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/export.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 #include <linux/stop_machine.h>
33
34 #include <asm/tlbflush.h>
35
36 #include "internal.h"
37
38 /*
39 * online_page_callback contains pointer to current page onlining function.
40 * Initially it is generic_online_page(). If it is required it could be
41 * changed by calling set_online_page_callback() for callback registration
42 * and restore_online_page_callback() for generic callback restore.
43 */
44
45 static void generic_online_page(struct page *page);
46
47 static online_page_callback_t online_page_callback = generic_online_page;
48
49 DEFINE_MUTEX(mem_hotplug_mutex);
50
51 void lock_memory_hotplug(void)
52 {
53 mutex_lock(&mem_hotplug_mutex);
54
55 /* for exclusive hibernation if CONFIG_HIBERNATION=y */
56 lock_system_sleep();
57 }
58
59 void unlock_memory_hotplug(void)
60 {
61 unlock_system_sleep();
62 mutex_unlock(&mem_hotplug_mutex);
63 }
64
65
66 /* add this memory to iomem resource */
67 static struct resource *register_memory_resource(u64 start, u64 size)
68 {
69 struct resource *res;
70 res = kzalloc(sizeof(struct resource), GFP_KERNEL);
71 BUG_ON(!res);
72
73 res->name = "System RAM";
74 res->start = start;
75 res->end = start + size - 1;
76 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
77 if (request_resource(&iomem_resource, res) < 0) {
78 printk("System RAM resource %pR cannot be added\n", res);
79 kfree(res);
80 res = NULL;
81 }
82 return res;
83 }
84
85 static void release_memory_resource(struct resource *res)
86 {
87 if (!res)
88 return;
89 release_resource(res);
90 kfree(res);
91 return;
92 }
93
94 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
95 void get_page_bootmem(unsigned long info, struct page *page,
96 unsigned long type)
97 {
98 page->lru.next = (struct list_head *) type;
99 SetPagePrivate(page);
100 set_page_private(page, info);
101 atomic_inc(&page->_count);
102 }
103
104 /* reference to __meminit __free_pages_bootmem is valid
105 * so use __ref to tell modpost not to generate a warning */
106 void __ref put_page_bootmem(struct page *page)
107 {
108 unsigned long type;
109 static DEFINE_MUTEX(ppb_lock);
110
111 type = (unsigned long) page->lru.next;
112 BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
113 type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
114
115 if (atomic_dec_return(&page->_count) == 1) {
116 ClearPagePrivate(page);
117 set_page_private(page, 0);
118 INIT_LIST_HEAD(&page->lru);
119
120 /*
121 * Please refer to comment for __free_pages_bootmem()
122 * for why we serialize here.
123 */
124 mutex_lock(&ppb_lock);
125 __free_pages_bootmem(page, 0);
126 mutex_unlock(&ppb_lock);
127 totalram_pages++;
128 }
129
130 }
131
132 #ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
133 #ifndef CONFIG_SPARSEMEM_VMEMMAP
134 static void register_page_bootmem_info_section(unsigned long start_pfn)
135 {
136 unsigned long *usemap, mapsize, section_nr, i;
137 struct mem_section *ms;
138 struct page *page, *memmap;
139
140 section_nr = pfn_to_section_nr(start_pfn);
141 ms = __nr_to_section(section_nr);
142
143 /* Get section's memmap address */
144 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
145
146 /*
147 * Get page for the memmap's phys address
148 * XXX: need more consideration for sparse_vmemmap...
149 */
150 page = virt_to_page(memmap);
151 mapsize = sizeof(struct page) * PAGES_PER_SECTION;
152 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
153
154 /* remember memmap's page */
155 for (i = 0; i < mapsize; i++, page++)
156 get_page_bootmem(section_nr, page, SECTION_INFO);
157
158 usemap = __nr_to_section(section_nr)->pageblock_flags;
159 page = virt_to_page(usemap);
160
161 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
162
163 for (i = 0; i < mapsize; i++, page++)
164 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
165
166 }
167 #else /* CONFIG_SPARSEMEM_VMEMMAP */
168 static void register_page_bootmem_info_section(unsigned long start_pfn)
169 {
170 unsigned long *usemap, mapsize, section_nr, i;
171 struct mem_section *ms;
172 struct page *page, *memmap;
173
174 if (!pfn_valid(start_pfn))
175 return;
176
177 section_nr = pfn_to_section_nr(start_pfn);
178 ms = __nr_to_section(section_nr);
179
180 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
181
182 register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
183
184 usemap = __nr_to_section(section_nr)->pageblock_flags;
185 page = virt_to_page(usemap);
186
187 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
188
189 for (i = 0; i < mapsize; i++, page++)
190 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
191 }
192 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
193
194 void register_page_bootmem_info_node(struct pglist_data *pgdat)
195 {
196 unsigned long i, pfn, end_pfn, nr_pages;
197 int node = pgdat->node_id;
198 struct page *page;
199 struct zone *zone;
200
201 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
202 page = virt_to_page(pgdat);
203
204 for (i = 0; i < nr_pages; i++, page++)
205 get_page_bootmem(node, page, NODE_INFO);
206
207 zone = &pgdat->node_zones[0];
208 for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
209 if (zone->wait_table) {
210 nr_pages = zone->wait_table_hash_nr_entries
211 * sizeof(wait_queue_head_t);
212 nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
213 page = virt_to_page(zone->wait_table);
214
215 for (i = 0; i < nr_pages; i++, page++)
216 get_page_bootmem(node, page, NODE_INFO);
217 }
218 }
219
220 pfn = pgdat->node_start_pfn;
221 end_pfn = pgdat_end_pfn(pgdat);
222
223 /* register_section info */
224 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
225 /*
226 * Some platforms can assign the same pfn to multiple nodes - on
227 * node0 as well as nodeN. To avoid registering a pfn against
228 * multiple nodes we check that this pfn does not already
229 * reside in some other node.
230 */
231 if (pfn_valid(pfn) && (pfn_to_nid(pfn) == node))
232 register_page_bootmem_info_section(pfn);
233 }
234 }
235 #endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
236
237 static void grow_zone_span(struct zone *zone, unsigned long start_pfn,
238 unsigned long end_pfn)
239 {
240 unsigned long old_zone_end_pfn;
241
242 zone_span_writelock(zone);
243
244 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
245 if (!zone->spanned_pages || start_pfn < zone->zone_start_pfn)
246 zone->zone_start_pfn = start_pfn;
247
248 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
249 zone->zone_start_pfn;
250
251 zone_span_writeunlock(zone);
252 }
253
254 static void resize_zone(struct zone *zone, unsigned long start_pfn,
255 unsigned long end_pfn)
256 {
257 zone_span_writelock(zone);
258
259 if (end_pfn - start_pfn) {
260 zone->zone_start_pfn = start_pfn;
261 zone->spanned_pages = end_pfn - start_pfn;
262 } else {
263 /*
264 * make it consist as free_area_init_core(),
265 * if spanned_pages = 0, then keep start_pfn = 0
266 */
267 zone->zone_start_pfn = 0;
268 zone->spanned_pages = 0;
269 }
270
271 zone_span_writeunlock(zone);
272 }
273
274 static void fix_zone_id(struct zone *zone, unsigned long start_pfn,
275 unsigned long end_pfn)
276 {
277 enum zone_type zid = zone_idx(zone);
278 int nid = zone->zone_pgdat->node_id;
279 unsigned long pfn;
280
281 for (pfn = start_pfn; pfn < end_pfn; pfn++)
282 set_page_links(pfn_to_page(pfn), zid, nid, pfn);
283 }
284
285 /* Can fail with -ENOMEM from allocating a wait table with vmalloc() or
286 * alloc_bootmem_node_nopanic() */
287 static int __ref ensure_zone_is_initialized(struct zone *zone,
288 unsigned long start_pfn, unsigned long num_pages)
289 {
290 if (!zone_is_initialized(zone))
291 return init_currently_empty_zone(zone, start_pfn, num_pages,
292 MEMMAP_HOTPLUG);
293 return 0;
294 }
295
296 static int __meminit move_pfn_range_left(struct zone *z1, struct zone *z2,
297 unsigned long start_pfn, unsigned long end_pfn)
298 {
299 int ret;
300 unsigned long flags;
301 unsigned long z1_start_pfn;
302
303 ret = ensure_zone_is_initialized(z1, start_pfn, end_pfn - start_pfn);
304 if (ret)
305 return ret;
306
307 pgdat_resize_lock(z1->zone_pgdat, &flags);
308
309 /* can't move pfns which are higher than @z2 */
310 if (end_pfn > zone_end_pfn(z2))
311 goto out_fail;
312 /* the move out part mast at the left most of @z2 */
313 if (start_pfn > z2->zone_start_pfn)
314 goto out_fail;
315 /* must included/overlap */
316 if (end_pfn <= z2->zone_start_pfn)
317 goto out_fail;
318
319 /* use start_pfn for z1's start_pfn if z1 is empty */
320 if (z1->spanned_pages)
321 z1_start_pfn = z1->zone_start_pfn;
322 else
323 z1_start_pfn = start_pfn;
324
325 resize_zone(z1, z1_start_pfn, end_pfn);
326 resize_zone(z2, end_pfn, zone_end_pfn(z2));
327
328 pgdat_resize_unlock(z1->zone_pgdat, &flags);
329
330 fix_zone_id(z1, start_pfn, end_pfn);
331
332 return 0;
333 out_fail:
334 pgdat_resize_unlock(z1->zone_pgdat, &flags);
335 return -1;
336 }
337
338 static int __meminit move_pfn_range_right(struct zone *z1, struct zone *z2,
339 unsigned long start_pfn, unsigned long end_pfn)
340 {
341 int ret;
342 unsigned long flags;
343 unsigned long z2_end_pfn;
344
345 ret = ensure_zone_is_initialized(z2, start_pfn, end_pfn - start_pfn);
346 if (ret)
347 return ret;
348
349 pgdat_resize_lock(z1->zone_pgdat, &flags);
350
351 /* can't move pfns which are lower than @z1 */
352 if (z1->zone_start_pfn > start_pfn)
353 goto out_fail;
354 /* the move out part mast at the right most of @z1 */
355 if (zone_end_pfn(z1) > end_pfn)
356 goto out_fail;
357 /* must included/overlap */
358 if (start_pfn >= zone_end_pfn(z1))
359 goto out_fail;
360
361 /* use end_pfn for z2's end_pfn if z2 is empty */
362 if (z2->spanned_pages)
363 z2_end_pfn = zone_end_pfn(z2);
364 else
365 z2_end_pfn = end_pfn;
366
367 resize_zone(z1, z1->zone_start_pfn, start_pfn);
368 resize_zone(z2, start_pfn, z2_end_pfn);
369
370 pgdat_resize_unlock(z1->zone_pgdat, &flags);
371
372 fix_zone_id(z2, start_pfn, end_pfn);
373
374 return 0;
375 out_fail:
376 pgdat_resize_unlock(z1->zone_pgdat, &flags);
377 return -1;
378 }
379
380 static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
381 unsigned long end_pfn)
382 {
383 unsigned long old_pgdat_end_pfn =
384 pgdat->node_start_pfn + pgdat->node_spanned_pages;
385
386 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
387 pgdat->node_start_pfn = start_pfn;
388
389 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
390 pgdat->node_start_pfn;
391 }
392
393 static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
394 {
395 struct pglist_data *pgdat = zone->zone_pgdat;
396 int nr_pages = PAGES_PER_SECTION;
397 int nid = pgdat->node_id;
398 int zone_type;
399 unsigned long flags;
400 int ret;
401
402 zone_type = zone - pgdat->node_zones;
403 ret = ensure_zone_is_initialized(zone, phys_start_pfn, nr_pages);
404 if (ret)
405 return ret;
406
407 pgdat_resize_lock(zone->zone_pgdat, &flags);
408 grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
409 grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
410 phys_start_pfn + nr_pages);
411 pgdat_resize_unlock(zone->zone_pgdat, &flags);
412 memmap_init_zone(nr_pages, nid, zone_type,
413 phys_start_pfn, MEMMAP_HOTPLUG);
414 return 0;
415 }
416
417 static int __meminit __add_section(int nid, struct zone *zone,
418 unsigned long phys_start_pfn)
419 {
420 int nr_pages = PAGES_PER_SECTION;
421 int ret;
422
423 if (pfn_valid(phys_start_pfn))
424 return -EEXIST;
425
426 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
427
428 if (ret < 0)
429 return ret;
430
431 ret = __add_zone(zone, phys_start_pfn);
432
433 if (ret < 0)
434 return ret;
435
436 return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
437 }
438
439 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */
440 static int find_smallest_section_pfn(int nid, struct zone *zone,
441 unsigned long start_pfn,
442 unsigned long end_pfn)
443 {
444 struct mem_section *ms;
445
446 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) {
447 ms = __pfn_to_section(start_pfn);
448
449 if (unlikely(!valid_section(ms)))
450 continue;
451
452 if (unlikely(pfn_to_nid(start_pfn) != nid))
453 continue;
454
455 if (zone && zone != page_zone(pfn_to_page(start_pfn)))
456 continue;
457
458 return start_pfn;
459 }
460
461 return 0;
462 }
463
464 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */
465 static int find_biggest_section_pfn(int nid, struct zone *zone,
466 unsigned long start_pfn,
467 unsigned long end_pfn)
468 {
469 struct mem_section *ms;
470 unsigned long pfn;
471
472 /* pfn is the end pfn of a memory section. */
473 pfn = end_pfn - 1;
474 for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) {
475 ms = __pfn_to_section(pfn);
476
477 if (unlikely(!valid_section(ms)))
478 continue;
479
480 if (unlikely(pfn_to_nid(pfn) != nid))
481 continue;
482
483 if (zone && zone != page_zone(pfn_to_page(pfn)))
484 continue;
485
486 return pfn;
487 }
488
489 return 0;
490 }
491
492 static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
493 unsigned long end_pfn)
494 {
495 unsigned long zone_start_pfn = zone->zone_start_pfn;
496 unsigned long zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
497 unsigned long pfn;
498 struct mem_section *ms;
499 int nid = zone_to_nid(zone);
500
501 zone_span_writelock(zone);
502 if (zone_start_pfn == start_pfn) {
503 /*
504 * If the section is smallest section in the zone, it need
505 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
506 * In this case, we find second smallest valid mem_section
507 * for shrinking zone.
508 */
509 pfn = find_smallest_section_pfn(nid, zone, end_pfn,
510 zone_end_pfn);
511 if (pfn) {
512 zone->zone_start_pfn = pfn;
513 zone->spanned_pages = zone_end_pfn - pfn;
514 }
515 } else if (zone_end_pfn == end_pfn) {
516 /*
517 * If the section is biggest section in the zone, it need
518 * shrink zone->spanned_pages.
519 * In this case, we find second biggest valid mem_section for
520 * shrinking zone.
521 */
522 pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
523 start_pfn);
524 if (pfn)
525 zone->spanned_pages = pfn - zone_start_pfn + 1;
526 }
527
528 /*
529 * The section is not biggest or smallest mem_section in the zone, it
530 * only creates a hole in the zone. So in this case, we need not
531 * change the zone. But perhaps, the zone has only hole data. Thus
532 * it check the zone has only hole or not.
533 */
534 pfn = zone_start_pfn;
535 for (; pfn < zone_end_pfn; pfn += PAGES_PER_SECTION) {
536 ms = __pfn_to_section(pfn);
537
538 if (unlikely(!valid_section(ms)))
539 continue;
540
541 if (page_zone(pfn_to_page(pfn)) != zone)
542 continue;
543
544 /* If the section is current section, it continues the loop */
545 if (start_pfn == pfn)
546 continue;
547
548 /* If we find valid section, we have nothing to do */
549 zone_span_writeunlock(zone);
550 return;
551 }
552
553 /* The zone has no valid section */
554 zone->zone_start_pfn = 0;
555 zone->spanned_pages = 0;
556 zone_span_writeunlock(zone);
557 }
558
559 static void shrink_pgdat_span(struct pglist_data *pgdat,
560 unsigned long start_pfn, unsigned long end_pfn)
561 {
562 unsigned long pgdat_start_pfn = pgdat->node_start_pfn;
563 unsigned long pgdat_end_pfn =
564 pgdat->node_start_pfn + pgdat->node_spanned_pages;
565 unsigned long pfn;
566 struct mem_section *ms;
567 int nid = pgdat->node_id;
568
569 if (pgdat_start_pfn == start_pfn) {
570 /*
571 * If the section is smallest section in the pgdat, it need
572 * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages.
573 * In this case, we find second smallest valid mem_section
574 * for shrinking zone.
575 */
576 pfn = find_smallest_section_pfn(nid, NULL, end_pfn,
577 pgdat_end_pfn);
578 if (pfn) {
579 pgdat->node_start_pfn = pfn;
580 pgdat->node_spanned_pages = pgdat_end_pfn - pfn;
581 }
582 } else if (pgdat_end_pfn == end_pfn) {
583 /*
584 * If the section is biggest section in the pgdat, it need
585 * shrink pgdat->node_spanned_pages.
586 * In this case, we find second biggest valid mem_section for
587 * shrinking zone.
588 */
589 pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn,
590 start_pfn);
591 if (pfn)
592 pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1;
593 }
594
595 /*
596 * If the section is not biggest or smallest mem_section in the pgdat,
597 * it only creates a hole in the pgdat. So in this case, we need not
598 * change the pgdat.
599 * But perhaps, the pgdat has only hole data. Thus it check the pgdat
600 * has only hole or not.
601 */
602 pfn = pgdat_start_pfn;
603 for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) {
604 ms = __pfn_to_section(pfn);
605
606 if (unlikely(!valid_section(ms)))
607 continue;
608
609 if (pfn_to_nid(pfn) != nid)
610 continue;
611
612 /* If the section is current section, it continues the loop */
613 if (start_pfn == pfn)
614 continue;
615
616 /* If we find valid section, we have nothing to do */
617 return;
618 }
619
620 /* The pgdat has no valid section */
621 pgdat->node_start_pfn = 0;
622 pgdat->node_spanned_pages = 0;
623 }
624
625 static void __remove_zone(struct zone *zone, unsigned long start_pfn)
626 {
627 struct pglist_data *pgdat = zone->zone_pgdat;
628 int nr_pages = PAGES_PER_SECTION;
629 int zone_type;
630 unsigned long flags;
631
632 zone_type = zone - pgdat->node_zones;
633
634 pgdat_resize_lock(zone->zone_pgdat, &flags);
635 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
636 shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages);
637 pgdat_resize_unlock(zone->zone_pgdat, &flags);
638 }
639
640 static int __remove_section(struct zone *zone, struct mem_section *ms)
641 {
642 unsigned long start_pfn;
643 int scn_nr;
644 int ret = -EINVAL;
645
646 if (!valid_section(ms))
647 return ret;
648
649 ret = unregister_memory_section(ms);
650 if (ret)
651 return ret;
652
653 scn_nr = __section_nr(ms);
654 start_pfn = section_nr_to_pfn(scn_nr);
655 __remove_zone(zone, start_pfn);
656
657 sparse_remove_one_section(zone, ms);
658 return 0;
659 }
660
661 /*
662 * Reasonably generic function for adding memory. It is
663 * expected that archs that support memory hotplug will
664 * call this function after deciding the zone to which to
665 * add the new pages.
666 */
667 int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
668 unsigned long nr_pages)
669 {
670 unsigned long i;
671 int err = 0;
672 int start_sec, end_sec;
673 /* during initialize mem_map, align hot-added range to section */
674 start_sec = pfn_to_section_nr(phys_start_pfn);
675 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
676
677 for (i = start_sec; i <= end_sec; i++) {
678 err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);
679
680 /*
681 * EEXIST is finally dealt with by ioresource collision
682 * check. see add_memory() => register_memory_resource()
683 * Warning will be printed if there is collision.
684 */
685 if (err && (err != -EEXIST))
686 break;
687 err = 0;
688 }
689
690 return err;
691 }
692 EXPORT_SYMBOL_GPL(__add_pages);
693
694 /**
695 * __remove_pages() - remove sections of pages from a zone
696 * @zone: zone from which pages need to be removed
697 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
698 * @nr_pages: number of pages to remove (must be multiple of section size)
699 *
700 * Generic helper function to remove section mappings and sysfs entries
701 * for the section of the memory we are removing. Caller needs to make
702 * sure that pages are marked reserved and zones are adjust properly by
703 * calling offline_pages().
704 */
705 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
706 unsigned long nr_pages)
707 {
708 unsigned long i, ret = 0;
709 int sections_to_remove;
710
711 /*
712 * We can only remove entire sections
713 */
714 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
715 BUG_ON(nr_pages % PAGES_PER_SECTION);
716
717 release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
718
719 sections_to_remove = nr_pages / PAGES_PER_SECTION;
720 for (i = 0; i < sections_to_remove; i++) {
721 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
722 ret = __remove_section(zone, __pfn_to_section(pfn));
723 if (ret)
724 break;
725 }
726 return ret;
727 }
728 EXPORT_SYMBOL_GPL(__remove_pages);
729
730 int set_online_page_callback(online_page_callback_t callback)
731 {
732 int rc = -EINVAL;
733
734 lock_memory_hotplug();
735
736 if (online_page_callback == generic_online_page) {
737 online_page_callback = callback;
738 rc = 0;
739 }
740
741 unlock_memory_hotplug();
742
743 return rc;
744 }
745 EXPORT_SYMBOL_GPL(set_online_page_callback);
746
747 int restore_online_page_callback(online_page_callback_t callback)
748 {
749 int rc = -EINVAL;
750
751 lock_memory_hotplug();
752
753 if (online_page_callback == callback) {
754 online_page_callback = generic_online_page;
755 rc = 0;
756 }
757
758 unlock_memory_hotplug();
759
760 return rc;
761 }
762 EXPORT_SYMBOL_GPL(restore_online_page_callback);
763
764 void __online_page_set_limits(struct page *page)
765 {
766 unsigned long pfn = page_to_pfn(page);
767
768 if (pfn >= num_physpages)
769 num_physpages = pfn + 1;
770 }
771 EXPORT_SYMBOL_GPL(__online_page_set_limits);
772
773 void __online_page_increment_counters(struct page *page)
774 {
775 totalram_pages++;
776
777 #ifdef CONFIG_HIGHMEM
778 if (PageHighMem(page))
779 totalhigh_pages++;
780 #endif
781 }
782 EXPORT_SYMBOL_GPL(__online_page_increment_counters);
783
784 void __online_page_free(struct page *page)
785 {
786 ClearPageReserved(page);
787 init_page_count(page);
788 __free_page(page);
789 }
790 EXPORT_SYMBOL_GPL(__online_page_free);
791
792 static void generic_online_page(struct page *page)
793 {
794 __online_page_set_limits(page);
795 __online_page_increment_counters(page);
796 __online_page_free(page);
797 }
798
799 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
800 void *arg)
801 {
802 unsigned long i;
803 unsigned long onlined_pages = *(unsigned long *)arg;
804 struct page *page;
805 if (PageReserved(pfn_to_page(start_pfn)))
806 for (i = 0; i < nr_pages; i++) {
807 page = pfn_to_page(start_pfn + i);
808 (*online_page_callback)(page);
809 onlined_pages++;
810 }
811 *(unsigned long *)arg = onlined_pages;
812 return 0;
813 }
814
815 #ifdef CONFIG_MOVABLE_NODE
816 /*
817 * When CONFIG_MOVABLE_NODE, we permit onlining of a node which doesn't have
818 * normal memory.
819 */
820 static bool can_online_high_movable(struct zone *zone)
821 {
822 return true;
823 }
824 #else /* CONFIG_MOVABLE_NODE */
825 /* ensure every online node has NORMAL memory */
826 static bool can_online_high_movable(struct zone *zone)
827 {
828 return node_state(zone_to_nid(zone), N_NORMAL_MEMORY);
829 }
830 #endif /* CONFIG_MOVABLE_NODE */
831
832 /* check which state of node_states will be changed when online memory */
833 static void node_states_check_changes_online(unsigned long nr_pages,
834 struct zone *zone, struct memory_notify *arg)
835 {
836 int nid = zone_to_nid(zone);
837 enum zone_type zone_last = ZONE_NORMAL;
838
839 /*
840 * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
841 * contains nodes which have zones of 0...ZONE_NORMAL,
842 * set zone_last to ZONE_NORMAL.
843 *
844 * If we don't have HIGHMEM nor movable node,
845 * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
846 * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
847 */
848 if (N_MEMORY == N_NORMAL_MEMORY)
849 zone_last = ZONE_MOVABLE;
850
851 /*
852 * if the memory to be online is in a zone of 0...zone_last, and
853 * the zones of 0...zone_last don't have memory before online, we will
854 * need to set the node to node_states[N_NORMAL_MEMORY] after
855 * the memory is online.
856 */
857 if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY))
858 arg->status_change_nid_normal = nid;
859 else
860 arg->status_change_nid_normal = -1;
861
862 #ifdef CONFIG_HIGHMEM
863 /*
864 * If we have movable node, node_states[N_HIGH_MEMORY]
865 * contains nodes which have zones of 0...ZONE_HIGHMEM,
866 * set zone_last to ZONE_HIGHMEM.
867 *
868 * If we don't have movable node, node_states[N_NORMAL_MEMORY]
869 * contains nodes which have zones of 0...ZONE_MOVABLE,
870 * set zone_last to ZONE_MOVABLE.
871 */
872 zone_last = ZONE_HIGHMEM;
873 if (N_MEMORY == N_HIGH_MEMORY)
874 zone_last = ZONE_MOVABLE;
875
876 if (zone_idx(zone) <= zone_last && !node_state(nid, N_HIGH_MEMORY))
877 arg->status_change_nid_high = nid;
878 else
879 arg->status_change_nid_high = -1;
880 #else
881 arg->status_change_nid_high = arg->status_change_nid_normal;
882 #endif
883
884 /*
885 * if the node don't have memory befor online, we will need to
886 * set the node to node_states[N_MEMORY] after the memory
887 * is online.
888 */
889 if (!node_state(nid, N_MEMORY))
890 arg->status_change_nid = nid;
891 else
892 arg->status_change_nid = -1;
893 }
894
895 static void node_states_set_node(int node, struct memory_notify *arg)
896 {
897 if (arg->status_change_nid_normal >= 0)
898 node_set_state(node, N_NORMAL_MEMORY);
899
900 if (arg->status_change_nid_high >= 0)
901 node_set_state(node, N_HIGH_MEMORY);
902
903 node_set_state(node, N_MEMORY);
904 }
905
906
907 int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
908 {
909 unsigned long onlined_pages = 0;
910 struct zone *zone;
911 int need_zonelists_rebuild = 0;
912 int nid;
913 int ret;
914 struct memory_notify arg;
915
916 lock_memory_hotplug();
917 /*
918 * This doesn't need a lock to do pfn_to_page().
919 * The section can't be removed here because of the
920 * memory_block->state_mutex.
921 */
922 zone = page_zone(pfn_to_page(pfn));
923
924 if ((zone_idx(zone) > ZONE_NORMAL || online_type == ONLINE_MOVABLE) &&
925 !can_online_high_movable(zone)) {
926 unlock_memory_hotplug();
927 return -1;
928 }
929
930 if (online_type == ONLINE_KERNEL && zone_idx(zone) == ZONE_MOVABLE) {
931 if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages)) {
932 unlock_memory_hotplug();
933 return -1;
934 }
935 }
936 if (online_type == ONLINE_MOVABLE && zone_idx(zone) == ZONE_MOVABLE - 1) {
937 if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages)) {
938 unlock_memory_hotplug();
939 return -1;
940 }
941 }
942
943 /* Previous code may changed the zone of the pfn range */
944 zone = page_zone(pfn_to_page(pfn));
945
946 arg.start_pfn = pfn;
947 arg.nr_pages = nr_pages;
948 node_states_check_changes_online(nr_pages, zone, &arg);
949
950 nid = page_to_nid(pfn_to_page(pfn));
951
952 ret = memory_notify(MEM_GOING_ONLINE, &arg);
953 ret = notifier_to_errno(ret);
954 if (ret) {
955 memory_notify(MEM_CANCEL_ONLINE, &arg);
956 unlock_memory_hotplug();
957 return ret;
958 }
959 /*
960 * If this zone is not populated, then it is not in zonelist.
961 * This means the page allocator ignores this zone.
962 * So, zonelist must be updated after online.
963 */
964 mutex_lock(&zonelists_mutex);
965 if (!populated_zone(zone)) {
966 need_zonelists_rebuild = 1;
967 build_all_zonelists(NULL, zone);
968 }
969
970 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
971 online_pages_range);
972 if (ret) {
973 if (need_zonelists_rebuild)
974 zone_pcp_reset(zone);
975 mutex_unlock(&zonelists_mutex);
976 printk(KERN_DEBUG "online_pages [mem %#010llx-%#010llx] failed\n",
977 (unsigned long long) pfn << PAGE_SHIFT,
978 (((unsigned long long) pfn + nr_pages)
979 << PAGE_SHIFT) - 1);
980 memory_notify(MEM_CANCEL_ONLINE, &arg);
981 unlock_memory_hotplug();
982 return ret;
983 }
984
985 zone->managed_pages += onlined_pages;
986 zone->present_pages += onlined_pages;
987 zone->zone_pgdat->node_present_pages += onlined_pages;
988 if (onlined_pages) {
989 node_states_set_node(zone_to_nid(zone), &arg);
990 if (need_zonelists_rebuild)
991 build_all_zonelists(NULL, NULL);
992 else
993 zone_pcp_update(zone);
994 }
995
996 mutex_unlock(&zonelists_mutex);
997
998 init_per_zone_wmark_min();
999
1000 if (onlined_pages)
1001 kswapd_run(zone_to_nid(zone));
1002
1003 vm_total_pages = nr_free_pagecache_pages();
1004
1005 writeback_set_ratelimit();
1006
1007 if (onlined_pages)
1008 memory_notify(MEM_ONLINE, &arg);
1009 unlock_memory_hotplug();
1010
1011 return 0;
1012 }
1013 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
1014
1015 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1016 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
1017 {
1018 struct pglist_data *pgdat;
1019 unsigned long zones_size[MAX_NR_ZONES] = {0};
1020 unsigned long zholes_size[MAX_NR_ZONES] = {0};
1021 unsigned long start_pfn = start >> PAGE_SHIFT;
1022
1023 pgdat = NODE_DATA(nid);
1024 if (!pgdat) {
1025 pgdat = arch_alloc_nodedata(nid);
1026 if (!pgdat)
1027 return NULL;
1028
1029 arch_refresh_nodedata(nid, pgdat);
1030 }
1031
1032 /* we can use NODE_DATA(nid) from here */
1033
1034 /* init node's zones as empty zones, we don't have any present pages.*/
1035 free_area_init_node(nid, zones_size, start_pfn, zholes_size);
1036
1037 /*
1038 * The node we allocated has no zone fallback lists. For avoiding
1039 * to access not-initialized zonelist, build here.
1040 */
1041 mutex_lock(&zonelists_mutex);
1042 build_all_zonelists(pgdat, NULL);
1043 mutex_unlock(&zonelists_mutex);
1044
1045 return pgdat;
1046 }
1047
1048 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
1049 {
1050 arch_refresh_nodedata(nid, NULL);
1051 arch_free_nodedata(pgdat);
1052 return;
1053 }
1054
1055
1056 /*
1057 * called by cpu_up() to online a node without onlined memory.
1058 */
1059 int mem_online_node(int nid)
1060 {
1061 pg_data_t *pgdat;
1062 int ret;
1063
1064 lock_memory_hotplug();
1065 pgdat = hotadd_new_pgdat(nid, 0);
1066 if (!pgdat) {
1067 ret = -ENOMEM;
1068 goto out;
1069 }
1070 node_set_online(nid);
1071 ret = register_one_node(nid);
1072 BUG_ON(ret);
1073
1074 out:
1075 unlock_memory_hotplug();
1076 return ret;
1077 }
1078
1079 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1080 int __ref add_memory(int nid, u64 start, u64 size)
1081 {
1082 pg_data_t *pgdat = NULL;
1083 bool new_pgdat;
1084 bool new_node;
1085 struct resource *res;
1086 int ret;
1087
1088 lock_memory_hotplug();
1089
1090 res = register_memory_resource(start, size);
1091 ret = -EEXIST;
1092 if (!res)
1093 goto out;
1094
1095 { /* Stupid hack to suppress address-never-null warning */
1096 void *p = NODE_DATA(nid);
1097 new_pgdat = !p;
1098 }
1099 new_node = !node_online(nid);
1100 if (new_node) {
1101 pgdat = hotadd_new_pgdat(nid, start);
1102 ret = -ENOMEM;
1103 if (!pgdat)
1104 goto error;
1105 }
1106
1107 /* call arch's memory hotadd */
1108 ret = arch_add_memory(nid, start, size);
1109
1110 if (ret < 0)
1111 goto error;
1112
1113 /* we online node here. we can't roll back from here. */
1114 node_set_online(nid);
1115
1116 if (new_node) {
1117 ret = register_one_node(nid);
1118 /*
1119 * If sysfs file of new node can't create, cpu on the node
1120 * can't be hot-added. There is no rollback way now.
1121 * So, check by BUG_ON() to catch it reluctantly..
1122 */
1123 BUG_ON(ret);
1124 }
1125
1126 /* create new memmap entry */
1127 firmware_map_add_hotplug(start, start + size, "System RAM");
1128
1129 goto out;
1130
1131 error:
1132 /* rollback pgdat allocation and others */
1133 if (new_pgdat)
1134 rollback_node_hotadd(nid, pgdat);
1135 release_memory_resource(res);
1136
1137 out:
1138 unlock_memory_hotplug();
1139 return ret;
1140 }
1141 EXPORT_SYMBOL_GPL(add_memory);
1142
1143 #ifdef CONFIG_MEMORY_HOTREMOVE
1144 /*
1145 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
1146 * set and the size of the free page is given by page_order(). Using this,
1147 * the function determines if the pageblock contains only free pages.
1148 * Due to buddy contraints, a free page at least the size of a pageblock will
1149 * be located at the start of the pageblock
1150 */
1151 static inline int pageblock_free(struct page *page)
1152 {
1153 return PageBuddy(page) && page_order(page) >= pageblock_order;
1154 }
1155
1156 /* Return the start of the next active pageblock after a given page */
1157 static struct page *next_active_pageblock(struct page *page)
1158 {
1159 /* Ensure the starting page is pageblock-aligned */
1160 BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
1161
1162 /* If the entire pageblock is free, move to the end of free page */
1163 if (pageblock_free(page)) {
1164 int order;
1165 /* be careful. we don't have locks, page_order can be changed.*/
1166 order = page_order(page);
1167 if ((order < MAX_ORDER) && (order >= pageblock_order))
1168 return page + (1 << order);
1169 }
1170
1171 return page + pageblock_nr_pages;
1172 }
1173
1174 /* Checks if this range of memory is likely to be hot-removable. */
1175 int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
1176 {
1177 struct page *page = pfn_to_page(start_pfn);
1178 struct page *end_page = page + nr_pages;
1179
1180 /* Check the starting page of each pageblock within the range */
1181 for (; page < end_page; page = next_active_pageblock(page)) {
1182 if (!is_pageblock_removable_nolock(page))
1183 return 0;
1184 cond_resched();
1185 }
1186
1187 /* All pageblocks in the memory block are likely to be hot-removable */
1188 return 1;
1189 }
1190
1191 /*
1192 * Confirm all pages in a range [start, end) is belongs to the same zone.
1193 */
1194 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
1195 {
1196 unsigned long pfn;
1197 struct zone *zone = NULL;
1198 struct page *page;
1199 int i;
1200 for (pfn = start_pfn;
1201 pfn < end_pfn;
1202 pfn += MAX_ORDER_NR_PAGES) {
1203 i = 0;
1204 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
1205 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
1206 i++;
1207 if (i == MAX_ORDER_NR_PAGES)
1208 continue;
1209 page = pfn_to_page(pfn + i);
1210 if (zone && page_zone(page) != zone)
1211 return 0;
1212 zone = page_zone(page);
1213 }
1214 return 1;
1215 }
1216
1217 /*
1218 * Scanning pfn is much easier than scanning lru list.
1219 * Scan pfn from start to end and Find LRU page.
1220 */
1221 static unsigned long scan_lru_pages(unsigned long start, unsigned long end)
1222 {
1223 unsigned long pfn;
1224 struct page *page;
1225 for (pfn = start; pfn < end; pfn++) {
1226 if (pfn_valid(pfn)) {
1227 page = pfn_to_page(pfn);
1228 if (PageLRU(page))
1229 return pfn;
1230 }
1231 }
1232 return 0;
1233 }
1234
1235 #define NR_OFFLINE_AT_ONCE_PAGES (256)
1236 static int
1237 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1238 {
1239 unsigned long pfn;
1240 struct page *page;
1241 int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
1242 int not_managed = 0;
1243 int ret = 0;
1244 LIST_HEAD(source);
1245
1246 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
1247 if (!pfn_valid(pfn))
1248 continue;
1249 page = pfn_to_page(pfn);
1250 if (!get_page_unless_zero(page))
1251 continue;
1252 /*
1253 * We can skip free pages. And we can only deal with pages on
1254 * LRU.
1255 */
1256 ret = isolate_lru_page(page);
1257 if (!ret) { /* Success */
1258 put_page(page);
1259 list_add_tail(&page->lru, &source);
1260 move_pages--;
1261 inc_zone_page_state(page, NR_ISOLATED_ANON +
1262 page_is_file_cache(page));
1263
1264 } else {
1265 #ifdef CONFIG_DEBUG_VM
1266 printk(KERN_ALERT "removing pfn %lx from LRU failed\n",
1267 pfn);
1268 dump_page(page);
1269 #endif
1270 put_page(page);
1271 /* Because we don't have big zone->lock. we should
1272 check this again here. */
1273 if (page_count(page)) {
1274 not_managed++;
1275 ret = -EBUSY;
1276 break;
1277 }
1278 }
1279 }
1280 if (!list_empty(&source)) {
1281 if (not_managed) {
1282 putback_lru_pages(&source);
1283 goto out;
1284 }
1285
1286 /*
1287 * alloc_migrate_target should be improooooved!!
1288 * migrate_pages returns # of failed pages.
1289 */
1290 ret = migrate_pages(&source, alloc_migrate_target, 0,
1291 MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
1292 if (ret)
1293 putback_lru_pages(&source);
1294 }
1295 out:
1296 return ret;
1297 }
1298
1299 /*
1300 * remove from free_area[] and mark all as Reserved.
1301 */
1302 static int
1303 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1304 void *data)
1305 {
1306 __offline_isolated_pages(start, start + nr_pages);
1307 return 0;
1308 }
1309
1310 static void
1311 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
1312 {
1313 walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
1314 offline_isolated_pages_cb);
1315 }
1316
1317 /*
1318 * Check all pages in range, recoreded as memory resource, are isolated.
1319 */
1320 static int
1321 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1322 void *data)
1323 {
1324 int ret;
1325 long offlined = *(long *)data;
1326 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
1327 offlined = nr_pages;
1328 if (!ret)
1329 *(long *)data += offlined;
1330 return ret;
1331 }
1332
1333 static long
1334 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
1335 {
1336 long offlined = 0;
1337 int ret;
1338
1339 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
1340 check_pages_isolated_cb);
1341 if (ret < 0)
1342 offlined = (long)ret;
1343 return offlined;
1344 }
1345
1346 #ifdef CONFIG_MOVABLE_NODE
1347 /*
1348 * When CONFIG_MOVABLE_NODE, we permit offlining of a node which doesn't have
1349 * normal memory.
1350 */
1351 static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1352 {
1353 return true;
1354 }
1355 #else /* CONFIG_MOVABLE_NODE */
1356 /* ensure the node has NORMAL memory if it is still online */
1357 static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1358 {
1359 struct pglist_data *pgdat = zone->zone_pgdat;
1360 unsigned long present_pages = 0;
1361 enum zone_type zt;
1362
1363 for (zt = 0; zt <= ZONE_NORMAL; zt++)
1364 present_pages += pgdat->node_zones[zt].present_pages;
1365
1366 if (present_pages > nr_pages)
1367 return true;
1368
1369 present_pages = 0;
1370 for (; zt <= ZONE_MOVABLE; zt++)
1371 present_pages += pgdat->node_zones[zt].present_pages;
1372
1373 /*
1374 * we can't offline the last normal memory until all
1375 * higher memory is offlined.
1376 */
1377 return present_pages == 0;
1378 }
1379 #endif /* CONFIG_MOVABLE_NODE */
1380
1381 /* check which state of node_states will be changed when offline memory */
1382 static void node_states_check_changes_offline(unsigned long nr_pages,
1383 struct zone *zone, struct memory_notify *arg)
1384 {
1385 struct pglist_data *pgdat = zone->zone_pgdat;
1386 unsigned long present_pages = 0;
1387 enum zone_type zt, zone_last = ZONE_NORMAL;
1388
1389 /*
1390 * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
1391 * contains nodes which have zones of 0...ZONE_NORMAL,
1392 * set zone_last to ZONE_NORMAL.
1393 *
1394 * If we don't have HIGHMEM nor movable node,
1395 * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
1396 * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
1397 */
1398 if (N_MEMORY == N_NORMAL_MEMORY)
1399 zone_last = ZONE_MOVABLE;
1400
1401 /*
1402 * check whether node_states[N_NORMAL_MEMORY] will be changed.
1403 * If the memory to be offline is in a zone of 0...zone_last,
1404 * and it is the last present memory, 0...zone_last will
1405 * become empty after offline , thus we can determind we will
1406 * need to clear the node from node_states[N_NORMAL_MEMORY].
1407 */
1408 for (zt = 0; zt <= zone_last; zt++)
1409 present_pages += pgdat->node_zones[zt].present_pages;
1410 if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1411 arg->status_change_nid_normal = zone_to_nid(zone);
1412 else
1413 arg->status_change_nid_normal = -1;
1414
1415 #ifdef CONFIG_HIGHMEM
1416 /*
1417 * If we have movable node, node_states[N_HIGH_MEMORY]
1418 * contains nodes which have zones of 0...ZONE_HIGHMEM,
1419 * set zone_last to ZONE_HIGHMEM.
1420 *
1421 * If we don't have movable node, node_states[N_NORMAL_MEMORY]
1422 * contains nodes which have zones of 0...ZONE_MOVABLE,
1423 * set zone_last to ZONE_MOVABLE.
1424 */
1425 zone_last = ZONE_HIGHMEM;
1426 if (N_MEMORY == N_HIGH_MEMORY)
1427 zone_last = ZONE_MOVABLE;
1428
1429 for (; zt <= zone_last; zt++)
1430 present_pages += pgdat->node_zones[zt].present_pages;
1431 if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1432 arg->status_change_nid_high = zone_to_nid(zone);
1433 else
1434 arg->status_change_nid_high = -1;
1435 #else
1436 arg->status_change_nid_high = arg->status_change_nid_normal;
1437 #endif
1438
1439 /*
1440 * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE
1441 */
1442 zone_last = ZONE_MOVABLE;
1443
1444 /*
1445 * check whether node_states[N_HIGH_MEMORY] will be changed
1446 * If we try to offline the last present @nr_pages from the node,
1447 * we can determind we will need to clear the node from
1448 * node_states[N_HIGH_MEMORY].
1449 */
1450 for (; zt <= zone_last; zt++)
1451 present_pages += pgdat->node_zones[zt].present_pages;
1452 if (nr_pages >= present_pages)
1453 arg->status_change_nid = zone_to_nid(zone);
1454 else
1455 arg->status_change_nid = -1;
1456 }
1457
1458 static void node_states_clear_node(int node, struct memory_notify *arg)
1459 {
1460 if (arg->status_change_nid_normal >= 0)
1461 node_clear_state(node, N_NORMAL_MEMORY);
1462
1463 if ((N_MEMORY != N_NORMAL_MEMORY) &&
1464 (arg->status_change_nid_high >= 0))
1465 node_clear_state(node, N_HIGH_MEMORY);
1466
1467 if ((N_MEMORY != N_HIGH_MEMORY) &&
1468 (arg->status_change_nid >= 0))
1469 node_clear_state(node, N_MEMORY);
1470 }
1471
1472 static int __ref __offline_pages(unsigned long start_pfn,
1473 unsigned long end_pfn, unsigned long timeout)
1474 {
1475 unsigned long pfn, nr_pages, expire;
1476 long offlined_pages;
1477 int ret, drain, retry_max, node;
1478 struct zone *zone;
1479 struct memory_notify arg;
1480
1481 BUG_ON(start_pfn >= end_pfn);
1482 /* at least, alignment against pageblock is necessary */
1483 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
1484 return -EINVAL;
1485 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
1486 return -EINVAL;
1487 /* This makes hotplug much easier...and readable.
1488 we assume this for now. .*/
1489 if (!test_pages_in_a_zone(start_pfn, end_pfn))
1490 return -EINVAL;
1491
1492 lock_memory_hotplug();
1493
1494 zone = page_zone(pfn_to_page(start_pfn));
1495 node = zone_to_nid(zone);
1496 nr_pages = end_pfn - start_pfn;
1497
1498 ret = -EINVAL;
1499 if (zone_idx(zone) <= ZONE_NORMAL && !can_offline_normal(zone, nr_pages))
1500 goto out;
1501
1502 /* set above range as isolated */
1503 ret = start_isolate_page_range(start_pfn, end_pfn,
1504 MIGRATE_MOVABLE, true);
1505 if (ret)
1506 goto out;
1507
1508 arg.start_pfn = start_pfn;
1509 arg.nr_pages = nr_pages;
1510 node_states_check_changes_offline(nr_pages, zone, &arg);
1511
1512 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1513 ret = notifier_to_errno(ret);
1514 if (ret)
1515 goto failed_removal;
1516
1517 pfn = start_pfn;
1518 expire = jiffies + timeout;
1519 drain = 0;
1520 retry_max = 5;
1521 repeat:
1522 /* start memory hot removal */
1523 ret = -EAGAIN;
1524 if (time_after(jiffies, expire))
1525 goto failed_removal;
1526 ret = -EINTR;
1527 if (signal_pending(current))
1528 goto failed_removal;
1529 ret = 0;
1530 if (drain) {
1531 lru_add_drain_all();
1532 cond_resched();
1533 drain_all_pages();
1534 }
1535
1536 pfn = scan_lru_pages(start_pfn, end_pfn);
1537 if (pfn) { /* We have page on LRU */
1538 ret = do_migrate_range(pfn, end_pfn);
1539 if (!ret) {
1540 drain = 1;
1541 goto repeat;
1542 } else {
1543 if (ret < 0)
1544 if (--retry_max == 0)
1545 goto failed_removal;
1546 yield();
1547 drain = 1;
1548 goto repeat;
1549 }
1550 }
1551 /* drain all zone's lru pagevec, this is asynchronous... */
1552 lru_add_drain_all();
1553 yield();
1554 /* drain pcp pages, this is synchronous. */
1555 drain_all_pages();
1556 /* check again */
1557 offlined_pages = check_pages_isolated(start_pfn, end_pfn);
1558 if (offlined_pages < 0) {
1559 ret = -EBUSY;
1560 goto failed_removal;
1561 }
1562 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
1563 /* Ok, all of our target is isolated.
1564 We cannot do rollback at this point. */
1565 offline_isolated_pages(start_pfn, end_pfn);
1566 /* reset pagetype flags and makes migrate type to be MOVABLE */
1567 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1568 /* removal success */
1569 zone->managed_pages -= offlined_pages;
1570 zone->present_pages -= offlined_pages;
1571 zone->zone_pgdat->node_present_pages -= offlined_pages;
1572 totalram_pages -= offlined_pages;
1573
1574 init_per_zone_wmark_min();
1575
1576 if (!populated_zone(zone)) {
1577 zone_pcp_reset(zone);
1578 mutex_lock(&zonelists_mutex);
1579 build_all_zonelists(NULL, NULL);
1580 mutex_unlock(&zonelists_mutex);
1581 } else
1582 zone_pcp_update(zone);
1583
1584 node_states_clear_node(node, &arg);
1585 if (arg.status_change_nid >= 0)
1586 kswapd_stop(node);
1587
1588 vm_total_pages = nr_free_pagecache_pages();
1589 writeback_set_ratelimit();
1590
1591 memory_notify(MEM_OFFLINE, &arg);
1592 unlock_memory_hotplug();
1593 return 0;
1594
1595 failed_removal:
1596 printk(KERN_INFO "memory offlining [mem %#010llx-%#010llx] failed\n",
1597 (unsigned long long) start_pfn << PAGE_SHIFT,
1598 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
1599 memory_notify(MEM_CANCEL_OFFLINE, &arg);
1600 /* pushback to free area */
1601 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1602
1603 out:
1604 unlock_memory_hotplug();
1605 return ret;
1606 }
1607
1608 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1609 {
1610 return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);
1611 }
1612
1613 /**
1614 * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn)
1615 * @start_pfn: start pfn of the memory range
1616 * @end_pfn: end pft of the memory range
1617 * @arg: argument passed to func
1618 * @func: callback for each memory section walked
1619 *
1620 * This function walks through all present mem sections in range
1621 * [start_pfn, end_pfn) and call func on each mem section.
1622 *
1623 * Returns the return value of func.
1624 */
1625 static int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
1626 void *arg, int (*func)(struct memory_block *, void *))
1627 {
1628 struct memory_block *mem = NULL;
1629 struct mem_section *section;
1630 unsigned long pfn, section_nr;
1631 int ret;
1632
1633 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1634 section_nr = pfn_to_section_nr(pfn);
1635 if (!present_section_nr(section_nr))
1636 continue;
1637
1638 section = __nr_to_section(section_nr);
1639 /* same memblock? */
1640 if (mem)
1641 if ((section_nr >= mem->start_section_nr) &&
1642 (section_nr <= mem->end_section_nr))
1643 continue;
1644
1645 mem = find_memory_block_hinted(section, mem);
1646 if (!mem)
1647 continue;
1648
1649 ret = func(mem, arg);
1650 if (ret) {
1651 kobject_put(&mem->dev.kobj);
1652 return ret;
1653 }
1654 }
1655
1656 if (mem)
1657 kobject_put(&mem->dev.kobj);
1658
1659 return 0;
1660 }
1661
1662 /**
1663 * offline_memory_block_cb - callback function for offlining memory block
1664 * @mem: the memory block to be offlined
1665 * @arg: buffer to hold error msg
1666 *
1667 * Always return 0, and put the error msg in arg if any.
1668 */
1669 static int offline_memory_block_cb(struct memory_block *mem, void *arg)
1670 {
1671 int *ret = arg;
1672 int error = offline_memory_block(mem);
1673
1674 if (error != 0 && *ret == 0)
1675 *ret = error;
1676
1677 return 0;
1678 }
1679
1680 static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
1681 {
1682 int ret = !is_memblock_offlined(mem);
1683
1684 if (unlikely(ret))
1685 pr_warn("removing memory fails, because memory "
1686 "[%#010llx-%#010llx] is onlined\n",
1687 PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)),
1688 PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1);
1689
1690 return ret;
1691 }
1692
1693 static int check_cpu_on_node(void *data)
1694 {
1695 struct pglist_data *pgdat = data;
1696 int cpu;
1697
1698 for_each_present_cpu(cpu) {
1699 if (cpu_to_node(cpu) == pgdat->node_id)
1700 /*
1701 * the cpu on this node isn't removed, and we can't
1702 * offline this node.
1703 */
1704 return -EBUSY;
1705 }
1706
1707 return 0;
1708 }
1709
1710 static void unmap_cpu_on_node(void *data)
1711 {
1712 #ifdef CONFIG_ACPI_NUMA
1713 struct pglist_data *pgdat = data;
1714 int cpu;
1715
1716 for_each_possible_cpu(cpu)
1717 if (cpu_to_node(cpu) == pgdat->node_id)
1718 numa_clear_node(cpu);
1719 #endif
1720 }
1721
1722 static int check_and_unmap_cpu_on_node(void *data)
1723 {
1724 int ret = check_cpu_on_node(data);
1725
1726 if (ret)
1727 return ret;
1728
1729 /*
1730 * the node will be offlined when we come here, so we can clear
1731 * the cpu_to_node() now.
1732 */
1733
1734 unmap_cpu_on_node(data);
1735 return 0;
1736 }
1737
1738 /* offline the node if all memory sections of this node are removed */
1739 void try_offline_node(int nid)
1740 {
1741 pg_data_t *pgdat = NODE_DATA(nid);
1742 unsigned long start_pfn = pgdat->node_start_pfn;
1743 unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
1744 unsigned long pfn;
1745 struct page *pgdat_page = virt_to_page(pgdat);
1746 int i;
1747
1748 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1749 unsigned long section_nr = pfn_to_section_nr(pfn);
1750
1751 if (!present_section_nr(section_nr))
1752 continue;
1753
1754 if (pfn_to_nid(pfn) != nid)
1755 continue;
1756
1757 /*
1758 * some memory sections of this node are not removed, and we
1759 * can't offline node now.
1760 */
1761 return;
1762 }
1763
1764 if (stop_machine(check_and_unmap_cpu_on_node, pgdat, NULL))
1765 return;
1766
1767 /*
1768 * all memory/cpu of this node are removed, we can offline this
1769 * node now.
1770 */
1771 node_set_offline(nid);
1772 unregister_one_node(nid);
1773
1774 if (!PageSlab(pgdat_page) && !PageCompound(pgdat_page))
1775 /* node data is allocated from boot memory */
1776 return;
1777
1778 /* free waittable in each zone */
1779 for (i = 0; i < MAX_NR_ZONES; i++) {
1780 struct zone *zone = pgdat->node_zones + i;
1781
1782 /*
1783 * wait_table may be allocated from boot memory,
1784 * here only free if it's allocated by vmalloc.
1785 */
1786 if (is_vmalloc_addr(zone->wait_table))
1787 vfree(zone->wait_table);
1788 }
1789
1790 /*
1791 * Since there is no way to guarentee the address of pgdat/zone is not
1792 * on stack of any kernel threads or used by other kernel objects
1793 * without reference counting or other symchronizing method, do not
1794 * reset node_data and free pgdat here. Just reset it to 0 and reuse
1795 * the memory when the node is online again.
1796 */
1797 memset(pgdat, 0, sizeof(*pgdat));
1798 }
1799 EXPORT_SYMBOL(try_offline_node);
1800
1801 int __ref remove_memory(int nid, u64 start, u64 size)
1802 {
1803 unsigned long start_pfn, end_pfn;
1804 int ret = 0;
1805 int retry = 1;
1806
1807 start_pfn = PFN_DOWN(start);
1808 end_pfn = PFN_UP(start + size - 1);
1809
1810 /*
1811 * When CONFIG_MEMCG is on, one memory block may be used by other
1812 * blocks to store page cgroup when onlining pages. But we don't know
1813 * in what order pages are onlined. So we iterate twice to offline
1814 * memory:
1815 * 1st iterate: offline every non primary memory block.
1816 * 2nd iterate: offline primary (i.e. first added) memory block.
1817 */
1818 repeat:
1819 walk_memory_range(start_pfn, end_pfn, &ret,
1820 offline_memory_block_cb);
1821 if (ret) {
1822 if (!retry)
1823 return ret;
1824
1825 retry = 0;
1826 ret = 0;
1827 goto repeat;
1828 }
1829
1830 lock_memory_hotplug();
1831
1832 /*
1833 * we have offlined all memory blocks like this:
1834 * 1. lock memory hotplug
1835 * 2. offline a memory block
1836 * 3. unlock memory hotplug
1837 *
1838 * repeat step1-3 to offline the memory block. All memory blocks
1839 * must be offlined before removing memory. But we don't hold the
1840 * lock in the whole operation. So we should check whether all
1841 * memory blocks are offlined.
1842 */
1843
1844 ret = walk_memory_range(start_pfn, end_pfn, NULL,
1845 is_memblock_offlined_cb);
1846 if (ret) {
1847 unlock_memory_hotplug();
1848 return ret;
1849 }
1850
1851 /* remove memmap entry */
1852 firmware_map_remove(start, start + size, "System RAM");
1853
1854 arch_remove_memory(start, size);
1855
1856 try_offline_node(nid);
1857
1858 unlock_memory_hotplug();
1859
1860 return 0;
1861 }
1862 #else
1863 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1864 {
1865 return -EINVAL;
1866 }
1867 int remove_memory(int nid, u64 start, u64 size)
1868 {
1869 return -EINVAL;
1870 }
1871 #endif /* CONFIG_MEMORY_HOTREMOVE */
1872 EXPORT_SYMBOL_GPL(remove_memory);
1873
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.