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1 | /* | |
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> | |
15 | #include <linux/sysctl.h> | |
16 | #include <linux/sysfs.h> | |
17 | #include <linux/balloon_compaction.h> | |
18 | #include <linux/page-isolation.h> | |
19 | #include "internal.h" | |
20 | ||
21 | #ifdef CONFIG_COMPACTION | |
22 | static inline void count_compact_event(enum vm_event_item item) | |
23 | { | |
24 | count_vm_event(item); | |
25 | } | |
26 | ||
27 | static inline void count_compact_events(enum vm_event_item item, long delta) | |
28 | { | |
29 | count_vm_events(item, delta); | |
30 | } | |
31 | #else | |
32 | #define count_compact_event(item) do { } while (0) | |
33 | #define count_compact_events(item, delta) do { } while (0) | |
34 | #endif | |
35 | ||
36 | #if defined CONFIG_COMPACTION || defined CONFIG_CMA | |
37 | ||
38 | #define CREATE_TRACE_POINTS | |
39 | #include <trace/events/compaction.h> | |
40 | ||
41 | static unsigned long release_freepages(struct list_head *freelist) | |
42 | { | |
43 | struct page *page, *next; | |
44 | unsigned long count = 0; | |
45 | ||
46 | list_for_each_entry_safe(page, next, freelist, lru) { | |
47 | list_del(&page->lru); | |
48 | __free_page(page); | |
49 | count++; | |
50 | } | |
51 | ||
52 | return count; | |
53 | } | |
54 | ||
55 | static void map_pages(struct list_head *list) | |
56 | { | |
57 | struct page *page; | |
58 | ||
59 | list_for_each_entry(page, list, lru) { | |
60 | arch_alloc_page(page, 0); | |
61 | kernel_map_pages(page, 1, 1); | |
62 | } | |
63 | } | |
64 | ||
65 | static inline bool migrate_async_suitable(int migratetype) | |
66 | { | |
67 | return is_migrate_cma(migratetype) || migratetype == MIGRATE_MOVABLE; | |
68 | } | |
69 | ||
70 | #ifdef CONFIG_COMPACTION | |
71 | /* Returns true if the pageblock should be scanned for pages to isolate. */ | |
72 | static inline bool isolation_suitable(struct compact_control *cc, | |
73 | struct page *page) | |
74 | { | |
75 | if (cc->ignore_skip_hint) | |
76 | return true; | |
77 | ||
78 | return !get_pageblock_skip(page); | |
79 | } | |
80 | ||
81 | /* | |
82 | * This function is called to clear all cached information on pageblocks that | |
83 | * should be skipped for page isolation when the migrate and free page scanner | |
84 | * meet. | |
85 | */ | |
86 | static void __reset_isolation_suitable(struct zone *zone) | |
87 | { | |
88 | unsigned long start_pfn = zone->zone_start_pfn; | |
89 | unsigned long end_pfn = zone_end_pfn(zone); | |
90 | unsigned long pfn; | |
91 | ||
92 | zone->compact_cached_migrate_pfn = start_pfn; | |
93 | zone->compact_cached_free_pfn = end_pfn; | |
94 | zone->compact_blockskip_flush = false; | |
95 | ||
96 | /* Walk the zone and mark every pageblock as suitable for isolation */ | |
97 | for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { | |
98 | struct page *page; | |
99 | ||
100 | cond_resched(); | |
101 | ||
102 | if (!pfn_valid(pfn)) | |
103 | continue; | |
104 | ||
105 | page = pfn_to_page(pfn); | |
106 | if (zone != page_zone(page)) | |
107 | continue; | |
108 | ||
109 | clear_pageblock_skip(page); | |
110 | } | |
111 | } | |
112 | ||
113 | void reset_isolation_suitable(pg_data_t *pgdat) | |
114 | { | |
115 | int zoneid; | |
116 | ||
117 | for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { | |
118 | struct zone *zone = &pgdat->node_zones[zoneid]; | |
119 | if (!populated_zone(zone)) | |
120 | continue; | |
121 | ||
122 | /* Only flush if a full compaction finished recently */ | |
123 | if (zone->compact_blockskip_flush) | |
124 | __reset_isolation_suitable(zone); | |
125 | } | |
126 | } | |
127 | ||
128 | /* | |
129 | * If no pages were isolated then mark this pageblock to be skipped in the | |
130 | * future. The information is later cleared by __reset_isolation_suitable(). | |
131 | */ | |
132 | static void update_pageblock_skip(struct compact_control *cc, | |
133 | struct page *page, unsigned long nr_isolated, | |
134 | bool migrate_scanner) | |
135 | { | |
136 | struct zone *zone = cc->zone; | |
137 | ||
138 | if (cc->ignore_skip_hint) | |
139 | return; | |
140 | ||
141 | if (!page) | |
142 | return; | |
143 | ||
144 | if (!nr_isolated) { | |
145 | unsigned long pfn = page_to_pfn(page); | |
146 | set_pageblock_skip(page); | |
147 | ||
148 | /* Update where compaction should restart */ | |
149 | if (migrate_scanner) { | |
150 | if (!cc->finished_update_migrate && | |
151 | pfn > zone->compact_cached_migrate_pfn) | |
152 | zone->compact_cached_migrate_pfn = pfn; | |
153 | } else { | |
154 | if (!cc->finished_update_free && | |
155 | pfn < zone->compact_cached_free_pfn) | |
156 | zone->compact_cached_free_pfn = pfn; | |
157 | } | |
158 | } | |
159 | } | |
160 | #else | |
161 | static inline bool isolation_suitable(struct compact_control *cc, | |
162 | struct page *page) | |
163 | { | |
164 | return true; | |
165 | } | |
166 | ||
167 | static void update_pageblock_skip(struct compact_control *cc, | |
168 | struct page *page, unsigned long nr_isolated, | |
169 | bool migrate_scanner) | |
170 | { | |
171 | } | |
172 | #endif /* CONFIG_COMPACTION */ | |
173 | ||
174 | static inline bool should_release_lock(spinlock_t *lock) | |
175 | { | |
176 | return need_resched() || spin_is_contended(lock); | |
177 | } | |
178 | ||
179 | /* | |
180 | * Compaction requires the taking of some coarse locks that are potentially | |
181 | * very heavily contended. Check if the process needs to be scheduled or | |
182 | * if the lock is contended. For async compaction, back out in the event | |
183 | * if contention is severe. For sync compaction, schedule. | |
184 | * | |
185 | * Returns true if the lock is held. | |
186 | * Returns false if the lock is released and compaction should abort | |
187 | */ | |
188 | static bool compact_checklock_irqsave(spinlock_t *lock, unsigned long *flags, | |
189 | bool locked, struct compact_control *cc) | |
190 | { | |
191 | if (should_release_lock(lock)) { | |
192 | if (locked) { | |
193 | spin_unlock_irqrestore(lock, *flags); | |
194 | locked = false; | |
195 | } | |
196 | ||
197 | /* async aborts if taking too long or contended */ | |
198 | if (!cc->sync) { | |
199 | cc->contended = true; | |
200 | return false; | |
201 | } | |
202 | ||
203 | cond_resched(); | |
204 | } | |
205 | ||
206 | if (!locked) | |
207 | spin_lock_irqsave(lock, *flags); | |
208 | return true; | |
209 | } | |
210 | ||
211 | /* Returns true if the page is within a block suitable for migration to */ | |
212 | static bool suitable_migration_target(struct page *page) | |
213 | { | |
214 | /* If the page is a large free page, then disallow migration */ | |
215 | if (PageBuddy(page) && page_order(page) >= pageblock_order) | |
216 | return false; | |
217 | ||
218 | /* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */ | |
219 | if (migrate_async_suitable(get_pageblock_migratetype(page))) | |
220 | return true; | |
221 | ||
222 | /* Otherwise skip the block */ | |
223 | return false; | |
224 | } | |
225 | ||
226 | /* | |
227 | * Isolate free pages onto a private freelist. If @strict is true, will abort | |
228 | * returning 0 on any invalid PFNs or non-free pages inside of the pageblock | |
229 | * (even though it may still end up isolating some pages). | |
230 | */ | |
231 | static unsigned long isolate_freepages_block(struct compact_control *cc, | |
232 | unsigned long blockpfn, | |
233 | unsigned long end_pfn, | |
234 | struct list_head *freelist, | |
235 | bool strict) | |
236 | { | |
237 | int nr_scanned = 0, total_isolated = 0; | |
238 | struct page *cursor, *valid_page = NULL; | |
239 | unsigned long flags; | |
240 | bool locked = false; | |
241 | bool checked_pageblock = false; | |
242 | ||
243 | cursor = pfn_to_page(blockpfn); | |
244 | ||
245 | /* Isolate free pages. */ | |
246 | for (; blockpfn < end_pfn; blockpfn++, cursor++) { | |
247 | int isolated, i; | |
248 | struct page *page = cursor; | |
249 | ||
250 | nr_scanned++; | |
251 | if (!pfn_valid_within(blockpfn)) | |
252 | goto isolate_fail; | |
253 | ||
254 | if (!valid_page) | |
255 | valid_page = page; | |
256 | if (!PageBuddy(page)) | |
257 | goto isolate_fail; | |
258 | ||
259 | /* | |
260 | * The zone lock must be held to isolate freepages. | |
261 | * Unfortunately this is a very coarse lock and can be | |
262 | * heavily contended if there are parallel allocations | |
263 | * or parallel compactions. For async compaction do not | |
264 | * spin on the lock and we acquire the lock as late as | |
265 | * possible. | |
266 | */ | |
267 | locked = compact_checklock_irqsave(&cc->zone->lock, &flags, | |
268 | locked, cc); | |
269 | if (!locked) | |
270 | break; | |
271 | ||
272 | /* Recheck this is a suitable migration target under lock */ | |
273 | if (!strict && !checked_pageblock) { | |
274 | /* | |
275 | * We need to check suitability of pageblock only once | |
276 | * and this isolate_freepages_block() is called with | |
277 | * pageblock range, so just check once is sufficient. | |
278 | */ | |
279 | checked_pageblock = true; | |
280 | if (!suitable_migration_target(page)) | |
281 | break; | |
282 | } | |
283 | ||
284 | /* Recheck this is a buddy page under lock */ | |
285 | if (!PageBuddy(page)) | |
286 | goto isolate_fail; | |
287 | ||
288 | /* Found a free page, break it into order-0 pages */ | |
289 | isolated = split_free_page(page); | |
290 | total_isolated += isolated; | |
291 | for (i = 0; i < isolated; i++) { | |
292 | list_add(&page->lru, freelist); | |
293 | page++; | |
294 | } | |
295 | ||
296 | /* If a page was split, advance to the end of it */ | |
297 | if (isolated) { | |
298 | blockpfn += isolated - 1; | |
299 | cursor += isolated - 1; | |
300 | continue; | |
301 | } | |
302 | ||
303 | isolate_fail: | |
304 | if (strict) | |
305 | break; | |
306 | else | |
307 | continue; | |
308 | ||
309 | } | |
310 | ||
311 | trace_mm_compaction_isolate_freepages(nr_scanned, total_isolated); | |
312 | ||
313 | /* | |
314 | * If strict isolation is requested by CMA then check that all the | |
315 | * pages requested were isolated. If there were any failures, 0 is | |
316 | * returned and CMA will fail. | |
317 | */ | |
318 | if (strict && blockpfn < end_pfn) | |
319 | total_isolated = 0; | |
320 | ||
321 | if (locked) | |
322 | spin_unlock_irqrestore(&cc->zone->lock, flags); | |
323 | ||
324 | /* Update the pageblock-skip if the whole pageblock was scanned */ | |
325 | if (blockpfn == end_pfn) | |
326 | update_pageblock_skip(cc, valid_page, total_isolated, false); | |
327 | ||
328 | count_compact_events(COMPACTFREE_SCANNED, nr_scanned); | |
329 | if (total_isolated) | |
330 | count_compact_events(COMPACTISOLATED, total_isolated); | |
331 | return total_isolated; | |
332 | } | |
333 | ||
334 | /** | |
335 | * isolate_freepages_range() - isolate free pages. | |
336 | * @start_pfn: The first PFN to start isolating. | |
337 | * @end_pfn: The one-past-last PFN. | |
338 | * | |
339 | * Non-free pages, invalid PFNs, or zone boundaries within the | |
340 | * [start_pfn, end_pfn) range are considered errors, cause function to | |
341 | * undo its actions and return zero. | |
342 | * | |
343 | * Otherwise, function returns one-past-the-last PFN of isolated page | |
344 | * (which may be greater then end_pfn if end fell in a middle of | |
345 | * a free page). | |
346 | */ | |
347 | unsigned long | |
348 | isolate_freepages_range(struct compact_control *cc, | |
349 | unsigned long start_pfn, unsigned long end_pfn) | |
350 | { | |
351 | unsigned long isolated, pfn, block_end_pfn; | |
352 | LIST_HEAD(freelist); | |
353 | ||
354 | for (pfn = start_pfn; pfn < end_pfn; pfn += isolated) { | |
355 | if (!pfn_valid(pfn) || cc->zone != page_zone(pfn_to_page(pfn))) | |
356 | break; | |
357 | ||
358 | /* | |
359 | * On subsequent iterations ALIGN() is actually not needed, | |
360 | * but we keep it that we not to complicate the code. | |
361 | */ | |
362 | block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages); | |
363 | block_end_pfn = min(block_end_pfn, end_pfn); | |
364 | ||
365 | isolated = isolate_freepages_block(cc, pfn, block_end_pfn, | |
366 | &freelist, true); | |
367 | ||
368 | /* | |
369 | * In strict mode, isolate_freepages_block() returns 0 if | |
370 | * there are any holes in the block (ie. invalid PFNs or | |
371 | * non-free pages). | |
372 | */ | |
373 | if (!isolated) | |
374 | break; | |
375 | ||
376 | /* | |
377 | * If we managed to isolate pages, it is always (1 << n) * | |
378 | * pageblock_nr_pages for some non-negative n. (Max order | |
379 | * page may span two pageblocks). | |
380 | */ | |
381 | } | |
382 | ||
383 | /* split_free_page does not map the pages */ | |
384 | map_pages(&freelist); | |
385 | ||
386 | if (pfn < end_pfn) { | |
387 | /* Loop terminated early, cleanup. */ | |
388 | release_freepages(&freelist); | |
389 | return 0; | |
390 | } | |
391 | ||
392 | /* We don't use freelists for anything. */ | |
393 | return pfn; | |
394 | } | |
395 | ||
396 | /* Update the number of anon and file isolated pages in the zone */ | |
397 | static void acct_isolated(struct zone *zone, bool locked, struct compact_control *cc) | |
398 | { | |
399 | struct page *page; | |
400 | unsigned int count[2] = { 0, }; | |
401 | ||
402 | list_for_each_entry(page, &cc->migratepages, lru) | |
403 | count[!!page_is_file_cache(page)]++; | |
404 | ||
405 | /* If locked we can use the interrupt unsafe versions */ | |
406 | if (locked) { | |
407 | __mod_zone_page_state(zone, NR_ISOLATED_ANON, count[0]); | |
408 | __mod_zone_page_state(zone, NR_ISOLATED_FILE, count[1]); | |
409 | } else { | |
410 | mod_zone_page_state(zone, NR_ISOLATED_ANON, count[0]); | |
411 | mod_zone_page_state(zone, NR_ISOLATED_FILE, count[1]); | |
412 | } | |
413 | } | |
414 | ||
415 | /* Similar to reclaim, but different enough that they don't share logic */ | |
416 | static bool too_many_isolated(struct zone *zone) | |
417 | { | |
418 | unsigned long active, inactive, isolated; | |
419 | ||
420 | inactive = zone_page_state(zone, NR_INACTIVE_FILE) + | |
421 | zone_page_state(zone, NR_INACTIVE_ANON); | |
422 | active = zone_page_state(zone, NR_ACTIVE_FILE) + | |
423 | zone_page_state(zone, NR_ACTIVE_ANON); | |
424 | isolated = zone_page_state(zone, NR_ISOLATED_FILE) + | |
425 | zone_page_state(zone, NR_ISOLATED_ANON); | |
426 | ||
427 | return isolated > (inactive + active) / 2; | |
428 | } | |
429 | ||
430 | /** | |
431 | * isolate_migratepages_range() - isolate all migrate-able pages in range. | |
432 | * @zone: Zone pages are in. | |
433 | * @cc: Compaction control structure. | |
434 | * @low_pfn: The first PFN of the range. | |
435 | * @end_pfn: The one-past-the-last PFN of the range. | |
436 | * @unevictable: true if it allows to isolate unevictable pages | |
437 | * | |
438 | * Isolate all pages that can be migrated from the range specified by | |
439 | * [low_pfn, end_pfn). Returns zero if there is a fatal signal | |
440 | * pending), otherwise PFN of the first page that was not scanned | |
441 | * (which may be both less, equal to or more then end_pfn). | |
442 | * | |
443 | * Assumes that cc->migratepages is empty and cc->nr_migratepages is | |
444 | * zero. | |
445 | * | |
446 | * Apart from cc->migratepages and cc->nr_migratetypes this function | |
447 | * does not modify any cc's fields, in particular it does not modify | |
448 | * (or read for that matter) cc->migrate_pfn. | |
449 | */ | |
450 | unsigned long | |
451 | isolate_migratepages_range(struct zone *zone, struct compact_control *cc, | |
452 | unsigned long low_pfn, unsigned long end_pfn, bool unevictable) | |
453 | { | |
454 | unsigned long last_pageblock_nr = 0, pageblock_nr; | |
455 | unsigned long nr_scanned = 0, nr_isolated = 0; | |
456 | struct list_head *migratelist = &cc->migratepages; | |
457 | struct lruvec *lruvec; | |
458 | unsigned long flags; | |
459 | bool locked = false; | |
460 | struct page *page = NULL, *valid_page = NULL; | |
461 | bool skipped_async_unsuitable = false; | |
462 | const isolate_mode_t mode = (!cc->sync ? ISOLATE_ASYNC_MIGRATE : 0) | | |
463 | (unevictable ? ISOLATE_UNEVICTABLE : 0); | |
464 | ||
465 | /* | |
466 | * Ensure that there are not too many pages isolated from the LRU | |
467 | * list by either parallel reclaimers or compaction. If there are, | |
468 | * delay for some time until fewer pages are isolated | |
469 | */ | |
470 | while (unlikely(too_many_isolated(zone))) { | |
471 | /* async migration should just abort */ | |
472 | if (!cc->sync) | |
473 | return 0; | |
474 | ||
475 | congestion_wait(BLK_RW_ASYNC, HZ/10); | |
476 | ||
477 | if (fatal_signal_pending(current)) | |
478 | return 0; | |
479 | } | |
480 | ||
481 | /* Time to isolate some pages for migration */ | |
482 | cond_resched(); | |
483 | for (; low_pfn < end_pfn; low_pfn++) { | |
484 | /* give a chance to irqs before checking need_resched() */ | |
485 | if (locked && !(low_pfn % SWAP_CLUSTER_MAX)) { | |
486 | if (should_release_lock(&zone->lru_lock)) { | |
487 | spin_unlock_irqrestore(&zone->lru_lock, flags); | |
488 | locked = false; | |
489 | } | |
490 | } | |
491 | ||
492 | /* | |
493 | * migrate_pfn does not necessarily start aligned to a | |
494 | * pageblock. Ensure that pfn_valid is called when moving | |
495 | * into a new MAX_ORDER_NR_PAGES range in case of large | |
496 | * memory holes within the zone | |
497 | */ | |
498 | if ((low_pfn & (MAX_ORDER_NR_PAGES - 1)) == 0) { | |
499 | if (!pfn_valid(low_pfn)) { | |
500 | low_pfn += MAX_ORDER_NR_PAGES - 1; | |
501 | continue; | |
502 | } | |
503 | } | |
504 | ||
505 | if (!pfn_valid_within(low_pfn)) | |
506 | continue; | |
507 | nr_scanned++; | |
508 | ||
509 | /* | |
510 | * Get the page and ensure the page is within the same zone. | |
511 | * See the comment in isolate_freepages about overlapping | |
512 | * nodes. It is deliberate that the new zone lock is not taken | |
513 | * as memory compaction should not move pages between nodes. | |
514 | */ | |
515 | page = pfn_to_page(low_pfn); | |
516 | if (page_zone(page) != zone) | |
517 | continue; | |
518 | ||
519 | if (!valid_page) | |
520 | valid_page = page; | |
521 | ||
522 | /* If isolation recently failed, do not retry */ | |
523 | pageblock_nr = low_pfn >> pageblock_order; | |
524 | if (last_pageblock_nr != pageblock_nr) { | |
525 | int mt; | |
526 | ||
527 | last_pageblock_nr = pageblock_nr; | |
528 | if (!isolation_suitable(cc, page)) | |
529 | goto next_pageblock; | |
530 | ||
531 | /* | |
532 | * For async migration, also only scan in MOVABLE | |
533 | * blocks. Async migration is optimistic to see if | |
534 | * the minimum amount of work satisfies the allocation | |
535 | */ | |
536 | mt = get_pageblock_migratetype(page); | |
537 | if (!cc->sync && !migrate_async_suitable(mt)) { | |
538 | cc->finished_update_migrate = true; | |
539 | skipped_async_unsuitable = true; | |
540 | goto next_pageblock; | |
541 | } | |
542 | } | |
543 | ||
544 | /* | |
545 | * Skip if free. page_order cannot be used without zone->lock | |
546 | * as nothing prevents parallel allocations or buddy merging. | |
547 | */ | |
548 | if (PageBuddy(page)) | |
549 | continue; | |
550 | ||
551 | /* | |
552 | * Check may be lockless but that's ok as we recheck later. | |
553 | * It's possible to migrate LRU pages and balloon pages | |
554 | * Skip any other type of page | |
555 | */ | |
556 | if (!PageLRU(page)) { | |
557 | if (unlikely(balloon_page_movable(page))) { | |
558 | if (locked && balloon_page_isolate(page)) { | |
559 | /* Successfully isolated */ | |
560 | goto isolate_success; | |
561 | } | |
562 | } | |
563 | continue; | |
564 | } | |
565 | ||
566 | /* | |
567 | * PageLRU is set. lru_lock normally excludes isolation | |
568 | * splitting and collapsing (collapsing has already happened | |
569 | * if PageLRU is set) but the lock is not necessarily taken | |
570 | * here and it is wasteful to take it just to check transhuge. | |
571 | * Check TransHuge without lock and skip the whole pageblock if | |
572 | * it's either a transhuge or hugetlbfs page, as calling | |
573 | * compound_order() without preventing THP from splitting the | |
574 | * page underneath us may return surprising results. | |
575 | */ | |
576 | if (PageTransHuge(page)) { | |
577 | if (!locked) | |
578 | goto next_pageblock; | |
579 | low_pfn += (1 << compound_order(page)) - 1; | |
580 | continue; | |
581 | } | |
582 | ||
583 | /* | |
584 | * Migration will fail if an anonymous page is pinned in memory, | |
585 | * so avoid taking lru_lock and isolating it unnecessarily in an | |
586 | * admittedly racy check. | |
587 | */ | |
588 | if (!page_mapping(page) && | |
589 | page_count(page) > page_mapcount(page)) | |
590 | continue; | |
591 | ||
592 | /* Check if it is ok to still hold the lock */ | |
593 | locked = compact_checklock_irqsave(&zone->lru_lock, &flags, | |
594 | locked, cc); | |
595 | if (!locked || fatal_signal_pending(current)) | |
596 | break; | |
597 | ||
598 | /* Recheck PageLRU and PageTransHuge under lock */ | |
599 | if (!PageLRU(page)) | |
600 | continue; | |
601 | if (PageTransHuge(page)) { | |
602 | low_pfn += (1 << compound_order(page)) - 1; | |
603 | continue; | |
604 | } | |
605 | ||
606 | lruvec = mem_cgroup_page_lruvec(page, zone); | |
607 | ||
608 | /* Try isolate the page */ | |
609 | if (__isolate_lru_page(page, mode) != 0) | |
610 | continue; | |
611 | ||
612 | VM_BUG_ON_PAGE(PageTransCompound(page), page); | |
613 | ||
614 | /* Successfully isolated */ | |
615 | del_page_from_lru_list(page, lruvec, page_lru(page)); | |
616 | ||
617 | isolate_success: | |
618 | cc->finished_update_migrate = true; | |
619 | list_add(&page->lru, migratelist); | |
620 | cc->nr_migratepages++; | |
621 | nr_isolated++; | |
622 | ||
623 | /* Avoid isolating too much */ | |
624 | if (cc->nr_migratepages == COMPACT_CLUSTER_MAX) { | |
625 | ++low_pfn; | |
626 | break; | |
627 | } | |
628 | ||
629 | continue; | |
630 | ||
631 | next_pageblock: | |
632 | low_pfn = ALIGN(low_pfn + 1, pageblock_nr_pages) - 1; | |
633 | } | |
634 | ||
635 | acct_isolated(zone, locked, cc); | |
636 | ||
637 | if (locked) | |
638 | spin_unlock_irqrestore(&zone->lru_lock, flags); | |
639 | ||
640 | /* | |
641 | * Update the pageblock-skip information and cached scanner pfn, | |
642 | * if the whole pageblock was scanned without isolating any page. | |
643 | * This is not done when pageblock was skipped due to being unsuitable | |
644 | * for async compaction, so that eventual sync compaction can try. | |
645 | */ | |
646 | if (low_pfn == end_pfn && !skipped_async_unsuitable) | |
647 | update_pageblock_skip(cc, valid_page, nr_isolated, true); | |
648 | ||
649 | trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated); | |
650 | ||
651 | count_compact_events(COMPACTMIGRATE_SCANNED, nr_scanned); | |
652 | if (nr_isolated) | |
653 | count_compact_events(COMPACTISOLATED, nr_isolated); | |
654 | ||
655 | return low_pfn; | |
656 | } | |
657 | ||
658 | #endif /* CONFIG_COMPACTION || CONFIG_CMA */ | |
659 | #ifdef CONFIG_COMPACTION | |
660 | /* | |
661 | * Based on information in the current compact_control, find blocks | |
662 | * suitable for isolating free pages from and then isolate them. | |
663 | */ | |
664 | static void isolate_freepages(struct zone *zone, | |
665 | struct compact_control *cc) | |
666 | { | |
667 | struct page *page; | |
668 | unsigned long high_pfn, low_pfn, pfn, z_end_pfn; | |
669 | int nr_freepages = cc->nr_freepages; | |
670 | struct list_head *freelist = &cc->freepages; | |
671 | ||
672 | /* | |
673 | * Initialise the free scanner. The starting point is where we last | |
674 | * successfully isolated from, zone-cached value, or the end of the | |
675 | * zone when isolating for the first time. We need this aligned to | |
676 | * the pageblock boundary, because we do pfn -= pageblock_nr_pages | |
677 | * in the for loop. | |
678 | * The low boundary is the end of the pageblock the migration scanner | |
679 | * is using. | |
680 | */ | |
681 | pfn = cc->free_pfn & ~(pageblock_nr_pages-1); | |
682 | low_pfn = ALIGN(cc->migrate_pfn + 1, pageblock_nr_pages); | |
683 | ||
684 | /* | |
685 | * Take care that if the migration scanner is at the end of the zone | |
686 | * that the free scanner does not accidentally move to the next zone | |
687 | * in the next isolation cycle. | |
688 | */ | |
689 | high_pfn = min(low_pfn, pfn); | |
690 | ||
691 | z_end_pfn = zone_end_pfn(zone); | |
692 | ||
693 | /* | |
694 | * Isolate free pages until enough are available to migrate the | |
695 | * pages on cc->migratepages. We stop searching if the migrate | |
696 | * and free page scanners meet or enough free pages are isolated. | |
697 | */ | |
698 | for (; pfn >= low_pfn && cc->nr_migratepages > nr_freepages; | |
699 | pfn -= pageblock_nr_pages) { | |
700 | unsigned long isolated; | |
701 | unsigned long end_pfn; | |
702 | ||
703 | /* | |
704 | * This can iterate a massively long zone without finding any | |
705 | * suitable migration targets, so periodically check if we need | |
706 | * to schedule. | |
707 | */ | |
708 | cond_resched(); | |
709 | ||
710 | if (!pfn_valid(pfn)) | |
711 | continue; | |
712 | ||
713 | /* | |
714 | * Check for overlapping nodes/zones. It's possible on some | |
715 | * configurations to have a setup like | |
716 | * node0 node1 node0 | |
717 | * i.e. it's possible that all pages within a zones range of | |
718 | * pages do not belong to a single zone. | |
719 | */ | |
720 | page = pfn_to_page(pfn); | |
721 | if (page_zone(page) != zone) | |
722 | continue; | |
723 | ||
724 | /* Check the block is suitable for migration */ | |
725 | if (!suitable_migration_target(page)) | |
726 | continue; | |
727 | ||
728 | /* If isolation recently failed, do not retry */ | |
729 | if (!isolation_suitable(cc, page)) | |
730 | continue; | |
731 | ||
732 | /* Found a block suitable for isolating free pages from */ | |
733 | ||
734 | /* | |
735 | * Take care when isolating in last pageblock of a zone which | |
736 | * ends in the middle of a pageblock. | |
737 | */ | |
738 | end_pfn = min(pfn + pageblock_nr_pages, z_end_pfn); | |
739 | isolated = isolate_freepages_block(cc, pfn, end_pfn, | |
740 | freelist, false); | |
741 | nr_freepages += isolated; | |
742 | ||
743 | /* | |
744 | * Record the highest PFN we isolated pages from. When next | |
745 | * looking for free pages, the search will restart here as | |
746 | * page migration may have returned some pages to the allocator | |
747 | */ | |
748 | if (isolated) { | |
749 | cc->finished_update_free = true; | |
750 | high_pfn = max(high_pfn, pfn); | |
751 | } | |
752 | } | |
753 | ||
754 | /* split_free_page does not map the pages */ | |
755 | map_pages(freelist); | |
756 | ||
757 | /* | |
758 | * If we crossed the migrate scanner, we want to keep it that way | |
759 | * so that compact_finished() may detect this | |
760 | */ | |
761 | if (pfn < low_pfn) | |
762 | cc->free_pfn = max(pfn, zone->zone_start_pfn); | |
763 | else | |
764 | cc->free_pfn = high_pfn; | |
765 | cc->nr_freepages = nr_freepages; | |
766 | } | |
767 | ||
768 | /* | |
769 | * This is a migrate-callback that "allocates" freepages by taking pages | |
770 | * from the isolated freelists in the block we are migrating to. | |
771 | */ | |
772 | static struct page *compaction_alloc(struct page *migratepage, | |
773 | unsigned long data, | |
774 | int **result) | |
775 | { | |
776 | struct compact_control *cc = (struct compact_control *)data; | |
777 | struct page *freepage; | |
778 | ||
779 | /* Isolate free pages if necessary */ | |
780 | if (list_empty(&cc->freepages)) { | |
781 | isolate_freepages(cc->zone, cc); | |
782 | ||
783 | if (list_empty(&cc->freepages)) | |
784 | return NULL; | |
785 | } | |
786 | ||
787 | freepage = list_entry(cc->freepages.next, struct page, lru); | |
788 | list_del(&freepage->lru); | |
789 | cc->nr_freepages--; | |
790 | ||
791 | return freepage; | |
792 | } | |
793 | ||
794 | /* | |
795 | * We cannot control nr_migratepages and nr_freepages fully when migration is | |
796 | * running as migrate_pages() has no knowledge of compact_control. When | |
797 | * migration is complete, we count the number of pages on the lists by hand. | |
798 | */ | |
799 | static void update_nr_listpages(struct compact_control *cc) | |
800 | { | |
801 | int nr_migratepages = 0; | |
802 | int nr_freepages = 0; | |
803 | struct page *page; | |
804 | ||
805 | list_for_each_entry(page, &cc->migratepages, lru) | |
806 | nr_migratepages++; | |
807 | list_for_each_entry(page, &cc->freepages, lru) | |
808 | nr_freepages++; | |
809 | ||
810 | cc->nr_migratepages = nr_migratepages; | |
811 | cc->nr_freepages = nr_freepages; | |
812 | } | |
813 | ||
814 | /* possible outcome of isolate_migratepages */ | |
815 | typedef enum { | |
816 | ISOLATE_ABORT, /* Abort compaction now */ | |
817 | ISOLATE_NONE, /* No pages isolated, continue scanning */ | |
818 | ISOLATE_SUCCESS, /* Pages isolated, migrate */ | |
819 | } isolate_migrate_t; | |
820 | ||
821 | /* | |
822 | * Isolate all pages that can be migrated from the block pointed to by | |
823 | * the migrate scanner within compact_control. | |
824 | */ | |
825 | static isolate_migrate_t isolate_migratepages(struct zone *zone, | |
826 | struct compact_control *cc) | |
827 | { | |
828 | unsigned long low_pfn, end_pfn; | |
829 | ||
830 | /* Do not scan outside zone boundaries */ | |
831 | low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn); | |
832 | ||
833 | /* Only scan within a pageblock boundary */ | |
834 | end_pfn = ALIGN(low_pfn + 1, pageblock_nr_pages); | |
835 | ||
836 | /* Do not cross the free scanner or scan within a memory hole */ | |
837 | if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) { | |
838 | cc->migrate_pfn = end_pfn; | |
839 | return ISOLATE_NONE; | |
840 | } | |
841 | ||
842 | /* Perform the isolation */ | |
843 | low_pfn = isolate_migratepages_range(zone, cc, low_pfn, end_pfn, false); | |
844 | if (!low_pfn || cc->contended) | |
845 | return ISOLATE_ABORT; | |
846 | ||
847 | cc->migrate_pfn = low_pfn; | |
848 | ||
849 | return ISOLATE_SUCCESS; | |
850 | } | |
851 | ||
852 | static int compact_finished(struct zone *zone, | |
853 | struct compact_control *cc) | |
854 | { | |
855 | unsigned int order; | |
856 | unsigned long watermark; | |
857 | ||
858 | if (fatal_signal_pending(current)) | |
859 | return COMPACT_PARTIAL; | |
860 | ||
861 | /* Compaction run completes if the migrate and free scanner meet */ | |
862 | if (cc->free_pfn <= cc->migrate_pfn) { | |
863 | /* Let the next compaction start anew. */ | |
864 | zone->compact_cached_migrate_pfn = zone->zone_start_pfn; | |
865 | zone->compact_cached_free_pfn = zone_end_pfn(zone); | |
866 | ||
867 | /* | |
868 | * Mark that the PG_migrate_skip information should be cleared | |
869 | * by kswapd when it goes to sleep. kswapd does not set the | |
870 | * flag itself as the decision to be clear should be directly | |
871 | * based on an allocation request. | |
872 | */ | |
873 | if (!current_is_kswapd()) | |
874 | zone->compact_blockskip_flush = true; | |
875 | ||
876 | return COMPACT_COMPLETE; | |
877 | } | |
878 | ||
879 | /* | |
880 | * order == -1 is expected when compacting via | |
881 | * /proc/sys/vm/compact_memory | |
882 | */ | |
883 | if (cc->order == -1) | |
884 | return COMPACT_CONTINUE; | |
885 | ||
886 | /* Compaction run is not finished if the watermark is not met */ | |
887 | watermark = low_wmark_pages(zone); | |
888 | watermark += (1 << cc->order); | |
889 | ||
890 | if (!zone_watermark_ok(zone, cc->order, watermark, 0, 0)) | |
891 | return COMPACT_CONTINUE; | |
892 | ||
893 | /* Direct compactor: Is a suitable page free? */ | |
894 | for (order = cc->order; order < MAX_ORDER; order++) { | |
895 | struct free_area *area = &zone->free_area[order]; | |
896 | ||
897 | /* Job done if page is free of the right migratetype */ | |
898 | if (!list_empty(&area->free_list[cc->migratetype])) | |
899 | return COMPACT_PARTIAL; | |
900 | ||
901 | /* Job done if allocation would set block type */ | |
902 | if (cc->order >= pageblock_order && area->nr_free) | |
903 | return COMPACT_PARTIAL; | |
904 | } | |
905 | ||
906 | return COMPACT_CONTINUE; | |
907 | } | |
908 | ||
909 | /* | |
910 | * compaction_suitable: Is this suitable to run compaction on this zone now? | |
911 | * Returns | |
912 | * COMPACT_SKIPPED - If there are too few free pages for compaction | |
913 | * COMPACT_PARTIAL - If the allocation would succeed without compaction | |
914 | * COMPACT_CONTINUE - If compaction should run now | |
915 | */ | |
916 | unsigned long compaction_suitable(struct zone *zone, int order) | |
917 | { | |
918 | int fragindex; | |
919 | unsigned long watermark; | |
920 | ||
921 | /* | |
922 | * order == -1 is expected when compacting via | |
923 | * /proc/sys/vm/compact_memory | |
924 | */ | |
925 | if (order == -1) | |
926 | return COMPACT_CONTINUE; | |
927 | ||
928 | /* | |
929 | * Watermarks for order-0 must be met for compaction. Note the 2UL. | |
930 | * This is because during migration, copies of pages need to be | |
931 | * allocated and for a short time, the footprint is higher | |
932 | */ | |
933 | watermark = low_wmark_pages(zone) + (2UL << order); | |
934 | if (!zone_watermark_ok(zone, 0, watermark, 0, 0)) | |
935 | return COMPACT_SKIPPED; | |
936 | ||
937 | /* | |
938 | * fragmentation index determines if allocation failures are due to | |
939 | * low memory or external fragmentation | |
940 | * | |
941 | * index of -1000 implies allocations might succeed depending on | |
942 | * watermarks | |
943 | * index towards 0 implies failure is due to lack of memory | |
944 | * index towards 1000 implies failure is due to fragmentation | |
945 | * | |
946 | * Only compact if a failure would be due to fragmentation. | |
947 | */ | |
948 | fragindex = fragmentation_index(zone, order); | |
949 | if (fragindex >= 0 && fragindex <= sysctl_extfrag_threshold) | |
950 | return COMPACT_SKIPPED; | |
951 | ||
952 | if (fragindex == -1000 && zone_watermark_ok(zone, order, watermark, | |
953 | 0, 0)) | |
954 | return COMPACT_PARTIAL; | |
955 | ||
956 | return COMPACT_CONTINUE; | |
957 | } | |
958 | ||
959 | static int compact_zone(struct zone *zone, struct compact_control *cc) | |
960 | { | |
961 | int ret; | |
962 | unsigned long start_pfn = zone->zone_start_pfn; | |
963 | unsigned long end_pfn = zone_end_pfn(zone); | |
964 | ||
965 | ret = compaction_suitable(zone, cc->order); | |
966 | switch (ret) { | |
967 | case COMPACT_PARTIAL: | |
968 | case COMPACT_SKIPPED: | |
969 | /* Compaction is likely to fail */ | |
970 | return ret; | |
971 | case COMPACT_CONTINUE: | |
972 | /* Fall through to compaction */ | |
973 | ; | |
974 | } | |
975 | ||
976 | /* | |
977 | * Clear pageblock skip if there were failures recently and compaction | |
978 | * is about to be retried after being deferred. kswapd does not do | |
979 | * this reset as it'll reset the cached information when going to sleep. | |
980 | */ | |
981 | if (compaction_restarting(zone, cc->order) && !current_is_kswapd()) | |
982 | __reset_isolation_suitable(zone); | |
983 | ||
984 | /* | |
985 | * Setup to move all movable pages to the end of the zone. Used cached | |
986 | * information on where the scanners should start but check that it | |
987 | * is initialised by ensuring the values are within zone boundaries. | |
988 | */ | |
989 | cc->migrate_pfn = zone->compact_cached_migrate_pfn; | |
990 | cc->free_pfn = zone->compact_cached_free_pfn; | |
991 | if (cc->free_pfn < start_pfn || cc->free_pfn > end_pfn) { | |
992 | cc->free_pfn = end_pfn & ~(pageblock_nr_pages-1); | |
993 | zone->compact_cached_free_pfn = cc->free_pfn; | |
994 | } | |
995 | if (cc->migrate_pfn < start_pfn || cc->migrate_pfn > end_pfn) { | |
996 | cc->migrate_pfn = start_pfn; | |
997 | zone->compact_cached_migrate_pfn = cc->migrate_pfn; | |
998 | } | |
999 | ||
1000 | trace_mm_compaction_begin(start_pfn, cc->migrate_pfn, cc->free_pfn, end_pfn); | |
1001 | ||
1002 | migrate_prep_local(); | |
1003 | ||
1004 | while ((ret = compact_finished(zone, cc)) == COMPACT_CONTINUE) { | |
1005 | unsigned long nr_migrate, nr_remaining; | |
1006 | int err; | |
1007 | ||
1008 | switch (isolate_migratepages(zone, cc)) { | |
1009 | case ISOLATE_ABORT: | |
1010 | ret = COMPACT_PARTIAL; | |
1011 | putback_movable_pages(&cc->migratepages); | |
1012 | cc->nr_migratepages = 0; | |
1013 | goto out; | |
1014 | case ISOLATE_NONE: | |
1015 | continue; | |
1016 | case ISOLATE_SUCCESS: | |
1017 | ; | |
1018 | } | |
1019 | ||
1020 | nr_migrate = cc->nr_migratepages; | |
1021 | err = migrate_pages(&cc->migratepages, compaction_alloc, | |
1022 | (unsigned long)cc, | |
1023 | cc->sync ? MIGRATE_SYNC_LIGHT : MIGRATE_ASYNC, | |
1024 | MR_COMPACTION); | |
1025 | update_nr_listpages(cc); | |
1026 | nr_remaining = cc->nr_migratepages; | |
1027 | ||
1028 | trace_mm_compaction_migratepages(nr_migrate - nr_remaining, | |
1029 | nr_remaining); | |
1030 | ||
1031 | /* Release isolated pages not migrated */ | |
1032 | if (err) { | |
1033 | putback_movable_pages(&cc->migratepages); | |
1034 | cc->nr_migratepages = 0; | |
1035 | /* | |
1036 | * migrate_pages() may return -ENOMEM when scanners meet | |
1037 | * and we want compact_finished() to detect it | |
1038 | */ | |
1039 | if (err == -ENOMEM && cc->free_pfn > cc->migrate_pfn) { | |
1040 | ret = COMPACT_PARTIAL; | |
1041 | goto out; | |
1042 | } | |
1043 | } | |
1044 | } | |
1045 | ||
1046 | out: | |
1047 | /* Release free pages and check accounting */ | |
1048 | cc->nr_freepages -= release_freepages(&cc->freepages); | |
1049 | VM_BUG_ON(cc->nr_freepages != 0); | |
1050 | ||
1051 | trace_mm_compaction_end(ret); | |
1052 | ||
1053 | return ret; | |
1054 | } | |
1055 | ||
1056 | static unsigned long compact_zone_order(struct zone *zone, | |
1057 | int order, gfp_t gfp_mask, | |
1058 | bool sync, bool *contended) | |
1059 | { | |
1060 | unsigned long ret; | |
1061 | struct compact_control cc = { | |
1062 | .nr_freepages = 0, | |
1063 | .nr_migratepages = 0, | |
1064 | .order = order, | |
1065 | .migratetype = allocflags_to_migratetype(gfp_mask), | |
1066 | .zone = zone, | |
1067 | .sync = sync, | |
1068 | }; | |
1069 | INIT_LIST_HEAD(&cc.freepages); | |
1070 | INIT_LIST_HEAD(&cc.migratepages); | |
1071 | ||
1072 | ret = compact_zone(zone, &cc); | |
1073 | ||
1074 | VM_BUG_ON(!list_empty(&cc.freepages)); | |
1075 | VM_BUG_ON(!list_empty(&cc.migratepages)); | |
1076 | ||
1077 | *contended = cc.contended; | |
1078 | return ret; | |
1079 | } | |
1080 | ||
1081 | int sysctl_extfrag_threshold = 500; | |
1082 | ||
1083 | /** | |
1084 | * try_to_compact_pages - Direct compact to satisfy a high-order allocation | |
1085 | * @zonelist: The zonelist used for the current allocation | |
1086 | * @order: The order of the current allocation | |
1087 | * @gfp_mask: The GFP mask of the current allocation | |
1088 | * @nodemask: The allowed nodes to allocate from | |
1089 | * @sync: Whether migration is synchronous or not | |
1090 | * @contended: Return value that is true if compaction was aborted due to lock contention | |
1091 | * @page: Optionally capture a free page of the requested order during compaction | |
1092 | * | |
1093 | * This is the main entry point for direct page compaction. | |
1094 | */ | |
1095 | unsigned long try_to_compact_pages(struct zonelist *zonelist, | |
1096 | int order, gfp_t gfp_mask, nodemask_t *nodemask, | |
1097 | bool sync, bool *contended) | |
1098 | { | |
1099 | enum zone_type high_zoneidx = gfp_zone(gfp_mask); | |
1100 | int may_enter_fs = gfp_mask & __GFP_FS; | |
1101 | int may_perform_io = gfp_mask & __GFP_IO; | |
1102 | struct zoneref *z; | |
1103 | struct zone *zone; | |
1104 | int rc = COMPACT_SKIPPED; | |
1105 | int alloc_flags = 0; | |
1106 | ||
1107 | /* Check if the GFP flags allow compaction */ | |
1108 | if (!order || !may_enter_fs || !may_perform_io) | |
1109 | return rc; | |
1110 | ||
1111 | count_compact_event(COMPACTSTALL); | |
1112 | ||
1113 | #ifdef CONFIG_CMA | |
1114 | if (allocflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE) | |
1115 | alloc_flags |= ALLOC_CMA; | |
1116 | #endif | |
1117 | /* Compact each zone in the list */ | |
1118 | for_each_zone_zonelist_nodemask(zone, z, zonelist, high_zoneidx, | |
1119 | nodemask) { | |
1120 | int status; | |
1121 | ||
1122 | status = compact_zone_order(zone, order, gfp_mask, sync, | |
1123 | contended); | |
1124 | rc = max(status, rc); | |
1125 | ||
1126 | /* If a normal allocation would succeed, stop compacting */ | |
1127 | if (zone_watermark_ok(zone, order, low_wmark_pages(zone), 0, | |
1128 | alloc_flags)) | |
1129 | break; | |
1130 | } | |
1131 | ||
1132 | return rc; | |
1133 | } | |
1134 | ||
1135 | ||
1136 | /* Compact all zones within a node */ | |
1137 | static void __compact_pgdat(pg_data_t *pgdat, struct compact_control *cc) | |
1138 | { | |
1139 | int zoneid; | |
1140 | struct zone *zone; | |
1141 | ||
1142 | for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { | |
1143 | ||
1144 | zone = &pgdat->node_zones[zoneid]; | |
1145 | if (!populated_zone(zone)) | |
1146 | continue; | |
1147 | ||
1148 | cc->nr_freepages = 0; | |
1149 | cc->nr_migratepages = 0; | |
1150 | cc->zone = zone; | |
1151 | INIT_LIST_HEAD(&cc->freepages); | |
1152 | INIT_LIST_HEAD(&cc->migratepages); | |
1153 | ||
1154 | if (cc->order == -1 || !compaction_deferred(zone, cc->order)) | |
1155 | compact_zone(zone, cc); | |
1156 | ||
1157 | if (cc->order > 0) { | |
1158 | if (zone_watermark_ok(zone, cc->order, | |
1159 | low_wmark_pages(zone), 0, 0)) | |
1160 | compaction_defer_reset(zone, cc->order, false); | |
1161 | } | |
1162 | ||
1163 | VM_BUG_ON(!list_empty(&cc->freepages)); | |
1164 | VM_BUG_ON(!list_empty(&cc->migratepages)); | |
1165 | } | |
1166 | } | |
1167 | ||
1168 | void compact_pgdat(pg_data_t *pgdat, int order) | |
1169 | { | |
1170 | struct compact_control cc = { | |
1171 | .order = order, | |
1172 | .sync = false, | |
1173 | }; | |
1174 | ||
1175 | if (!order) | |
1176 | return; | |
1177 | ||
1178 | __compact_pgdat(pgdat, &cc); | |
1179 | } | |
1180 | ||
1181 | static void compact_node(int nid) | |
1182 | { | |
1183 | struct compact_control cc = { | |
1184 | .order = -1, | |
1185 | .sync = true, | |
1186 | .ignore_skip_hint = true, | |
1187 | }; | |
1188 | ||
1189 | __compact_pgdat(NODE_DATA(nid), &cc); | |
1190 | } | |
1191 | ||
1192 | /* Compact all nodes in the system */ | |
1193 | static void compact_nodes(void) | |
1194 | { | |
1195 | int nid; | |
1196 | ||
1197 | /* Flush pending updates to the LRU lists */ | |
1198 | lru_add_drain_all(); | |
1199 | ||
1200 | for_each_online_node(nid) | |
1201 | compact_node(nid); | |
1202 | } | |
1203 | ||
1204 | /* The written value is actually unused, all memory is compacted */ | |
1205 | int sysctl_compact_memory; | |
1206 | ||
1207 | /* This is the entry point for compacting all nodes via /proc/sys/vm */ | |
1208 | int sysctl_compaction_handler(struct ctl_table *table, int write, | |
1209 | void __user *buffer, size_t *length, loff_t *ppos) | |
1210 | { | |
1211 | if (write) | |
1212 | compact_nodes(); | |
1213 | ||
1214 | return 0; | |
1215 | } | |
1216 | ||
1217 | int sysctl_extfrag_handler(struct ctl_table *table, int write, | |
1218 | void __user *buffer, size_t *length, loff_t *ppos) | |
1219 | { | |
1220 | proc_dointvec_minmax(table, write, buffer, length, ppos); | |
1221 | ||
1222 | return 0; | |
1223 | } | |
1224 | ||
1225 | #if defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) | |
1226 | static ssize_t sysfs_compact_node(struct device *dev, | |
1227 | struct device_attribute *attr, | |
1228 | const char *buf, size_t count) | |
1229 | { | |
1230 | int nid = dev->id; | |
1231 | ||
1232 | if (nid >= 0 && nid < nr_node_ids && node_online(nid)) { | |
1233 | /* Flush pending updates to the LRU lists */ | |
1234 | lru_add_drain_all(); | |
1235 | ||
1236 | compact_node(nid); | |
1237 | } | |
1238 | ||
1239 | return count; | |
1240 | } | |
1241 | static DEVICE_ATTR(compact, S_IWUSR, NULL, sysfs_compact_node); | |
1242 | ||
1243 | int compaction_register_node(struct node *node) | |
1244 | { | |
1245 | return device_create_file(&node->dev, &dev_attr_compact); | |
1246 | } | |
1247 | ||
1248 | void compaction_unregister_node(struct node *node) | |
1249 | { | |
1250 | return device_remove_file(&node->dev, &dev_attr_compact); | |
1251 | } | |
1252 | #endif /* CONFIG_SYSFS && CONFIG_NUMA */ | |
1253 | ||
1254 | #endif /* CONFIG_COMPACTION */ |