, bool set_node_online)
1273{
1274 pg_data_t *pgdat;
1275 int ret = 1;
1276
1277 if (node_online(nid))
1278 return 0;
1279
1280 pgdat = hotadd_init_pgdat(nid);
1281 if (!pgdat) {
1282 pr_err("Cannot online node %d due to NULL pgdat\n", nid);
1283 ret = -ENOMEM;
1284 goto out;
1285 }
1286
1287 if (set_node_online) {
1288 node_set_online(nid);
1289 ret = register_one_node(nid);
1290 BUG_ON(ret);
1291 }
1292out:
1293 return ret;
1294}
1295
1296/*
1297 * Users of this function always want to online/register the node
1298 */
1299int try_online_node(int nid)
1300{
1301 int ret;
1302
1303 mem_hotplug_begin();
1304 ret = __try_online_node(nid, true);
1305 mem_hotplug_done();
1306 return ret;
1307}
1308
1309static int check_hotplug_memory_range(u64 start, u64 size)
1310{
1311 /* memory range must be block size aligned */
1312 if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) ||
1313 !IS_ALIGNED(size, memory_block_size_bytes())) {
1314 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
1315 memory_block_size_bytes(), start, size);
1316 return -EINVAL;
1317 }
1318
1319 return 0;
1320}
1321
1322static int online_memory_block(struct memory_block *mem, void *arg)
1323{
1324 mem->online_type = mhp_default_online_type;
1325 return device_online(&mem->dev);
1326}
1327
1328#ifndef arch_supports_memmap_on_memory
1329static inline bool arch_supports_memmap_on_memory(unsigned long vmemmap_size)
1330{
1331 /*
1332 * As default, we want the vmemmap to span a complete PMD such that we
1333 * can map the vmemmap using a single PMD if supported by the
1334 * architecture.
1335 */
1336 return IS_ALIGNED(vmemmap_size, PMD_SIZE);
1337}
1338#endif
1339
1340bool mhp_supports_memmap_on_memory(void)
1341{
1342 unsigned long vmemmap_size = memory_block_memmap_size();
1343 unsigned long memmap_pages = memory_block_memmap_on_memory_pages();
1344
1345 /*
1346 * Besides having arch support and the feature enabled at runtime, we
1347 * need a few more assumptions to hold true:
1348 *
1349 * a) The vmemmap pages span complete PMDs: We don't want vmemmap code
1350 * to populate memory from the altmap for unrelated parts (i.e.,
1351 * other memory blocks)
1352 *
1353 * b) The vmemmap pages (and thereby the pages that will be exposed to
1354 * the buddy) have to cover full pageblocks: memory onlining/offlining
1355 * code requires applicable ranges to be page-aligned, for example, to
1356 * set the migratetypes properly.
1357 *
1358 * TODO: Although we have a check here to make sure that vmemmap pages
1359 * fully populate a PMD, it is not the right place to check for
1360 * this. A much better solution involves improving vmemmap code
1361 * to fallback to base pages when trying to populate vmemmap using
1362 * altmap as an alternative source of memory, and we do not exactly
1363 * populate a single PMD.
1364 */
1365 if (!mhp_memmap_on_memory())
1366 return false;
1367
1368 /*
1369 * Make sure the vmemmap allocation is fully contained
1370 * so that we always allocate vmemmap memory from altmap area.
1371 */
1372 if (!IS_ALIGNED(vmemmap_size, PAGE_SIZE))
1373 return false;
1374
1375 /*
1376 * start pfn should be pageblock_nr_pages aligned for correctly
1377 * setting migrate types
1378 */
1379 if (!pageblock_aligned(memmap_pages))
1380 return false;
1381
1382 if (memmap_pages == PHYS_PFN(memory_block_size_bytes()))
1383 /* No effective hotplugged memory doesn't make sense. */
1384 return false;
1385
1386 return arch_supports_memmap_on_memory(vmemmap_size);
1387}
1388EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory);
1389
1390static void __ref remove_memory_blocks_and_altmaps(u64 start, u64 size)
1391{
1392 unsigned long memblock_size = memory_block_size_bytes();
1393 u64 cur_start;
1394
1395 /*
1396 * For memmap_on_memory, the altmaps were added on a per-memblock
1397 * basis; we have to process each individual memory block.
1398 */
1399 for (cur_start = start; cur_start < start + size;
1400 cur_start += memblock_size) {
1401 struct vmem_altmap *altmap = NULL;
1402 struct memory_block *mem;
1403
1404 mem = find_memory_block(pfn_to_section_nr(PFN_DOWN(cur_start)));
1405 if (WARN_ON_ONCE(!mem))
1406 continue;
1407
1408 altmap = mem->altmap;
1409 mem->altmap = NULL;
1410
1411 remove_memory_block_devices(cur_start, memblock_size);
1412
1413 arch_remove_memory(cur_start, memblock_size, altmap);
1414
1415 /* Verify that all vmemmap pages have actually been freed. */
1416 WARN(altmap->alloc, "Altmap not fully unmapped");
1417 kfree(altmap);
1418 }
1419}
1420
1421static int create_altmaps_and_memory_blocks(int nid, struct memory_group *group,
1422 u64 start, u64 size, mhp_t mhp_flags)
1423{
1424 unsigned long memblock_size = memory_block_size_bytes();
1425 u64 cur_start;
1426 int ret;
1427
1428 for (cur_start = start; cur_start < start + size;
1429 cur_start += memblock_size) {
1430 struct mhp_params params = { .pgprot =
1431 pgprot_mhp(PAGE_KERNEL) };
1432 struct vmem_altmap mhp_altmap = {
1433 .base_pfn = PHYS_PFN(cur_start),
1434 .end_pfn = PHYS_PFN(cur_start + memblock_size - 1),
1435 };
1436
1437 mhp_altmap.free = memory_block_memmap_on_memory_pages();
1438 if (mhp_flags & MHP_OFFLINE_INACCESSIBLE)
1439 mhp_altmap.inaccessible = true;
1440 params.altmap = kmemdup(&mhp_altmap, sizeof(struct vmem_altmap),
1441 GFP_KERNEL);
1442 if (!params.altmap) {
1443 ret = -ENOMEM;
1444 goto out;
1445 }
1446
1447 /* call arch's memory hotadd */
1448 ret = arch_add_memory(nid, cur_start, memblock_size, ¶ms);
1449 if (ret < 0) {
1450 kfree(params.altmap);
1451 goto out;
1452 }
1453
1454 /* create memory block devices after memory was added */
1455 ret = create_memory_block_devices(cur_start, memblock_size,
1456 params.altmap, group);
1457 if (ret) {
1458 arch_remove_memory(cur_start, memblock_size, NULL);
1459 kfree(params.altmap);
1460 goto out;
1461 }
1462 }
1463
1464 return 0;
1465out:
1466 if (ret && cur_start != start)
1467 remove_memory_blocks_and_altmaps(start, cur_start - start);
1468 return ret;
1469}
1470
1471/*
1472 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1473 * and online/offline operations (triggered e.g. by sysfs).
1474 *
1475 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
1476 */
1477int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
1478{
1479 struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
1480 enum memblock_flags memblock_flags = MEMBLOCK_NONE;
1481 struct memory_group *group = NULL;
1482 u64 start, size;
1483 bool new_node = false;
1484 int ret;
1485
1486 start = res->start;
1487 size = resource_size(res);
1488
1489 ret = check_hotplug_memory_range(start, size);
1490 if (ret)
1491 return ret;
1492
1493 if (mhp_flags & MHP_NID_IS_MGID) {
1494 group = memory_group_find_by_id(nid);
1495 if (!group)
1496 return -EINVAL;
1497 nid = group->nid;
1498 }
1499
1500 if (!node_possible(nid)) {
1501 WARN(1, "node %d was absent from the node_possible_map\n", nid);
1502 return -EINVAL;
1503 }
1504
1505 mem_hotplug_begin();
1506
1507 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
1508 if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
1509 memblock_flags = MEMBLOCK_DRIVER_MANAGED;
1510 ret = memblock_add_node(start, size, nid, memblock_flags);
1511 if (ret)
1512 goto error_mem_hotplug_end;
1513 }
1514
1515 ret = __try_online_node(nid, false);
1516 if (ret < 0)
1517 goto error;
1518 new_node = ret;
1519
1520 /*
1521 * Self hosted memmap array
1522 */
1523 if ((mhp_flags & MHP_MEMMAP_ON_MEMORY) &&
1524 mhp_supports_memmap_on_memory()) {
1525 ret = create_altmaps_and_memory_blocks(nid, group, start, size, mhp_flags);
1526 if (ret)
1527 goto error;
1528 } else {
1529 ret = arch_add_memory(nid, start, size, ¶ms);
1530 if (ret < 0)
1531 goto error;
1532
1533 /* create memory block devices after memory was added */
1534 ret = create_memory_block_devices(start, size, NULL, group);
1535 if (ret) {
1536 arch_remove_memory(start, size, params.altmap);
1537 goto error;
1538 }
1539 }
1540
1541 if (new_node) {
1542 /* If sysfs file of new node can't be created, cpu on the node
1543 * can't be hot-added. There is no rollback way now.
1544 * So, check by BUG_ON() to catch it reluctantly..
1545 * We online node here. We can't roll back from here.
1546 */
1547 node_set_online(nid);
1548 ret = __register_one_node(nid);
1549 BUG_ON(ret);
1550 }
1551
1552 register_memory_blocks_under_node(nid, PFN_DOWN(start),
1553 PFN_UP(start + size - 1),
1554 MEMINIT_HOTPLUG);
1555
1556 /* create new memmap entry */
1557 if (!strcmp(res->name, "System RAM"))
1558 firmware_map_add_hotplug(start, start + size, "System RAM");
1559
1560 /* device_online() will take the lock when calling online_pages() */
1561 mem_hotplug_done();
1562
1563 /*
1564 * In case we're allowed to merge the resource, flag it and trigger
1565 * merging now that adding succeeded.
1566 */
1567 if (mhp_flags & MHP_MERGE_RESOURCE)
1568 merge_system_ram_resource(res);
1569
1570 /* online pages if requested */
1571 if (mhp_default_online_type != MMOP_OFFLINE)
1572 walk_memory_blocks(start, size, NULL, online_memory_block);
1573
1574 return ret;
1575error:
1576 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
1577 memblock_remove(start, size);
1578error_mem_hotplug_end:
1579 mem_hotplug_done();
1580 return ret;
1581}
1582
1583/* requires device_hotplug_lock, see add_memory_resource() */
1584int __ref __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
1585{
1586 struct resource *res;
1587 int ret;
1588
1589 res = register_memory_resource(start, size, "System RAM");
1590 if (IS_ERR(res))
1591 return PTR_ERR(res);
1592
1593 ret = add_memory_resource(nid, res, mhp_flags);
1594 if (ret < 0)
1595 release_memory_resource(res);
1596 return ret;
1597}
1598
1599int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
1600{
1601 int rc;
1602
1603 lock_device_hotplug();
1604 rc = __add_memory(nid, start, size, mhp_flags);
1605 unlock_device_hotplug();
1606
1607 return rc;
1608}
1609EXPORT_SYMBOL_GPL(add_memory);
1610
1611/*
1612 * Add special, driver-managed memory to the system as system RAM. Such
1613 * memory is not exposed via the raw firmware-provided memmap as system
1614 * RAM, instead, it is detected and added by a driver - during cold boot,
1615 * after a reboot, and after kexec.
1616 *
1617 * Reasons why this memory should not be used for the initial memmap of a
1618 * kexec kernel or for placing kexec images:
1619 * - The booting kernel is in charge of determining how this memory will be
1620 * used (e.g., use persistent memory as system RAM)
1621 * - Coordination with a hypervisor is required before this memory
1622 * can be used (e.g., inaccessible parts).
1623 *
1624 * For this memory, no entries in /sys/firmware/memmap ("raw firmware-provided
1625 * memory map") are created. Also, the created memory resource is flagged
1626 * with IORESOURCE_SYSRAM_DRIVER_MANAGED, so in-kernel users can special-case
1627 * this memory as well (esp., not place kexec images onto it).
1628 *
1629 * The resource_name (visible via /proc/iomem) has to have the format
1630 * "System RAM ($DRIVER)".
1631 */
1632int add_memory_driver_managed(int nid, u64 start, u64 size,
1633 const char *resource_name, mhp_t mhp_flags)
1634{
1635 struct resource *res;
1636 int rc;
1637
1638 if (!resource_name ||
1639 strstr(resource_name, "System RAM (") != resource_name ||
1640 resource_name[strlen(resource_name) - 1] != ')')
1641 return -EINVAL;
1642
1643 lock_device_hotplug();
1644
1645 res = register_memory_resource(start, size, resource_name);
1646 if (IS_ERR(res)) {
1647 rc = PTR_ERR(res);
1648 goto out_unlock;
1649 }
1650
1651 rc = add_memory_resource(nid, res, mhp_flags);
1652 if (rc < 0)
1653 release_memory_resource(res);
1654
1655out_unlock:
1656 unlock_device_hotplug();
1657 return rc;
1658}
1659EXPORT_SYMBOL_GPL(add_memory_driver_managed);
1660
1661/*
1662 * Platforms should define arch_get_mappable_range() that provides
1663 * maximum possible addressable physical memory range for which the
1664 * linear mapping could be created. The platform returned address
1665 * range must adhere to these following semantics.
1666 *
1667 * - range.start <= range.end
1668 * - Range includes both end points [range.start..range.end]
1669 *
1670 * There is also a fallback definition provided here, allowing the
1671 * entire possible physical address range in case any platform does
1672 * not define arch_get_mappable_range().
1673 */
1674struct range __weak arch_get_mappable_range(void)
1675{
1676 struct range mhp_range = {
1677 .start = 0UL,
1678 .end = -1ULL,
1679 };
1680 return mhp_range;
1681}
1682
1683struct range mhp_get_pluggable_range(bool need_mapping)
1684{
1685 const u64 max_phys = (1ULL << MAX_PHYSMEM_BITS) - 1;
1686 struct range mhp_range;
1687
1688 if (need_mapping) {
1689 mhp_range = arch_get_mappable_range();
1690 if (mhp_range.start > max_phys) {
1691 mhp_range.start = 0;
1692 mhp_range.end = 0;
1693 }
1694 mhp_range.end = min_t(u64, mhp_range.end, max_phys);
1695 } else {
1696 mhp_range.start = 0;
1697 mhp_range.end = max_phys;
1698 }
1699 return mhp_range;
1700}
1701EXPORT_SYMBOL_GPL(mhp_get_pluggable_range);
1702
1703bool mhp_range_allowed(u64 start, u64 size, bool need_mapping)
1704{
1705 struct range mhp_range = mhp_get_pluggable_range(need_mapping);
1706 u64 end = start + size;
1707
1708 if (start < end && start >= mhp_range.start && (end - 1) <= mhp_range.end)
1709 return true;
1710
1711 pr_warn("Hotplug memory [%#llx-%#llx] exceeds maximum addressable range [%#llx-%#llx]\n",
1712 start, end, mhp_range.start, mhp_range.end);
1713 return false;
1714}
1715
1716#ifdef CONFIG_MEMORY_HOTREMOVE
1717/*
1718 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
1719 * non-lru movable pages and hugepages). Will skip over most unmovable
1720 * pages (esp., pages that can be skipped when offlining), but bail out on
1721 * definitely unmovable pages.
1722 *
1723 * Returns:
1724 * 0 in case a movable page is found and movable_pfn was updated.
1725 * -ENOENT in case no movable page was found.
1726 * -EBUSY in case a definitely unmovable page was found.
1727 */
1728static int scan_movable_pages(unsigned long start, unsigned long end,
1729 unsigned long *movable_pfn)
1730{
1731 unsigned long pfn;
1732
1733 for (pfn = start; pfn < end; pfn++) {
1734 struct page *page, *head;
1735 unsigned long skip;
1736
1737 if (!pfn_valid(pfn))
1738 continue;
1739 page = pfn_to_page(pfn);
1740 if (PageLRU(page))
1741 goto found;
1742 if (__PageMovable(page))
1743 goto found;
1744
1745 /*
1746 * PageOffline() pages that are not marked __PageMovable() and
1747 * have a reference count > 0 (after MEM_GOING_OFFLINE) are
1748 * definitely unmovable. If their reference count would be 0,
1749 * they could at least be skipped when offlining memory.
1750 */
1751 if (PageOffline(page) && page_count(page))
1752 return -EBUSY;
1753
1754 if (!PageHuge(page))
1755 continue;
1756 head = compound_head(page);
1757 /*
1758 * This test is racy as we hold no reference or lock. The
1759 * hugetlb page could have been free'ed and head is no longer
1760 * a hugetlb page before the following check. In such unlikely
1761 * cases false positives and negatives are possible. Calling
1762 * code must deal with these scenarios.
1763 */
1764 if (HPageMigratable(head))
1765 goto found;
1766 skip = compound_nr(head) - (pfn - page_to_pfn(head));
1767 pfn += skip - 1;
1768 }
1769 return -ENOENT;
1770found:
1771 *movable_pfn = pfn;
1772 return 0;
1773}
1774
1775static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1776{
1777 unsigned long pfn;
1778 struct page *page, *head;
1779 LIST_HEAD(source);
1780 static DEFINE_RATELIMIT_STATE(migrate_rs, DEFAULT_RATELIMIT_INTERVAL,
1781 DEFAULT_RATELIMIT_BURST);
1782
1783 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1784 struct folio *folio;
1785 bool isolated;
1786
1787 if (!pfn_valid(pfn))
1788 continue;
1789 page = pfn_to_page(pfn);
1790 folio = page_folio(page);
1791 head = &folio->page;
1792
1793 if (PageHuge(page)) {
1794 pfn = page_to_pfn(head) + compound_nr(head) - 1;
1795 isolate_hugetlb(folio, &source);
1796 continue;
1797 } else if (PageTransHuge(page))
1798 pfn = page_to_pfn(head) + thp_nr_pages(page) - 1;
1799
1800 /*
1801 * HWPoison pages have elevated reference counts so the migration would
1802 * fail on them. It also doesn't make any sense to migrate them in the
1803 * first place. Still try to unmap such a page in case it is still mapped
1804 * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep
1805 * the unmap as the catch all safety net).
1806 */
1807 if (PageHWPoison(page)) {
1808 if (WARN_ON(folio_test_lru(folio)))
1809 folio_isolate_lru(folio);
1810 if (folio_mapped(folio))
1811 try_to_unmap(folio, TTU_IGNORE_MLOCK);
1812 continue;
1813 }
1814
1815 if (!get_page_unless_zero(page))
1816 continue;
1817 /*
1818 * We can skip free pages. And we can deal with pages on
1819 * LRU and non-lru movable pages.
1820 */
1821 if (PageLRU(page))
1822 isolated = isolate_lru_page(page);
1823 else
1824 isolated = isolate_movable_page(page, ISOLATE_UNEVICTABLE);
1825 if (isolated) {
1826 list_add_tail(&page->lru, &source);
1827 if (!__PageMovable(page))
1828 inc_node_page_state(page, NR_ISOLATED_ANON +
1829 page_is_file_lru(page));
1830
1831 } else {
1832 if (__ratelimit(&migrate_rs)) {
1833 pr_warn("failed to isolate pfn %lx\n", pfn);
1834 dump_page(page, "isolation failed");
1835 }
1836 }
1837 put_page(page);
1838 }
1839 if (!list_empty(&source)) {
1840 nodemask_t nmask = node_states[N_MEMORY];
1841 struct migration_target_control mtc = {
1842 .nmask = &nmask,
1843 .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
1844 };
1845 int ret;
1846
1847 /*
1848 * We have checked that migration range is on a single zone so
1849 * we can use the nid of the first page to all the others.
1850 */
1851 mtc.nid = page_to_nid(list_first_entry(&source, struct page, lru));
1852
1853 /*
1854 * try to allocate from a different node but reuse this node
1855 * if there are no other online nodes to be used (e.g. we are
1856 * offlining a part of the only existing node)
1857 */
1858 node_clear(mtc.nid, nmask);
1859 if (nodes_empty(nmask))
1860 node_set(mtc.nid, nmask);
1861 ret = migrate_pages(&source, alloc_migration_target, NULL,
1862 (unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG, NULL);
1863 if (ret) {
1864 list_for_each_entry(page, &source, lru) {
1865 if (__ratelimit(&migrate_rs)) {
1866 pr_warn("migrating pfn %lx failed ret:%d\n",
1867 page_to_pfn(page), ret);
1868 dump_page(page, "migration failure");
1869 }
1870 }
1871 putback_movable_pages(&source);
1872 }
1873 }
1874}
1875
1876static int __init cmdline_parse_movable_node(char *p)
1877{
1878 movable_node_enabled = true;
1879 return 0;
1880}
1881early_param("movable_node", cmdline_parse_movable_node);
1882
1883/* check which state of node_states will be changed when offline memory */
1884static void node_states_check_changes_offline(unsigned long nr_pages,
1885 struct zone *zone, struct memory_notify *arg)
1886{
1887 struct pglist_data *pgdat = zone->zone_pgdat;
1888 unsigned long present_pages = 0;
1889 enum zone_type zt;
1890
1891 arg->status_change_nid = NUMA_NO_NODE;
1892 arg->status_change_nid_normal = NUMA_NO_NODE;
1893
1894 /*
1895 * Check whether node_states[N_NORMAL_MEMORY] will be changed.
1896 * If the memory to be offline is within the range
1897 * [0..ZONE_NORMAL], and it is the last present memory there,
1898 * the zones in that range will become empty after the offlining,
1899 * thus we can determine that we need to clear the node from
1900 * node_states[N_NORMAL_MEMORY].
1901 */
1902 for (zt = 0; zt <= ZONE_NORMAL; zt++)
1903 present_pages += pgdat->node_zones[zt].present_pages;
1904 if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages)
1905 arg->status_change_nid_normal = zone_to_nid(zone);
1906
1907 /*
1908 * We have accounted the pages from [0..ZONE_NORMAL); ZONE_HIGHMEM
1909 * does not apply as we don't support 32bit.
1910 * Here we count the possible pages from ZONE_MOVABLE.
1911 * If after having accounted all the pages, we see that the nr_pages
1912 * to be offlined is over or equal to the accounted pages,
1913 * we know that the node will become empty, and so, we can clear
1914 * it for N_MEMORY as well.
1915 */
1916 present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages;
1917
1918 if (nr_pages >= present_pages)
1919 arg->status_change_nid = zone_to_nid(zone);
1920}
1921
1922static void node_states_clear_node(int node, struct memory_notify *arg)
1923{
1924 if (arg->status_change_nid_normal >= 0)
1925 node_clear_state(node, N_NORMAL_MEMORY);
1926
1927 if (arg->status_change_nid >= 0)
1928 node_clear_state(node, N_MEMORY);
1929}
1930
1931static int count_system_ram_pages_cb(unsigned long start_pfn,
1932 unsigned long nr_pages, void *data)
1933{
1934 unsigned long *nr_system_ram_pages = data;
1935
1936 *nr_system_ram_pages += nr_pages;
1937 return 0;
1938}
1939
1940/*
1941 * Must be called with mem_hotplug_lock in write mode.
1942 */
1943int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages,
1944 struct zone *zone, struct memory_group *group)
1945{
1946 const unsigned long end_pfn = start_pfn + nr_pages;
1947 unsigned long pfn, system_ram_pages = 0;
1948 const int node = zone_to_nid(zone);
1949 unsigned long flags;
1950 struct memory_notify arg;
1951 char *reason;
1952 int ret;
1953
1954 /*
1955 * {on,off}lining is constrained to full memory sections (or more
1956 * precisely to memory blocks from the user space POV).
1957 * memmap_on_memory is an exception because it reserves initial part
1958 * of the physical memory space for vmemmaps. That space is pageblock
1959 * aligned.
1960 */
1961 if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(start_pfn) ||
1962 !IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION)))
1963 return -EINVAL;
1964
1965 /*
1966 * Don't allow to offline memory blocks that contain holes.
1967 * Consequently, memory blocks with holes can never get onlined
1968 * via the hotplug path - online_pages() - as hotplugged memory has
1969 * no holes. This way, we e.g., don't have to worry about marking
1970 * memory holes PG_reserved, don't need pfn_valid() checks, and can
1971 * avoid using walk_system_ram_range() later.
1972 */
1973 walk_system_ram_range(start_pfn, nr_pages, &system_ram_pages,
1974 count_system_ram_pages_cb);
1975 if (system_ram_pages != nr_pages) {
1976 ret = -EINVAL;
1977 reason = "memory holes";
1978 goto failed_removal;
1979 }
1980
1981 /*
1982 * We only support offlining of memory blocks managed by a single zone,
1983 * checked by calling code. This is just a sanity check that we might
1984 * want to remove in the future.
1985 */
1986 if (WARN_ON_ONCE(page_zone(pfn_to_page(start_pfn)) != zone ||
1987 page_zone(pfn_to_page(end_pfn - 1)) != zone)) {
1988 ret = -EINVAL;
1989 reason = "multizone range";
1990 goto failed_removal;
1991 }
1992
1993 /*
1994 * Disable pcplists so that page isolation cannot race with freeing
1995 * in a way that pages from isolated pageblock are left on pcplists.
1996 */
1997 zone_pcp_disable(zone);
1998 lru_cache_disable();
1999
2000 /* set above range as isolated */
2001 ret = start_isolate_page_range(start_pfn, end_pfn,
2002 MIGRATE_MOVABLE,
2003 MEMORY_OFFLINE | REPORT_FAILURE,
2004 GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL);
2005 if (ret) {
2006 reason = "failure to isolate range";
2007 goto failed_removal_pcplists_disabled;
2008 }
2009
2010 arg.start_pfn = start_pfn;
2011 arg.nr_pages = nr_pages;
2012 node_states_check_changes_offline(nr_pages, zone, &arg);
2013
2014 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
2015 ret = notifier_to_errno(ret);
2016 if (ret) {
2017 reason = "notifier failure";
2018 goto failed_removal_isolated;
2019 }
2020
2021 do {
2022 pfn = start_pfn;
2023 do {
2024 /*
2025 * Historically we always checked for any signal and
2026 * can't limit it to fatal signals without eventually
2027 * breaking user space.
2028 */
2029 if (signal_pending(current)) {
2030 ret = -EINTR;
2031 reason = "signal backoff";
2032 goto failed_removal_isolated;
2033 }
2034
2035 cond_resched();
2036
2037 ret = scan_movable_pages(pfn, end_pfn, &pfn);
2038 if (!ret) {
2039 /*
2040 * TODO: fatal migration failures should bail
2041 * out
2042 */
2043 do_migrate_range(pfn, end_pfn);
2044 }
2045 } while (!ret);
2046
2047 if (ret != -ENOENT) {
2048 reason = "unmovable page";
2049 goto failed_removal_isolated;
2050 }
2051
2052 /*
2053 * Dissolve free hugepages in the memory block before doing
2054 * offlining actually in order to make hugetlbfs's object
2055 * counting consistent.
2056 */
2057 ret = dissolve_free_huge_pages(start_pfn, end_pfn);
2058 if (ret) {
2059 reason = "failure to dissolve huge pages";
2060 goto failed_removal_isolated;
2061 }
2062
2063 ret = test_pages_isolated(start_pfn, end_pfn, MEMORY_OFFLINE);
2064
2065 } while (ret);
2066
2067 /* Mark all sections offline and remove free pages from the buddy. */
2068 __offline_isolated_pages(start_pfn, end_pfn);
2069 pr_debug("Offlined Pages %ld\n", nr_pages);
2070
2071 /*
2072 * The memory sections are marked offline, and the pageblock flags
2073 * effectively stale; nobody should be touching them. Fixup the number
2074 * of isolated pageblocks, memory onlining will properly revert this.
2075 */
2076 spin_lock_irqsave(&zone->lock, flags);
2077 zone->nr_isolate_pageblock -= nr_pages / pageblock_nr_pages;
2078 spin_unlock_irqrestore(&zone->lock, flags);
2079
2080 lru_cache_enable();
2081 zone_pcp_enable(zone);
2082
2083 /* removal success */
2084 adjust_managed_page_count(pfn_to_page(start_pfn), -nr_pages);
2085 adjust_present_page_count(pfn_to_page(start_pfn), group, -nr_pages);
2086
2087 /* reinitialise watermarks and update pcp limits */
2088 init_per_zone_wmark_min();
2089
2090 /*
2091 * Make sure to mark the node as memory-less before rebuilding the zone
2092 * list. Otherwise this node would still appear in the fallback lists.
2093 */
2094 node_states_clear_node(node, &arg);
2095 if (!populated_zone(zone)) {
2096 zone_pcp_reset(zone);
2097 build_all_zonelists(NULL);
2098 }
2099
2100 if (arg.status_change_nid >= 0) {
2101 kcompactd_stop(node);
2102 kswapd_stop(node);
2103 }
2104
2105 writeback_set_ratelimit();
2106
2107 memory_notify(MEM_OFFLINE, &arg);
2108 remove_pfn_range_from_zone(zone, start_pfn, nr_pages);
2109 return 0;
2110
2111failed_removal_isolated:
2112 /* pushback to free area */
2113 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
2114 memory_notify(MEM_CANCEL_OFFLINE, &arg);
2115failed_removal_pcplists_disabled:
2116 lru_cache_enable();
2117 zone_pcp_enable(zone);
2118failed_removal:
2119 pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n",
2120 (unsigned long long) start_pfn << PAGE_SHIFT,
2121 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1,
2122 reason);
2123 return ret;
2124}
2125
2126static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
2127{
2128 int *nid = arg;
2129
2130 *nid = mem->nid;
2131 if (unlikely(mem->state != MEM_OFFLINE)) {
2132 phys_addr_t beginpa, endpa;
2133
2134 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
2135 endpa = beginpa + memory_block_size_bytes() - 1;
2136 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
2137 &beginpa, &endpa);
2138
2139 return -EBUSY;
2140 }
2141 return 0;
2142}
2143
2144static int count_memory_range_altmaps_cb(struct memory_block *mem, void *arg)
2145{
2146 u64 *num_altmaps = (u64 *)arg;
2147
2148 if (mem->altmap)
2149 *num_altmaps += 1;
2150
2151 return 0;
2152}
2153
2154static int check_cpu_on_node(int nid)
2155{
2156 int cpu;
2157
2158 for_each_present_cpu(cpu) {
2159 if (cpu_to_node(cpu) == nid)
2160 /*
2161 * the cpu on this node isn't removed, and we can't
2162 * offline this node.
2163 */
2164 return -EBUSY;
2165 }
2166
2167 return 0;
2168}
2169
2170static int check_no_memblock_for_node_cb(struct memory_block *mem, void *arg)
2171{
2172 int nid = *(int *)arg;
2173
2174 /*
2175 * If a memory block belongs to multiple nodes, the stored nid is not
2176 * reliable. However, such blocks are always online (e.g., cannot get
2177 * offlined) and, therefore, are still spanned by the node.
2178 */
2179 return mem->nid == nid ? -EEXIST : 0;
2180}
2181
2182/**
2183 * try_offline_node
2184 * @nid: the node ID
2185 *
2186 * Offline a node if all memory sections and cpus of the node are removed.
2187 *
2188 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2189 * and online/offline operations before this call.
2190 */
2191void try_offline_node(int nid)
2192{
2193 int rc;
2194
2195 /*
2196 * If the node still spans pages (especially ZONE_DEVICE), don't
2197 * offline it. A node spans memory after move_pfn_range_to_zone(),
2198 * e.g., after the memory block was onlined.
2199 */
2200 if (node_spanned_pages(nid))
2201 return;
2202
2203 /*
2204 * Especially offline memory blocks might not be spanned by the
2205 * node. They will get spanned by the node once they get onlined.
2206 * However, they link to the node in sysfs and can get onlined later.
2207 */
2208 rc = for_each_memory_block(&nid, check_no_memblock_for_node_cb);
2209 if (rc)
2210 return;
2211
2212 if (check_cpu_on_node(nid))
2213 return;
2214
2215 /*
2216 * all memory/cpu of this node are removed, we can offline this
2217 * node now.
2218 */
2219 node_set_offline(nid);
2220 unregister_one_node(nid);
2221}
2222EXPORT_SYMBOL(try_offline_node);
2223
2224static int memory_blocks_have_altmaps(u64 start, u64 size)
2225{
2226 u64 num_memblocks = size / memory_block_size_bytes();
2227 u64 num_altmaps = 0;
2228
2229 if (!mhp_memmap_on_memory())
2230 return 0;
2231
2232 walk_memory_blocks(start, size, &num_altmaps,
2233 count_memory_range_altmaps_cb);
2234
2235 if (num_altmaps == 0)
2236 return 0;
2237
2238 if (WARN_ON_ONCE(num_memblocks != num_altmaps))
2239 return -EINVAL;
2240
2241 return 1;
2242}
2243
2244static int __ref try_remove_memory(u64 start, u64 size)
2245{
2246 int rc, nid = NUMA_NO_NODE;
2247
2248 BUG_ON(check_hotplug_memory_range(start, size));
2249
2250 /*
2251 * All memory blocks must be offlined before removing memory. Check
2252 * whether all memory blocks in question are offline and return error
2253 * if this is not the case.
2254 *
2255 * While at it, determine the nid. Note that if we'd have mixed nodes,
2256 * we'd only try to offline the last determined one -- which is good
2257 * enough for the cases we care about.
2258 */
2259 rc = walk_memory_blocks(start, size, &nid, check_memblock_offlined_cb);
2260 if (rc)
2261 return rc;
2262
2263 /* remove memmap entry */
2264 firmware_map_remove(start, start + size, "System RAM");
2265
2266 mem_hotplug_begin();
2267
2268 rc = memory_blocks_have_altmaps(start, size);
2269 if (rc < 0) {
2270 mem_hotplug_done();
2271 return rc;
2272 } else if (!rc) {
2273 /*
2274 * Memory block device removal under the device_hotplug_lock is
2275 * a barrier against racing online attempts.
2276 * No altmaps present, do the removal directly
2277 */
2278 remove_memory_block_devices(start, size);
2279 arch_remove_memory(start, size, NULL);
2280 } else {
2281 /* all memblocks in the range have altmaps */
2282 remove_memory_blocks_and_altmaps(start, size);
2283 }
2284
2285 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
2286 memblock_phys_free(start, size);
2287 memblock_remove(start, size);
2288 }
2289
2290 release_mem_region_adjustable(start, size);
2291
2292 if (nid != NUMA_NO_NODE)
2293 try_offline_node(nid);
2294
2295 mem_hotplug_done();
2296 return 0;
2297}
2298
2299/**
2300 * __remove_memory - Remove memory if every memory block is offline
2301 * @start: physical address of the region to remove
2302 * @size: size of the region to remove
2303 *
2304 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2305 * and online/offline operations before this call, as required by
2306 * try_offline_node().
2307 */
2308void __remove_memory(u64 start, u64 size)
2309{
2310
2311 /*
2312 * trigger BUG() if some memory is not offlined prior to calling this
2313 * function
2314 */
2315 if (try_remove_memory(start, size))
2316 BUG();
2317}
2318
2319/*
2320 * Remove memory if every memory block is offline, otherwise return -EBUSY is
2321 * some memory is not offline
2322 */
2323int remove_memory(u64 start, u64 size)
2324{
2325 int rc;
2326
2327 lock_device_hotplug();
2328 rc = try_remove_memory(start, size);
2329 unlock_device_hotplug();
2330
2331 return rc;
2332}
2333EXPORT_SYMBOL_GPL(remove_memory);
2334
2335static int try_offline_memory_block(struct memory_block *mem, void *arg)
2336{
2337 uint8_t online_type = MMOP_ONLINE_KERNEL;
2338 uint8_t **online_types = arg;
2339 struct page *page;
2340 int rc;
2341
2342 /*
2343 * Sense the online_type via the zone of the memory block. Offlining
2344 * with multiple zones within one memory block will be rejected
2345 * by offlining code ... so we don't care about that.
2346 */
2347 page = pfn_to_online_page(section_nr_to_pfn(mem->start_section_nr));
2348 if (page && zone_idx(page_zone(page)) == ZONE_MOVABLE)
2349 online_type = MMOP_ONLINE_MOVABLE;
2350
2351 rc = device_offline(&mem->dev);
2352 /*
2353 * Default is MMOP_OFFLINE - change it only if offlining succeeded,
2354 * so try_reonline_memory_block() can do the right thing.
2355 */
2356 if (!rc)
2357 **online_types = online_type;
2358
2359 (*online_types)++;
2360 /* Ignore if already offline. */
2361 return rc < 0 ? rc : 0;
2362}
2363
2364static int try_reonline_memory_block(struct memory_block *mem, void *arg)
2365{
2366 uint8_t **online_types = arg;
2367 int rc;
2368
2369 if (**online_types != MMOP_OFFLINE) {
2370 mem->online_type = **online_types;
2371 rc = device_online(&mem->dev);
2372 if (rc < 0)
2373 pr_warn("%s: Failed to re-online memory: %d",
2374 __func__, rc);
2375 }
2376
2377 /* Continue processing all remaining memory blocks. */
2378 (*online_types)++;
2379 return 0;
2380}
2381
2382/*
2383 * Try to offline and remove memory. Might take a long time to finish in case
2384 * memory is still in use. Primarily useful for memory devices that logically
2385 * unplugged all memory (so it's no longer in use) and want to offline + remove
2386 * that memory.
2387 */
2388int offline_and_remove_memory(u64 start, u64 size)
2389{
2390 const unsigned long mb_count = size / memory_block_size_bytes();
2391 uint8_t *online_types, *tmp;
2392 int rc;
2393
2394 if (!IS_ALIGNED(start, memory_block_size_bytes()) ||
2395 !IS_ALIGNED(size, memory_block_size_bytes()) || !size)
2396 return -EINVAL;
2397
2398 /*
2399 * We'll remember the old online type of each memory block, so we can
2400 * try to revert whatever we did when offlining one memory block fails
2401 * after offlining some others succeeded.
2402 */
2403 online_types = kmalloc_array(mb_count, sizeof(*online_types),
2404 GFP_KERNEL);
2405 if (!online_types)
2406 return -ENOMEM;
2407 /*
2408 * Initialize all states to MMOP_OFFLINE, so when we abort processing in
2409 * try_offline_memory_block(), we'll skip all unprocessed blocks in
2410 * try_reonline_memory_block().
2411 */
2412 memset(online_types, MMOP_OFFLINE, mb_count);
2413
2414 lock_device_hotplug();
2415
2416 tmp = online_types;
2417 rc = walk_memory_blocks(start, size, &tmp, try_offline_memory_block);
2418
2419 /*
2420 * In case we succeeded to offline all memory, remove it.
2421 * This cannot fail as it cannot get onlined in the meantime.
2422 */
2423 if (!rc) {
2424 rc = try_remove_memory(start, size);
2425 if (rc)
2426 pr_err("%s: Failed to remove memory: %d", __func__, rc);
2427 }
2428
2429 /*
2430 * Rollback what we did. While memory onlining might theoretically fail
2431 * (nacked by a notifier), it barely ever happens.
2432 */
2433 if (rc) {
2434 tmp = online_types;
2435 walk_memory_blocks(start, size, &tmp,
2436 try_reonline_memory_block);
2437 }
2438 unlock_device_hotplug();
2439
2440 kfree(online_types);
2441 return rc;
2442}
2443EXPORT_SYMBOL_GPL(offline_and_remove_memory);
2444#endif /* CONFIG_MEMORY_HOTREMOVE */