Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/mm/swap.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
183ff22b | 8 | * This file contains the default values for the operation of the |
1da177e4 LT |
9 | * Linux VM subsystem. Fine-tuning documentation can be found in |
10 | * Documentation/sysctl/vm.txt. | |
11 | * Started 18.12.91 | |
12 | * Swap aging added 23.2.95, Stephen Tweedie. | |
13 | * Buffermem limits added 12.3.98, Rik van Riel. | |
14 | */ | |
15 | ||
16 | #include <linux/mm.h> | |
17 | #include <linux/sched.h> | |
18 | #include <linux/kernel_stat.h> | |
19 | #include <linux/swap.h> | |
20 | #include <linux/mman.h> | |
21 | #include <linux/pagemap.h> | |
22 | #include <linux/pagevec.h> | |
23 | #include <linux/init.h> | |
b95f1b31 | 24 | #include <linux/export.h> |
1da177e4 | 25 | #include <linux/mm_inline.h> |
1da177e4 LT |
26 | #include <linux/percpu_counter.h> |
27 | #include <linux/percpu.h> | |
28 | #include <linux/cpu.h> | |
29 | #include <linux/notifier.h> | |
e0bf68dd | 30 | #include <linux/backing-dev.h> |
66e1707b | 31 | #include <linux/memcontrol.h> |
5a0e3ad6 | 32 | #include <linux/gfp.h> |
a27bb332 | 33 | #include <linux/uio.h> |
7cb2ef56 | 34 | #include <linux/hugetlb.h> |
1da177e4 | 35 | |
64d6519d LS |
36 | #include "internal.h" |
37 | ||
c6286c98 MG |
38 | #define CREATE_TRACE_POINTS |
39 | #include <trace/events/pagemap.h> | |
40 | ||
1da177e4 LT |
41 | /* How many pages do we try to swap or page in/out together? */ |
42 | int page_cluster; | |
43 | ||
13f7f789 | 44 | static DEFINE_PER_CPU(struct pagevec, lru_add_pvec); |
f84f9504 | 45 | static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs); |
31560180 | 46 | static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs); |
902aaed0 | 47 | |
b221385b AB |
48 | /* |
49 | * This path almost never happens for VM activity - pages are normally | |
50 | * freed via pagevecs. But it gets used by networking. | |
51 | */ | |
920c7a5d | 52 | static void __page_cache_release(struct page *page) |
b221385b AB |
53 | { |
54 | if (PageLRU(page)) { | |
b221385b | 55 | struct zone *zone = page_zone(page); |
fa9add64 HD |
56 | struct lruvec *lruvec; |
57 | unsigned long flags; | |
b221385b AB |
58 | |
59 | spin_lock_irqsave(&zone->lru_lock, flags); | |
fa9add64 | 60 | lruvec = mem_cgroup_page_lruvec(page, zone); |
b221385b AB |
61 | VM_BUG_ON(!PageLRU(page)); |
62 | __ClearPageLRU(page); | |
fa9add64 | 63 | del_page_from_lru_list(page, lruvec, page_off_lru(page)); |
b221385b AB |
64 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
65 | } | |
91807063 AA |
66 | } |
67 | ||
68 | static void __put_single_page(struct page *page) | |
69 | { | |
70 | __page_cache_release(page); | |
fc91668e | 71 | free_hot_cold_page(page, 0); |
b221385b AB |
72 | } |
73 | ||
91807063 | 74 | static void __put_compound_page(struct page *page) |
1da177e4 | 75 | { |
91807063 | 76 | compound_page_dtor *dtor; |
1da177e4 | 77 | |
91807063 AA |
78 | __page_cache_release(page); |
79 | dtor = get_compound_page_dtor(page); | |
80 | (*dtor)(page); | |
81 | } | |
82 | ||
83 | static void put_compound_page(struct page *page) | |
84 | { | |
7cb2ef56 KA |
85 | /* |
86 | * hugetlbfs pages cannot be split from under us. If this is a | |
87 | * hugetlbfs page, check refcount on head page and release the page if | |
88 | * the refcount becomes zero. | |
89 | */ | |
90 | if (PageHuge(page)) { | |
91 | page = compound_head(page); | |
92 | if (put_page_testzero(page)) | |
93 | __put_compound_page(page); | |
94 | ||
95 | return; | |
96 | } | |
97 | ||
91807063 AA |
98 | if (unlikely(PageTail(page))) { |
99 | /* __split_huge_page_refcount can run under us */ | |
70b50f94 AA |
100 | struct page *page_head = compound_trans_head(page); |
101 | ||
102 | if (likely(page != page_head && | |
103 | get_page_unless_zero(page_head))) { | |
91807063 | 104 | unsigned long flags; |
5bf5f03c PS |
105 | |
106 | /* | |
107 | * THP can not break up slab pages so avoid taking | |
108 | * compound_lock(). Slab performs non-atomic bit ops | |
109 | * on page->flags for better performance. In particular | |
110 | * slab_unlock() in slub used to be a hot path. It is | |
111 | * still hot on arches that do not support | |
112 | * this_cpu_cmpxchg_double(). | |
113 | */ | |
114 | if (PageSlab(page_head)) { | |
115 | if (PageTail(page)) { | |
116 | if (put_page_testzero(page_head)) | |
117 | VM_BUG_ON(1); | |
118 | ||
119 | atomic_dec(&page->_mapcount); | |
120 | goto skip_lock_tail; | |
121 | } else | |
122 | goto skip_lock; | |
123 | } | |
91807063 | 124 | /* |
70b50f94 AA |
125 | * page_head wasn't a dangling pointer but it |
126 | * may not be a head page anymore by the time | |
127 | * we obtain the lock. That is ok as long as it | |
128 | * can't be freed from under us. | |
91807063 | 129 | */ |
91807063 AA |
130 | flags = compound_lock_irqsave(page_head); |
131 | if (unlikely(!PageTail(page))) { | |
132 | /* __split_huge_page_refcount run before us */ | |
133 | compound_unlock_irqrestore(page_head, flags); | |
5bf5f03c | 134 | skip_lock: |
91807063 AA |
135 | if (put_page_testzero(page_head)) |
136 | __put_single_page(page_head); | |
5bf5f03c | 137 | out_put_single: |
91807063 AA |
138 | if (put_page_testzero(page)) |
139 | __put_single_page(page); | |
140 | return; | |
141 | } | |
142 | VM_BUG_ON(page_head != page->first_page); | |
143 | /* | |
144 | * We can release the refcount taken by | |
70b50f94 AA |
145 | * get_page_unless_zero() now that |
146 | * __split_huge_page_refcount() is blocked on | |
147 | * the compound_lock. | |
91807063 AA |
148 | */ |
149 | if (put_page_testzero(page_head)) | |
150 | VM_BUG_ON(1); | |
151 | /* __split_huge_page_refcount will wait now */ | |
70b50f94 AA |
152 | VM_BUG_ON(page_mapcount(page) <= 0); |
153 | atomic_dec(&page->_mapcount); | |
91807063 | 154 | VM_BUG_ON(atomic_read(&page_head->_count) <= 0); |
70b50f94 | 155 | VM_BUG_ON(atomic_read(&page->_count) != 0); |
91807063 | 156 | compound_unlock_irqrestore(page_head, flags); |
5bf5f03c PS |
157 | |
158 | skip_lock_tail: | |
a95a82e9 AA |
159 | if (put_page_testzero(page_head)) { |
160 | if (PageHead(page_head)) | |
161 | __put_compound_page(page_head); | |
162 | else | |
163 | __put_single_page(page_head); | |
164 | } | |
91807063 AA |
165 | } else { |
166 | /* page_head is a dangling pointer */ | |
167 | VM_BUG_ON(PageTail(page)); | |
168 | goto out_put_single; | |
169 | } | |
170 | } else if (put_page_testzero(page)) { | |
171 | if (PageHead(page)) | |
172 | __put_compound_page(page); | |
173 | else | |
174 | __put_single_page(page); | |
1da177e4 | 175 | } |
8519fb30 NP |
176 | } |
177 | ||
178 | void put_page(struct page *page) | |
179 | { | |
180 | if (unlikely(PageCompound(page))) | |
181 | put_compound_page(page); | |
182 | else if (put_page_testzero(page)) | |
91807063 | 183 | __put_single_page(page); |
1da177e4 LT |
184 | } |
185 | EXPORT_SYMBOL(put_page); | |
1da177e4 | 186 | |
70b50f94 AA |
187 | /* |
188 | * This function is exported but must not be called by anything other | |
189 | * than get_page(). It implements the slow path of get_page(). | |
190 | */ | |
191 | bool __get_page_tail(struct page *page) | |
192 | { | |
193 | /* | |
194 | * This takes care of get_page() if run on a tail page | |
195 | * returned by one of the get_user_pages/follow_page variants. | |
196 | * get_user_pages/follow_page itself doesn't need the compound | |
197 | * lock because it runs __get_page_tail_foll() under the | |
198 | * proper PT lock that already serializes against | |
199 | * split_huge_page(). | |
200 | */ | |
70b50f94 | 201 | bool got = false; |
7cb2ef56 | 202 | struct page *page_head; |
70b50f94 | 203 | |
7cb2ef56 KA |
204 | /* |
205 | * If this is a hugetlbfs page it cannot be split under us. Simply | |
206 | * increment refcount for the head page. | |
207 | */ | |
208 | if (PageHuge(page)) { | |
209 | page_head = compound_head(page); | |
210 | atomic_inc(&page_head->_count); | |
211 | got = true; | |
212 | } else { | |
213 | unsigned long flags; | |
214 | ||
215 | page_head = compound_trans_head(page); | |
216 | if (likely(page != page_head && | |
217 | get_page_unless_zero(page_head))) { | |
218 | ||
219 | /* Ref to put_compound_page() comment. */ | |
220 | if (PageSlab(page_head)) { | |
221 | if (likely(PageTail(page))) { | |
222 | __get_page_tail_foll(page, false); | |
223 | return true; | |
224 | } else { | |
225 | put_page(page_head); | |
226 | return false; | |
227 | } | |
228 | } | |
5bf5f03c | 229 | |
7cb2ef56 KA |
230 | /* |
231 | * page_head wasn't a dangling pointer but it | |
232 | * may not be a head page anymore by the time | |
233 | * we obtain the lock. That is ok as long as it | |
234 | * can't be freed from under us. | |
235 | */ | |
236 | flags = compound_lock_irqsave(page_head); | |
237 | /* here __split_huge_page_refcount won't run anymore */ | |
5bf5f03c PS |
238 | if (likely(PageTail(page))) { |
239 | __get_page_tail_foll(page, false); | |
7cb2ef56 | 240 | got = true; |
5bf5f03c | 241 | } |
7cb2ef56 KA |
242 | compound_unlock_irqrestore(page_head, flags); |
243 | if (unlikely(!got)) | |
244 | put_page(page_head); | |
5bf5f03c | 245 | } |
70b50f94 AA |
246 | } |
247 | return got; | |
248 | } | |
249 | EXPORT_SYMBOL(__get_page_tail); | |
250 | ||
1d7ea732 | 251 | /** |
7682486b RD |
252 | * put_pages_list() - release a list of pages |
253 | * @pages: list of pages threaded on page->lru | |
1d7ea732 AZ |
254 | * |
255 | * Release a list of pages which are strung together on page.lru. Currently | |
256 | * used by read_cache_pages() and related error recovery code. | |
1d7ea732 AZ |
257 | */ |
258 | void put_pages_list(struct list_head *pages) | |
259 | { | |
260 | while (!list_empty(pages)) { | |
261 | struct page *victim; | |
262 | ||
263 | victim = list_entry(pages->prev, struct page, lru); | |
264 | list_del(&victim->lru); | |
265 | page_cache_release(victim); | |
266 | } | |
267 | } | |
268 | EXPORT_SYMBOL(put_pages_list); | |
269 | ||
18022c5d MG |
270 | /* |
271 | * get_kernel_pages() - pin kernel pages in memory | |
272 | * @kiov: An array of struct kvec structures | |
273 | * @nr_segs: number of segments to pin | |
274 | * @write: pinning for read/write, currently ignored | |
275 | * @pages: array that receives pointers to the pages pinned. | |
276 | * Should be at least nr_segs long. | |
277 | * | |
278 | * Returns number of pages pinned. This may be fewer than the number | |
279 | * requested. If nr_pages is 0 or negative, returns 0. If no pages | |
280 | * were pinned, returns -errno. Each page returned must be released | |
281 | * with a put_page() call when it is finished with. | |
282 | */ | |
283 | int get_kernel_pages(const struct kvec *kiov, int nr_segs, int write, | |
284 | struct page **pages) | |
285 | { | |
286 | int seg; | |
287 | ||
288 | for (seg = 0; seg < nr_segs; seg++) { | |
289 | if (WARN_ON(kiov[seg].iov_len != PAGE_SIZE)) | |
290 | return seg; | |
291 | ||
5a178119 | 292 | pages[seg] = kmap_to_page(kiov[seg].iov_base); |
18022c5d MG |
293 | page_cache_get(pages[seg]); |
294 | } | |
295 | ||
296 | return seg; | |
297 | } | |
298 | EXPORT_SYMBOL_GPL(get_kernel_pages); | |
299 | ||
300 | /* | |
301 | * get_kernel_page() - pin a kernel page in memory | |
302 | * @start: starting kernel address | |
303 | * @write: pinning for read/write, currently ignored | |
304 | * @pages: array that receives pointer to the page pinned. | |
305 | * Must be at least nr_segs long. | |
306 | * | |
307 | * Returns 1 if page is pinned. If the page was not pinned, returns | |
308 | * -errno. The page returned must be released with a put_page() call | |
309 | * when it is finished with. | |
310 | */ | |
311 | int get_kernel_page(unsigned long start, int write, struct page **pages) | |
312 | { | |
313 | const struct kvec kiov = { | |
314 | .iov_base = (void *)start, | |
315 | .iov_len = PAGE_SIZE | |
316 | }; | |
317 | ||
318 | return get_kernel_pages(&kiov, 1, write, pages); | |
319 | } | |
320 | EXPORT_SYMBOL_GPL(get_kernel_page); | |
321 | ||
3dd7ae8e | 322 | static void pagevec_lru_move_fn(struct pagevec *pvec, |
fa9add64 HD |
323 | void (*move_fn)(struct page *page, struct lruvec *lruvec, void *arg), |
324 | void *arg) | |
902aaed0 HH |
325 | { |
326 | int i; | |
902aaed0 | 327 | struct zone *zone = NULL; |
fa9add64 | 328 | struct lruvec *lruvec; |
3dd7ae8e | 329 | unsigned long flags = 0; |
902aaed0 HH |
330 | |
331 | for (i = 0; i < pagevec_count(pvec); i++) { | |
332 | struct page *page = pvec->pages[i]; | |
333 | struct zone *pagezone = page_zone(page); | |
334 | ||
335 | if (pagezone != zone) { | |
336 | if (zone) | |
3dd7ae8e | 337 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
902aaed0 | 338 | zone = pagezone; |
3dd7ae8e | 339 | spin_lock_irqsave(&zone->lru_lock, flags); |
902aaed0 | 340 | } |
3dd7ae8e | 341 | |
fa9add64 HD |
342 | lruvec = mem_cgroup_page_lruvec(page, zone); |
343 | (*move_fn)(page, lruvec, arg); | |
902aaed0 HH |
344 | } |
345 | if (zone) | |
3dd7ae8e | 346 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
83896fb5 LT |
347 | release_pages(pvec->pages, pvec->nr, pvec->cold); |
348 | pagevec_reinit(pvec); | |
d8505dee SL |
349 | } |
350 | ||
fa9add64 HD |
351 | static void pagevec_move_tail_fn(struct page *page, struct lruvec *lruvec, |
352 | void *arg) | |
3dd7ae8e SL |
353 | { |
354 | int *pgmoved = arg; | |
3dd7ae8e SL |
355 | |
356 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { | |
357 | enum lru_list lru = page_lru_base_type(page); | |
925b7673 | 358 | list_move_tail(&page->lru, &lruvec->lists[lru]); |
3dd7ae8e SL |
359 | (*pgmoved)++; |
360 | } | |
361 | } | |
362 | ||
363 | /* | |
364 | * pagevec_move_tail() must be called with IRQ disabled. | |
365 | * Otherwise this may cause nasty races. | |
366 | */ | |
367 | static void pagevec_move_tail(struct pagevec *pvec) | |
368 | { | |
369 | int pgmoved = 0; | |
370 | ||
371 | pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, &pgmoved); | |
372 | __count_vm_events(PGROTATED, pgmoved); | |
373 | } | |
374 | ||
1da177e4 LT |
375 | /* |
376 | * Writeback is about to end against a page which has been marked for immediate | |
377 | * reclaim. If it still appears to be reclaimable, move it to the tail of the | |
902aaed0 | 378 | * inactive list. |
1da177e4 | 379 | */ |
3dd7ae8e | 380 | void rotate_reclaimable_page(struct page *page) |
1da177e4 | 381 | { |
ac6aadb2 | 382 | if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) && |
894bc310 | 383 | !PageUnevictable(page) && PageLRU(page)) { |
ac6aadb2 MS |
384 | struct pagevec *pvec; |
385 | unsigned long flags; | |
386 | ||
387 | page_cache_get(page); | |
388 | local_irq_save(flags); | |
389 | pvec = &__get_cpu_var(lru_rotate_pvecs); | |
390 | if (!pagevec_add(pvec, page)) | |
391 | pagevec_move_tail(pvec); | |
392 | local_irq_restore(flags); | |
393 | } | |
1da177e4 LT |
394 | } |
395 | ||
fa9add64 | 396 | static void update_page_reclaim_stat(struct lruvec *lruvec, |
3e2f41f1 KM |
397 | int file, int rotated) |
398 | { | |
fa9add64 | 399 | struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat; |
3e2f41f1 KM |
400 | |
401 | reclaim_stat->recent_scanned[file]++; | |
402 | if (rotated) | |
403 | reclaim_stat->recent_rotated[file]++; | |
3e2f41f1 KM |
404 | } |
405 | ||
fa9add64 HD |
406 | static void __activate_page(struct page *page, struct lruvec *lruvec, |
407 | void *arg) | |
1da177e4 | 408 | { |
744ed144 | 409 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { |
7a608572 LT |
410 | int file = page_is_file_cache(page); |
411 | int lru = page_lru_base_type(page); | |
744ed144 | 412 | |
fa9add64 | 413 | del_page_from_lru_list(page, lruvec, lru); |
7a608572 LT |
414 | SetPageActive(page); |
415 | lru += LRU_ACTIVE; | |
fa9add64 | 416 | add_page_to_lru_list(page, lruvec, lru); |
c6286c98 | 417 | trace_mm_lru_activate(page, page_to_pfn(page)); |
4f98a2fe | 418 | |
fa9add64 HD |
419 | __count_vm_event(PGACTIVATE); |
420 | update_page_reclaim_stat(lruvec, file, 1); | |
1da177e4 | 421 | } |
eb709b0d SL |
422 | } |
423 | ||
424 | #ifdef CONFIG_SMP | |
425 | static DEFINE_PER_CPU(struct pagevec, activate_page_pvecs); | |
426 | ||
427 | static void activate_page_drain(int cpu) | |
428 | { | |
429 | struct pagevec *pvec = &per_cpu(activate_page_pvecs, cpu); | |
430 | ||
431 | if (pagevec_count(pvec)) | |
432 | pagevec_lru_move_fn(pvec, __activate_page, NULL); | |
433 | } | |
434 | ||
435 | void activate_page(struct page *page) | |
436 | { | |
437 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { | |
438 | struct pagevec *pvec = &get_cpu_var(activate_page_pvecs); | |
439 | ||
440 | page_cache_get(page); | |
441 | if (!pagevec_add(pvec, page)) | |
442 | pagevec_lru_move_fn(pvec, __activate_page, NULL); | |
443 | put_cpu_var(activate_page_pvecs); | |
444 | } | |
445 | } | |
446 | ||
447 | #else | |
448 | static inline void activate_page_drain(int cpu) | |
449 | { | |
450 | } | |
451 | ||
452 | void activate_page(struct page *page) | |
453 | { | |
454 | struct zone *zone = page_zone(page); | |
455 | ||
456 | spin_lock_irq(&zone->lru_lock); | |
fa9add64 | 457 | __activate_page(page, mem_cgroup_page_lruvec(page, zone), NULL); |
1da177e4 LT |
458 | spin_unlock_irq(&zone->lru_lock); |
459 | } | |
eb709b0d | 460 | #endif |
1da177e4 | 461 | |
059285a2 MG |
462 | static void __lru_cache_activate_page(struct page *page) |
463 | { | |
464 | struct pagevec *pvec = &get_cpu_var(lru_add_pvec); | |
465 | int i; | |
466 | ||
467 | /* | |
468 | * Search backwards on the optimistic assumption that the page being | |
469 | * activated has just been added to this pagevec. Note that only | |
470 | * the local pagevec is examined as a !PageLRU page could be in the | |
471 | * process of being released, reclaimed, migrated or on a remote | |
472 | * pagevec that is currently being drained. Furthermore, marking | |
473 | * a remote pagevec's page PageActive potentially hits a race where | |
474 | * a page is marked PageActive just after it is added to the inactive | |
475 | * list causing accounting errors and BUG_ON checks to trigger. | |
476 | */ | |
477 | for (i = pagevec_count(pvec) - 1; i >= 0; i--) { | |
478 | struct page *pagevec_page = pvec->pages[i]; | |
479 | ||
480 | if (pagevec_page == page) { | |
481 | SetPageActive(page); | |
482 | break; | |
483 | } | |
484 | } | |
485 | ||
486 | put_cpu_var(lru_add_pvec); | |
487 | } | |
488 | ||
1da177e4 LT |
489 | /* |
490 | * Mark a page as having seen activity. | |
491 | * | |
492 | * inactive,unreferenced -> inactive,referenced | |
493 | * inactive,referenced -> active,unreferenced | |
494 | * active,unreferenced -> active,referenced | |
495 | */ | |
920c7a5d | 496 | void mark_page_accessed(struct page *page) |
1da177e4 | 497 | { |
894bc310 | 498 | if (!PageActive(page) && !PageUnevictable(page) && |
059285a2 MG |
499 | PageReferenced(page)) { |
500 | ||
501 | /* | |
502 | * If the page is on the LRU, queue it for activation via | |
503 | * activate_page_pvecs. Otherwise, assume the page is on a | |
504 | * pagevec, mark it active and it'll be moved to the active | |
505 | * LRU on the next drain. | |
506 | */ | |
507 | if (PageLRU(page)) | |
508 | activate_page(page); | |
509 | else | |
510 | __lru_cache_activate_page(page); | |
1da177e4 LT |
511 | ClearPageReferenced(page); |
512 | } else if (!PageReferenced(page)) { | |
513 | SetPageReferenced(page); | |
514 | } | |
515 | } | |
1da177e4 LT |
516 | EXPORT_SYMBOL(mark_page_accessed); |
517 | ||
d741c9cd | 518 | /* |
13f7f789 MG |
519 | * Queue the page for addition to the LRU via pagevec. The decision on whether |
520 | * to add the page to the [in]active [file|anon] list is deferred until the | |
521 | * pagevec is drained. This gives a chance for the caller of __lru_cache_add() | |
522 | * have the page added to the active list using mark_page_accessed(). | |
d741c9cd | 523 | */ |
c53954a0 | 524 | void __lru_cache_add(struct page *page) |
1da177e4 | 525 | { |
13f7f789 MG |
526 | struct pagevec *pvec = &get_cpu_var(lru_add_pvec); |
527 | ||
1da177e4 | 528 | page_cache_get(page); |
d741c9cd | 529 | if (!pagevec_space(pvec)) |
a0b8cab3 | 530 | __pagevec_lru_add(pvec); |
d741c9cd | 531 | pagevec_add(pvec, page); |
13f7f789 | 532 | put_cpu_var(lru_add_pvec); |
1da177e4 | 533 | } |
47846b06 | 534 | EXPORT_SYMBOL(__lru_cache_add); |
1da177e4 | 535 | |
f04e9ebb | 536 | /** |
c53954a0 | 537 | * lru_cache_add - add a page to a page list |
f04e9ebb | 538 | * @page: the page to be added to the LRU. |
f04e9ebb | 539 | */ |
c53954a0 | 540 | void lru_cache_add(struct page *page) |
1da177e4 | 541 | { |
ef2a2cbd | 542 | VM_BUG_ON(PageActive(page) && PageUnevictable(page)); |
13f7f789 | 543 | VM_BUG_ON(PageLRU(page)); |
c53954a0 | 544 | __lru_cache_add(page); |
1da177e4 LT |
545 | } |
546 | ||
894bc310 LS |
547 | /** |
548 | * add_page_to_unevictable_list - add a page to the unevictable list | |
549 | * @page: the page to be added to the unevictable list | |
550 | * | |
551 | * Add page directly to its zone's unevictable list. To avoid races with | |
552 | * tasks that might be making the page evictable, through eg. munlock, | |
553 | * munmap or exit, while it's not on the lru, we want to add the page | |
554 | * while it's locked or otherwise "invisible" to other tasks. This is | |
555 | * difficult to do when using the pagevec cache, so bypass that. | |
556 | */ | |
557 | void add_page_to_unevictable_list(struct page *page) | |
558 | { | |
559 | struct zone *zone = page_zone(page); | |
fa9add64 | 560 | struct lruvec *lruvec; |
894bc310 LS |
561 | |
562 | spin_lock_irq(&zone->lru_lock); | |
fa9add64 | 563 | lruvec = mem_cgroup_page_lruvec(page, zone); |
ef2a2cbd | 564 | ClearPageActive(page); |
894bc310 LS |
565 | SetPageUnevictable(page); |
566 | SetPageLRU(page); | |
fa9add64 | 567 | add_page_to_lru_list(page, lruvec, LRU_UNEVICTABLE); |
894bc310 LS |
568 | spin_unlock_irq(&zone->lru_lock); |
569 | } | |
570 | ||
31560180 MK |
571 | /* |
572 | * If the page can not be invalidated, it is moved to the | |
573 | * inactive list to speed up its reclaim. It is moved to the | |
574 | * head of the list, rather than the tail, to give the flusher | |
575 | * threads some time to write it out, as this is much more | |
576 | * effective than the single-page writeout from reclaim. | |
278df9f4 MK |
577 | * |
578 | * If the page isn't page_mapped and dirty/writeback, the page | |
579 | * could reclaim asap using PG_reclaim. | |
580 | * | |
581 | * 1. active, mapped page -> none | |
582 | * 2. active, dirty/writeback page -> inactive, head, PG_reclaim | |
583 | * 3. inactive, mapped page -> none | |
584 | * 4. inactive, dirty/writeback page -> inactive, head, PG_reclaim | |
585 | * 5. inactive, clean -> inactive, tail | |
586 | * 6. Others -> none | |
587 | * | |
588 | * In 4, why it moves inactive's head, the VM expects the page would | |
589 | * be write it out by flusher threads as this is much more effective | |
590 | * than the single-page writeout from reclaim. | |
31560180 | 591 | */ |
fa9add64 HD |
592 | static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec, |
593 | void *arg) | |
31560180 MK |
594 | { |
595 | int lru, file; | |
278df9f4 | 596 | bool active; |
31560180 | 597 | |
278df9f4 | 598 | if (!PageLRU(page)) |
31560180 MK |
599 | return; |
600 | ||
bad49d9c MK |
601 | if (PageUnevictable(page)) |
602 | return; | |
603 | ||
31560180 MK |
604 | /* Some processes are using the page */ |
605 | if (page_mapped(page)) | |
606 | return; | |
607 | ||
278df9f4 | 608 | active = PageActive(page); |
31560180 MK |
609 | file = page_is_file_cache(page); |
610 | lru = page_lru_base_type(page); | |
fa9add64 HD |
611 | |
612 | del_page_from_lru_list(page, lruvec, lru + active); | |
31560180 MK |
613 | ClearPageActive(page); |
614 | ClearPageReferenced(page); | |
fa9add64 | 615 | add_page_to_lru_list(page, lruvec, lru); |
31560180 | 616 | |
278df9f4 MK |
617 | if (PageWriteback(page) || PageDirty(page)) { |
618 | /* | |
619 | * PG_reclaim could be raced with end_page_writeback | |
620 | * It can make readahead confusing. But race window | |
621 | * is _really_ small and it's non-critical problem. | |
622 | */ | |
623 | SetPageReclaim(page); | |
624 | } else { | |
625 | /* | |
626 | * The page's writeback ends up during pagevec | |
627 | * We moves tha page into tail of inactive. | |
628 | */ | |
925b7673 | 629 | list_move_tail(&page->lru, &lruvec->lists[lru]); |
278df9f4 MK |
630 | __count_vm_event(PGROTATED); |
631 | } | |
632 | ||
633 | if (active) | |
634 | __count_vm_event(PGDEACTIVATE); | |
fa9add64 | 635 | update_page_reclaim_stat(lruvec, file, 0); |
31560180 MK |
636 | } |
637 | ||
902aaed0 HH |
638 | /* |
639 | * Drain pages out of the cpu's pagevecs. | |
640 | * Either "cpu" is the current CPU, and preemption has already been | |
641 | * disabled; or "cpu" is being hot-unplugged, and is already dead. | |
642 | */ | |
f0cb3c76 | 643 | void lru_add_drain_cpu(int cpu) |
1da177e4 | 644 | { |
13f7f789 | 645 | struct pagevec *pvec = &per_cpu(lru_add_pvec, cpu); |
1da177e4 | 646 | |
13f7f789 | 647 | if (pagevec_count(pvec)) |
a0b8cab3 | 648 | __pagevec_lru_add(pvec); |
902aaed0 HH |
649 | |
650 | pvec = &per_cpu(lru_rotate_pvecs, cpu); | |
651 | if (pagevec_count(pvec)) { | |
652 | unsigned long flags; | |
653 | ||
654 | /* No harm done if a racing interrupt already did this */ | |
655 | local_irq_save(flags); | |
656 | pagevec_move_tail(pvec); | |
657 | local_irq_restore(flags); | |
658 | } | |
31560180 MK |
659 | |
660 | pvec = &per_cpu(lru_deactivate_pvecs, cpu); | |
661 | if (pagevec_count(pvec)) | |
3dd7ae8e | 662 | pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL); |
eb709b0d SL |
663 | |
664 | activate_page_drain(cpu); | |
31560180 MK |
665 | } |
666 | ||
667 | /** | |
668 | * deactivate_page - forcefully deactivate a page | |
669 | * @page: page to deactivate | |
670 | * | |
671 | * This function hints the VM that @page is a good reclaim candidate, | |
672 | * for example if its invalidation fails due to the page being dirty | |
673 | * or under writeback. | |
674 | */ | |
675 | void deactivate_page(struct page *page) | |
676 | { | |
821ed6bb MK |
677 | /* |
678 | * In a workload with many unevictable page such as mprotect, unevictable | |
679 | * page deactivation for accelerating reclaim is pointless. | |
680 | */ | |
681 | if (PageUnevictable(page)) | |
682 | return; | |
683 | ||
31560180 MK |
684 | if (likely(get_page_unless_zero(page))) { |
685 | struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs); | |
686 | ||
687 | if (!pagevec_add(pvec, page)) | |
3dd7ae8e | 688 | pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL); |
31560180 MK |
689 | put_cpu_var(lru_deactivate_pvecs); |
690 | } | |
80bfed90 AM |
691 | } |
692 | ||
693 | void lru_add_drain(void) | |
694 | { | |
f0cb3c76 | 695 | lru_add_drain_cpu(get_cpu()); |
80bfed90 | 696 | put_cpu(); |
1da177e4 LT |
697 | } |
698 | ||
c4028958 | 699 | static void lru_add_drain_per_cpu(struct work_struct *dummy) |
053837fc NP |
700 | { |
701 | lru_add_drain(); | |
702 | } | |
703 | ||
704 | /* | |
705 | * Returns 0 for success | |
706 | */ | |
707 | int lru_add_drain_all(void) | |
708 | { | |
c4028958 | 709 | return schedule_on_each_cpu(lru_add_drain_per_cpu); |
053837fc NP |
710 | } |
711 | ||
1da177e4 LT |
712 | /* |
713 | * Batched page_cache_release(). Decrement the reference count on all the | |
714 | * passed pages. If it fell to zero then remove the page from the LRU and | |
715 | * free it. | |
716 | * | |
717 | * Avoid taking zone->lru_lock if possible, but if it is taken, retain it | |
718 | * for the remainder of the operation. | |
719 | * | |
ab33dc09 FLVC |
720 | * The locking in this function is against shrink_inactive_list(): we recheck |
721 | * the page count inside the lock to see whether shrink_inactive_list() | |
722 | * grabbed the page via the LRU. If it did, give up: shrink_inactive_list() | |
723 | * will free it. | |
1da177e4 LT |
724 | */ |
725 | void release_pages(struct page **pages, int nr, int cold) | |
726 | { | |
727 | int i; | |
cc59850e | 728 | LIST_HEAD(pages_to_free); |
1da177e4 | 729 | struct zone *zone = NULL; |
fa9add64 | 730 | struct lruvec *lruvec; |
902aaed0 | 731 | unsigned long uninitialized_var(flags); |
1da177e4 | 732 | |
1da177e4 LT |
733 | for (i = 0; i < nr; i++) { |
734 | struct page *page = pages[i]; | |
1da177e4 | 735 | |
8519fb30 NP |
736 | if (unlikely(PageCompound(page))) { |
737 | if (zone) { | |
902aaed0 | 738 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
8519fb30 NP |
739 | zone = NULL; |
740 | } | |
741 | put_compound_page(page); | |
742 | continue; | |
743 | } | |
744 | ||
b5810039 | 745 | if (!put_page_testzero(page)) |
1da177e4 LT |
746 | continue; |
747 | ||
46453a6e NP |
748 | if (PageLRU(page)) { |
749 | struct zone *pagezone = page_zone(page); | |
894bc310 | 750 | |
46453a6e NP |
751 | if (pagezone != zone) { |
752 | if (zone) | |
902aaed0 HH |
753 | spin_unlock_irqrestore(&zone->lru_lock, |
754 | flags); | |
46453a6e | 755 | zone = pagezone; |
902aaed0 | 756 | spin_lock_irqsave(&zone->lru_lock, flags); |
46453a6e | 757 | } |
fa9add64 HD |
758 | |
759 | lruvec = mem_cgroup_page_lruvec(page, zone); | |
725d704e | 760 | VM_BUG_ON(!PageLRU(page)); |
67453911 | 761 | __ClearPageLRU(page); |
fa9add64 | 762 | del_page_from_lru_list(page, lruvec, page_off_lru(page)); |
46453a6e NP |
763 | } |
764 | ||
c53954a0 MG |
765 | /* Clear Active bit in case of parallel mark_page_accessed */ |
766 | ClearPageActive(page); | |
767 | ||
cc59850e | 768 | list_add(&page->lru, &pages_to_free); |
1da177e4 LT |
769 | } |
770 | if (zone) | |
902aaed0 | 771 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
1da177e4 | 772 | |
cc59850e | 773 | free_hot_cold_page_list(&pages_to_free, cold); |
1da177e4 | 774 | } |
0be8557b | 775 | EXPORT_SYMBOL(release_pages); |
1da177e4 LT |
776 | |
777 | /* | |
778 | * The pages which we're about to release may be in the deferred lru-addition | |
779 | * queues. That would prevent them from really being freed right now. That's | |
780 | * OK from a correctness point of view but is inefficient - those pages may be | |
781 | * cache-warm and we want to give them back to the page allocator ASAP. | |
782 | * | |
783 | * So __pagevec_release() will drain those queues here. __pagevec_lru_add() | |
784 | * and __pagevec_lru_add_active() call release_pages() directly to avoid | |
785 | * mutual recursion. | |
786 | */ | |
787 | void __pagevec_release(struct pagevec *pvec) | |
788 | { | |
789 | lru_add_drain(); | |
790 | release_pages(pvec->pages, pagevec_count(pvec), pvec->cold); | |
791 | pagevec_reinit(pvec); | |
792 | } | |
7f285701 SF |
793 | EXPORT_SYMBOL(__pagevec_release); |
794 | ||
12d27107 | 795 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
71e3aac0 | 796 | /* used by __split_huge_page_refcount() */ |
fa9add64 | 797 | void lru_add_page_tail(struct page *page, struct page *page_tail, |
5bc7b8ac | 798 | struct lruvec *lruvec, struct list_head *list) |
71e3aac0 | 799 | { |
71e3aac0 | 800 | const int file = 0; |
71e3aac0 AA |
801 | |
802 | VM_BUG_ON(!PageHead(page)); | |
803 | VM_BUG_ON(PageCompound(page_tail)); | |
804 | VM_BUG_ON(PageLRU(page_tail)); | |
fa9add64 HD |
805 | VM_BUG_ON(NR_CPUS != 1 && |
806 | !spin_is_locked(&lruvec_zone(lruvec)->lru_lock)); | |
71e3aac0 | 807 | |
5bc7b8ac SL |
808 | if (!list) |
809 | SetPageLRU(page_tail); | |
71e3aac0 | 810 | |
12d27107 HD |
811 | if (likely(PageLRU(page))) |
812 | list_add_tail(&page_tail->lru, &page->lru); | |
5bc7b8ac SL |
813 | else if (list) { |
814 | /* page reclaim is reclaiming a huge page */ | |
815 | get_page(page_tail); | |
816 | list_add_tail(&page_tail->lru, list); | |
817 | } else { | |
12d27107 HD |
818 | struct list_head *list_head; |
819 | /* | |
820 | * Head page has not yet been counted, as an hpage, | |
821 | * so we must account for each subpage individually. | |
822 | * | |
823 | * Use the standard add function to put page_tail on the list, | |
824 | * but then correct its position so they all end up in order. | |
825 | */ | |
e180cf80 | 826 | add_page_to_lru_list(page_tail, lruvec, page_lru(page_tail)); |
12d27107 HD |
827 | list_head = page_tail->lru.prev; |
828 | list_move_tail(&page_tail->lru, list_head); | |
71e3aac0 | 829 | } |
7512102c HD |
830 | |
831 | if (!PageUnevictable(page)) | |
e180cf80 | 832 | update_page_reclaim_stat(lruvec, file, PageActive(page_tail)); |
71e3aac0 | 833 | } |
12d27107 | 834 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |
71e3aac0 | 835 | |
fa9add64 HD |
836 | static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec, |
837 | void *arg) | |
3dd7ae8e | 838 | { |
13f7f789 MG |
839 | int file = page_is_file_cache(page); |
840 | int active = PageActive(page); | |
841 | enum lru_list lru = page_lru(page); | |
3dd7ae8e | 842 | |
3dd7ae8e SL |
843 | VM_BUG_ON(PageLRU(page)); |
844 | ||
845 | SetPageLRU(page); | |
fa9add64 HD |
846 | add_page_to_lru_list(page, lruvec, lru); |
847 | update_page_reclaim_stat(lruvec, file, active); | |
c6286c98 | 848 | trace_mm_lru_insertion(page, page_to_pfn(page), lru, trace_pagemap_flags(page)); |
3dd7ae8e SL |
849 | } |
850 | ||
1da177e4 LT |
851 | /* |
852 | * Add the passed pages to the LRU, then drop the caller's refcount | |
853 | * on them. Reinitialises the caller's pagevec. | |
854 | */ | |
a0b8cab3 | 855 | void __pagevec_lru_add(struct pagevec *pvec) |
1da177e4 | 856 | { |
a0b8cab3 | 857 | pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn, NULL); |
1da177e4 | 858 | } |
5095ae83 | 859 | EXPORT_SYMBOL(__pagevec_lru_add); |
1da177e4 | 860 | |
1da177e4 LT |
861 | /** |
862 | * pagevec_lookup - gang pagecache lookup | |
863 | * @pvec: Where the resulting pages are placed | |
864 | * @mapping: The address_space to search | |
865 | * @start: The starting page index | |
866 | * @nr_pages: The maximum number of pages | |
867 | * | |
868 | * pagevec_lookup() will search for and return a group of up to @nr_pages pages | |
869 | * in the mapping. The pages are placed in @pvec. pagevec_lookup() takes a | |
870 | * reference against the pages in @pvec. | |
871 | * | |
872 | * The search returns a group of mapping-contiguous pages with ascending | |
873 | * indexes. There may be holes in the indices due to not-present pages. | |
874 | * | |
875 | * pagevec_lookup() returns the number of pages which were found. | |
876 | */ | |
877 | unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping, | |
878 | pgoff_t start, unsigned nr_pages) | |
879 | { | |
880 | pvec->nr = find_get_pages(mapping, start, nr_pages, pvec->pages); | |
881 | return pagevec_count(pvec); | |
882 | } | |
78539fdf CH |
883 | EXPORT_SYMBOL(pagevec_lookup); |
884 | ||
1da177e4 LT |
885 | unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping, |
886 | pgoff_t *index, int tag, unsigned nr_pages) | |
887 | { | |
888 | pvec->nr = find_get_pages_tag(mapping, index, tag, | |
889 | nr_pages, pvec->pages); | |
890 | return pagevec_count(pvec); | |
891 | } | |
7f285701 | 892 | EXPORT_SYMBOL(pagevec_lookup_tag); |
1da177e4 | 893 | |
1da177e4 LT |
894 | /* |
895 | * Perform any setup for the swap system | |
896 | */ | |
897 | void __init swap_setup(void) | |
898 | { | |
4481374c | 899 | unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT); |
e0bf68dd | 900 | #ifdef CONFIG_SWAP |
33806f06 SL |
901 | int i; |
902 | ||
903 | bdi_init(swapper_spaces[0].backing_dev_info); | |
904 | for (i = 0; i < MAX_SWAPFILES; i++) { | |
905 | spin_lock_init(&swapper_spaces[i].tree_lock); | |
906 | INIT_LIST_HEAD(&swapper_spaces[i].i_mmap_nonlinear); | |
907 | } | |
e0bf68dd PZ |
908 | #endif |
909 | ||
1da177e4 LT |
910 | /* Use a smaller cluster for small-memory machines */ |
911 | if (megs < 16) | |
912 | page_cluster = 2; | |
913 | else | |
914 | page_cluster = 3; | |
915 | /* | |
916 | * Right now other parts of the system means that we | |
917 | * _really_ don't want to cluster much more | |
918 | */ | |
1da177e4 | 919 | } |