]>
Commit | Line | Data |
---|---|---|
748446bb MG |
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> | |
76ab0f53 | 15 | #include <linux/sysctl.h> |
ed4a6d7f | 16 | #include <linux/sysfs.h> |
bf6bddf1 | 17 | #include <linux/balloon_compaction.h> |
748446bb MG |
18 | #include "internal.h" |
19 | ||
010fc29a MK |
20 | #ifdef CONFIG_COMPACTION |
21 | static inline void count_compact_event(enum vm_event_item item) | |
22 | { | |
23 | count_vm_event(item); | |
24 | } | |
25 | ||
26 | static inline void count_compact_events(enum vm_event_item item, long delta) | |
27 | { | |
28 | count_vm_events(item, delta); | |
29 | } | |
30 | #else | |
31 | #define count_compact_event(item) do { } while (0) | |
32 | #define count_compact_events(item, delta) do { } while (0) | |
33 | #endif | |
34 | ||
ff9543fd MN |
35 | #if defined CONFIG_COMPACTION || defined CONFIG_CMA |
36 | ||
b7aba698 MG |
37 | #define CREATE_TRACE_POINTS |
38 | #include <trace/events/compaction.h> | |
39 | ||
748446bb MG |
40 | static unsigned long release_freepages(struct list_head *freelist) |
41 | { | |
42 | struct page *page, *next; | |
43 | unsigned long count = 0; | |
44 | ||
45 | list_for_each_entry_safe(page, next, freelist, lru) { | |
46 | list_del(&page->lru); | |
47 | __free_page(page); | |
48 | count++; | |
49 | } | |
50 | ||
51 | return count; | |
52 | } | |
53 | ||
ff9543fd MN |
54 | static void map_pages(struct list_head *list) |
55 | { | |
56 | struct page *page; | |
57 | ||
58 | list_for_each_entry(page, list, lru) { | |
59 | arch_alloc_page(page, 0); | |
60 | kernel_map_pages(page, 1, 1); | |
61 | } | |
62 | } | |
63 | ||
47118af0 MN |
64 | static inline bool migrate_async_suitable(int migratetype) |
65 | { | |
66 | return is_migrate_cma(migratetype) || migratetype == MIGRATE_MOVABLE; | |
67 | } | |
68 | ||
bb13ffeb MG |
69 | #ifdef CONFIG_COMPACTION |
70 | /* Returns true if the pageblock should be scanned for pages to isolate. */ | |
71 | static inline bool isolation_suitable(struct compact_control *cc, | |
72 | struct page *page) | |
73 | { | |
74 | if (cc->ignore_skip_hint) | |
75 | return true; | |
76 | ||
77 | return !get_pageblock_skip(page); | |
78 | } | |
79 | ||
80 | /* | |
81 | * This function is called to clear all cached information on pageblocks that | |
82 | * should be skipped for page isolation when the migrate and free page scanner | |
83 | * meet. | |
84 | */ | |
62997027 | 85 | static void __reset_isolation_suitable(struct zone *zone) |
bb13ffeb MG |
86 | { |
87 | unsigned long start_pfn = zone->zone_start_pfn; | |
88 | unsigned long end_pfn = zone->zone_start_pfn + zone->spanned_pages; | |
89 | unsigned long pfn; | |
90 | ||
c89511ab MG |
91 | zone->compact_cached_migrate_pfn = start_pfn; |
92 | zone->compact_cached_free_pfn = end_pfn; | |
62997027 | 93 | zone->compact_blockskip_flush = false; |
bb13ffeb MG |
94 | |
95 | /* Walk the zone and mark every pageblock as suitable for isolation */ | |
96 | for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { | |
97 | struct page *page; | |
98 | ||
99 | cond_resched(); | |
100 | ||
101 | if (!pfn_valid(pfn)) | |
102 | continue; | |
103 | ||
104 | page = pfn_to_page(pfn); | |
105 | if (zone != page_zone(page)) | |
106 | continue; | |
107 | ||
108 | clear_pageblock_skip(page); | |
109 | } | |
110 | } | |
111 | ||
62997027 MG |
112 | void reset_isolation_suitable(pg_data_t *pgdat) |
113 | { | |
114 | int zoneid; | |
115 | ||
116 | for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { | |
117 | struct zone *zone = &pgdat->node_zones[zoneid]; | |
118 | if (!populated_zone(zone)) | |
119 | continue; | |
120 | ||
121 | /* Only flush if a full compaction finished recently */ | |
122 | if (zone->compact_blockskip_flush) | |
123 | __reset_isolation_suitable(zone); | |
124 | } | |
125 | } | |
126 | ||
bb13ffeb MG |
127 | /* |
128 | * If no pages were isolated then mark this pageblock to be skipped in the | |
62997027 | 129 | * future. The information is later cleared by __reset_isolation_suitable(). |
bb13ffeb | 130 | */ |
c89511ab MG |
131 | static void update_pageblock_skip(struct compact_control *cc, |
132 | struct page *page, unsigned long nr_isolated, | |
133 | bool migrate_scanner) | |
bb13ffeb | 134 | { |
c89511ab | 135 | struct zone *zone = cc->zone; |
bb13ffeb MG |
136 | if (!page) |
137 | return; | |
138 | ||
c89511ab MG |
139 | if (!nr_isolated) { |
140 | unsigned long pfn = page_to_pfn(page); | |
bb13ffeb | 141 | set_pageblock_skip(page); |
c89511ab MG |
142 | |
143 | /* Update where compaction should restart */ | |
144 | if (migrate_scanner) { | |
145 | if (!cc->finished_update_migrate && | |
146 | pfn > zone->compact_cached_migrate_pfn) | |
147 | zone->compact_cached_migrate_pfn = pfn; | |
148 | } else { | |
149 | if (!cc->finished_update_free && | |
150 | pfn < zone->compact_cached_free_pfn) | |
151 | zone->compact_cached_free_pfn = pfn; | |
152 | } | |
153 | } | |
bb13ffeb MG |
154 | } |
155 | #else | |
156 | static inline bool isolation_suitable(struct compact_control *cc, | |
157 | struct page *page) | |
158 | { | |
159 | return true; | |
160 | } | |
161 | ||
c89511ab MG |
162 | static void update_pageblock_skip(struct compact_control *cc, |
163 | struct page *page, unsigned long nr_isolated, | |
164 | bool migrate_scanner) | |
bb13ffeb MG |
165 | { |
166 | } | |
167 | #endif /* CONFIG_COMPACTION */ | |
168 | ||
2a1402aa MG |
169 | static inline bool should_release_lock(spinlock_t *lock) |
170 | { | |
171 | return need_resched() || spin_is_contended(lock); | |
172 | } | |
173 | ||
c67fe375 MG |
174 | /* |
175 | * Compaction requires the taking of some coarse locks that are potentially | |
176 | * very heavily contended. Check if the process needs to be scheduled or | |
177 | * if the lock is contended. For async compaction, back out in the event | |
178 | * if contention is severe. For sync compaction, schedule. | |
179 | * | |
180 | * Returns true if the lock is held. | |
181 | * Returns false if the lock is released and compaction should abort | |
182 | */ | |
183 | static bool compact_checklock_irqsave(spinlock_t *lock, unsigned long *flags, | |
184 | bool locked, struct compact_control *cc) | |
185 | { | |
2a1402aa | 186 | if (should_release_lock(lock)) { |
c67fe375 MG |
187 | if (locked) { |
188 | spin_unlock_irqrestore(lock, *flags); | |
189 | locked = false; | |
190 | } | |
191 | ||
192 | /* async aborts if taking too long or contended */ | |
193 | if (!cc->sync) { | |
e64c5237 | 194 | cc->contended = true; |
c67fe375 MG |
195 | return false; |
196 | } | |
197 | ||
198 | cond_resched(); | |
c67fe375 MG |
199 | } |
200 | ||
201 | if (!locked) | |
202 | spin_lock_irqsave(lock, *flags); | |
203 | return true; | |
204 | } | |
205 | ||
206 | static inline bool compact_trylock_irqsave(spinlock_t *lock, | |
207 | unsigned long *flags, struct compact_control *cc) | |
208 | { | |
209 | return compact_checklock_irqsave(lock, flags, false, cc); | |
210 | } | |
211 | ||
f40d1e42 MG |
212 | /* Returns true if the page is within a block suitable for migration to */ |
213 | static bool suitable_migration_target(struct page *page) | |
214 | { | |
215 | int migratetype = get_pageblock_migratetype(page); | |
216 | ||
217 | /* Don't interfere with memory hot-remove or the min_free_kbytes blocks */ | |
218 | if (migratetype == MIGRATE_ISOLATE || migratetype == MIGRATE_RESERVE) | |
219 | return false; | |
220 | ||
221 | /* If the page is a large free page, then allow migration */ | |
222 | if (PageBuddy(page) && page_order(page) >= pageblock_order) | |
223 | return true; | |
224 | ||
225 | /* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */ | |
226 | if (migrate_async_suitable(migratetype)) | |
227 | return true; | |
228 | ||
229 | /* Otherwise skip the block */ | |
230 | return false; | |
231 | } | |
232 | ||
85aa125f MN |
233 | /* |
234 | * Isolate free pages onto a private freelist. Caller must hold zone->lock. | |
235 | * If @strict is true, will abort returning 0 on any invalid PFNs or non-free | |
236 | * pages inside of the pageblock (even though it may still end up isolating | |
237 | * some pages). | |
238 | */ | |
f40d1e42 MG |
239 | static unsigned long isolate_freepages_block(struct compact_control *cc, |
240 | unsigned long blockpfn, | |
85aa125f MN |
241 | unsigned long end_pfn, |
242 | struct list_head *freelist, | |
243 | bool strict) | |
748446bb | 244 | { |
b7aba698 | 245 | int nr_scanned = 0, total_isolated = 0; |
bb13ffeb | 246 | struct page *cursor, *valid_page = NULL; |
f40d1e42 MG |
247 | unsigned long nr_strict_required = end_pfn - blockpfn; |
248 | unsigned long flags; | |
249 | bool locked = false; | |
748446bb | 250 | |
748446bb MG |
251 | cursor = pfn_to_page(blockpfn); |
252 | ||
f40d1e42 | 253 | /* Isolate free pages. */ |
748446bb MG |
254 | for (; blockpfn < end_pfn; blockpfn++, cursor++) { |
255 | int isolated, i; | |
256 | struct page *page = cursor; | |
257 | ||
b7aba698 | 258 | nr_scanned++; |
f40d1e42 MG |
259 | if (!pfn_valid_within(blockpfn)) |
260 | continue; | |
bb13ffeb MG |
261 | if (!valid_page) |
262 | valid_page = page; | |
f40d1e42 MG |
263 | if (!PageBuddy(page)) |
264 | continue; | |
265 | ||
266 | /* | |
267 | * The zone lock must be held to isolate freepages. | |
268 | * Unfortunately this is a very coarse lock and can be | |
269 | * heavily contended if there are parallel allocations | |
270 | * or parallel compactions. For async compaction do not | |
271 | * spin on the lock and we acquire the lock as late as | |
272 | * possible. | |
273 | */ | |
274 | locked = compact_checklock_irqsave(&cc->zone->lock, &flags, | |
275 | locked, cc); | |
276 | if (!locked) | |
277 | break; | |
278 | ||
279 | /* Recheck this is a suitable migration target under lock */ | |
280 | if (!strict && !suitable_migration_target(page)) | |
281 | break; | |
748446bb | 282 | |
f40d1e42 MG |
283 | /* Recheck this is a buddy page under lock */ |
284 | if (!PageBuddy(page)) | |
748446bb MG |
285 | continue; |
286 | ||
287 | /* Found a free page, break it into order-0 pages */ | |
288 | isolated = split_free_page(page); | |
85aa125f | 289 | if (!isolated && strict) |
f40d1e42 | 290 | break; |
748446bb MG |
291 | total_isolated += isolated; |
292 | for (i = 0; i < isolated; i++) { | |
293 | list_add(&page->lru, freelist); | |
294 | page++; | |
295 | } | |
296 | ||
297 | /* If a page was split, advance to the end of it */ | |
298 | if (isolated) { | |
299 | blockpfn += isolated - 1; | |
300 | cursor += isolated - 1; | |
301 | } | |
302 | } | |
303 | ||
b7aba698 | 304 | trace_mm_compaction_isolate_freepages(nr_scanned, total_isolated); |
f40d1e42 MG |
305 | |
306 | /* | |
307 | * If strict isolation is requested by CMA then check that all the | |
308 | * pages requested were isolated. If there were any failures, 0 is | |
309 | * returned and CMA will fail. | |
310 | */ | |
0db63d7e | 311 | if (strict && nr_strict_required > total_isolated) |
f40d1e42 MG |
312 | total_isolated = 0; |
313 | ||
314 | if (locked) | |
315 | spin_unlock_irqrestore(&cc->zone->lock, flags); | |
316 | ||
bb13ffeb MG |
317 | /* Update the pageblock-skip if the whole pageblock was scanned */ |
318 | if (blockpfn == end_pfn) | |
c89511ab | 319 | update_pageblock_skip(cc, valid_page, total_isolated, false); |
bb13ffeb | 320 | |
010fc29a | 321 | count_compact_events(COMPACTFREE_SCANNED, nr_scanned); |
397487db | 322 | if (total_isolated) |
010fc29a | 323 | count_compact_events(COMPACTISOLATED, total_isolated); |
748446bb MG |
324 | return total_isolated; |
325 | } | |
326 | ||
85aa125f MN |
327 | /** |
328 | * isolate_freepages_range() - isolate free pages. | |
329 | * @start_pfn: The first PFN to start isolating. | |
330 | * @end_pfn: The one-past-last PFN. | |
331 | * | |
332 | * Non-free pages, invalid PFNs, or zone boundaries within the | |
333 | * [start_pfn, end_pfn) range are considered errors, cause function to | |
334 | * undo its actions and return zero. | |
335 | * | |
336 | * Otherwise, function returns one-past-the-last PFN of isolated page | |
337 | * (which may be greater then end_pfn if end fell in a middle of | |
338 | * a free page). | |
339 | */ | |
ff9543fd | 340 | unsigned long |
bb13ffeb MG |
341 | isolate_freepages_range(struct compact_control *cc, |
342 | unsigned long start_pfn, unsigned long end_pfn) | |
85aa125f | 343 | { |
f40d1e42 | 344 | unsigned long isolated, pfn, block_end_pfn; |
85aa125f MN |
345 | LIST_HEAD(freelist); |
346 | ||
85aa125f | 347 | for (pfn = start_pfn; pfn < end_pfn; pfn += isolated) { |
bb13ffeb | 348 | if (!pfn_valid(pfn) || cc->zone != page_zone(pfn_to_page(pfn))) |
85aa125f MN |
349 | break; |
350 | ||
351 | /* | |
352 | * On subsequent iterations ALIGN() is actually not needed, | |
353 | * but we keep it that we not to complicate the code. | |
354 | */ | |
355 | block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages); | |
356 | block_end_pfn = min(block_end_pfn, end_pfn); | |
357 | ||
bb13ffeb | 358 | isolated = isolate_freepages_block(cc, pfn, block_end_pfn, |
85aa125f | 359 | &freelist, true); |
85aa125f MN |
360 | |
361 | /* | |
362 | * In strict mode, isolate_freepages_block() returns 0 if | |
363 | * there are any holes in the block (ie. invalid PFNs or | |
364 | * non-free pages). | |
365 | */ | |
366 | if (!isolated) | |
367 | break; | |
368 | ||
369 | /* | |
370 | * If we managed to isolate pages, it is always (1 << n) * | |
371 | * pageblock_nr_pages for some non-negative n. (Max order | |
372 | * page may span two pageblocks). | |
373 | */ | |
374 | } | |
375 | ||
376 | /* split_free_page does not map the pages */ | |
377 | map_pages(&freelist); | |
378 | ||
379 | if (pfn < end_pfn) { | |
380 | /* Loop terminated early, cleanup. */ | |
381 | release_freepages(&freelist); | |
382 | return 0; | |
383 | } | |
384 | ||
385 | /* We don't use freelists for anything. */ | |
386 | return pfn; | |
387 | } | |
388 | ||
748446bb | 389 | /* Update the number of anon and file isolated pages in the zone */ |
c67fe375 | 390 | static void acct_isolated(struct zone *zone, bool locked, struct compact_control *cc) |
748446bb MG |
391 | { |
392 | struct page *page; | |
b9e84ac1 | 393 | unsigned int count[2] = { 0, }; |
748446bb | 394 | |
b9e84ac1 MK |
395 | list_for_each_entry(page, &cc->migratepages, lru) |
396 | count[!!page_is_file_cache(page)]++; | |
748446bb | 397 | |
c67fe375 MG |
398 | /* If locked we can use the interrupt unsafe versions */ |
399 | if (locked) { | |
400 | __mod_zone_page_state(zone, NR_ISOLATED_ANON, count[0]); | |
401 | __mod_zone_page_state(zone, NR_ISOLATED_FILE, count[1]); | |
402 | } else { | |
403 | mod_zone_page_state(zone, NR_ISOLATED_ANON, count[0]); | |
404 | mod_zone_page_state(zone, NR_ISOLATED_FILE, count[1]); | |
405 | } | |
748446bb MG |
406 | } |
407 | ||
408 | /* Similar to reclaim, but different enough that they don't share logic */ | |
409 | static bool too_many_isolated(struct zone *zone) | |
410 | { | |
bc693045 | 411 | unsigned long active, inactive, isolated; |
748446bb MG |
412 | |
413 | inactive = zone_page_state(zone, NR_INACTIVE_FILE) + | |
414 | zone_page_state(zone, NR_INACTIVE_ANON); | |
bc693045 MK |
415 | active = zone_page_state(zone, NR_ACTIVE_FILE) + |
416 | zone_page_state(zone, NR_ACTIVE_ANON); | |
748446bb MG |
417 | isolated = zone_page_state(zone, NR_ISOLATED_FILE) + |
418 | zone_page_state(zone, NR_ISOLATED_ANON); | |
419 | ||
bc693045 | 420 | return isolated > (inactive + active) / 2; |
748446bb MG |
421 | } |
422 | ||
2fe86e00 MN |
423 | /** |
424 | * isolate_migratepages_range() - isolate all migrate-able pages in range. | |
425 | * @zone: Zone pages are in. | |
426 | * @cc: Compaction control structure. | |
427 | * @low_pfn: The first PFN of the range. | |
428 | * @end_pfn: The one-past-the-last PFN of the range. | |
e46a2879 | 429 | * @unevictable: true if it allows to isolate unevictable pages |
2fe86e00 MN |
430 | * |
431 | * Isolate all pages that can be migrated from the range specified by | |
432 | * [low_pfn, end_pfn). Returns zero if there is a fatal signal | |
433 | * pending), otherwise PFN of the first page that was not scanned | |
434 | * (which may be both less, equal to or more then end_pfn). | |
435 | * | |
436 | * Assumes that cc->migratepages is empty and cc->nr_migratepages is | |
437 | * zero. | |
438 | * | |
439 | * Apart from cc->migratepages and cc->nr_migratetypes this function | |
440 | * does not modify any cc's fields, in particular it does not modify | |
441 | * (or read for that matter) cc->migrate_pfn. | |
748446bb | 442 | */ |
ff9543fd | 443 | unsigned long |
2fe86e00 | 444 | isolate_migratepages_range(struct zone *zone, struct compact_control *cc, |
e46a2879 | 445 | unsigned long low_pfn, unsigned long end_pfn, bool unevictable) |
748446bb | 446 | { |
9927af74 | 447 | unsigned long last_pageblock_nr = 0, pageblock_nr; |
b7aba698 | 448 | unsigned long nr_scanned = 0, nr_isolated = 0; |
748446bb | 449 | struct list_head *migratelist = &cc->migratepages; |
f3fd4a61 | 450 | isolate_mode_t mode = 0; |
fa9add64 | 451 | struct lruvec *lruvec; |
c67fe375 | 452 | unsigned long flags; |
2a1402aa | 453 | bool locked = false; |
bb13ffeb | 454 | struct page *page = NULL, *valid_page = NULL; |
748446bb | 455 | |
748446bb MG |
456 | /* |
457 | * Ensure that there are not too many pages isolated from the LRU | |
458 | * list by either parallel reclaimers or compaction. If there are, | |
459 | * delay for some time until fewer pages are isolated | |
460 | */ | |
461 | while (unlikely(too_many_isolated(zone))) { | |
f9e35b3b | 462 | /* async migration should just abort */ |
68e3e926 | 463 | if (!cc->sync) |
2fe86e00 | 464 | return 0; |
f9e35b3b | 465 | |
748446bb MG |
466 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
467 | ||
468 | if (fatal_signal_pending(current)) | |
2fe86e00 | 469 | return 0; |
748446bb MG |
470 | } |
471 | ||
472 | /* Time to isolate some pages for migration */ | |
b2eef8c0 | 473 | cond_resched(); |
748446bb | 474 | for (; low_pfn < end_pfn; low_pfn++) { |
b2eef8c0 | 475 | /* give a chance to irqs before checking need_resched() */ |
2a1402aa MG |
476 | if (locked && !((low_pfn+1) % SWAP_CLUSTER_MAX)) { |
477 | if (should_release_lock(&zone->lru_lock)) { | |
478 | spin_unlock_irqrestore(&zone->lru_lock, flags); | |
479 | locked = false; | |
480 | } | |
b2eef8c0 | 481 | } |
c67fe375 | 482 | |
0bf380bc MG |
483 | /* |
484 | * migrate_pfn does not necessarily start aligned to a | |
485 | * pageblock. Ensure that pfn_valid is called when moving | |
486 | * into a new MAX_ORDER_NR_PAGES range in case of large | |
487 | * memory holes within the zone | |
488 | */ | |
489 | if ((low_pfn & (MAX_ORDER_NR_PAGES - 1)) == 0) { | |
490 | if (!pfn_valid(low_pfn)) { | |
491 | low_pfn += MAX_ORDER_NR_PAGES - 1; | |
492 | continue; | |
493 | } | |
494 | } | |
495 | ||
748446bb MG |
496 | if (!pfn_valid_within(low_pfn)) |
497 | continue; | |
b7aba698 | 498 | nr_scanned++; |
748446bb | 499 | |
dc908600 MG |
500 | /* |
501 | * Get the page and ensure the page is within the same zone. | |
502 | * See the comment in isolate_freepages about overlapping | |
503 | * nodes. It is deliberate that the new zone lock is not taken | |
504 | * as memory compaction should not move pages between nodes. | |
505 | */ | |
748446bb | 506 | page = pfn_to_page(low_pfn); |
dc908600 MG |
507 | if (page_zone(page) != zone) |
508 | continue; | |
509 | ||
bb13ffeb MG |
510 | if (!valid_page) |
511 | valid_page = page; | |
512 | ||
513 | /* If isolation recently failed, do not retry */ | |
514 | pageblock_nr = low_pfn >> pageblock_order; | |
515 | if (!isolation_suitable(cc, page)) | |
516 | goto next_pageblock; | |
517 | ||
dc908600 | 518 | /* Skip if free */ |
748446bb MG |
519 | if (PageBuddy(page)) |
520 | continue; | |
521 | ||
9927af74 MG |
522 | /* |
523 | * For async migration, also only scan in MOVABLE blocks. Async | |
524 | * migration is optimistic to see if the minimum amount of work | |
525 | * satisfies the allocation | |
526 | */ | |
68e3e926 | 527 | if (!cc->sync && last_pageblock_nr != pageblock_nr && |
47118af0 | 528 | !migrate_async_suitable(get_pageblock_migratetype(page))) { |
c89511ab | 529 | cc->finished_update_migrate = true; |
2a1402aa | 530 | goto next_pageblock; |
9927af74 MG |
531 | } |
532 | ||
bf6bddf1 RA |
533 | /* |
534 | * Check may be lockless but that's ok as we recheck later. | |
535 | * It's possible to migrate LRU pages and balloon pages | |
536 | * Skip any other type of page | |
537 | */ | |
538 | if (!PageLRU(page)) { | |
539 | if (unlikely(balloon_page_movable(page))) { | |
540 | if (locked && balloon_page_isolate(page)) { | |
541 | /* Successfully isolated */ | |
542 | cc->finished_update_migrate = true; | |
543 | list_add(&page->lru, migratelist); | |
544 | cc->nr_migratepages++; | |
545 | nr_isolated++; | |
546 | goto check_compact_cluster; | |
547 | } | |
548 | } | |
bc835011 | 549 | continue; |
bf6bddf1 | 550 | } |
bc835011 AA |
551 | |
552 | /* | |
2a1402aa MG |
553 | * PageLRU is set. lru_lock normally excludes isolation |
554 | * splitting and collapsing (collapsing has already happened | |
555 | * if PageLRU is set) but the lock is not necessarily taken | |
556 | * here and it is wasteful to take it just to check transhuge. | |
557 | * Check TransHuge without lock and skip the whole pageblock if | |
558 | * it's either a transhuge or hugetlbfs page, as calling | |
559 | * compound_order() without preventing THP from splitting the | |
560 | * page underneath us may return surprising results. | |
bc835011 | 561 | */ |
2a1402aa MG |
562 | if (PageTransHuge(page)) { |
563 | if (!locked) | |
564 | goto next_pageblock; | |
565 | low_pfn += (1 << compound_order(page)) - 1; | |
566 | continue; | |
567 | } | |
568 | ||
569 | /* Check if it is ok to still hold the lock */ | |
570 | locked = compact_checklock_irqsave(&zone->lru_lock, &flags, | |
571 | locked, cc); | |
572 | if (!locked || fatal_signal_pending(current)) | |
573 | break; | |
574 | ||
575 | /* Recheck PageLRU and PageTransHuge under lock */ | |
576 | if (!PageLRU(page)) | |
577 | continue; | |
bc835011 AA |
578 | if (PageTransHuge(page)) { |
579 | low_pfn += (1 << compound_order(page)) - 1; | |
580 | continue; | |
581 | } | |
582 | ||
68e3e926 | 583 | if (!cc->sync) |
c8244935 MG |
584 | mode |= ISOLATE_ASYNC_MIGRATE; |
585 | ||
e46a2879 MK |
586 | if (unevictable) |
587 | mode |= ISOLATE_UNEVICTABLE; | |
588 | ||
fa9add64 HD |
589 | lruvec = mem_cgroup_page_lruvec(page, zone); |
590 | ||
748446bb | 591 | /* Try isolate the page */ |
f3fd4a61 | 592 | if (__isolate_lru_page(page, mode) != 0) |
748446bb MG |
593 | continue; |
594 | ||
bc835011 AA |
595 | VM_BUG_ON(PageTransCompound(page)); |
596 | ||
748446bb | 597 | /* Successfully isolated */ |
c89511ab | 598 | cc->finished_update_migrate = true; |
fa9add64 | 599 | del_page_from_lru_list(page, lruvec, page_lru(page)); |
748446bb | 600 | list_add(&page->lru, migratelist); |
748446bb | 601 | cc->nr_migratepages++; |
b7aba698 | 602 | nr_isolated++; |
748446bb | 603 | |
bf6bddf1 | 604 | check_compact_cluster: |
748446bb | 605 | /* Avoid isolating too much */ |
31b8384a HD |
606 | if (cc->nr_migratepages == COMPACT_CLUSTER_MAX) { |
607 | ++low_pfn; | |
748446bb | 608 | break; |
31b8384a | 609 | } |
2a1402aa MG |
610 | |
611 | continue; | |
612 | ||
613 | next_pageblock: | |
614 | low_pfn += pageblock_nr_pages; | |
615 | low_pfn = ALIGN(low_pfn, pageblock_nr_pages) - 1; | |
616 | last_pageblock_nr = pageblock_nr; | |
748446bb MG |
617 | } |
618 | ||
c67fe375 | 619 | acct_isolated(zone, locked, cc); |
748446bb | 620 | |
c67fe375 MG |
621 | if (locked) |
622 | spin_unlock_irqrestore(&zone->lru_lock, flags); | |
748446bb | 623 | |
bb13ffeb MG |
624 | /* Update the pageblock-skip if the whole pageblock was scanned */ |
625 | if (low_pfn == end_pfn) | |
c89511ab | 626 | update_pageblock_skip(cc, valid_page, nr_isolated, true); |
bb13ffeb | 627 | |
b7aba698 MG |
628 | trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated); |
629 | ||
010fc29a | 630 | count_compact_events(COMPACTMIGRATE_SCANNED, nr_scanned); |
397487db | 631 | if (nr_isolated) |
010fc29a | 632 | count_compact_events(COMPACTISOLATED, nr_isolated); |
397487db | 633 | |
2fe86e00 MN |
634 | return low_pfn; |
635 | } | |
636 | ||
ff9543fd MN |
637 | #endif /* CONFIG_COMPACTION || CONFIG_CMA */ |
638 | #ifdef CONFIG_COMPACTION | |
2fe86e00 | 639 | /* |
ff9543fd MN |
640 | * Based on information in the current compact_control, find blocks |
641 | * suitable for isolating free pages from and then isolate them. | |
2fe86e00 | 642 | */ |
ff9543fd MN |
643 | static void isolate_freepages(struct zone *zone, |
644 | struct compact_control *cc) | |
2fe86e00 | 645 | { |
ff9543fd MN |
646 | struct page *page; |
647 | unsigned long high_pfn, low_pfn, pfn, zone_end_pfn, end_pfn; | |
ff9543fd MN |
648 | int nr_freepages = cc->nr_freepages; |
649 | struct list_head *freelist = &cc->freepages; | |
2fe86e00 | 650 | |
ff9543fd MN |
651 | /* |
652 | * Initialise the free scanner. The starting point is where we last | |
653 | * scanned from (or the end of the zone if starting). The low point | |
654 | * is the end of the pageblock the migration scanner is using. | |
655 | */ | |
656 | pfn = cc->free_pfn; | |
657 | low_pfn = cc->migrate_pfn + pageblock_nr_pages; | |
2fe86e00 | 658 | |
ff9543fd MN |
659 | /* |
660 | * Take care that if the migration scanner is at the end of the zone | |
661 | * that the free scanner does not accidentally move to the next zone | |
662 | * in the next isolation cycle. | |
663 | */ | |
664 | high_pfn = min(low_pfn, pfn); | |
2fe86e00 | 665 | |
ff9543fd | 666 | zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; |
2fe86e00 | 667 | |
ff9543fd MN |
668 | /* |
669 | * Isolate free pages until enough are available to migrate the | |
670 | * pages on cc->migratepages. We stop searching if the migrate | |
671 | * and free page scanners meet or enough free pages are isolated. | |
672 | */ | |
673 | for (; pfn > low_pfn && cc->nr_migratepages > nr_freepages; | |
674 | pfn -= pageblock_nr_pages) { | |
675 | unsigned long isolated; | |
2fe86e00 | 676 | |
ff9543fd MN |
677 | if (!pfn_valid(pfn)) |
678 | continue; | |
2fe86e00 | 679 | |
ff9543fd MN |
680 | /* |
681 | * Check for overlapping nodes/zones. It's possible on some | |
682 | * configurations to have a setup like | |
683 | * node0 node1 node0 | |
684 | * i.e. it's possible that all pages within a zones range of | |
685 | * pages do not belong to a single zone. | |
686 | */ | |
687 | page = pfn_to_page(pfn); | |
688 | if (page_zone(page) != zone) | |
689 | continue; | |
690 | ||
691 | /* Check the block is suitable for migration */ | |
68e3e926 | 692 | if (!suitable_migration_target(page)) |
ff9543fd | 693 | continue; |
68e3e926 | 694 | |
bb13ffeb MG |
695 | /* If isolation recently failed, do not retry */ |
696 | if (!isolation_suitable(cc, page)) | |
697 | continue; | |
698 | ||
f40d1e42 | 699 | /* Found a block suitable for isolating free pages from */ |
ff9543fd | 700 | isolated = 0; |
60177d31 MG |
701 | |
702 | /* | |
703 | * As pfn may not start aligned, pfn+pageblock_nr_page | |
704 | * may cross a MAX_ORDER_NR_PAGES boundary and miss | |
705 | * a pfn_valid check. Ensure isolate_freepages_block() | |
706 | * only scans within a pageblock | |
707 | */ | |
708 | end_pfn = ALIGN(pfn + 1, pageblock_nr_pages); | |
709 | end_pfn = min(end_pfn, zone_end_pfn); | |
f40d1e42 MG |
710 | isolated = isolate_freepages_block(cc, pfn, end_pfn, |
711 | freelist, false); | |
712 | nr_freepages += isolated; | |
ff9543fd MN |
713 | |
714 | /* | |
715 | * Record the highest PFN we isolated pages from. When next | |
716 | * looking for free pages, the search will restart here as | |
717 | * page migration may have returned some pages to the allocator | |
718 | */ | |
c89511ab MG |
719 | if (isolated) { |
720 | cc->finished_update_free = true; | |
ff9543fd | 721 | high_pfn = max(high_pfn, pfn); |
c89511ab | 722 | } |
ff9543fd MN |
723 | } |
724 | ||
725 | /* split_free_page does not map the pages */ | |
726 | map_pages(freelist); | |
727 | ||
728 | cc->free_pfn = high_pfn; | |
729 | cc->nr_freepages = nr_freepages; | |
748446bb MG |
730 | } |
731 | ||
732 | /* | |
733 | * This is a migrate-callback that "allocates" freepages by taking pages | |
734 | * from the isolated freelists in the block we are migrating to. | |
735 | */ | |
736 | static struct page *compaction_alloc(struct page *migratepage, | |
737 | unsigned long data, | |
738 | int **result) | |
739 | { | |
740 | struct compact_control *cc = (struct compact_control *)data; | |
741 | struct page *freepage; | |
742 | ||
743 | /* Isolate free pages if necessary */ | |
744 | if (list_empty(&cc->freepages)) { | |
745 | isolate_freepages(cc->zone, cc); | |
746 | ||
747 | if (list_empty(&cc->freepages)) | |
748 | return NULL; | |
749 | } | |
750 | ||
751 | freepage = list_entry(cc->freepages.next, struct page, lru); | |
752 | list_del(&freepage->lru); | |
753 | cc->nr_freepages--; | |
754 | ||
755 | return freepage; | |
756 | } | |
757 | ||
758 | /* | |
759 | * We cannot control nr_migratepages and nr_freepages fully when migration is | |
760 | * running as migrate_pages() has no knowledge of compact_control. When | |
761 | * migration is complete, we count the number of pages on the lists by hand. | |
762 | */ | |
763 | static void update_nr_listpages(struct compact_control *cc) | |
764 | { | |
765 | int nr_migratepages = 0; | |
766 | int nr_freepages = 0; | |
767 | struct page *page; | |
768 | ||
769 | list_for_each_entry(page, &cc->migratepages, lru) | |
770 | nr_migratepages++; | |
771 | list_for_each_entry(page, &cc->freepages, lru) | |
772 | nr_freepages++; | |
773 | ||
774 | cc->nr_migratepages = nr_migratepages; | |
775 | cc->nr_freepages = nr_freepages; | |
776 | } | |
777 | ||
ff9543fd MN |
778 | /* possible outcome of isolate_migratepages */ |
779 | typedef enum { | |
780 | ISOLATE_ABORT, /* Abort compaction now */ | |
781 | ISOLATE_NONE, /* No pages isolated, continue scanning */ | |
782 | ISOLATE_SUCCESS, /* Pages isolated, migrate */ | |
783 | } isolate_migrate_t; | |
784 | ||
785 | /* | |
786 | * Isolate all pages that can be migrated from the block pointed to by | |
787 | * the migrate scanner within compact_control. | |
788 | */ | |
789 | static isolate_migrate_t isolate_migratepages(struct zone *zone, | |
790 | struct compact_control *cc) | |
791 | { | |
792 | unsigned long low_pfn, end_pfn; | |
793 | ||
794 | /* Do not scan outside zone boundaries */ | |
795 | low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn); | |
796 | ||
797 | /* Only scan within a pageblock boundary */ | |
798 | end_pfn = ALIGN(low_pfn + pageblock_nr_pages, pageblock_nr_pages); | |
799 | ||
800 | /* Do not cross the free scanner or scan within a memory hole */ | |
801 | if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) { | |
802 | cc->migrate_pfn = end_pfn; | |
803 | return ISOLATE_NONE; | |
804 | } | |
805 | ||
806 | /* Perform the isolation */ | |
e46a2879 | 807 | low_pfn = isolate_migratepages_range(zone, cc, low_pfn, end_pfn, false); |
e64c5237 | 808 | if (!low_pfn || cc->contended) |
ff9543fd MN |
809 | return ISOLATE_ABORT; |
810 | ||
811 | cc->migrate_pfn = low_pfn; | |
812 | ||
813 | return ISOLATE_SUCCESS; | |
814 | } | |
815 | ||
748446bb | 816 | static int compact_finished(struct zone *zone, |
5a03b051 | 817 | struct compact_control *cc) |
748446bb | 818 | { |
5a03b051 | 819 | unsigned long watermark; |
56de7263 | 820 | |
748446bb MG |
821 | if (fatal_signal_pending(current)) |
822 | return COMPACT_PARTIAL; | |
823 | ||
753341a4 | 824 | /* Compaction run completes if the migrate and free scanner meet */ |
bb13ffeb | 825 | if (cc->free_pfn <= cc->migrate_pfn) { |
62997027 MG |
826 | /* |
827 | * Mark that the PG_migrate_skip information should be cleared | |
828 | * by kswapd when it goes to sleep. kswapd does not set the | |
829 | * flag itself as the decision to be clear should be directly | |
830 | * based on an allocation request. | |
831 | */ | |
832 | if (!current_is_kswapd()) | |
833 | zone->compact_blockskip_flush = true; | |
834 | ||
748446bb | 835 | return COMPACT_COMPLETE; |
bb13ffeb | 836 | } |
748446bb | 837 | |
82478fb7 JW |
838 | /* |
839 | * order == -1 is expected when compacting via | |
840 | * /proc/sys/vm/compact_memory | |
841 | */ | |
56de7263 MG |
842 | if (cc->order == -1) |
843 | return COMPACT_CONTINUE; | |
844 | ||
3957c776 MH |
845 | /* Compaction run is not finished if the watermark is not met */ |
846 | watermark = low_wmark_pages(zone); | |
847 | watermark += (1 << cc->order); | |
848 | ||
849 | if (!zone_watermark_ok(zone, cc->order, watermark, 0, 0)) | |
850 | return COMPACT_CONTINUE; | |
851 | ||
56de7263 | 852 | /* Direct compactor: Is a suitable page free? */ |
1fb3f8ca MG |
853 | if (cc->page) { |
854 | /* Was a suitable page captured? */ | |
855 | if (*cc->page) | |
56de7263 | 856 | return COMPACT_PARTIAL; |
1fb3f8ca MG |
857 | } else { |
858 | unsigned int order; | |
859 | for (order = cc->order; order < MAX_ORDER; order++) { | |
860 | struct free_area *area = &zone->free_area[cc->order]; | |
861 | /* Job done if page is free of the right migratetype */ | |
862 | if (!list_empty(&area->free_list[cc->migratetype])) | |
863 | return COMPACT_PARTIAL; | |
864 | ||
865 | /* Job done if allocation would set block type */ | |
866 | if (cc->order >= pageblock_order && area->nr_free) | |
867 | return COMPACT_PARTIAL; | |
868 | } | |
56de7263 MG |
869 | } |
870 | ||
748446bb MG |
871 | return COMPACT_CONTINUE; |
872 | } | |
873 | ||
3e7d3449 MG |
874 | /* |
875 | * compaction_suitable: Is this suitable to run compaction on this zone now? | |
876 | * Returns | |
877 | * COMPACT_SKIPPED - If there are too few free pages for compaction | |
878 | * COMPACT_PARTIAL - If the allocation would succeed without compaction | |
879 | * COMPACT_CONTINUE - If compaction should run now | |
880 | */ | |
881 | unsigned long compaction_suitable(struct zone *zone, int order) | |
882 | { | |
883 | int fragindex; | |
884 | unsigned long watermark; | |
885 | ||
3957c776 MH |
886 | /* |
887 | * order == -1 is expected when compacting via | |
888 | * /proc/sys/vm/compact_memory | |
889 | */ | |
890 | if (order == -1) | |
891 | return COMPACT_CONTINUE; | |
892 | ||
3e7d3449 MG |
893 | /* |
894 | * Watermarks for order-0 must be met for compaction. Note the 2UL. | |
895 | * This is because during migration, copies of pages need to be | |
896 | * allocated and for a short time, the footprint is higher | |
897 | */ | |
898 | watermark = low_wmark_pages(zone) + (2UL << order); | |
899 | if (!zone_watermark_ok(zone, 0, watermark, 0, 0)) | |
900 | return COMPACT_SKIPPED; | |
901 | ||
902 | /* | |
903 | * fragmentation index determines if allocation failures are due to | |
904 | * low memory or external fragmentation | |
905 | * | |
a582a738 SL |
906 | * index of -1000 implies allocations might succeed depending on |
907 | * watermarks | |
3e7d3449 MG |
908 | * index towards 0 implies failure is due to lack of memory |
909 | * index towards 1000 implies failure is due to fragmentation | |
910 | * | |
911 | * Only compact if a failure would be due to fragmentation. | |
912 | */ | |
913 | fragindex = fragmentation_index(zone, order); | |
914 | if (fragindex >= 0 && fragindex <= sysctl_extfrag_threshold) | |
915 | return COMPACT_SKIPPED; | |
916 | ||
a582a738 SL |
917 | if (fragindex == -1000 && zone_watermark_ok(zone, order, watermark, |
918 | 0, 0)) | |
3e7d3449 MG |
919 | return COMPACT_PARTIAL; |
920 | ||
921 | return COMPACT_CONTINUE; | |
922 | } | |
923 | ||
c8bf2d8b TR |
924 | static void compact_capture_page(struct compact_control *cc) |
925 | { | |
926 | unsigned long flags; | |
927 | int mtype, mtype_low, mtype_high; | |
928 | ||
929 | if (!cc->page || *cc->page) | |
930 | return; | |
931 | ||
932 | /* | |
933 | * For MIGRATE_MOVABLE allocations we capture a suitable page ASAP | |
934 | * regardless of the migratetype of the freelist is is captured from. | |
935 | * This is fine because the order for a high-order MIGRATE_MOVABLE | |
936 | * allocation is typically at least a pageblock size and overall | |
937 | * fragmentation is not impaired. Other allocation types must | |
938 | * capture pages from their own migratelist because otherwise they | |
939 | * could pollute other pageblocks like MIGRATE_MOVABLE with | |
940 | * difficult to move pages and making fragmentation worse overall. | |
941 | */ | |
942 | if (cc->migratetype == MIGRATE_MOVABLE) { | |
943 | mtype_low = 0; | |
944 | mtype_high = MIGRATE_PCPTYPES; | |
945 | } else { | |
946 | mtype_low = cc->migratetype; | |
947 | mtype_high = cc->migratetype + 1; | |
948 | } | |
949 | ||
950 | /* Speculatively examine the free lists without zone lock */ | |
951 | for (mtype = mtype_low; mtype < mtype_high; mtype++) { | |
952 | int order; | |
953 | for (order = cc->order; order < MAX_ORDER; order++) { | |
954 | struct page *page; | |
955 | struct free_area *area; | |
956 | area = &(cc->zone->free_area[order]); | |
957 | if (list_empty(&area->free_list[mtype])) | |
958 | continue; | |
959 | ||
960 | /* Take the lock and attempt capture of the page */ | |
961 | if (!compact_trylock_irqsave(&cc->zone->lock, &flags, cc)) | |
962 | return; | |
963 | if (!list_empty(&area->free_list[mtype])) { | |
964 | page = list_entry(area->free_list[mtype].next, | |
965 | struct page, lru); | |
966 | if (capture_free_page(page, cc->order, mtype)) { | |
967 | spin_unlock_irqrestore(&cc->zone->lock, | |
968 | flags); | |
969 | *cc->page = page; | |
970 | return; | |
971 | } | |
972 | } | |
973 | spin_unlock_irqrestore(&cc->zone->lock, flags); | |
974 | } | |
975 | } | |
976 | } | |
977 | ||
748446bb MG |
978 | static int compact_zone(struct zone *zone, struct compact_control *cc) |
979 | { | |
980 | int ret; | |
c89511ab MG |
981 | unsigned long start_pfn = zone->zone_start_pfn; |
982 | unsigned long end_pfn = zone->zone_start_pfn + zone->spanned_pages; | |
748446bb | 983 | |
3e7d3449 MG |
984 | ret = compaction_suitable(zone, cc->order); |
985 | switch (ret) { | |
986 | case COMPACT_PARTIAL: | |
987 | case COMPACT_SKIPPED: | |
988 | /* Compaction is likely to fail */ | |
989 | return ret; | |
990 | case COMPACT_CONTINUE: | |
991 | /* Fall through to compaction */ | |
992 | ; | |
993 | } | |
994 | ||
c89511ab MG |
995 | /* |
996 | * Setup to move all movable pages to the end of the zone. Used cached | |
997 | * information on where the scanners should start but check that it | |
998 | * is initialised by ensuring the values are within zone boundaries. | |
999 | */ | |
1000 | cc->migrate_pfn = zone->compact_cached_migrate_pfn; | |
1001 | cc->free_pfn = zone->compact_cached_free_pfn; | |
1002 | if (cc->free_pfn < start_pfn || cc->free_pfn > end_pfn) { | |
1003 | cc->free_pfn = end_pfn & ~(pageblock_nr_pages-1); | |
1004 | zone->compact_cached_free_pfn = cc->free_pfn; | |
1005 | } | |
1006 | if (cc->migrate_pfn < start_pfn || cc->migrate_pfn > end_pfn) { | |
1007 | cc->migrate_pfn = start_pfn; | |
1008 | zone->compact_cached_migrate_pfn = cc->migrate_pfn; | |
1009 | } | |
748446bb | 1010 | |
62997027 MG |
1011 | /* |
1012 | * Clear pageblock skip if there were failures recently and compaction | |
1013 | * is about to be retried after being deferred. kswapd does not do | |
1014 | * this reset as it'll reset the cached information when going to sleep. | |
1015 | */ | |
1016 | if (compaction_restarting(zone, cc->order) && !current_is_kswapd()) | |
1017 | __reset_isolation_suitable(zone); | |
bb13ffeb | 1018 | |
748446bb MG |
1019 | migrate_prep_local(); |
1020 | ||
1021 | while ((ret = compact_finished(zone, cc)) == COMPACT_CONTINUE) { | |
1022 | unsigned long nr_migrate, nr_remaining; | |
9d502c1c | 1023 | int err; |
748446bb | 1024 | |
f9e35b3b MG |
1025 | switch (isolate_migratepages(zone, cc)) { |
1026 | case ISOLATE_ABORT: | |
1027 | ret = COMPACT_PARTIAL; | |
5733c7d1 | 1028 | putback_movable_pages(&cc->migratepages); |
e64c5237 | 1029 | cc->nr_migratepages = 0; |
f9e35b3b MG |
1030 | goto out; |
1031 | case ISOLATE_NONE: | |
748446bb | 1032 | continue; |
f9e35b3b MG |
1033 | case ISOLATE_SUCCESS: |
1034 | ; | |
1035 | } | |
748446bb MG |
1036 | |
1037 | nr_migrate = cc->nr_migratepages; | |
9d502c1c | 1038 | err = migrate_pages(&cc->migratepages, compaction_alloc, |
68e3e926 | 1039 | (unsigned long)cc, false, |
7b2a2d4a MG |
1040 | cc->sync ? MIGRATE_SYNC_LIGHT : MIGRATE_ASYNC, |
1041 | MR_COMPACTION); | |
748446bb MG |
1042 | update_nr_listpages(cc); |
1043 | nr_remaining = cc->nr_migratepages; | |
1044 | ||
b7aba698 MG |
1045 | trace_mm_compaction_migratepages(nr_migrate - nr_remaining, |
1046 | nr_remaining); | |
748446bb | 1047 | |
5733c7d1 | 1048 | /* Release isolated pages not migrated */ |
9d502c1c | 1049 | if (err) { |
5733c7d1 | 1050 | putback_movable_pages(&cc->migratepages); |
748446bb | 1051 | cc->nr_migratepages = 0; |
4bf2bba3 DR |
1052 | if (err == -ENOMEM) { |
1053 | ret = COMPACT_PARTIAL; | |
1054 | goto out; | |
1055 | } | |
748446bb | 1056 | } |
1fb3f8ca MG |
1057 | |
1058 | /* Capture a page now if it is a suitable size */ | |
1059 | compact_capture_page(cc); | |
748446bb MG |
1060 | } |
1061 | ||
f9e35b3b | 1062 | out: |
748446bb MG |
1063 | /* Release free pages and check accounting */ |
1064 | cc->nr_freepages -= release_freepages(&cc->freepages); | |
1065 | VM_BUG_ON(cc->nr_freepages != 0); | |
1066 | ||
1067 | return ret; | |
1068 | } | |
76ab0f53 | 1069 | |
d43a87e6 | 1070 | static unsigned long compact_zone_order(struct zone *zone, |
5a03b051 | 1071 | int order, gfp_t gfp_mask, |
1fb3f8ca MG |
1072 | bool sync, bool *contended, |
1073 | struct page **page) | |
56de7263 | 1074 | { |
e64c5237 | 1075 | unsigned long ret; |
56de7263 MG |
1076 | struct compact_control cc = { |
1077 | .nr_freepages = 0, | |
1078 | .nr_migratepages = 0, | |
1079 | .order = order, | |
1080 | .migratetype = allocflags_to_migratetype(gfp_mask), | |
1081 | .zone = zone, | |
68e3e926 | 1082 | .sync = sync, |
1fb3f8ca | 1083 | .page = page, |
56de7263 MG |
1084 | }; |
1085 | INIT_LIST_HEAD(&cc.freepages); | |
1086 | INIT_LIST_HEAD(&cc.migratepages); | |
1087 | ||
e64c5237 SL |
1088 | ret = compact_zone(zone, &cc); |
1089 | ||
1090 | VM_BUG_ON(!list_empty(&cc.freepages)); | |
1091 | VM_BUG_ON(!list_empty(&cc.migratepages)); | |
1092 | ||
1093 | *contended = cc.contended; | |
1094 | return ret; | |
56de7263 MG |
1095 | } |
1096 | ||
5e771905 MG |
1097 | int sysctl_extfrag_threshold = 500; |
1098 | ||
56de7263 MG |
1099 | /** |
1100 | * try_to_compact_pages - Direct compact to satisfy a high-order allocation | |
1101 | * @zonelist: The zonelist used for the current allocation | |
1102 | * @order: The order of the current allocation | |
1103 | * @gfp_mask: The GFP mask of the current allocation | |
1104 | * @nodemask: The allowed nodes to allocate from | |
77f1fe6b | 1105 | * @sync: Whether migration is synchronous or not |
661c4cb9 MG |
1106 | * @contended: Return value that is true if compaction was aborted due to lock contention |
1107 | * @page: Optionally capture a free page of the requested order during compaction | |
56de7263 MG |
1108 | * |
1109 | * This is the main entry point for direct page compaction. | |
1110 | */ | |
1111 | unsigned long try_to_compact_pages(struct zonelist *zonelist, | |
77f1fe6b | 1112 | int order, gfp_t gfp_mask, nodemask_t *nodemask, |
1fb3f8ca | 1113 | bool sync, bool *contended, struct page **page) |
56de7263 MG |
1114 | { |
1115 | enum zone_type high_zoneidx = gfp_zone(gfp_mask); | |
1116 | int may_enter_fs = gfp_mask & __GFP_FS; | |
1117 | int may_perform_io = gfp_mask & __GFP_IO; | |
56de7263 MG |
1118 | struct zoneref *z; |
1119 | struct zone *zone; | |
1120 | int rc = COMPACT_SKIPPED; | |
d95ea5d1 | 1121 | int alloc_flags = 0; |
56de7263 | 1122 | |
4ffb6335 | 1123 | /* Check if the GFP flags allow compaction */ |
c5a73c3d | 1124 | if (!order || !may_enter_fs || !may_perform_io) |
56de7263 MG |
1125 | return rc; |
1126 | ||
010fc29a | 1127 | count_compact_event(COMPACTSTALL); |
56de7263 | 1128 | |
d95ea5d1 BZ |
1129 | #ifdef CONFIG_CMA |
1130 | if (allocflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE) | |
1131 | alloc_flags |= ALLOC_CMA; | |
1132 | #endif | |
56de7263 MG |
1133 | /* Compact each zone in the list */ |
1134 | for_each_zone_zonelist_nodemask(zone, z, zonelist, high_zoneidx, | |
1135 | nodemask) { | |
56de7263 MG |
1136 | int status; |
1137 | ||
c67fe375 | 1138 | status = compact_zone_order(zone, order, gfp_mask, sync, |
1fb3f8ca | 1139 | contended, page); |
56de7263 MG |
1140 | rc = max(status, rc); |
1141 | ||
3e7d3449 | 1142 | /* If a normal allocation would succeed, stop compacting */ |
d95ea5d1 BZ |
1143 | if (zone_watermark_ok(zone, order, low_wmark_pages(zone), 0, |
1144 | alloc_flags)) | |
56de7263 MG |
1145 | break; |
1146 | } | |
1147 | ||
1148 | return rc; | |
1149 | } | |
1150 | ||
1151 | ||
76ab0f53 | 1152 | /* Compact all zones within a node */ |
7be62de9 | 1153 | static int __compact_pgdat(pg_data_t *pgdat, struct compact_control *cc) |
76ab0f53 MG |
1154 | { |
1155 | int zoneid; | |
76ab0f53 MG |
1156 | struct zone *zone; |
1157 | ||
76ab0f53 | 1158 | for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { |
76ab0f53 MG |
1159 | |
1160 | zone = &pgdat->node_zones[zoneid]; | |
1161 | if (!populated_zone(zone)) | |
1162 | continue; | |
1163 | ||
7be62de9 RR |
1164 | cc->nr_freepages = 0; |
1165 | cc->nr_migratepages = 0; | |
1166 | cc->zone = zone; | |
1167 | INIT_LIST_HEAD(&cc->freepages); | |
1168 | INIT_LIST_HEAD(&cc->migratepages); | |
76ab0f53 | 1169 | |
aad6ec37 | 1170 | if (cc->order == -1 || !compaction_deferred(zone, cc->order)) |
7be62de9 | 1171 | compact_zone(zone, cc); |
76ab0f53 | 1172 | |
aff62249 RR |
1173 | if (cc->order > 0) { |
1174 | int ok = zone_watermark_ok(zone, cc->order, | |
1175 | low_wmark_pages(zone), 0, 0); | |
c81758fb | 1176 | if (ok && cc->order >= zone->compact_order_failed) |
aff62249 RR |
1177 | zone->compact_order_failed = cc->order + 1; |
1178 | /* Currently async compaction is never deferred. */ | |
68e3e926 | 1179 | else if (!ok && cc->sync) |
aff62249 RR |
1180 | defer_compaction(zone, cc->order); |
1181 | } | |
1182 | ||
7be62de9 RR |
1183 | VM_BUG_ON(!list_empty(&cc->freepages)); |
1184 | VM_BUG_ON(!list_empty(&cc->migratepages)); | |
76ab0f53 MG |
1185 | } |
1186 | ||
1187 | return 0; | |
1188 | } | |
1189 | ||
7be62de9 RR |
1190 | int compact_pgdat(pg_data_t *pgdat, int order) |
1191 | { | |
1192 | struct compact_control cc = { | |
1193 | .order = order, | |
68e3e926 | 1194 | .sync = false, |
1fb3f8ca | 1195 | .page = NULL, |
7be62de9 RR |
1196 | }; |
1197 | ||
1198 | return __compact_pgdat(pgdat, &cc); | |
1199 | } | |
1200 | ||
1201 | static int compact_node(int nid) | |
1202 | { | |
7be62de9 RR |
1203 | struct compact_control cc = { |
1204 | .order = -1, | |
68e3e926 | 1205 | .sync = true, |
1fb3f8ca | 1206 | .page = NULL, |
7be62de9 RR |
1207 | }; |
1208 | ||
8575ec29 | 1209 | return __compact_pgdat(NODE_DATA(nid), &cc); |
7be62de9 RR |
1210 | } |
1211 | ||
76ab0f53 MG |
1212 | /* Compact all nodes in the system */ |
1213 | static int compact_nodes(void) | |
1214 | { | |
1215 | int nid; | |
1216 | ||
8575ec29 HD |
1217 | /* Flush pending updates to the LRU lists */ |
1218 | lru_add_drain_all(); | |
1219 | ||
76ab0f53 MG |
1220 | for_each_online_node(nid) |
1221 | compact_node(nid); | |
1222 | ||
1223 | return COMPACT_COMPLETE; | |
1224 | } | |
1225 | ||
1226 | /* The written value is actually unused, all memory is compacted */ | |
1227 | int sysctl_compact_memory; | |
1228 | ||
1229 | /* This is the entry point for compacting all nodes via /proc/sys/vm */ | |
1230 | int sysctl_compaction_handler(struct ctl_table *table, int write, | |
1231 | void __user *buffer, size_t *length, loff_t *ppos) | |
1232 | { | |
1233 | if (write) | |
1234 | return compact_nodes(); | |
1235 | ||
1236 | return 0; | |
1237 | } | |
ed4a6d7f | 1238 | |
5e771905 MG |
1239 | int sysctl_extfrag_handler(struct ctl_table *table, int write, |
1240 | void __user *buffer, size_t *length, loff_t *ppos) | |
1241 | { | |
1242 | proc_dointvec_minmax(table, write, buffer, length, ppos); | |
1243 | ||
1244 | return 0; | |
1245 | } | |
1246 | ||
ed4a6d7f | 1247 | #if defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) |
10fbcf4c KS |
1248 | ssize_t sysfs_compact_node(struct device *dev, |
1249 | struct device_attribute *attr, | |
ed4a6d7f MG |
1250 | const char *buf, size_t count) |
1251 | { | |
8575ec29 HD |
1252 | int nid = dev->id; |
1253 | ||
1254 | if (nid >= 0 && nid < nr_node_ids && node_online(nid)) { | |
1255 | /* Flush pending updates to the LRU lists */ | |
1256 | lru_add_drain_all(); | |
1257 | ||
1258 | compact_node(nid); | |
1259 | } | |
ed4a6d7f MG |
1260 | |
1261 | return count; | |
1262 | } | |
10fbcf4c | 1263 | static DEVICE_ATTR(compact, S_IWUSR, NULL, sysfs_compact_node); |
ed4a6d7f MG |
1264 | |
1265 | int compaction_register_node(struct node *node) | |
1266 | { | |
10fbcf4c | 1267 | return device_create_file(&node->dev, &dev_attr_compact); |
ed4a6d7f MG |
1268 | } |
1269 | ||
1270 | void compaction_unregister_node(struct node *node) | |
1271 | { | |
10fbcf4c | 1272 | return device_remove_file(&node->dev, &dev_attr_compact); |
ed4a6d7f MG |
1273 | } |
1274 | #endif /* CONFIG_SYSFS && CONFIG_NUMA */ | |
ff9543fd MN |
1275 | |
1276 | #endif /* CONFIG_COMPACTION */ |