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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> | |
24 | #include <linux/module.h> | |
25 | #include <linux/mm_inline.h> | |
26 | #include <linux/buffer_head.h> /* for try_to_release_page() */ | |
1da177e4 LT |
27 | #include <linux/percpu_counter.h> |
28 | #include <linux/percpu.h> | |
29 | #include <linux/cpu.h> | |
30 | #include <linux/notifier.h> | |
e0bf68dd | 31 | #include <linux/backing-dev.h> |
66e1707b | 32 | #include <linux/memcontrol.h> |
1da177e4 | 33 | |
64d6519d LS |
34 | #include "internal.h" |
35 | ||
1da177e4 LT |
36 | /* How many pages do we try to swap or page in/out together? */ |
37 | int page_cluster; | |
38 | ||
f04e9ebb | 39 | static DEFINE_PER_CPU(struct pagevec[NR_LRU_LISTS], lru_add_pvecs); |
f84f9504 | 40 | static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs); |
902aaed0 | 41 | |
b221385b AB |
42 | /* |
43 | * This path almost never happens for VM activity - pages are normally | |
44 | * freed via pagevecs. But it gets used by networking. | |
45 | */ | |
920c7a5d | 46 | static void __page_cache_release(struct page *page) |
b221385b AB |
47 | { |
48 | if (PageLRU(page)) { | |
49 | unsigned long flags; | |
50 | struct zone *zone = page_zone(page); | |
51 | ||
52 | spin_lock_irqsave(&zone->lru_lock, flags); | |
53 | VM_BUG_ON(!PageLRU(page)); | |
54 | __ClearPageLRU(page); | |
55 | del_page_from_lru(zone, page); | |
56 | spin_unlock_irqrestore(&zone->lru_lock, flags); | |
57 | } | |
58 | free_hot_page(page); | |
59 | } | |
60 | ||
8519fb30 | 61 | static void put_compound_page(struct page *page) |
1da177e4 | 62 | { |
d85f3385 | 63 | page = compound_head(page); |
8519fb30 | 64 | if (put_page_testzero(page)) { |
33f2ef89 | 65 | compound_page_dtor *dtor; |
1da177e4 | 66 | |
33f2ef89 | 67 | dtor = get_compound_page_dtor(page); |
8519fb30 | 68 | (*dtor)(page); |
1da177e4 | 69 | } |
8519fb30 NP |
70 | } |
71 | ||
72 | void put_page(struct page *page) | |
73 | { | |
74 | if (unlikely(PageCompound(page))) | |
75 | put_compound_page(page); | |
76 | else if (put_page_testzero(page)) | |
1da177e4 LT |
77 | __page_cache_release(page); |
78 | } | |
79 | EXPORT_SYMBOL(put_page); | |
1da177e4 | 80 | |
1d7ea732 | 81 | /** |
7682486b RD |
82 | * put_pages_list() - release a list of pages |
83 | * @pages: list of pages threaded on page->lru | |
1d7ea732 AZ |
84 | * |
85 | * Release a list of pages which are strung together on page.lru. Currently | |
86 | * used by read_cache_pages() and related error recovery code. | |
1d7ea732 AZ |
87 | */ |
88 | void put_pages_list(struct list_head *pages) | |
89 | { | |
90 | while (!list_empty(pages)) { | |
91 | struct page *victim; | |
92 | ||
93 | victim = list_entry(pages->prev, struct page, lru); | |
94 | list_del(&victim->lru); | |
95 | page_cache_release(victim); | |
96 | } | |
97 | } | |
98 | EXPORT_SYMBOL(put_pages_list); | |
99 | ||
902aaed0 HH |
100 | /* |
101 | * pagevec_move_tail() must be called with IRQ disabled. | |
102 | * Otherwise this may cause nasty races. | |
103 | */ | |
104 | static void pagevec_move_tail(struct pagevec *pvec) | |
105 | { | |
106 | int i; | |
107 | int pgmoved = 0; | |
108 | struct zone *zone = NULL; | |
109 | ||
110 | for (i = 0; i < pagevec_count(pvec); i++) { | |
111 | struct page *page = pvec->pages[i]; | |
112 | struct zone *pagezone = page_zone(page); | |
113 | ||
114 | if (pagezone != zone) { | |
115 | if (zone) | |
116 | spin_unlock(&zone->lru_lock); | |
117 | zone = pagezone; | |
118 | spin_lock(&zone->lru_lock); | |
119 | } | |
894bc310 | 120 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { |
4f98a2fe RR |
121 | int lru = page_is_file_cache(page); |
122 | list_move_tail(&page->lru, &zone->lru[lru].list); | |
902aaed0 HH |
123 | pgmoved++; |
124 | } | |
125 | } | |
126 | if (zone) | |
127 | spin_unlock(&zone->lru_lock); | |
128 | __count_vm_events(PGROTATED, pgmoved); | |
129 | release_pages(pvec->pages, pvec->nr, pvec->cold); | |
130 | pagevec_reinit(pvec); | |
131 | } | |
132 | ||
1da177e4 LT |
133 | /* |
134 | * Writeback is about to end against a page which has been marked for immediate | |
135 | * reclaim. If it still appears to be reclaimable, move it to the tail of the | |
902aaed0 | 136 | * inactive list. |
1da177e4 | 137 | */ |
ac6aadb2 | 138 | void rotate_reclaimable_page(struct page *page) |
1da177e4 | 139 | { |
ac6aadb2 | 140 | if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) && |
894bc310 | 141 | !PageUnevictable(page) && PageLRU(page)) { |
ac6aadb2 MS |
142 | struct pagevec *pvec; |
143 | unsigned long flags; | |
144 | ||
145 | page_cache_get(page); | |
146 | local_irq_save(flags); | |
147 | pvec = &__get_cpu_var(lru_rotate_pvecs); | |
148 | if (!pagevec_add(pvec, page)) | |
149 | pagevec_move_tail(pvec); | |
150 | local_irq_restore(flags); | |
151 | } | |
1da177e4 LT |
152 | } |
153 | ||
154 | /* | |
155 | * FIXME: speed this up? | |
156 | */ | |
920c7a5d | 157 | void activate_page(struct page *page) |
1da177e4 LT |
158 | { |
159 | struct zone *zone = page_zone(page); | |
6e901571 | 160 | struct zone_reclaim_stat *reclaim_stat = &zone->reclaim_stat; |
1da177e4 LT |
161 | |
162 | spin_lock_irq(&zone->lru_lock); | |
894bc310 | 163 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { |
4f98a2fe RR |
164 | int file = page_is_file_cache(page); |
165 | int lru = LRU_BASE + file; | |
166 | del_page_from_lru_list(zone, page, lru); | |
167 | ||
1da177e4 | 168 | SetPageActive(page); |
4f98a2fe RR |
169 | lru += LRU_ACTIVE; |
170 | add_page_to_lru_list(zone, page, lru); | |
f8891e5e | 171 | __count_vm_event(PGACTIVATE); |
4f98a2fe | 172 | |
6e901571 KM |
173 | reclaim_stat->recent_rotated[!!file]++; |
174 | reclaim_stat->recent_scanned[!!file]++; | |
1da177e4 LT |
175 | } |
176 | spin_unlock_irq(&zone->lru_lock); | |
177 | } | |
178 | ||
179 | /* | |
180 | * Mark a page as having seen activity. | |
181 | * | |
182 | * inactive,unreferenced -> inactive,referenced | |
183 | * inactive,referenced -> active,unreferenced | |
184 | * active,unreferenced -> active,referenced | |
185 | */ | |
920c7a5d | 186 | void mark_page_accessed(struct page *page) |
1da177e4 | 187 | { |
894bc310 LS |
188 | if (!PageActive(page) && !PageUnevictable(page) && |
189 | PageReferenced(page) && PageLRU(page)) { | |
1da177e4 LT |
190 | activate_page(page); |
191 | ClearPageReferenced(page); | |
192 | } else if (!PageReferenced(page)) { | |
193 | SetPageReferenced(page); | |
194 | } | |
195 | } | |
196 | ||
197 | EXPORT_SYMBOL(mark_page_accessed); | |
198 | ||
f04e9ebb | 199 | void __lru_cache_add(struct page *page, enum lru_list lru) |
1da177e4 | 200 | { |
f04e9ebb | 201 | struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru]; |
1da177e4 LT |
202 | |
203 | page_cache_get(page); | |
204 | if (!pagevec_add(pvec, page)) | |
f04e9ebb | 205 | ____pagevec_lru_add(pvec, lru); |
1da177e4 LT |
206 | put_cpu_var(lru_add_pvecs); |
207 | } | |
208 | ||
f04e9ebb KM |
209 | /** |
210 | * lru_cache_add_lru - add a page to a page list | |
211 | * @page: the page to be added to the LRU. | |
212 | * @lru: the LRU list to which the page is added. | |
213 | */ | |
214 | void lru_cache_add_lru(struct page *page, enum lru_list lru) | |
1da177e4 | 215 | { |
f04e9ebb | 216 | if (PageActive(page)) { |
894bc310 | 217 | VM_BUG_ON(PageUnevictable(page)); |
f04e9ebb | 218 | ClearPageActive(page); |
894bc310 LS |
219 | } else if (PageUnevictable(page)) { |
220 | VM_BUG_ON(PageActive(page)); | |
221 | ClearPageUnevictable(page); | |
f04e9ebb | 222 | } |
1da177e4 | 223 | |
894bc310 | 224 | VM_BUG_ON(PageLRU(page) || PageActive(page) || PageUnevictable(page)); |
f04e9ebb | 225 | __lru_cache_add(page, lru); |
1da177e4 LT |
226 | } |
227 | ||
894bc310 LS |
228 | /** |
229 | * add_page_to_unevictable_list - add a page to the unevictable list | |
230 | * @page: the page to be added to the unevictable list | |
231 | * | |
232 | * Add page directly to its zone's unevictable list. To avoid races with | |
233 | * tasks that might be making the page evictable, through eg. munlock, | |
234 | * munmap or exit, while it's not on the lru, we want to add the page | |
235 | * while it's locked or otherwise "invisible" to other tasks. This is | |
236 | * difficult to do when using the pagevec cache, so bypass that. | |
237 | */ | |
238 | void add_page_to_unevictable_list(struct page *page) | |
239 | { | |
240 | struct zone *zone = page_zone(page); | |
241 | ||
242 | spin_lock_irq(&zone->lru_lock); | |
243 | SetPageUnevictable(page); | |
244 | SetPageLRU(page); | |
245 | add_page_to_lru_list(zone, page, LRU_UNEVICTABLE); | |
246 | spin_unlock_irq(&zone->lru_lock); | |
247 | } | |
248 | ||
902aaed0 HH |
249 | /* |
250 | * Drain pages out of the cpu's pagevecs. | |
251 | * Either "cpu" is the current CPU, and preemption has already been | |
252 | * disabled; or "cpu" is being hot-unplugged, and is already dead. | |
253 | */ | |
254 | static void drain_cpu_pagevecs(int cpu) | |
1da177e4 | 255 | { |
f04e9ebb | 256 | struct pagevec *pvecs = per_cpu(lru_add_pvecs, cpu); |
902aaed0 | 257 | struct pagevec *pvec; |
f04e9ebb | 258 | int lru; |
1da177e4 | 259 | |
f04e9ebb KM |
260 | for_each_lru(lru) { |
261 | pvec = &pvecs[lru - LRU_BASE]; | |
262 | if (pagevec_count(pvec)) | |
263 | ____pagevec_lru_add(pvec, lru); | |
264 | } | |
902aaed0 HH |
265 | |
266 | pvec = &per_cpu(lru_rotate_pvecs, cpu); | |
267 | if (pagevec_count(pvec)) { | |
268 | unsigned long flags; | |
269 | ||
270 | /* No harm done if a racing interrupt already did this */ | |
271 | local_irq_save(flags); | |
272 | pagevec_move_tail(pvec); | |
273 | local_irq_restore(flags); | |
274 | } | |
80bfed90 AM |
275 | } |
276 | ||
277 | void lru_add_drain(void) | |
278 | { | |
902aaed0 | 279 | drain_cpu_pagevecs(get_cpu()); |
80bfed90 | 280 | put_cpu(); |
1da177e4 LT |
281 | } |
282 | ||
c4028958 | 283 | static void lru_add_drain_per_cpu(struct work_struct *dummy) |
053837fc NP |
284 | { |
285 | lru_add_drain(); | |
286 | } | |
287 | ||
288 | /* | |
289 | * Returns 0 for success | |
290 | */ | |
291 | int lru_add_drain_all(void) | |
292 | { | |
c4028958 | 293 | return schedule_on_each_cpu(lru_add_drain_per_cpu); |
053837fc NP |
294 | } |
295 | ||
1da177e4 LT |
296 | /* |
297 | * Batched page_cache_release(). Decrement the reference count on all the | |
298 | * passed pages. If it fell to zero then remove the page from the LRU and | |
299 | * free it. | |
300 | * | |
301 | * Avoid taking zone->lru_lock if possible, but if it is taken, retain it | |
302 | * for the remainder of the operation. | |
303 | * | |
ab33dc09 FLVC |
304 | * The locking in this function is against shrink_inactive_list(): we recheck |
305 | * the page count inside the lock to see whether shrink_inactive_list() | |
306 | * grabbed the page via the LRU. If it did, give up: shrink_inactive_list() | |
307 | * will free it. | |
1da177e4 LT |
308 | */ |
309 | void release_pages(struct page **pages, int nr, int cold) | |
310 | { | |
311 | int i; | |
312 | struct pagevec pages_to_free; | |
313 | struct zone *zone = NULL; | |
902aaed0 | 314 | unsigned long uninitialized_var(flags); |
1da177e4 LT |
315 | |
316 | pagevec_init(&pages_to_free, cold); | |
317 | for (i = 0; i < nr; i++) { | |
318 | struct page *page = pages[i]; | |
1da177e4 | 319 | |
8519fb30 NP |
320 | if (unlikely(PageCompound(page))) { |
321 | if (zone) { | |
902aaed0 | 322 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
8519fb30 NP |
323 | zone = NULL; |
324 | } | |
325 | put_compound_page(page); | |
326 | continue; | |
327 | } | |
328 | ||
b5810039 | 329 | if (!put_page_testzero(page)) |
1da177e4 LT |
330 | continue; |
331 | ||
46453a6e NP |
332 | if (PageLRU(page)) { |
333 | struct zone *pagezone = page_zone(page); | |
894bc310 | 334 | |
46453a6e NP |
335 | if (pagezone != zone) { |
336 | if (zone) | |
902aaed0 HH |
337 | spin_unlock_irqrestore(&zone->lru_lock, |
338 | flags); | |
46453a6e | 339 | zone = pagezone; |
902aaed0 | 340 | spin_lock_irqsave(&zone->lru_lock, flags); |
46453a6e | 341 | } |
725d704e | 342 | VM_BUG_ON(!PageLRU(page)); |
67453911 | 343 | __ClearPageLRU(page); |
1da177e4 | 344 | del_page_from_lru(zone, page); |
46453a6e NP |
345 | } |
346 | ||
347 | if (!pagevec_add(&pages_to_free, page)) { | |
348 | if (zone) { | |
902aaed0 | 349 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
46453a6e | 350 | zone = NULL; |
1da177e4 | 351 | } |
46453a6e NP |
352 | __pagevec_free(&pages_to_free); |
353 | pagevec_reinit(&pages_to_free); | |
354 | } | |
1da177e4 LT |
355 | } |
356 | if (zone) | |
902aaed0 | 357 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
1da177e4 LT |
358 | |
359 | pagevec_free(&pages_to_free); | |
360 | } | |
361 | ||
362 | /* | |
363 | * The pages which we're about to release may be in the deferred lru-addition | |
364 | * queues. That would prevent them from really being freed right now. That's | |
365 | * OK from a correctness point of view but is inefficient - those pages may be | |
366 | * cache-warm and we want to give them back to the page allocator ASAP. | |
367 | * | |
368 | * So __pagevec_release() will drain those queues here. __pagevec_lru_add() | |
369 | * and __pagevec_lru_add_active() call release_pages() directly to avoid | |
370 | * mutual recursion. | |
371 | */ | |
372 | void __pagevec_release(struct pagevec *pvec) | |
373 | { | |
374 | lru_add_drain(); | |
375 | release_pages(pvec->pages, pagevec_count(pvec), pvec->cold); | |
376 | pagevec_reinit(pvec); | |
377 | } | |
378 | ||
7f285701 SF |
379 | EXPORT_SYMBOL(__pagevec_release); |
380 | ||
1da177e4 LT |
381 | /* |
382 | * Add the passed pages to the LRU, then drop the caller's refcount | |
383 | * on them. Reinitialises the caller's pagevec. | |
384 | */ | |
f04e9ebb | 385 | void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru) |
1da177e4 LT |
386 | { |
387 | int i; | |
388 | struct zone *zone = NULL; | |
6e901571 KM |
389 | struct zone_reclaim_stat *reclaim_stat = NULL; |
390 | ||
894bc310 | 391 | VM_BUG_ON(is_unevictable_lru(lru)); |
1da177e4 LT |
392 | |
393 | for (i = 0; i < pagevec_count(pvec); i++) { | |
394 | struct page *page = pvec->pages[i]; | |
395 | struct zone *pagezone = page_zone(page); | |
9ff473b9 | 396 | int file; |
1da177e4 LT |
397 | |
398 | if (pagezone != zone) { | |
399 | if (zone) | |
400 | spin_unlock_irq(&zone->lru_lock); | |
401 | zone = pagezone; | |
6e901571 | 402 | reclaim_stat = &zone->reclaim_stat; |
1da177e4 LT |
403 | spin_lock_irq(&zone->lru_lock); |
404 | } | |
894bc310 LS |
405 | VM_BUG_ON(PageActive(page)); |
406 | VM_BUG_ON(PageUnevictable(page)); | |
725d704e | 407 | VM_BUG_ON(PageLRU(page)); |
8d438f96 | 408 | SetPageLRU(page); |
9ff473b9 | 409 | file = is_file_lru(lru); |
6e901571 | 410 | reclaim_stat->recent_scanned[file]++; |
9ff473b9 | 411 | if (is_active_lru(lru)) { |
f04e9ebb | 412 | SetPageActive(page); |
6e901571 | 413 | reclaim_stat->recent_rotated[file]++; |
9ff473b9 | 414 | } |
f04e9ebb | 415 | add_page_to_lru_list(zone, page, lru); |
1da177e4 LT |
416 | } |
417 | if (zone) | |
418 | spin_unlock_irq(&zone->lru_lock); | |
419 | release_pages(pvec->pages, pvec->nr, pvec->cold); | |
420 | pagevec_reinit(pvec); | |
421 | } | |
422 | ||
f04e9ebb | 423 | EXPORT_SYMBOL(____pagevec_lru_add); |
1da177e4 LT |
424 | |
425 | /* | |
426 | * Try to drop buffers from the pages in a pagevec | |
427 | */ | |
428 | void pagevec_strip(struct pagevec *pvec) | |
429 | { | |
430 | int i; | |
431 | ||
432 | for (i = 0; i < pagevec_count(pvec); i++) { | |
433 | struct page *page = pvec->pages[i]; | |
434 | ||
529ae9aa | 435 | if (PagePrivate(page) && trylock_page(page)) { |
5b40dc78 CL |
436 | if (PagePrivate(page)) |
437 | try_to_release_page(page, 0); | |
1da177e4 LT |
438 | unlock_page(page); |
439 | } | |
440 | } | |
441 | } | |
442 | ||
68a22394 RR |
443 | /** |
444 | * pagevec_swap_free - try to free swap space from the pages in a pagevec | |
445 | * @pvec: pagevec with swapcache pages to free the swap space of | |
446 | * | |
447 | * The caller needs to hold an extra reference to each page and | |
448 | * not hold the page lock on the pages. This function uses a | |
449 | * trylock on the page lock so it may not always free the swap | |
450 | * space associated with a page. | |
451 | */ | |
452 | void pagevec_swap_free(struct pagevec *pvec) | |
453 | { | |
454 | int i; | |
455 | ||
456 | for (i = 0; i < pagevec_count(pvec); i++) { | |
457 | struct page *page = pvec->pages[i]; | |
458 | ||
459 | if (PageSwapCache(page) && trylock_page(page)) { | |
a2c43eed | 460 | try_to_free_swap(page); |
68a22394 RR |
461 | unlock_page(page); |
462 | } | |
463 | } | |
464 | } | |
465 | ||
1da177e4 LT |
466 | /** |
467 | * pagevec_lookup - gang pagecache lookup | |
468 | * @pvec: Where the resulting pages are placed | |
469 | * @mapping: The address_space to search | |
470 | * @start: The starting page index | |
471 | * @nr_pages: The maximum number of pages | |
472 | * | |
473 | * pagevec_lookup() will search for and return a group of up to @nr_pages pages | |
474 | * in the mapping. The pages are placed in @pvec. pagevec_lookup() takes a | |
475 | * reference against the pages in @pvec. | |
476 | * | |
477 | * The search returns a group of mapping-contiguous pages with ascending | |
478 | * indexes. There may be holes in the indices due to not-present pages. | |
479 | * | |
480 | * pagevec_lookup() returns the number of pages which were found. | |
481 | */ | |
482 | unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping, | |
483 | pgoff_t start, unsigned nr_pages) | |
484 | { | |
485 | pvec->nr = find_get_pages(mapping, start, nr_pages, pvec->pages); | |
486 | return pagevec_count(pvec); | |
487 | } | |
488 | ||
78539fdf CH |
489 | EXPORT_SYMBOL(pagevec_lookup); |
490 | ||
1da177e4 LT |
491 | unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping, |
492 | pgoff_t *index, int tag, unsigned nr_pages) | |
493 | { | |
494 | pvec->nr = find_get_pages_tag(mapping, index, tag, | |
495 | nr_pages, pvec->pages); | |
496 | return pagevec_count(pvec); | |
497 | } | |
498 | ||
7f285701 | 499 | EXPORT_SYMBOL(pagevec_lookup_tag); |
1da177e4 LT |
500 | |
501 | #ifdef CONFIG_SMP | |
502 | /* | |
503 | * We tolerate a little inaccuracy to avoid ping-ponging the counter between | |
504 | * CPUs | |
505 | */ | |
506 | #define ACCT_THRESHOLD max(16, NR_CPUS * 2) | |
507 | ||
f84f9504 | 508 | static DEFINE_PER_CPU(long, committed_space); |
1da177e4 LT |
509 | |
510 | void vm_acct_memory(long pages) | |
511 | { | |
512 | long *local; | |
513 | ||
514 | preempt_disable(); | |
515 | local = &__get_cpu_var(committed_space); | |
516 | *local += pages; | |
517 | if (*local > ACCT_THRESHOLD || *local < -ACCT_THRESHOLD) { | |
80119ef5 | 518 | atomic_long_add(*local, &vm_committed_space); |
1da177e4 LT |
519 | *local = 0; |
520 | } | |
521 | preempt_enable(); | |
522 | } | |
1da177e4 LT |
523 | |
524 | #ifdef CONFIG_HOTPLUG_CPU | |
1da177e4 LT |
525 | |
526 | /* Drop the CPU's cached committed space back into the central pool. */ | |
527 | static int cpu_swap_callback(struct notifier_block *nfb, | |
528 | unsigned long action, | |
529 | void *hcpu) | |
530 | { | |
531 | long *committed; | |
532 | ||
533 | committed = &per_cpu(committed_space, (long)hcpu); | |
8bb78442 | 534 | if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { |
80119ef5 | 535 | atomic_long_add(*committed, &vm_committed_space); |
1da177e4 | 536 | *committed = 0; |
902aaed0 | 537 | drain_cpu_pagevecs((long)hcpu); |
1da177e4 LT |
538 | } |
539 | return NOTIFY_OK; | |
540 | } | |
541 | #endif /* CONFIG_HOTPLUG_CPU */ | |
542 | #endif /* CONFIG_SMP */ | |
543 | ||
1da177e4 LT |
544 | /* |
545 | * Perform any setup for the swap system | |
546 | */ | |
547 | void __init swap_setup(void) | |
548 | { | |
549 | unsigned long megs = num_physpages >> (20 - PAGE_SHIFT); | |
550 | ||
e0bf68dd PZ |
551 | #ifdef CONFIG_SWAP |
552 | bdi_init(swapper_space.backing_dev_info); | |
553 | #endif | |
554 | ||
1da177e4 LT |
555 | /* Use a smaller cluster for small-memory machines */ |
556 | if (megs < 16) | |
557 | page_cluster = 2; | |
558 | else | |
559 | page_cluster = 3; | |
560 | /* | |
561 | * Right now other parts of the system means that we | |
562 | * _really_ don't want to cluster much more | |
563 | */ | |
02316067 | 564 | #ifdef CONFIG_HOTPLUG_CPU |
1da177e4 | 565 | hotcpu_notifier(cpu_swap_callback, 0); |
02316067 | 566 | #endif |
1da177e4 | 567 | } |