freezer: do not sync filesystems from freeze_processes
[linux-2.6/mini2440.git] / mm / memory_hotplug.c
blob091b9c6c252973dd1cf5e89ffcf73de1afba173c
1 /*
2 * linux/mm/memory_hotplug.c
4 * Copyright (C)
5 */
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/cpuset.h>
26 #include <linux/delay.h>
27 #include <linux/migrate.h>
28 #include <linux/page-isolation.h>
30 #include <asm/tlbflush.h>
32 /* add this memory to iomem resource */
33 static struct resource *register_memory_resource(u64 start, u64 size)
35 struct resource *res;
36 res = kzalloc(sizeof(struct resource), GFP_KERNEL);
37 BUG_ON(!res);
39 res->name = "System RAM";
40 res->start = start;
41 res->end = start + size - 1;
42 res->flags = IORESOURCE_MEM;
43 if (request_resource(&iomem_resource, res) < 0) {
44 printk("System RAM resource %llx - %llx cannot be added\n",
45 (unsigned long long)res->start, (unsigned long long)res->end);
46 kfree(res);
47 res = NULL;
49 return res;
52 static void release_memory_resource(struct resource *res)
54 if (!res)
55 return;
56 release_resource(res);
57 kfree(res);
58 return;
62 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
63 static int __add_zone(struct zone *zone, unsigned long phys_start_pfn)
65 struct pglist_data *pgdat = zone->zone_pgdat;
66 int nr_pages = PAGES_PER_SECTION;
67 int nid = pgdat->node_id;
68 int zone_type;
70 zone_type = zone - pgdat->node_zones;
71 if (!zone->wait_table) {
72 int ret = 0;
73 ret = init_currently_empty_zone(zone, phys_start_pfn,
74 nr_pages, MEMMAP_HOTPLUG);
75 if (ret < 0)
76 return ret;
78 memmap_init_zone(nr_pages, nid, zone_type,
79 phys_start_pfn, MEMMAP_HOTPLUG);
80 return 0;
83 static int __add_section(struct zone *zone, unsigned long phys_start_pfn)
85 int nr_pages = PAGES_PER_SECTION;
86 int ret;
88 if (pfn_valid(phys_start_pfn))
89 return -EEXIST;
91 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
93 if (ret < 0)
94 return ret;
96 ret = __add_zone(zone, phys_start_pfn);
98 if (ret < 0)
99 return ret;
101 return register_new_memory(__pfn_to_section(phys_start_pfn));
105 * Reasonably generic function for adding memory. It is
106 * expected that archs that support memory hotplug will
107 * call this function after deciding the zone to which to
108 * add the new pages.
110 int __add_pages(struct zone *zone, unsigned long phys_start_pfn,
111 unsigned long nr_pages)
113 unsigned long i;
114 int err = 0;
115 int start_sec, end_sec;
116 /* during initialize mem_map, align hot-added range to section */
117 start_sec = pfn_to_section_nr(phys_start_pfn);
118 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
120 for (i = start_sec; i <= end_sec; i++) {
121 err = __add_section(zone, i << PFN_SECTION_SHIFT);
124 * EEXIST is finally dealed with by ioresource collision
125 * check. see add_memory() => register_memory_resource()
126 * Warning will be printed if there is collision.
128 if (err && (err != -EEXIST))
129 break;
130 err = 0;
133 return err;
135 EXPORT_SYMBOL_GPL(__add_pages);
137 static void grow_zone_span(struct zone *zone,
138 unsigned long start_pfn, unsigned long end_pfn)
140 unsigned long old_zone_end_pfn;
142 zone_span_writelock(zone);
144 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
145 if (start_pfn < zone->zone_start_pfn)
146 zone->zone_start_pfn = start_pfn;
148 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
149 zone->zone_start_pfn;
151 zone_span_writeunlock(zone);
154 static void grow_pgdat_span(struct pglist_data *pgdat,
155 unsigned long start_pfn, unsigned long end_pfn)
157 unsigned long old_pgdat_end_pfn =
158 pgdat->node_start_pfn + pgdat->node_spanned_pages;
160 if (start_pfn < pgdat->node_start_pfn)
161 pgdat->node_start_pfn = start_pfn;
163 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
164 pgdat->node_start_pfn;
167 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
168 void *arg)
170 unsigned long i;
171 unsigned long onlined_pages = *(unsigned long *)arg;
172 struct page *page;
173 if (PageReserved(pfn_to_page(start_pfn)))
174 for (i = 0; i < nr_pages; i++) {
175 page = pfn_to_page(start_pfn + i);
176 online_page(page);
177 onlined_pages++;
179 *(unsigned long *)arg = onlined_pages;
180 return 0;
184 int online_pages(unsigned long pfn, unsigned long nr_pages)
186 unsigned long flags;
187 unsigned long onlined_pages = 0;
188 struct zone *zone;
189 int need_zonelists_rebuild = 0;
192 * This doesn't need a lock to do pfn_to_page().
193 * The section can't be removed here because of the
194 * memory_block->state_sem.
196 zone = page_zone(pfn_to_page(pfn));
197 pgdat_resize_lock(zone->zone_pgdat, &flags);
198 grow_zone_span(zone, pfn, pfn + nr_pages);
199 grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages);
200 pgdat_resize_unlock(zone->zone_pgdat, &flags);
203 * If this zone is not populated, then it is not in zonelist.
204 * This means the page allocator ignores this zone.
205 * So, zonelist must be updated after online.
207 if (!populated_zone(zone))
208 need_zonelists_rebuild = 1;
210 walk_memory_resource(pfn, nr_pages, &onlined_pages,
211 online_pages_range);
212 zone->present_pages += onlined_pages;
213 zone->zone_pgdat->node_present_pages += onlined_pages;
215 setup_per_zone_pages_min();
216 if (onlined_pages) {
217 kswapd_run(zone_to_nid(zone));
218 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY);
221 if (need_zonelists_rebuild)
222 build_all_zonelists();
223 vm_total_pages = nr_free_pagecache_pages();
224 writeback_set_ratelimit();
225 return 0;
227 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
229 static pg_data_t *hotadd_new_pgdat(int nid, u64 start)
231 struct pglist_data *pgdat;
232 unsigned long zones_size[MAX_NR_ZONES] = {0};
233 unsigned long zholes_size[MAX_NR_ZONES] = {0};
234 unsigned long start_pfn = start >> PAGE_SHIFT;
236 pgdat = arch_alloc_nodedata(nid);
237 if (!pgdat)
238 return NULL;
240 arch_refresh_nodedata(nid, pgdat);
242 /* we can use NODE_DATA(nid) from here */
244 /* init node's zones as empty zones, we don't have any present pages.*/
245 free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size);
247 return pgdat;
250 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
252 arch_refresh_nodedata(nid, NULL);
253 arch_free_nodedata(pgdat);
254 return;
258 int add_memory(int nid, u64 start, u64 size)
260 pg_data_t *pgdat = NULL;
261 int new_pgdat = 0;
262 struct resource *res;
263 int ret;
265 res = register_memory_resource(start, size);
266 if (!res)
267 return -EEXIST;
269 if (!node_online(nid)) {
270 pgdat = hotadd_new_pgdat(nid, start);
271 if (!pgdat)
272 return -ENOMEM;
273 new_pgdat = 1;
276 /* call arch's memory hotadd */
277 ret = arch_add_memory(nid, start, size);
279 if (ret < 0)
280 goto error;
282 /* we online node here. we can't roll back from here. */
283 node_set_online(nid);
285 cpuset_track_online_nodes();
287 if (new_pgdat) {
288 ret = register_one_node(nid);
290 * If sysfs file of new node can't create, cpu on the node
291 * can't be hot-added. There is no rollback way now.
292 * So, check by BUG_ON() to catch it reluctantly..
294 BUG_ON(ret);
297 return ret;
298 error:
299 /* rollback pgdat allocation and others */
300 if (new_pgdat)
301 rollback_node_hotadd(nid, pgdat);
302 if (res)
303 release_memory_resource(res);
305 return ret;
307 EXPORT_SYMBOL_GPL(add_memory);
309 #ifdef CONFIG_MEMORY_HOTREMOVE
311 * Confirm all pages in a range [start, end) is belongs to the same zone.
313 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
315 unsigned long pfn;
316 struct zone *zone = NULL;
317 struct page *page;
318 int i;
319 for (pfn = start_pfn;
320 pfn < end_pfn;
321 pfn += MAX_ORDER_NR_PAGES) {
322 i = 0;
323 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
324 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
325 i++;
326 if (i == MAX_ORDER_NR_PAGES)
327 continue;
328 page = pfn_to_page(pfn + i);
329 if (zone && page_zone(page) != zone)
330 return 0;
331 zone = page_zone(page);
333 return 1;
337 * Scanning pfn is much easier than scanning lru list.
338 * Scan pfn from start to end and Find LRU page.
340 int scan_lru_pages(unsigned long start, unsigned long end)
342 unsigned long pfn;
343 struct page *page;
344 for (pfn = start; pfn < end; pfn++) {
345 if (pfn_valid(pfn)) {
346 page = pfn_to_page(pfn);
347 if (PageLRU(page))
348 return pfn;
351 return 0;
354 static struct page *
355 hotremove_migrate_alloc(struct page *page,
356 unsigned long private,
357 int **x)
359 /* This should be improoooooved!! */
360 return alloc_page(GFP_HIGHUSER_PAGECACHE);
364 #define NR_OFFLINE_AT_ONCE_PAGES (256)
365 static int
366 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
368 unsigned long pfn;
369 struct page *page;
370 int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
371 int not_managed = 0;
372 int ret = 0;
373 LIST_HEAD(source);
375 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
376 if (!pfn_valid(pfn))
377 continue;
378 page = pfn_to_page(pfn);
379 if (!page_count(page))
380 continue;
382 * We can skip free pages. And we can only deal with pages on
383 * LRU.
385 ret = isolate_lru_page(page, &source);
386 if (!ret) { /* Success */
387 move_pages--;
388 } else {
389 /* Becasue we don't have big zone->lock. we should
390 check this again here. */
391 if (page_count(page))
392 not_managed++;
393 #ifdef CONFIG_DEBUG_VM
394 printk(KERN_INFO "removing from LRU failed"
395 " %lx/%d/%lx\n",
396 pfn, page_count(page), page->flags);
397 #endif
400 ret = -EBUSY;
401 if (not_managed) {
402 if (!list_empty(&source))
403 putback_lru_pages(&source);
404 goto out;
406 ret = 0;
407 if (list_empty(&source))
408 goto out;
409 /* this function returns # of failed pages */
410 ret = migrate_pages(&source, hotremove_migrate_alloc, 0);
412 out:
413 return ret;
417 * remove from free_area[] and mark all as Reserved.
419 static int
420 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
421 void *data)
423 __offline_isolated_pages(start, start + nr_pages);
424 return 0;
427 static void
428 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
430 walk_memory_resource(start_pfn, end_pfn - start_pfn, NULL,
431 offline_isolated_pages_cb);
435 * Check all pages in range, recoreded as memory resource, are isolated.
437 static int
438 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
439 void *data)
441 int ret;
442 long offlined = *(long *)data;
443 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages);
444 offlined = nr_pages;
445 if (!ret)
446 *(long *)data += offlined;
447 return ret;
450 static long
451 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
453 long offlined = 0;
454 int ret;
456 ret = walk_memory_resource(start_pfn, end_pfn - start_pfn, &offlined,
457 check_pages_isolated_cb);
458 if (ret < 0)
459 offlined = (long)ret;
460 return offlined;
463 extern void drain_all_local_pages(void);
465 int offline_pages(unsigned long start_pfn,
466 unsigned long end_pfn, unsigned long timeout)
468 unsigned long pfn, nr_pages, expire;
469 long offlined_pages;
470 int ret, drain, retry_max;
471 struct zone *zone;
473 BUG_ON(start_pfn >= end_pfn);
474 /* at least, alignment against pageblock is necessary */
475 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
476 return -EINVAL;
477 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
478 return -EINVAL;
479 /* This makes hotplug much easier...and readable.
480 we assume this for now. .*/
481 if (!test_pages_in_a_zone(start_pfn, end_pfn))
482 return -EINVAL;
483 /* set above range as isolated */
484 ret = start_isolate_page_range(start_pfn, end_pfn);
485 if (ret)
486 return ret;
487 nr_pages = end_pfn - start_pfn;
488 pfn = start_pfn;
489 expire = jiffies + timeout;
490 drain = 0;
491 retry_max = 5;
492 repeat:
493 /* start memory hot removal */
494 ret = -EAGAIN;
495 if (time_after(jiffies, expire))
496 goto failed_removal;
497 ret = -EINTR;
498 if (signal_pending(current))
499 goto failed_removal;
500 ret = 0;
501 if (drain) {
502 lru_add_drain_all();
503 flush_scheduled_work();
504 cond_resched();
505 drain_all_local_pages();
508 pfn = scan_lru_pages(start_pfn, end_pfn);
509 if (pfn) { /* We have page on LRU */
510 ret = do_migrate_range(pfn, end_pfn);
511 if (!ret) {
512 drain = 1;
513 goto repeat;
514 } else {
515 if (ret < 0)
516 if (--retry_max == 0)
517 goto failed_removal;
518 yield();
519 drain = 1;
520 goto repeat;
523 /* drain all zone's lru pagevec, this is asyncronous... */
524 lru_add_drain_all();
525 flush_scheduled_work();
526 yield();
527 /* drain pcp pages , this is synchrouns. */
528 drain_all_local_pages();
529 /* check again */
530 offlined_pages = check_pages_isolated(start_pfn, end_pfn);
531 if (offlined_pages < 0) {
532 ret = -EBUSY;
533 goto failed_removal;
535 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
536 /* Ok, all of our target is islaoted.
537 We cannot do rollback at this point. */
538 offline_isolated_pages(start_pfn, end_pfn);
539 /* reset pagetype flags */
540 start_isolate_page_range(start_pfn, end_pfn);
541 /* removal success */
542 zone = page_zone(pfn_to_page(start_pfn));
543 zone->present_pages -= offlined_pages;
544 zone->zone_pgdat->node_present_pages -= offlined_pages;
545 totalram_pages -= offlined_pages;
546 num_physpages -= offlined_pages;
547 vm_total_pages = nr_free_pagecache_pages();
548 writeback_set_ratelimit();
549 return 0;
551 failed_removal:
552 printk(KERN_INFO "memory offlining %lx to %lx failed\n",
553 start_pfn, end_pfn);
554 /* pushback to free area */
555 undo_isolate_page_range(start_pfn, end_pfn);
556 return ret;
558 #else
559 int remove_memory(u64 start, u64 size)
561 return -EINVAL;
563 EXPORT_SYMBOL_GPL(remove_memory);
564 #endif /* CONFIG_MEMORY_HOTREMOVE */