blob: 47fca1069343c82f448b8e56db7237d8843eb8eb [file] [log] [blame]
Mel Gorman748446b2010-05-24 14:32:27 -07001/*
2 * linux/mm/compaction.c
3 *
4 * Memory compaction for the reduction of external fragmentation. Note that
5 * this heavily depends upon page migration to do all the real heavy
6 * lifting
7 *
8 * Copyright IBM Corp. 2007-2010 Mel Gorman <mel@csn.ul.ie>
9 */
10#include <linux/swap.h>
11#include <linux/migrate.h>
12#include <linux/compaction.h>
13#include <linux/mm_inline.h>
14#include <linux/backing-dev.h>
Mel Gorman76ab0f52010-05-24 14:32:28 -070015#include <linux/sysctl.h>
Mel Gormaned4a6d72010-05-24 14:32:29 -070016#include <linux/sysfs.h>
Mel Gorman748446b2010-05-24 14:32:27 -070017#include "internal.h"
18
Mel Gormanb7aba692011-01-13 15:45:54 -080019#define CREATE_TRACE_POINTS
20#include <trace/events/compaction.h>
21
Mel Gorman748446b2010-05-24 14:32:27 -070022/*
23 * compact_control is used to track pages being migrated and the free pages
24 * they are being migrated to during memory compaction. The free_pfn starts
25 * at the end of a zone and migrate_pfn begins at the start. Movable pages
26 * are moved to the end of a zone during a compaction run and the run
27 * completes when free_pfn <= migrate_pfn
28 */
29struct compact_control {
30 struct list_head freepages; /* List of free pages to migrate to */
31 struct list_head migratepages; /* List of pages being migrated */
32 unsigned long nr_freepages; /* Number of isolated free pages */
33 unsigned long nr_migratepages; /* Number of pages to migrate */
34 unsigned long free_pfn; /* isolate_freepages search base */
35 unsigned long migrate_pfn; /* isolate_migratepages search base */
Mel Gorman77f1fe62011-01-13 15:45:57 -080036 bool sync; /* Synchronous migration */
Mel Gorman748446b2010-05-24 14:32:27 -070037
38 /* Account for isolated anon and file pages */
39 unsigned long nr_anon;
40 unsigned long nr_file;
41
Mel Gorman56de7262010-05-24 14:32:30 -070042 unsigned int order; /* order a direct compactor needs */
43 int migratetype; /* MOVABLE, RECLAIMABLE etc */
Mel Gorman748446b2010-05-24 14:32:27 -070044 struct zone *zone;
45};
46
47static unsigned long release_freepages(struct list_head *freelist)
48{
49 struct page *page, *next;
50 unsigned long count = 0;
51
52 list_for_each_entry_safe(page, next, freelist, lru) {
53 list_del(&page->lru);
54 __free_page(page);
55 count++;
56 }
57
58 return count;
59}
60
61/* Isolate free pages onto a private freelist. Must hold zone->lock */
62static unsigned long isolate_freepages_block(struct zone *zone,
63 unsigned long blockpfn,
64 struct list_head *freelist)
65{
66 unsigned long zone_end_pfn, end_pfn;
Mel Gormanb7aba692011-01-13 15:45:54 -080067 int nr_scanned = 0, total_isolated = 0;
Mel Gorman748446b2010-05-24 14:32:27 -070068 struct page *cursor;
69
70 /* Get the last PFN we should scan for free pages at */
71 zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
72 end_pfn = min(blockpfn + pageblock_nr_pages, zone_end_pfn);
73
74 /* Find the first usable PFN in the block to initialse page cursor */
75 for (; blockpfn < end_pfn; blockpfn++) {
76 if (pfn_valid_within(blockpfn))
77 break;
78 }
79 cursor = pfn_to_page(blockpfn);
80
81 /* Isolate free pages. This assumes the block is valid */
82 for (; blockpfn < end_pfn; blockpfn++, cursor++) {
83 int isolated, i;
84 struct page *page = cursor;
85
86 if (!pfn_valid_within(blockpfn))
87 continue;
Mel Gormanb7aba692011-01-13 15:45:54 -080088 nr_scanned++;
Mel Gorman748446b2010-05-24 14:32:27 -070089
90 if (!PageBuddy(page))
91 continue;
92
93 /* Found a free page, break it into order-0 pages */
94 isolated = split_free_page(page);
95 total_isolated += isolated;
96 for (i = 0; i < isolated; i++) {
97 list_add(&page->lru, freelist);
98 page++;
99 }
100
101 /* If a page was split, advance to the end of it */
102 if (isolated) {
103 blockpfn += isolated - 1;
104 cursor += isolated - 1;
105 }
106 }
107
Mel Gormanb7aba692011-01-13 15:45:54 -0800108 trace_mm_compaction_isolate_freepages(nr_scanned, total_isolated);
Mel Gorman748446b2010-05-24 14:32:27 -0700109 return total_isolated;
110}
111
112/* Returns true if the page is within a block suitable for migration to */
113static bool suitable_migration_target(struct page *page)
114{
115
116 int migratetype = get_pageblock_migratetype(page);
117
118 /* Don't interfere with memory hot-remove or the min_free_kbytes blocks */
119 if (migratetype == MIGRATE_ISOLATE || migratetype == MIGRATE_RESERVE)
120 return false;
121
122 /* If the page is a large free page, then allow migration */
123 if (PageBuddy(page) && page_order(page) >= pageblock_order)
124 return true;
125
126 /* If the block is MIGRATE_MOVABLE, allow migration */
127 if (migratetype == MIGRATE_MOVABLE)
128 return true;
129
130 /* Otherwise skip the block */
131 return false;
132}
133
134/*
135 * Based on information in the current compact_control, find blocks
136 * suitable for isolating free pages from and then isolate them.
137 */
138static void isolate_freepages(struct zone *zone,
139 struct compact_control *cc)
140{
141 struct page *page;
142 unsigned long high_pfn, low_pfn, pfn;
143 unsigned long flags;
144 int nr_freepages = cc->nr_freepages;
145 struct list_head *freelist = &cc->freepages;
146
147 pfn = cc->free_pfn;
148 low_pfn = cc->migrate_pfn + pageblock_nr_pages;
149 high_pfn = low_pfn;
150
151 /*
152 * Isolate free pages until enough are available to migrate the
153 * pages on cc->migratepages. We stop searching if the migrate
154 * and free page scanners meet or enough free pages are isolated.
155 */
156 spin_lock_irqsave(&zone->lock, flags);
157 for (; pfn > low_pfn && cc->nr_migratepages > nr_freepages;
158 pfn -= pageblock_nr_pages) {
159 unsigned long isolated;
160
161 if (!pfn_valid(pfn))
162 continue;
163
164 /*
165 * Check for overlapping nodes/zones. It's possible on some
166 * configurations to have a setup like
167 * node0 node1 node0
168 * i.e. it's possible that all pages within a zones range of
169 * pages do not belong to a single zone.
170 */
171 page = pfn_to_page(pfn);
172 if (page_zone(page) != zone)
173 continue;
174
175 /* Check the block is suitable for migration */
176 if (!suitable_migration_target(page))
177 continue;
178
179 /* Found a block suitable for isolating free pages from */
180 isolated = isolate_freepages_block(zone, pfn, freelist);
181 nr_freepages += isolated;
182
183 /*
184 * Record the highest PFN we isolated pages from. When next
185 * looking for free pages, the search will restart here as
186 * page migration may have returned some pages to the allocator
187 */
188 if (isolated)
189 high_pfn = max(high_pfn, pfn);
190 }
191 spin_unlock_irqrestore(&zone->lock, flags);
192
193 /* split_free_page does not map the pages */
194 list_for_each_entry(page, freelist, lru) {
195 arch_alloc_page(page, 0);
196 kernel_map_pages(page, 1, 1);
197 }
198
199 cc->free_pfn = high_pfn;
200 cc->nr_freepages = nr_freepages;
201}
202
203/* Update the number of anon and file isolated pages in the zone */
204static void acct_isolated(struct zone *zone, struct compact_control *cc)
205{
206 struct page *page;
207 unsigned int count[NR_LRU_LISTS] = { 0, };
208
209 list_for_each_entry(page, &cc->migratepages, lru) {
210 int lru = page_lru_base_type(page);
211 count[lru]++;
212 }
213
214 cc->nr_anon = count[LRU_ACTIVE_ANON] + count[LRU_INACTIVE_ANON];
215 cc->nr_file = count[LRU_ACTIVE_FILE] + count[LRU_INACTIVE_FILE];
216 __mod_zone_page_state(zone, NR_ISOLATED_ANON, cc->nr_anon);
217 __mod_zone_page_state(zone, NR_ISOLATED_FILE, cc->nr_file);
218}
219
220/* Similar to reclaim, but different enough that they don't share logic */
221static bool too_many_isolated(struct zone *zone)
222{
Minchan Kimbc693042010-09-09 16:38:00 -0700223 unsigned long active, inactive, isolated;
Mel Gorman748446b2010-05-24 14:32:27 -0700224
225 inactive = zone_page_state(zone, NR_INACTIVE_FILE) +
226 zone_page_state(zone, NR_INACTIVE_ANON);
Minchan Kimbc693042010-09-09 16:38:00 -0700227 active = zone_page_state(zone, NR_ACTIVE_FILE) +
228 zone_page_state(zone, NR_ACTIVE_ANON);
Mel Gorman748446b2010-05-24 14:32:27 -0700229 isolated = zone_page_state(zone, NR_ISOLATED_FILE) +
230 zone_page_state(zone, NR_ISOLATED_ANON);
231
Minchan Kimbc693042010-09-09 16:38:00 -0700232 return isolated > (inactive + active) / 2;
Mel Gorman748446b2010-05-24 14:32:27 -0700233}
234
235/*
236 * Isolate all pages that can be migrated from the block pointed to by
237 * the migrate scanner within compact_control.
238 */
239static unsigned long isolate_migratepages(struct zone *zone,
240 struct compact_control *cc)
241{
242 unsigned long low_pfn, end_pfn;
Mel Gormanb7aba692011-01-13 15:45:54 -0800243 unsigned long nr_scanned = 0, nr_isolated = 0;
Mel Gorman748446b2010-05-24 14:32:27 -0700244 struct list_head *migratelist = &cc->migratepages;
245
246 /* Do not scan outside zone boundaries */
247 low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn);
248
249 /* Only scan within a pageblock boundary */
250 end_pfn = ALIGN(low_pfn + pageblock_nr_pages, pageblock_nr_pages);
251
252 /* Do not cross the free scanner or scan within a memory hole */
253 if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) {
254 cc->migrate_pfn = end_pfn;
255 return 0;
256 }
257
258 /*
259 * Ensure that there are not too many pages isolated from the LRU
260 * list by either parallel reclaimers or compaction. If there are,
261 * delay for some time until fewer pages are isolated
262 */
263 while (unlikely(too_many_isolated(zone))) {
264 congestion_wait(BLK_RW_ASYNC, HZ/10);
265
266 if (fatal_signal_pending(current))
267 return 0;
268 }
269
270 /* Time to isolate some pages for migration */
271 spin_lock_irq(&zone->lru_lock);
272 for (; low_pfn < end_pfn; low_pfn++) {
273 struct page *page;
274 if (!pfn_valid_within(low_pfn))
275 continue;
Mel Gormanb7aba692011-01-13 15:45:54 -0800276 nr_scanned++;
Mel Gorman748446b2010-05-24 14:32:27 -0700277
278 /* Get the page and skip if free */
279 page = pfn_to_page(low_pfn);
280 if (PageBuddy(page))
281 continue;
282
283 /* Try isolate the page */
284 if (__isolate_lru_page(page, ISOLATE_BOTH, 0) != 0)
285 continue;
286
287 /* Successfully isolated */
288 del_page_from_lru_list(zone, page, page_lru(page));
289 list_add(&page->lru, migratelist);
Mel Gorman748446b2010-05-24 14:32:27 -0700290 cc->nr_migratepages++;
Mel Gormanb7aba692011-01-13 15:45:54 -0800291 nr_isolated++;
Mel Gorman748446b2010-05-24 14:32:27 -0700292
293 /* Avoid isolating too much */
294 if (cc->nr_migratepages == COMPACT_CLUSTER_MAX)
295 break;
296 }
297
298 acct_isolated(zone, cc);
299
300 spin_unlock_irq(&zone->lru_lock);
301 cc->migrate_pfn = low_pfn;
302
Mel Gormanb7aba692011-01-13 15:45:54 -0800303 trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated);
304
Mel Gorman748446b2010-05-24 14:32:27 -0700305 return cc->nr_migratepages;
306}
307
308/*
309 * This is a migrate-callback that "allocates" freepages by taking pages
310 * from the isolated freelists in the block we are migrating to.
311 */
312static struct page *compaction_alloc(struct page *migratepage,
313 unsigned long data,
314 int **result)
315{
316 struct compact_control *cc = (struct compact_control *)data;
317 struct page *freepage;
318
319 /* Isolate free pages if necessary */
320 if (list_empty(&cc->freepages)) {
321 isolate_freepages(cc->zone, cc);
322
323 if (list_empty(&cc->freepages))
324 return NULL;
325 }
326
327 freepage = list_entry(cc->freepages.next, struct page, lru);
328 list_del(&freepage->lru);
329 cc->nr_freepages--;
330
331 return freepage;
332}
333
334/*
335 * We cannot control nr_migratepages and nr_freepages fully when migration is
336 * running as migrate_pages() has no knowledge of compact_control. When
337 * migration is complete, we count the number of pages on the lists by hand.
338 */
339static void update_nr_listpages(struct compact_control *cc)
340{
341 int nr_migratepages = 0;
342 int nr_freepages = 0;
343 struct page *page;
344
345 list_for_each_entry(page, &cc->migratepages, lru)
346 nr_migratepages++;
347 list_for_each_entry(page, &cc->freepages, lru)
348 nr_freepages++;
349
350 cc->nr_migratepages = nr_migratepages;
351 cc->nr_freepages = nr_freepages;
352}
353
354static int compact_finished(struct zone *zone,
355 struct compact_control *cc)
356{
Mel Gorman56de7262010-05-24 14:32:30 -0700357 unsigned int order;
358 unsigned long watermark = low_wmark_pages(zone) + (1 << cc->order);
359
Mel Gorman748446b2010-05-24 14:32:27 -0700360 if (fatal_signal_pending(current))
361 return COMPACT_PARTIAL;
362
363 /* Compaction run completes if the migrate and free scanner meet */
364 if (cc->free_pfn <= cc->migrate_pfn)
365 return COMPACT_COMPLETE;
366
Mel Gorman56de7262010-05-24 14:32:30 -0700367 /* Compaction run is not finished if the watermark is not met */
368 if (!zone_watermark_ok(zone, cc->order, watermark, 0, 0))
369 return COMPACT_CONTINUE;
370
371 if (cc->order == -1)
372 return COMPACT_CONTINUE;
373
374 /* Direct compactor: Is a suitable page free? */
375 for (order = cc->order; order < MAX_ORDER; order++) {
376 /* Job done if page is free of the right migratetype */
377 if (!list_empty(&zone->free_area[order].free_list[cc->migratetype]))
378 return COMPACT_PARTIAL;
379
380 /* Job done if allocation would set block type */
381 if (order >= pageblock_order && zone->free_area[order].nr_free)
382 return COMPACT_PARTIAL;
383 }
384
Mel Gorman748446b2010-05-24 14:32:27 -0700385 return COMPACT_CONTINUE;
386}
387
Mel Gorman3e7d3442011-01-13 15:45:56 -0800388/*
389 * compaction_suitable: Is this suitable to run compaction on this zone now?
390 * Returns
391 * COMPACT_SKIPPED - If there are too few free pages for compaction
392 * COMPACT_PARTIAL - If the allocation would succeed without compaction
393 * COMPACT_CONTINUE - If compaction should run now
394 */
395unsigned long compaction_suitable(struct zone *zone, int order)
396{
397 int fragindex;
398 unsigned long watermark;
399
400 /*
401 * Watermarks for order-0 must be met for compaction. Note the 2UL.
402 * This is because during migration, copies of pages need to be
403 * allocated and for a short time, the footprint is higher
404 */
405 watermark = low_wmark_pages(zone) + (2UL << order);
406 if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
407 return COMPACT_SKIPPED;
408
409 /*
410 * fragmentation index determines if allocation failures are due to
411 * low memory or external fragmentation
412 *
413 * index of -1 implies allocations might succeed dependingon watermarks
414 * index towards 0 implies failure is due to lack of memory
415 * index towards 1000 implies failure is due to fragmentation
416 *
417 * Only compact if a failure would be due to fragmentation.
418 */
419 fragindex = fragmentation_index(zone, order);
420 if (fragindex >= 0 && fragindex <= sysctl_extfrag_threshold)
421 return COMPACT_SKIPPED;
422
423 if (fragindex == -1 && zone_watermark_ok(zone, order, watermark, 0, 0))
424 return COMPACT_PARTIAL;
425
426 return COMPACT_CONTINUE;
427}
428
Mel Gorman748446b2010-05-24 14:32:27 -0700429static int compact_zone(struct zone *zone, struct compact_control *cc)
430{
431 int ret;
432
Mel Gorman3e7d3442011-01-13 15:45:56 -0800433 ret = compaction_suitable(zone, cc->order);
434 switch (ret) {
435 case COMPACT_PARTIAL:
436 case COMPACT_SKIPPED:
437 /* Compaction is likely to fail */
438 return ret;
439 case COMPACT_CONTINUE:
440 /* Fall through to compaction */
441 ;
442 }
443
Mel Gorman748446b2010-05-24 14:32:27 -0700444 /* Setup to move all movable pages to the end of the zone */
445 cc->migrate_pfn = zone->zone_start_pfn;
446 cc->free_pfn = cc->migrate_pfn + zone->spanned_pages;
447 cc->free_pfn &= ~(pageblock_nr_pages-1);
448
449 migrate_prep_local();
450
451 while ((ret = compact_finished(zone, cc)) == COMPACT_CONTINUE) {
452 unsigned long nr_migrate, nr_remaining;
453
454 if (!isolate_migratepages(zone, cc))
455 continue;
456
457 nr_migrate = cc->nr_migratepages;
458 migrate_pages(&cc->migratepages, compaction_alloc,
Mel Gorman77f1fe62011-01-13 15:45:57 -0800459 (unsigned long)cc, 0,
460 cc->sync);
Mel Gorman748446b2010-05-24 14:32:27 -0700461 update_nr_listpages(cc);
462 nr_remaining = cc->nr_migratepages;
463
464 count_vm_event(COMPACTBLOCKS);
465 count_vm_events(COMPACTPAGES, nr_migrate - nr_remaining);
466 if (nr_remaining)
467 count_vm_events(COMPACTPAGEFAILED, nr_remaining);
Mel Gormanb7aba692011-01-13 15:45:54 -0800468 trace_mm_compaction_migratepages(nr_migrate - nr_remaining,
469 nr_remaining);
Mel Gorman748446b2010-05-24 14:32:27 -0700470
471 /* Release LRU pages not migrated */
472 if (!list_empty(&cc->migratepages)) {
473 putback_lru_pages(&cc->migratepages);
474 cc->nr_migratepages = 0;
475 }
476
477 }
478
479 /* Release free pages and check accounting */
480 cc->nr_freepages -= release_freepages(&cc->freepages);
481 VM_BUG_ON(cc->nr_freepages != 0);
482
483 return ret;
484}
Mel Gorman76ab0f52010-05-24 14:32:28 -0700485
Mel Gorman3e7d3442011-01-13 15:45:56 -0800486unsigned long compact_zone_order(struct zone *zone,
Mel Gorman77f1fe62011-01-13 15:45:57 -0800487 int order, gfp_t gfp_mask,
488 bool sync)
Mel Gorman56de7262010-05-24 14:32:30 -0700489{
490 struct compact_control cc = {
491 .nr_freepages = 0,
492 .nr_migratepages = 0,
493 .order = order,
494 .migratetype = allocflags_to_migratetype(gfp_mask),
495 .zone = zone,
Mel Gorman77f1fe62011-01-13 15:45:57 -0800496 .sync = sync,
Mel Gorman56de7262010-05-24 14:32:30 -0700497 };
498 INIT_LIST_HEAD(&cc.freepages);
499 INIT_LIST_HEAD(&cc.migratepages);
500
501 return compact_zone(zone, &cc);
502}
503
Mel Gorman5e771902010-05-24 14:32:31 -0700504int sysctl_extfrag_threshold = 500;
505
Mel Gorman56de7262010-05-24 14:32:30 -0700506/**
507 * try_to_compact_pages - Direct compact to satisfy a high-order allocation
508 * @zonelist: The zonelist used for the current allocation
509 * @order: The order of the current allocation
510 * @gfp_mask: The GFP mask of the current allocation
511 * @nodemask: The allowed nodes to allocate from
Mel Gorman77f1fe62011-01-13 15:45:57 -0800512 * @sync: Whether migration is synchronous or not
Mel Gorman56de7262010-05-24 14:32:30 -0700513 *
514 * This is the main entry point for direct page compaction.
515 */
516unsigned long try_to_compact_pages(struct zonelist *zonelist,
Mel Gorman77f1fe62011-01-13 15:45:57 -0800517 int order, gfp_t gfp_mask, nodemask_t *nodemask,
518 bool sync)
Mel Gorman56de7262010-05-24 14:32:30 -0700519{
520 enum zone_type high_zoneidx = gfp_zone(gfp_mask);
521 int may_enter_fs = gfp_mask & __GFP_FS;
522 int may_perform_io = gfp_mask & __GFP_IO;
Mel Gorman56de7262010-05-24 14:32:30 -0700523 struct zoneref *z;
524 struct zone *zone;
525 int rc = COMPACT_SKIPPED;
526
527 /*
528 * Check whether it is worth even starting compaction. The order check is
529 * made because an assumption is made that the page allocator can satisfy
530 * the "cheaper" orders without taking special steps
531 */
532 if (order <= PAGE_ALLOC_COSTLY_ORDER || !may_enter_fs || !may_perform_io)
533 return rc;
534
535 count_vm_event(COMPACTSTALL);
536
537 /* Compact each zone in the list */
538 for_each_zone_zonelist_nodemask(zone, z, zonelist, high_zoneidx,
539 nodemask) {
Mel Gorman56de7262010-05-24 14:32:30 -0700540 int status;
541
Mel Gorman77f1fe62011-01-13 15:45:57 -0800542 status = compact_zone_order(zone, order, gfp_mask, sync);
Mel Gorman56de7262010-05-24 14:32:30 -0700543 rc = max(status, rc);
544
Mel Gorman3e7d3442011-01-13 15:45:56 -0800545 /* If a normal allocation would succeed, stop compacting */
546 if (zone_watermark_ok(zone, order, low_wmark_pages(zone), 0, 0))
Mel Gorman56de7262010-05-24 14:32:30 -0700547 break;
548 }
549
550 return rc;
551}
552
553
Mel Gorman76ab0f52010-05-24 14:32:28 -0700554/* Compact all zones within a node */
555static int compact_node(int nid)
556{
557 int zoneid;
558 pg_data_t *pgdat;
559 struct zone *zone;
560
561 if (nid < 0 || nid >= nr_node_ids || !node_online(nid))
562 return -EINVAL;
563 pgdat = NODE_DATA(nid);
564
565 /* Flush pending updates to the LRU lists */
566 lru_add_drain_all();
567
568 for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
569 struct compact_control cc = {
570 .nr_freepages = 0,
571 .nr_migratepages = 0,
Mel Gorman56de7262010-05-24 14:32:30 -0700572 .order = -1,
Mel Gorman76ab0f52010-05-24 14:32:28 -0700573 };
574
575 zone = &pgdat->node_zones[zoneid];
576 if (!populated_zone(zone))
577 continue;
578
579 cc.zone = zone;
580 INIT_LIST_HEAD(&cc.freepages);
581 INIT_LIST_HEAD(&cc.migratepages);
582
583 compact_zone(zone, &cc);
584
585 VM_BUG_ON(!list_empty(&cc.freepages));
586 VM_BUG_ON(!list_empty(&cc.migratepages));
587 }
588
589 return 0;
590}
591
592/* Compact all nodes in the system */
593static int compact_nodes(void)
594{
595 int nid;
596
597 for_each_online_node(nid)
598 compact_node(nid);
599
600 return COMPACT_COMPLETE;
601}
602
603/* The written value is actually unused, all memory is compacted */
604int sysctl_compact_memory;
605
606/* This is the entry point for compacting all nodes via /proc/sys/vm */
607int sysctl_compaction_handler(struct ctl_table *table, int write,
608 void __user *buffer, size_t *length, loff_t *ppos)
609{
610 if (write)
611 return compact_nodes();
612
613 return 0;
614}
Mel Gormaned4a6d72010-05-24 14:32:29 -0700615
Mel Gorman5e771902010-05-24 14:32:31 -0700616int sysctl_extfrag_handler(struct ctl_table *table, int write,
617 void __user *buffer, size_t *length, loff_t *ppos)
618{
619 proc_dointvec_minmax(table, write, buffer, length, ppos);
620
621 return 0;
622}
623
Mel Gormaned4a6d72010-05-24 14:32:29 -0700624#if defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
625ssize_t sysfs_compact_node(struct sys_device *dev,
626 struct sysdev_attribute *attr,
627 const char *buf, size_t count)
628{
629 compact_node(dev->id);
630
631 return count;
632}
633static SYSDEV_ATTR(compact, S_IWUSR, NULL, sysfs_compact_node);
634
635int compaction_register_node(struct node *node)
636{
637 return sysdev_create_file(&node->sysdev, &attr_compact);
638}
639
640void compaction_unregister_node(struct node *node)
641{
642 return sysdev_remove_file(&node->sysdev, &attr_compact);
643}
644#endif /* CONFIG_SYSFS && CONFIG_NUMA */