Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Newer
Older
100644 944 lines (802 sloc) 22.982 kb
4906e26 @omegamoon Initial commit; Original 'BQ Edison' code
authored
1 /*
2 * linux/mm/memory_hotplug.c
3 *
4 * Copyright (C)
5 */
6
7 #include <linux/stddef.h>
8 #include <linux/mm.h>
9 #include <linux/swap.h>
10 #include <linux/interrupt.h>
11 #include <linux/pagemap.h>
12 #include <linux/bootmem.h>
13 #include <linux/compiler.h>
14 #include <linux/module.h>
15 #include <linux/pagevec.h>
16 #include <linux/writeback.h>
17 #include <linux/slab.h>
18 #include <linux/sysctl.h>
19 #include <linux/cpu.h>
20 #include <linux/memory.h>
21 #include <linux/memory_hotplug.h>
22 #include <linux/highmem.h>
23 #include <linux/vmalloc.h>
24 #include <linux/ioport.h>
25 #include <linux/delay.h>
26 #include <linux/migrate.h>
27 #include <linux/page-isolation.h>
28 #include <linux/pfn.h>
29 #include <linux/suspend.h>
30 #include <linux/mm_inline.h>
31 #include <linux/firmware-map.h>
32
33 #include <asm/tlbflush.h>
34
35 #include "internal.h"
36
37 DEFINE_MUTEX(mem_hotplug_mutex);
38
39 void lock_memory_hotplug(void)
40 {
41 mutex_lock(&mem_hotplug_mutex);
42
43 /* for exclusive hibernation if CONFIG_HIBERNATION=y */
44 lock_system_sleep();
45 }
46
47 void unlock_memory_hotplug(void)
48 {
49 unlock_system_sleep();
50 mutex_unlock(&mem_hotplug_mutex);
51 }
52
53
54 /* add this memory to iomem resource */
55 static struct resource *register_memory_resource(u64 start, u64 size)
56 {
57 struct resource *res;
58 res = kzalloc(sizeof(struct resource), GFP_KERNEL);
59 BUG_ON(!res);
60
61 res->name = "System RAM";
62 res->start = start;
63 res->end = start + size - 1;
64 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
65 if (request_resource(&iomem_resource, res) < 0) {
66 printk("System RAM resource %llx - %llx cannot be added\n",
67 (unsigned long long)res->start, (unsigned long long)res->end);
68 kfree(res);
69 res = NULL;
70 }
71 return res;
72 }
73
74 static void release_memory_resource(struct resource *res)
75 {
76 if (!res)
77 return;
78 release_resource(res);
79 kfree(res);
80 return;
81 }
82
83 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
84 #ifndef CONFIG_SPARSEMEM_VMEMMAP
85 static void get_page_bootmem(unsigned long info, struct page *page,
86 unsigned long type)
87 {
88 page->lru.next = (struct list_head *) type;
89 SetPagePrivate(page);
90 set_page_private(page, info);
91 atomic_inc(&page->_count);
92 }
93
94 /* reference to __meminit __free_pages_bootmem is valid
95 * so use __ref to tell modpost not to generate a warning */
96 void __ref put_page_bootmem(struct page *page)
97 {
98 unsigned long type;
99
100 type = (unsigned long) page->lru.next;
101 BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
102 type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
103
104 if (atomic_dec_return(&page->_count) == 1) {
105 ClearPagePrivate(page);
106 set_page_private(page, 0);
107 INIT_LIST_HEAD(&page->lru);
108 __free_pages_bootmem(page, 0);
109 }
110
111 }
112
113 static void register_page_bootmem_info_section(unsigned long start_pfn)
114 {
115 unsigned long *usemap, mapsize, section_nr, i;
116 struct mem_section *ms;
117 struct page *page, *memmap;
118
119 if (!pfn_valid(start_pfn))
120 return;
121
122 section_nr = pfn_to_section_nr(start_pfn);
123 ms = __nr_to_section(section_nr);
124
125 /* Get section's memmap address */
126 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
127
128 /*
129 * Get page for the memmap's phys address
130 * XXX: need more consideration for sparse_vmemmap...
131 */
132 page = virt_to_page(memmap);
133 mapsize = sizeof(struct page) * PAGES_PER_SECTION;
134 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
135
136 /* remember memmap's page */
137 for (i = 0; i < mapsize; i++, page++)
138 get_page_bootmem(section_nr, page, SECTION_INFO);
139
140 usemap = __nr_to_section(section_nr)->pageblock_flags;
141 page = virt_to_page(usemap);
142
143 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
144
145 for (i = 0; i < mapsize; i++, page++)
146 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
147
148 }
149
150 void register_page_bootmem_info_node(struct pglist_data *pgdat)
151 {
152 unsigned long i, pfn, end_pfn, nr_pages;
153 int node = pgdat->node_id;
154 struct page *page;
155 struct zone *zone;
156
157 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
158 page = virt_to_page(pgdat);
159
160 for (i = 0; i < nr_pages; i++, page++)
161 get_page_bootmem(node, page, NODE_INFO);
162
163 zone = &pgdat->node_zones[0];
164 for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
165 if (zone->wait_table) {
166 nr_pages = zone->wait_table_hash_nr_entries
167 * sizeof(wait_queue_head_t);
168 nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
169 page = virt_to_page(zone->wait_table);
170
171 for (i = 0; i < nr_pages; i++, page++)
172 get_page_bootmem(node, page, NODE_INFO);
173 }
174 }
175
176 pfn = pgdat->node_start_pfn;
177 end_pfn = pfn + pgdat->node_spanned_pages;
178
179 /* register_section info */
180 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION)
181 register_page_bootmem_info_section(pfn);
182
183 }
184 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
185
186 static void grow_zone_span(struct zone *zone, unsigned long start_pfn,
187 unsigned long end_pfn)
188 {
189 unsigned long old_zone_end_pfn;
190
191 zone_span_writelock(zone);
192
193 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
194 if (start_pfn < zone->zone_start_pfn)
195 zone->zone_start_pfn = start_pfn;
196
197 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
198 zone->zone_start_pfn;
199
200 zone_span_writeunlock(zone);
201 }
202
203 static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
204 unsigned long end_pfn)
205 {
206 unsigned long old_pgdat_end_pfn =
207 pgdat->node_start_pfn + pgdat->node_spanned_pages;
208
209 if (start_pfn < pgdat->node_start_pfn)
210 pgdat->node_start_pfn = start_pfn;
211
212 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
213 pgdat->node_start_pfn;
214 }
215
216 static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
217 {
218 struct pglist_data *pgdat = zone->zone_pgdat;
219 int nr_pages = PAGES_PER_SECTION;
220 int nid = pgdat->node_id;
221 int zone_type;
222 unsigned long flags;
223
224 zone_type = zone - pgdat->node_zones;
225 if (!zone->wait_table) {
226 int ret;
227
228 ret = init_currently_empty_zone(zone, phys_start_pfn,
229 nr_pages, MEMMAP_HOTPLUG);
230 if (ret)
231 return ret;
232 }
233 pgdat_resize_lock(zone->zone_pgdat, &flags);
234 grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
235 grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
236 phys_start_pfn + nr_pages);
237 pgdat_resize_unlock(zone->zone_pgdat, &flags);
238 memmap_init_zone(nr_pages, nid, zone_type,
239 phys_start_pfn, MEMMAP_HOTPLUG);
240 return 0;
241 }
242
243 static int __meminit __add_section(int nid, struct zone *zone,
244 unsigned long phys_start_pfn)
245 {
246 int nr_pages = PAGES_PER_SECTION;
247 int ret;
248
249 if (pfn_valid(phys_start_pfn))
250 return -EEXIST;
251
252 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
253
254 if (ret < 0)
255 return ret;
256
257 ret = __add_zone(zone, phys_start_pfn);
258
259 if (ret < 0)
260 return ret;
261
262 return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
263 }
264
265 #ifdef CONFIG_SPARSEMEM_VMEMMAP
266 static int __remove_section(struct zone *zone, struct mem_section *ms)
267 {
268 /*
269 * XXX: Freeing memmap with vmemmap is not implement yet.
270 * This should be removed later.
271 */
272 return -EBUSY;
273 }
274 #else
275 static int __remove_section(struct zone *zone, struct mem_section *ms)
276 {
277 unsigned long flags;
278 struct pglist_data *pgdat = zone->zone_pgdat;
279 int ret = -EINVAL;
280
281 if (!valid_section(ms))
282 return ret;
283
284 ret = unregister_memory_section(ms);
285 if (ret)
286 return ret;
287
288 pgdat_resize_lock(pgdat, &flags);
289 sparse_remove_one_section(zone, ms);
290 pgdat_resize_unlock(pgdat, &flags);
291 return 0;
292 }
293 #endif
294
295 /*
296 * Reasonably generic function for adding memory. It is
297 * expected that archs that support memory hotplug will
298 * call this function after deciding the zone to which to
299 * add the new pages.
300 */
301 int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
302 unsigned long nr_pages)
303 {
304 unsigned long i;
305 int err = 0;
306 int start_sec, end_sec;
307 /* during initialize mem_map, align hot-added range to section */
308 start_sec = pfn_to_section_nr(phys_start_pfn);
309 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
310
311 for (i = start_sec; i <= end_sec; i++) {
312 err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);
313
314 /*
315 * EEXIST is finally dealt with by ioresource collision
316 * check. see add_memory() => register_memory_resource()
317 * Warning will be printed if there is collision.
318 */
319 if (err && (err != -EEXIST))
320 break;
321 err = 0;
322 }
323
324 return err;
325 }
326 EXPORT_SYMBOL_GPL(__add_pages);
327
328 /**
329 * __remove_pages() - remove sections of pages from a zone
330 * @zone: zone from which pages need to be removed
331 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
332 * @nr_pages: number of pages to remove (must be multiple of section size)
333 *
334 * Generic helper function to remove section mappings and sysfs entries
335 * for the section of the memory we are removing. Caller needs to make
336 * sure that pages are marked reserved and zones are adjust properly by
337 * calling offline_pages().
338 */
339 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
340 unsigned long nr_pages)
341 {
342 unsigned long i, ret = 0;
343 int sections_to_remove;
344
345 /*
346 * We can only remove entire sections
347 */
348 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
349 BUG_ON(nr_pages % PAGES_PER_SECTION);
350
351 sections_to_remove = nr_pages / PAGES_PER_SECTION;
352 for (i = 0; i < sections_to_remove; i++) {
353 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
354 release_mem_region(pfn << PAGE_SHIFT,
355 PAGES_PER_SECTION << PAGE_SHIFT);
356 ret = __remove_section(zone, __pfn_to_section(pfn));
357 if (ret)
358 break;
359 }
360 return ret;
361 }
362 EXPORT_SYMBOL_GPL(__remove_pages);
363
364 void online_page(struct page *page)
365 {
366 unsigned long pfn = page_to_pfn(page);
367
368 totalram_pages++;
369 if (pfn >= num_physpages)
370 num_physpages = pfn + 1;
371
372 #ifdef CONFIG_HIGHMEM
373 if (PageHighMem(page))
374 totalhigh_pages++;
375 #endif
376
377 ClearPageReserved(page);
378 init_page_count(page);
379 __free_page(page);
380 }
381
382 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
383 void *arg)
384 {
385 unsigned long i;
386 unsigned long onlined_pages = *(unsigned long *)arg;
387 struct page *page;
388 if (PageReserved(pfn_to_page(start_pfn)))
389 for (i = 0; i < nr_pages; i++) {
390 page = pfn_to_page(start_pfn + i);
391 online_page(page);
392 onlined_pages++;
393 }
394 *(unsigned long *)arg = onlined_pages;
395 return 0;
396 }
397
398
399 int __ref online_pages(unsigned long pfn, unsigned long nr_pages)
400 {
401 unsigned long onlined_pages = 0;
402 struct zone *zone;
403 int need_zonelists_rebuild = 0;
404 int nid;
405 int ret;
406 struct memory_notify arg;
407
408 lock_memory_hotplug();
409 arg.start_pfn = pfn;
410 arg.nr_pages = nr_pages;
411 arg.status_change_nid = -1;
412
413 nid = page_to_nid(pfn_to_page(pfn));
414 if (node_present_pages(nid) == 0)
415 arg.status_change_nid = nid;
416
417 ret = memory_notify(MEM_GOING_ONLINE, &arg);
418 ret = notifier_to_errno(ret);
419 if (ret) {
420 memory_notify(MEM_CANCEL_ONLINE, &arg);
421 unlock_memory_hotplug();
422 return ret;
423 }
424 /*
425 * This doesn't need a lock to do pfn_to_page().
426 * The section can't be removed here because of the
427 * memory_block->state_mutex.
428 */
429 zone = page_zone(pfn_to_page(pfn));
430 /*
431 * If this zone is not populated, then it is not in zonelist.
432 * This means the page allocator ignores this zone.
433 * So, zonelist must be updated after online.
434 */
435 mutex_lock(&zonelists_mutex);
436 if (!populated_zone(zone))
437 need_zonelists_rebuild = 1;
438
439 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
440 online_pages_range);
441 if (ret) {
442 mutex_unlock(&zonelists_mutex);
443 printk(KERN_DEBUG "online_pages %lx at %lx failed\n",
444 nr_pages, pfn);
445 memory_notify(MEM_CANCEL_ONLINE, &arg);
446 unlock_memory_hotplug();
447 return ret;
448 }
449
450 zone->present_pages += onlined_pages;
451 zone->zone_pgdat->node_present_pages += onlined_pages;
452 if (need_zonelists_rebuild)
453 build_all_zonelists(zone);
454 else
455 zone_pcp_update(zone);
456
457 mutex_unlock(&zonelists_mutex);
458
459 init_per_zone_wmark_min();
460
461 if (onlined_pages) {
462 kswapd_run(zone_to_nid(zone));
463 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY);
464 }
465
466 vm_total_pages = nr_free_pagecache_pages();
467
468 writeback_set_ratelimit();
469
470 if (onlined_pages)
471 memory_notify(MEM_ONLINE, &arg);
472 unlock_memory_hotplug();
473
474 return 0;
475 }
476 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
477
478 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
479 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
480 {
481 struct pglist_data *pgdat;
482 unsigned long zones_size[MAX_NR_ZONES] = {0};
483 unsigned long zholes_size[MAX_NR_ZONES] = {0};
484 unsigned long start_pfn = start >> PAGE_SHIFT;
485
486 pgdat = arch_alloc_nodedata(nid);
487 if (!pgdat)
488 return NULL;
489
490 arch_refresh_nodedata(nid, pgdat);
491
492 /* we can use NODE_DATA(nid) from here */
493
494 /* init node's zones as empty zones, we don't have any present pages.*/
495 free_area_init_node(nid, zones_size, start_pfn, zholes_size);
496
497 /*
498 * The node we allocated has no zone fallback lists. For avoiding
499 * to access not-initialized zonelist, build here.
500 */
501 mutex_lock(&zonelists_mutex);
502 build_all_zonelists(NULL);
503 mutex_unlock(&zonelists_mutex);
504
505 return pgdat;
506 }
507
508 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
509 {
510 arch_refresh_nodedata(nid, NULL);
511 arch_free_nodedata(pgdat);
512 return;
513 }
514
515
516 /*
517 * called by cpu_up() to online a node without onlined memory.
518 */
519 int mem_online_node(int nid)
520 {
521 pg_data_t *pgdat;
522 int ret;
523
524 lock_memory_hotplug();
525 pgdat = hotadd_new_pgdat(nid, 0);
526 if (!pgdat) {
527 ret = -ENOMEM;
528 goto out;
529 }
530 node_set_online(nid);
531 ret = register_one_node(nid);
532 BUG_ON(ret);
533
534 out:
535 unlock_memory_hotplug();
536 return ret;
537 }
538
539 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
540 int __ref add_memory(int nid, u64 start, u64 size)
541 {
542 pg_data_t *pgdat = NULL;
543 int new_pgdat = 0;
544 struct resource *res;
545 int ret;
546
547 lock_memory_hotplug();
548
549 res = register_memory_resource(start, size);
550 ret = -EEXIST;
551 if (!res)
552 goto out;
553
554 if (!node_online(nid)) {
555 pgdat = hotadd_new_pgdat(nid, start);
556 ret = -ENOMEM;
557 if (!pgdat)
558 goto out;
559 new_pgdat = 1;
560 }
561
562 /* call arch's memory hotadd */
563 ret = arch_add_memory(nid, start, size);
564
565 if (ret < 0)
566 goto error;
567
568 /* we online node here. we can't roll back from here. */
569 node_set_online(nid);
570
571 if (new_pgdat) {
572 ret = register_one_node(nid);
573 /*
574 * If sysfs file of new node can't create, cpu on the node
575 * can't be hot-added. There is no rollback way now.
576 * So, check by BUG_ON() to catch it reluctantly..
577 */
578 BUG_ON(ret);
579 }
580
581 /* create new memmap entry */
582 firmware_map_add_hotplug(start, start + size, "System RAM");
583
584 goto out;
585
586 error:
587 /* rollback pgdat allocation and others */
588 if (new_pgdat)
589 rollback_node_hotadd(nid, pgdat);
590 if (res)
591 release_memory_resource(res);
592
593 out:
594 unlock_memory_hotplug();
595 return ret;
596 }
597 EXPORT_SYMBOL_GPL(add_memory);
598
599 #ifdef CONFIG_MEMORY_HOTREMOVE
600 /*
601 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
602 * set and the size of the free page is given by page_order(). Using this,
603 * the function determines if the pageblock contains only free pages.
604 * Due to buddy contraints, a free page at least the size of a pageblock will
605 * be located at the start of the pageblock
606 */
607 static inline int pageblock_free(struct page *page)
608 {
609 return PageBuddy(page) && page_order(page) >= pageblock_order;
610 }
611
612 /* Return the start of the next active pageblock after a given page */
613 static struct page *next_active_pageblock(struct page *page)
614 {
615 /* Ensure the starting page is pageblock-aligned */
616 BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
617
618 /* If the entire pageblock is free, move to the end of free page */
619 if (pageblock_free(page)) {
620 int order;
621 /* be careful. we don't have locks, page_order can be changed.*/
622 order = page_order(page);
623 if ((order < MAX_ORDER) && (order >= pageblock_order))
624 return page + (1 << order);
625 }
626
627 return page + pageblock_nr_pages;
628 }
629
630 /* Checks if this range of memory is likely to be hot-removable. */
631 int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
632 {
633 struct page *page = pfn_to_page(start_pfn);
634 struct page *end_page = page + nr_pages;
635
636 /* Check the starting page of each pageblock within the range */
637 for (; page < end_page; page = next_active_pageblock(page)) {
638 if (!is_pageblock_removable_nolock(page))
639 return 0;
640 cond_resched();
641 }
642
643 /* All pageblocks in the memory block are likely to be hot-removable */
644 return 1;
645 }
646
647 /*
648 * Confirm all pages in a range [start, end) is belongs to the same zone.
649 */
650 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
651 {
652 unsigned long pfn;
653 struct zone *zone = NULL;
654 struct page *page;
655 int i;
656 for (pfn = start_pfn;
657 pfn < end_pfn;
658 pfn += MAX_ORDER_NR_PAGES) {
659 i = 0;
660 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
661 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
662 i++;
663 if (i == MAX_ORDER_NR_PAGES)
664 continue;
665 page = pfn_to_page(pfn + i);
666 if (zone && page_zone(page) != zone)
667 return 0;
668 zone = page_zone(page);
669 }
670 return 1;
671 }
672
673 /*
674 * Scanning pfn is much easier than scanning lru list.
675 * Scan pfn from start to end and Find LRU page.
676 */
677 static unsigned long scan_lru_pages(unsigned long start, unsigned long end)
678 {
679 unsigned long pfn;
680 struct page *page;
681 for (pfn = start; pfn < end; pfn++) {
682 if (pfn_valid(pfn)) {
683 page = pfn_to_page(pfn);
684 if (PageLRU(page))
685 return pfn;
686 }
687 }
688 return 0;
689 }
690
691 static struct page *
692 hotremove_migrate_alloc(struct page *page, unsigned long private, int **x)
693 {
694 /* This should be improooooved!! */
695 return alloc_page(GFP_HIGHUSER_MOVABLE);
696 }
697
698 #define NR_OFFLINE_AT_ONCE_PAGES (256)
699 static int
700 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
701 {
702 unsigned long pfn;
703 struct page *page;
704 int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
705 int not_managed = 0;
706 int ret = 0;
707 LIST_HEAD(source);
708
709 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
710 if (!pfn_valid(pfn))
711 continue;
712 page = pfn_to_page(pfn);
713 if (!get_page_unless_zero(page))
714 continue;
715 /*
716 * We can skip free pages. And we can only deal with pages on
717 * LRU.
718 */
719 ret = isolate_lru_page(page);
720 if (!ret) { /* Success */
721 put_page(page);
722 list_add_tail(&page->lru, &source);
723 move_pages--;
724 inc_zone_page_state(page, NR_ISOLATED_ANON +
725 page_is_file_cache(page));
726
727 } else {
728 #ifdef CONFIG_DEBUG_VM
729 printk(KERN_ALERT "removing pfn %lx from LRU failed\n",
730 pfn);
731 dump_page(page);
732 #endif
733 put_page(page);
734 /* Because we don't have big zone->lock. we should
735 check this again here. */
736 if (page_count(page)) {
737 not_managed++;
738 ret = -EBUSY;
739 break;
740 }
741 }
742 }
743 if (!list_empty(&source)) {
744 if (not_managed) {
745 putback_lru_pages(&source);
746 goto out;
747 }
748 /* this function returns # of failed pages */
749 ret = migrate_pages(&source, hotremove_migrate_alloc, 0,
750 true, true);
751 if (ret)
752 putback_lru_pages(&source);
753 }
754 out:
755 return ret;
756 }
757
758 /*
759 * remove from free_area[] and mark all as Reserved.
760 */
761 static int
762 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
763 void *data)
764 {
765 __offline_isolated_pages(start, start + nr_pages);
766 return 0;
767 }
768
769 static void
770 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
771 {
772 walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
773 offline_isolated_pages_cb);
774 }
775
776 /*
777 * Check all pages in range, recoreded as memory resource, are isolated.
778 */
779 static int
780 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
781 void *data)
782 {
783 int ret;
784 long offlined = *(long *)data;
785 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages);
786 offlined = nr_pages;
787 if (!ret)
788 *(long *)data += offlined;
789 return ret;
790 }
791
792 static long
793 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
794 {
795 long offlined = 0;
796 int ret;
797
798 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
799 check_pages_isolated_cb);
800 if (ret < 0)
801 offlined = (long)ret;
802 return offlined;
803 }
804
805 static int __ref offline_pages(unsigned long start_pfn,
806 unsigned long end_pfn, unsigned long timeout)
807 {
808 unsigned long pfn, nr_pages, expire;
809 long offlined_pages;
810 int ret, drain, retry_max, node;
811 struct zone *zone;
812 struct memory_notify arg;
813
814 BUG_ON(start_pfn >= end_pfn);
815 /* at least, alignment against pageblock is necessary */
816 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
817 return -EINVAL;
818 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
819 return -EINVAL;
820 /* This makes hotplug much easier...and readable.
821 we assume this for now. .*/
822 if (!test_pages_in_a_zone(start_pfn, end_pfn))
823 return -EINVAL;
824
825 lock_memory_hotplug();
826
827 zone = page_zone(pfn_to_page(start_pfn));
828 node = zone_to_nid(zone);
829 nr_pages = end_pfn - start_pfn;
830
831 /* set above range as isolated */
832 ret = start_isolate_page_range(start_pfn, end_pfn);
833 if (ret)
834 goto out;
835
836 arg.start_pfn = start_pfn;
837 arg.nr_pages = nr_pages;
838 arg.status_change_nid = -1;
839 if (nr_pages >= node_present_pages(node))
840 arg.status_change_nid = node;
841
842 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
843 ret = notifier_to_errno(ret);
844 if (ret)
845 goto failed_removal;
846
847 pfn = start_pfn;
848 expire = jiffies + timeout;
849 drain = 0;
850 retry_max = 5;
851 repeat:
852 /* start memory hot removal */
853 ret = -EAGAIN;
854 if (time_after(jiffies, expire))
855 goto failed_removal;
856 ret = -EINTR;
857 if (signal_pending(current))
858 goto failed_removal;
859 ret = 0;
860 if (drain) {
861 lru_add_drain_all();
862 cond_resched();
863 drain_all_pages();
864 }
865
866 pfn = scan_lru_pages(start_pfn, end_pfn);
867 if (pfn) { /* We have page on LRU */
868 ret = do_migrate_range(pfn, end_pfn);
869 if (!ret) {
870 drain = 1;
871 goto repeat;
872 } else {
873 if (ret < 0)
874 if (--retry_max == 0)
875 goto failed_removal;
876 yield();
877 drain = 1;
878 goto repeat;
879 }
880 }
881 /* drain all zone's lru pagevec, this is asyncronous... */
882 lru_add_drain_all();
883 yield();
884 /* drain pcp pages , this is synchrouns. */
885 drain_all_pages();
886 /* check again */
887 offlined_pages = check_pages_isolated(start_pfn, end_pfn);
888 if (offlined_pages < 0) {
889 ret = -EBUSY;
890 goto failed_removal;
891 }
892 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
893 /* Ok, all of our target is islaoted.
894 We cannot do rollback at this point. */
895 offline_isolated_pages(start_pfn, end_pfn);
896 /* reset pagetype flags and makes migrate type to be MOVABLE */
897 undo_isolate_page_range(start_pfn, end_pfn);
898 /* removal success */
899 zone->present_pages -= offlined_pages;
900 zone->zone_pgdat->node_present_pages -= offlined_pages;
901 totalram_pages -= offlined_pages;
902
903 init_per_zone_wmark_min();
904
905 if (!node_present_pages(node)) {
906 node_clear_state(node, N_HIGH_MEMORY);
907 kswapd_stop(node);
908 }
909
910 vm_total_pages = nr_free_pagecache_pages();
911 writeback_set_ratelimit();
912
913 memory_notify(MEM_OFFLINE, &arg);
914 unlock_memory_hotplug();
915 return 0;
916
917 failed_removal:
918 printk(KERN_INFO "memory offlining %lx to %lx failed\n",
919 start_pfn, end_pfn);
920 memory_notify(MEM_CANCEL_OFFLINE, &arg);
921 /* pushback to free area */
922 undo_isolate_page_range(start_pfn, end_pfn);
923
924 out:
925 unlock_memory_hotplug();
926 return ret;
927 }
928
929 int remove_memory(u64 start, u64 size)
930 {
931 unsigned long start_pfn, end_pfn;
932
933 start_pfn = PFN_DOWN(start);
934 end_pfn = start_pfn + PFN_DOWN(size);
935 return offline_pages(start_pfn, end_pfn, 120 * HZ);
936 }
937 #else
938 int remove_memory(u64 start, u64 size)
939 {
940 return -EINVAL;
941 }
942 #endif /* CONFIG_MEMORY_HOTREMOVE */
943 EXPORT_SYMBOL_GPL(remove_memory);
Something went wrong with that request. Please try again.