Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/mm/vmscan.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds |
| 5 | * |
| 6 | * Swap reorganised 29.12.95, Stephen Tweedie. |
| 7 | * kswapd added: 7.1.96 sct |
| 8 | * Removed kswapd_ctl limits, and swap out as many pages as needed |
| 9 | * to bring the system back to freepages.high: 2.4.97, Rik van Riel. |
| 10 | * Zone aware kswapd started 02/00, Kanoj Sarcar (kanoj@sgi.com). |
| 11 | * Multiqueue VM started 5.8.00, Rik van Riel. |
| 12 | */ |
| 13 | |
| 14 | #include <linux/mm.h> |
| 15 | #include <linux/module.h> |
| 16 | #include <linux/slab.h> |
| 17 | #include <linux/kernel_stat.h> |
| 18 | #include <linux/swap.h> |
| 19 | #include <linux/pagemap.h> |
| 20 | #include <linux/init.h> |
| 21 | #include <linux/highmem.h> |
Andrew Morton | e129b5c | 2006-09-27 01:50:00 -0700 | [diff] [blame] | 22 | #include <linux/vmstat.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | #include <linux/file.h> |
| 24 | #include <linux/writeback.h> |
| 25 | #include <linux/blkdev.h> |
| 26 | #include <linux/buffer_head.h> /* for try_to_release_page(), |
| 27 | buffer_heads_over_limit */ |
| 28 | #include <linux/mm_inline.h> |
| 29 | #include <linux/pagevec.h> |
| 30 | #include <linux/backing-dev.h> |
| 31 | #include <linux/rmap.h> |
| 32 | #include <linux/topology.h> |
| 33 | #include <linux/cpu.h> |
| 34 | #include <linux/cpuset.h> |
| 35 | #include <linux/notifier.h> |
| 36 | #include <linux/rwsem.h> |
Rafael J. Wysocki | 248a030 | 2006-03-22 00:09:04 -0800 | [diff] [blame] | 37 | #include <linux/delay.h> |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 38 | #include <linux/kthread.h> |
Nigel Cunningham | 7dfb710 | 2006-12-06 20:34:23 -0800 | [diff] [blame] | 39 | #include <linux/freezer.h> |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 40 | #include <linux/memcontrol.h> |
Keika Kobayashi | 873b477 | 2008-07-25 01:48:52 -0700 | [diff] [blame] | 41 | #include <linux/delayacct.h> |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 42 | #include <linux/sysctl.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | |
| 44 | #include <asm/tlbflush.h> |
| 45 | #include <asm/div64.h> |
| 46 | |
| 47 | #include <linux/swapops.h> |
| 48 | |
Nick Piggin | 0f8053a | 2006-03-22 00:08:33 -0800 | [diff] [blame] | 49 | #include "internal.h" |
| 50 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | struct scan_control { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | /* Incremented by the number of inactive pages that were scanned */ |
| 53 | unsigned long nr_scanned; |
| 54 | |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 55 | /* Number of pages freed so far during a call to shrink_zones() */ |
| 56 | unsigned long nr_reclaimed; |
| 57 | |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 58 | /* How many pages shrink_list() should reclaim */ |
| 59 | unsigned long nr_to_reclaim; |
| 60 | |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame^] | 61 | unsigned long hibernation_mode; |
| 62 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | /* This context's GFP mask */ |
Al Viro | 6daa0e2 | 2005-10-21 03:18:50 -0400 | [diff] [blame] | 64 | gfp_t gfp_mask; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 65 | |
| 66 | int may_writepage; |
| 67 | |
Johannes Weiner | a6dc60f | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 68 | /* Can mapped pages be reclaimed? */ |
| 69 | int may_unmap; |
Christoph Lameter | f1fd106 | 2006-01-18 17:42:30 -0800 | [diff] [blame] | 70 | |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 71 | /* Can pages be swapped as part of reclaim? */ |
| 72 | int may_swap; |
| 73 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | /* This context's SWAP_CLUSTER_MAX. If freeing memory for |
| 75 | * suspend, we effectively ignore SWAP_CLUSTER_MAX. |
| 76 | * In this context, it doesn't matter that we scan the |
| 77 | * whole list at once. */ |
| 78 | int swap_cluster_max; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 79 | |
| 80 | int swappiness; |
Nick Piggin | 408d854 | 2006-09-25 23:31:27 -0700 | [diff] [blame] | 81 | |
| 82 | int all_unreclaimable; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 83 | |
| 84 | int order; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 85 | |
| 86 | /* Which cgroup do we reclaim from */ |
| 87 | struct mem_cgroup *mem_cgroup; |
| 88 | |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 89 | /* |
| 90 | * Nodemask of nodes allowed by the caller. If NULL, all nodes |
| 91 | * are scanned. |
| 92 | */ |
| 93 | nodemask_t *nodemask; |
| 94 | |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 95 | /* Pluggable isolate pages callback */ |
| 96 | unsigned long (*isolate_pages)(unsigned long nr, struct list_head *dst, |
| 97 | unsigned long *scanned, int order, int mode, |
| 98 | struct zone *z, struct mem_cgroup *mem_cont, |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 99 | int active, int file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | }; |
| 101 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 102 | #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru)) |
| 103 | |
| 104 | #ifdef ARCH_HAS_PREFETCH |
| 105 | #define prefetch_prev_lru_page(_page, _base, _field) \ |
| 106 | do { \ |
| 107 | if ((_page)->lru.prev != _base) { \ |
| 108 | struct page *prev; \ |
| 109 | \ |
| 110 | prev = lru_to_page(&(_page->lru)); \ |
| 111 | prefetch(&prev->_field); \ |
| 112 | } \ |
| 113 | } while (0) |
| 114 | #else |
| 115 | #define prefetch_prev_lru_page(_page, _base, _field) do { } while (0) |
| 116 | #endif |
| 117 | |
| 118 | #ifdef ARCH_HAS_PREFETCHW |
| 119 | #define prefetchw_prev_lru_page(_page, _base, _field) \ |
| 120 | do { \ |
| 121 | if ((_page)->lru.prev != _base) { \ |
| 122 | struct page *prev; \ |
| 123 | \ |
| 124 | prev = lru_to_page(&(_page->lru)); \ |
| 125 | prefetchw(&prev->_field); \ |
| 126 | } \ |
| 127 | } while (0) |
| 128 | #else |
| 129 | #define prefetchw_prev_lru_page(_page, _base, _field) do { } while (0) |
| 130 | #endif |
| 131 | |
| 132 | /* |
| 133 | * From 0 .. 100. Higher means more swappy. |
| 134 | */ |
| 135 | int vm_swappiness = 60; |
Andrew Morton | bd1e22b | 2006-06-23 02:03:47 -0700 | [diff] [blame] | 136 | long vm_total_pages; /* The total number of pages which the VM controls */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 137 | |
| 138 | static LIST_HEAD(shrinker_list); |
| 139 | static DECLARE_RWSEM(shrinker_rwsem); |
| 140 | |
Balbir Singh | 00f0b82 | 2008-03-04 14:28:39 -0800 | [diff] [blame] | 141 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 142 | #define scanning_global_lru(sc) (!(sc)->mem_cgroup) |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 143 | #else |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 144 | #define scanning_global_lru(sc) (1) |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 145 | #endif |
| 146 | |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 147 | static struct zone_reclaim_stat *get_reclaim_stat(struct zone *zone, |
| 148 | struct scan_control *sc) |
| 149 | { |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 150 | if (!scanning_global_lru(sc)) |
KOSAKI Motohiro | 3e2f41f | 2009-01-07 18:08:20 -0800 | [diff] [blame] | 151 | return mem_cgroup_get_reclaim_stat(sc->mem_cgroup, zone); |
| 152 | |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 153 | return &zone->reclaim_stat; |
| 154 | } |
| 155 | |
Vincent Li | 0b21767 | 2009-09-21 17:03:09 -0700 | [diff] [blame] | 156 | static unsigned long zone_nr_lru_pages(struct zone *zone, |
| 157 | struct scan_control *sc, enum lru_list lru) |
KOSAKI Motohiro | c9f299d | 2009-01-07 18:08:16 -0800 | [diff] [blame] | 158 | { |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 159 | if (!scanning_global_lru(sc)) |
KOSAKI Motohiro | a3d8e05 | 2009-01-07 18:08:19 -0800 | [diff] [blame] | 160 | return mem_cgroup_zone_nr_pages(sc->mem_cgroup, zone, lru); |
| 161 | |
KOSAKI Motohiro | c9f299d | 2009-01-07 18:08:16 -0800 | [diff] [blame] | 162 | return zone_page_state(zone, NR_LRU_BASE + lru); |
| 163 | } |
| 164 | |
| 165 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | /* |
| 167 | * Add a shrinker callback to be called from the vm |
| 168 | */ |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 169 | void register_shrinker(struct shrinker *shrinker) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | { |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 171 | shrinker->nr = 0; |
| 172 | down_write(&shrinker_rwsem); |
| 173 | list_add_tail(&shrinker->list, &shrinker_list); |
| 174 | up_write(&shrinker_rwsem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 175 | } |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 176 | EXPORT_SYMBOL(register_shrinker); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | |
| 178 | /* |
| 179 | * Remove one |
| 180 | */ |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 181 | void unregister_shrinker(struct shrinker *shrinker) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | { |
| 183 | down_write(&shrinker_rwsem); |
| 184 | list_del(&shrinker->list); |
| 185 | up_write(&shrinker_rwsem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 186 | } |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 187 | EXPORT_SYMBOL(unregister_shrinker); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 188 | |
| 189 | #define SHRINK_BATCH 128 |
| 190 | /* |
| 191 | * Call the shrink functions to age shrinkable caches |
| 192 | * |
| 193 | * Here we assume it costs one seek to replace a lru page and that it also |
| 194 | * takes a seek to recreate a cache object. With this in mind we age equal |
| 195 | * percentages of the lru and ageable caches. This should balance the seeks |
| 196 | * generated by these structures. |
| 197 | * |
Simon Arlott | 183ff22 | 2007-10-20 01:27:18 +0200 | [diff] [blame] | 198 | * If the vm encountered mapped pages on the LRU it increase the pressure on |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | * slab to avoid swapping. |
| 200 | * |
| 201 | * We do weird things to avoid (scanned*seeks*entries) overflowing 32 bits. |
| 202 | * |
| 203 | * `lru_pages' represents the number of on-LRU pages in all the zones which |
| 204 | * are eligible for the caller's allocation attempt. It is used for balancing |
| 205 | * slab reclaim versus page reclaim. |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 206 | * |
| 207 | * Returns the number of slab objects which we shrunk. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 208 | */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 209 | unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask, |
| 210 | unsigned long lru_pages) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 211 | { |
| 212 | struct shrinker *shrinker; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 213 | unsigned long ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 214 | |
| 215 | if (scanned == 0) |
| 216 | scanned = SWAP_CLUSTER_MAX; |
| 217 | |
| 218 | if (!down_read_trylock(&shrinker_rwsem)) |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 219 | return 1; /* Assume we'll be able to shrink next time */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | |
| 221 | list_for_each_entry(shrinker, &shrinker_list, list) { |
| 222 | unsigned long long delta; |
| 223 | unsigned long total_scan; |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 224 | unsigned long max_pass = (*shrinker->shrink)(0, gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 225 | |
| 226 | delta = (4 * scanned) / shrinker->seeks; |
Andrea Arcangeli | ea164d7 | 2005-11-28 13:44:15 -0800 | [diff] [blame] | 227 | delta *= max_pass; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 228 | do_div(delta, lru_pages + 1); |
| 229 | shrinker->nr += delta; |
Andrea Arcangeli | ea164d7 | 2005-11-28 13:44:15 -0800 | [diff] [blame] | 230 | if (shrinker->nr < 0) { |
David Rientjes | 88c3bd7 | 2009-03-31 15:23:29 -0700 | [diff] [blame] | 231 | printk(KERN_ERR "shrink_slab: %pF negative objects to " |
| 232 | "delete nr=%ld\n", |
| 233 | shrinker->shrink, shrinker->nr); |
Andrea Arcangeli | ea164d7 | 2005-11-28 13:44:15 -0800 | [diff] [blame] | 234 | shrinker->nr = max_pass; |
| 235 | } |
| 236 | |
| 237 | /* |
| 238 | * Avoid risking looping forever due to too large nr value: |
| 239 | * never try to free more than twice the estimate number of |
| 240 | * freeable entries. |
| 241 | */ |
| 242 | if (shrinker->nr > max_pass * 2) |
| 243 | shrinker->nr = max_pass * 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 244 | |
| 245 | total_scan = shrinker->nr; |
| 246 | shrinker->nr = 0; |
| 247 | |
| 248 | while (total_scan >= SHRINK_BATCH) { |
| 249 | long this_scan = SHRINK_BATCH; |
| 250 | int shrink_ret; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 251 | int nr_before; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 252 | |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 253 | nr_before = (*shrinker->shrink)(0, gfp_mask); |
| 254 | shrink_ret = (*shrinker->shrink)(this_scan, gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 255 | if (shrink_ret == -1) |
| 256 | break; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 257 | if (shrink_ret < nr_before) |
| 258 | ret += nr_before - shrink_ret; |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 259 | count_vm_events(SLABS_SCANNED, this_scan); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 260 | total_scan -= this_scan; |
| 261 | |
| 262 | cond_resched(); |
| 263 | } |
| 264 | |
| 265 | shrinker->nr += total_scan; |
| 266 | } |
| 267 | up_read(&shrinker_rwsem); |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 268 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | } |
| 270 | |
| 271 | /* Called without lock on whether page is mapped, so answer is unstable */ |
| 272 | static inline int page_mapping_inuse(struct page *page) |
| 273 | { |
| 274 | struct address_space *mapping; |
| 275 | |
| 276 | /* Page is in somebody's page tables. */ |
| 277 | if (page_mapped(page)) |
| 278 | return 1; |
| 279 | |
| 280 | /* Be more reluctant to reclaim swapcache than pagecache */ |
| 281 | if (PageSwapCache(page)) |
| 282 | return 1; |
| 283 | |
| 284 | mapping = page_mapping(page); |
| 285 | if (!mapping) |
| 286 | return 0; |
| 287 | |
| 288 | /* File is mmap'd by somebody? */ |
| 289 | return mapping_mapped(mapping); |
| 290 | } |
| 291 | |
| 292 | static inline int is_page_cache_freeable(struct page *page) |
| 293 | { |
Johannes Weiner | ceddc3a | 2009-09-21 17:03:00 -0700 | [diff] [blame] | 294 | /* |
| 295 | * A freeable page cache page is referenced only by the caller |
| 296 | * that isolated the page, the page cache radix tree and |
| 297 | * optional buffer heads at page->private. |
| 298 | */ |
Johannes Weiner | edcf474 | 2009-09-21 17:02:59 -0700 | [diff] [blame] | 299 | return page_count(page) - page_has_private(page) == 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 300 | } |
| 301 | |
| 302 | static int may_write_to_queue(struct backing_dev_info *bdi) |
| 303 | { |
Christoph Lameter | 930d915 | 2006-01-08 01:00:47 -0800 | [diff] [blame] | 304 | if (current->flags & PF_SWAPWRITE) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | return 1; |
| 306 | if (!bdi_write_congested(bdi)) |
| 307 | return 1; |
| 308 | if (bdi == current->backing_dev_info) |
| 309 | return 1; |
| 310 | return 0; |
| 311 | } |
| 312 | |
| 313 | /* |
| 314 | * We detected a synchronous write error writing a page out. Probably |
| 315 | * -ENOSPC. We need to propagate that into the address_space for a subsequent |
| 316 | * fsync(), msync() or close(). |
| 317 | * |
| 318 | * The tricky part is that after writepage we cannot touch the mapping: nothing |
| 319 | * prevents it from being freed up. But we have a ref on the page and once |
| 320 | * that page is locked, the mapping is pinned. |
| 321 | * |
| 322 | * We're allowed to run sleeping lock_page() here because we know the caller has |
| 323 | * __GFP_FS. |
| 324 | */ |
| 325 | static void handle_write_error(struct address_space *mapping, |
| 326 | struct page *page, int error) |
| 327 | { |
| 328 | lock_page(page); |
Guillaume Chazarain | 3e9f45b | 2007-05-08 00:23:25 -0700 | [diff] [blame] | 329 | if (page_mapping(page) == mapping) |
| 330 | mapping_set_error(mapping, error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | unlock_page(page); |
| 332 | } |
| 333 | |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 334 | /* Request for sync pageout. */ |
| 335 | enum pageout_io { |
| 336 | PAGEOUT_IO_ASYNC, |
| 337 | PAGEOUT_IO_SYNC, |
| 338 | }; |
| 339 | |
Christoph Lameter | 04e62a2 | 2006-06-23 02:03:38 -0700 | [diff] [blame] | 340 | /* possible outcome of pageout() */ |
| 341 | typedef enum { |
| 342 | /* failed to write page out, page is locked */ |
| 343 | PAGE_KEEP, |
| 344 | /* move page to the active list, page is locked */ |
| 345 | PAGE_ACTIVATE, |
| 346 | /* page has been sent to the disk successfully, page is unlocked */ |
| 347 | PAGE_SUCCESS, |
| 348 | /* page is clean and locked */ |
| 349 | PAGE_CLEAN, |
| 350 | } pageout_t; |
| 351 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 352 | /* |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 353 | * pageout is called by shrink_page_list() for each dirty page. |
| 354 | * Calls ->writepage(). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 355 | */ |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 356 | static pageout_t pageout(struct page *page, struct address_space *mapping, |
| 357 | enum pageout_io sync_writeback) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 358 | { |
| 359 | /* |
| 360 | * If the page is dirty, only perform writeback if that write |
| 361 | * will be non-blocking. To prevent this allocation from being |
| 362 | * stalled by pagecache activity. But note that there may be |
| 363 | * stalls if we need to run get_block(). We could test |
| 364 | * PagePrivate for that. |
| 365 | * |
Vincent Li | 6aceb53 | 2009-12-14 17:58:49 -0800 | [diff] [blame] | 366 | * If this process is currently in __generic_file_aio_write() against |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 367 | * this page's queue, we can perform writeback even if that |
| 368 | * will block. |
| 369 | * |
| 370 | * If the page is swapcache, write it back even if that would |
| 371 | * block, for some throttling. This happens by accident, because |
| 372 | * swap_backing_dev_info is bust: it doesn't reflect the |
| 373 | * congestion state of the swapdevs. Easy to fix, if needed. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 374 | */ |
| 375 | if (!is_page_cache_freeable(page)) |
| 376 | return PAGE_KEEP; |
| 377 | if (!mapping) { |
| 378 | /* |
| 379 | * Some data journaling orphaned pages can have |
| 380 | * page->mapping == NULL while being dirty with clean buffers. |
| 381 | */ |
David Howells | 266cf65 | 2009-04-03 16:42:36 +0100 | [diff] [blame] | 382 | if (page_has_private(page)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 383 | if (try_to_free_buffers(page)) { |
| 384 | ClearPageDirty(page); |
Harvey Harrison | d40cee2 | 2008-04-30 00:55:07 -0700 | [diff] [blame] | 385 | printk("%s: orphaned page\n", __func__); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 386 | return PAGE_CLEAN; |
| 387 | } |
| 388 | } |
| 389 | return PAGE_KEEP; |
| 390 | } |
| 391 | if (mapping->a_ops->writepage == NULL) |
| 392 | return PAGE_ACTIVATE; |
| 393 | if (!may_write_to_queue(mapping->backing_dev_info)) |
| 394 | return PAGE_KEEP; |
| 395 | |
| 396 | if (clear_page_dirty_for_io(page)) { |
| 397 | int res; |
| 398 | struct writeback_control wbc = { |
| 399 | .sync_mode = WB_SYNC_NONE, |
| 400 | .nr_to_write = SWAP_CLUSTER_MAX, |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 401 | .range_start = 0, |
| 402 | .range_end = LLONG_MAX, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 403 | .nonblocking = 1, |
| 404 | .for_reclaim = 1, |
| 405 | }; |
| 406 | |
| 407 | SetPageReclaim(page); |
| 408 | res = mapping->a_ops->writepage(page, &wbc); |
| 409 | if (res < 0) |
| 410 | handle_write_error(mapping, page, res); |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 411 | if (res == AOP_WRITEPAGE_ACTIVATE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 412 | ClearPageReclaim(page); |
| 413 | return PAGE_ACTIVATE; |
| 414 | } |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 415 | |
| 416 | /* |
| 417 | * Wait on writeback if requested to. This happens when |
| 418 | * direct reclaiming a large contiguous area and the |
| 419 | * first attempt to free a range of pages fails. |
| 420 | */ |
| 421 | if (PageWriteback(page) && sync_writeback == PAGEOUT_IO_SYNC) |
| 422 | wait_on_page_writeback(page); |
| 423 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 424 | if (!PageWriteback(page)) { |
| 425 | /* synchronous write or broken a_ops? */ |
| 426 | ClearPageReclaim(page); |
| 427 | } |
Andrew Morton | e129b5c | 2006-09-27 01:50:00 -0700 | [diff] [blame] | 428 | inc_zone_page_state(page, NR_VMSCAN_WRITE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 429 | return PAGE_SUCCESS; |
| 430 | } |
| 431 | |
| 432 | return PAGE_CLEAN; |
| 433 | } |
| 434 | |
Andrew Morton | a649fd9 | 2006-10-17 00:09:36 -0700 | [diff] [blame] | 435 | /* |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 436 | * Same as remove_mapping, but if the page is removed from the mapping, it |
| 437 | * gets returned with a refcount of 0. |
Andrew Morton | a649fd9 | 2006-10-17 00:09:36 -0700 | [diff] [blame] | 438 | */ |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 439 | static int __remove_mapping(struct address_space *mapping, struct page *page) |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 440 | { |
Nick Piggin | 28e4d96 | 2006-09-25 23:31:23 -0700 | [diff] [blame] | 441 | BUG_ON(!PageLocked(page)); |
| 442 | BUG_ON(mapping != page_mapping(page)); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 443 | |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 444 | spin_lock_irq(&mapping->tree_lock); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 445 | /* |
Nick Piggin | 0fd0e6b | 2006-09-27 01:50:02 -0700 | [diff] [blame] | 446 | * The non racy check for a busy page. |
| 447 | * |
| 448 | * Must be careful with the order of the tests. When someone has |
| 449 | * a ref to the page, it may be possible that they dirty it then |
| 450 | * drop the reference. So if PageDirty is tested before page_count |
| 451 | * here, then the following race may occur: |
| 452 | * |
| 453 | * get_user_pages(&page); |
| 454 | * [user mapping goes away] |
| 455 | * write_to(page); |
| 456 | * !PageDirty(page) [good] |
| 457 | * SetPageDirty(page); |
| 458 | * put_page(page); |
| 459 | * !page_count(page) [good, discard it] |
| 460 | * |
| 461 | * [oops, our write_to data is lost] |
| 462 | * |
| 463 | * Reversing the order of the tests ensures such a situation cannot |
| 464 | * escape unnoticed. The smp_rmb is needed to ensure the page->flags |
| 465 | * load is not satisfied before that of page->_count. |
| 466 | * |
| 467 | * Note that if SetPageDirty is always performed via set_page_dirty, |
| 468 | * and thus under tree_lock, then this ordering is not required. |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 469 | */ |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 470 | if (!page_freeze_refs(page, 2)) |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 471 | goto cannot_free; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 472 | /* note: atomic_cmpxchg in page_freeze_refs provides the smp_rmb */ |
| 473 | if (unlikely(PageDirty(page))) { |
| 474 | page_unfreeze_refs(page, 2); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 475 | goto cannot_free; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 476 | } |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 477 | |
| 478 | if (PageSwapCache(page)) { |
| 479 | swp_entry_t swap = { .val = page_private(page) }; |
| 480 | __delete_from_swap_cache(page); |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 481 | spin_unlock_irq(&mapping->tree_lock); |
KAMEZAWA Hiroyuki | cb4b86b | 2009-06-16 15:32:52 -0700 | [diff] [blame] | 482 | swapcache_free(swap, page); |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 483 | } else { |
| 484 | __remove_from_page_cache(page); |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 485 | spin_unlock_irq(&mapping->tree_lock); |
Daisuke Nishimura | e767e05 | 2009-05-28 14:34:28 -0700 | [diff] [blame] | 486 | mem_cgroup_uncharge_cache_page(page); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 487 | } |
| 488 | |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 489 | return 1; |
| 490 | |
| 491 | cannot_free: |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 492 | spin_unlock_irq(&mapping->tree_lock); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 493 | return 0; |
| 494 | } |
| 495 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 496 | /* |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 497 | * Attempt to detach a locked page from its ->mapping. If it is dirty or if |
| 498 | * someone else has a ref on the page, abort and return 0. If it was |
| 499 | * successfully detached, return 1. Assumes the caller has a single ref on |
| 500 | * this page. |
| 501 | */ |
| 502 | int remove_mapping(struct address_space *mapping, struct page *page) |
| 503 | { |
| 504 | if (__remove_mapping(mapping, page)) { |
| 505 | /* |
| 506 | * Unfreezing the refcount with 1 rather than 2 effectively |
| 507 | * drops the pagecache ref for us without requiring another |
| 508 | * atomic operation. |
| 509 | */ |
| 510 | page_unfreeze_refs(page, 1); |
| 511 | return 1; |
| 512 | } |
| 513 | return 0; |
| 514 | } |
| 515 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 516 | /** |
| 517 | * putback_lru_page - put previously isolated page onto appropriate LRU list |
| 518 | * @page: page to be put back to appropriate lru list |
| 519 | * |
| 520 | * Add previously isolated @page to appropriate LRU list. |
| 521 | * Page may still be unevictable for other reasons. |
| 522 | * |
| 523 | * lru_lock must not be held, interrupts must be enabled. |
| 524 | */ |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 525 | void putback_lru_page(struct page *page) |
| 526 | { |
| 527 | int lru; |
| 528 | int active = !!TestClearPageActive(page); |
Lee Schermerhorn | bbfd28e | 2008-10-18 20:26:40 -0700 | [diff] [blame] | 529 | int was_unevictable = PageUnevictable(page); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 530 | |
| 531 | VM_BUG_ON(PageLRU(page)); |
| 532 | |
| 533 | redo: |
| 534 | ClearPageUnevictable(page); |
| 535 | |
| 536 | if (page_evictable(page, NULL)) { |
| 537 | /* |
| 538 | * For evictable pages, we can use the cache. |
| 539 | * In event of a race, worst case is we end up with an |
| 540 | * unevictable page on [in]active list. |
| 541 | * We know how to handle that. |
| 542 | */ |
Johannes Weiner | 401a8e1 | 2009-09-21 17:02:58 -0700 | [diff] [blame] | 543 | lru = active + page_lru_base_type(page); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 544 | lru_cache_add_lru(page, lru); |
| 545 | } else { |
| 546 | /* |
| 547 | * Put unevictable pages directly on zone's unevictable |
| 548 | * list. |
| 549 | */ |
| 550 | lru = LRU_UNEVICTABLE; |
| 551 | add_page_to_unevictable_list(page); |
Johannes Weiner | 6a7b954 | 2009-10-26 16:50:00 -0700 | [diff] [blame] | 552 | /* |
| 553 | * When racing with an mlock clearing (page is |
| 554 | * unlocked), make sure that if the other thread does |
| 555 | * not observe our setting of PG_lru and fails |
| 556 | * isolation, we see PG_mlocked cleared below and move |
| 557 | * the page back to the evictable list. |
| 558 | * |
| 559 | * The other side is TestClearPageMlocked(). |
| 560 | */ |
| 561 | smp_mb(); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 562 | } |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 563 | |
| 564 | /* |
| 565 | * page's status can change while we move it among lru. If an evictable |
| 566 | * page is on unevictable list, it never be freed. To avoid that, |
| 567 | * check after we added it to the list, again. |
| 568 | */ |
| 569 | if (lru == LRU_UNEVICTABLE && page_evictable(page, NULL)) { |
| 570 | if (!isolate_lru_page(page)) { |
| 571 | put_page(page); |
| 572 | goto redo; |
| 573 | } |
| 574 | /* This means someone else dropped this page from LRU |
| 575 | * So, it will be freed or putback to LRU again. There is |
| 576 | * nothing to do here. |
| 577 | */ |
| 578 | } |
| 579 | |
Lee Schermerhorn | bbfd28e | 2008-10-18 20:26:40 -0700 | [diff] [blame] | 580 | if (was_unevictable && lru != LRU_UNEVICTABLE) |
| 581 | count_vm_event(UNEVICTABLE_PGRESCUED); |
| 582 | else if (!was_unevictable && lru == LRU_UNEVICTABLE) |
| 583 | count_vm_event(UNEVICTABLE_PGCULLED); |
| 584 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 585 | put_page(page); /* drop ref from isolate */ |
| 586 | } |
| 587 | |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 588 | /* |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 589 | * shrink_page_list() returns the number of reclaimed pages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 590 | */ |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 591 | static unsigned long shrink_page_list(struct list_head *page_list, |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 592 | struct scan_control *sc, |
| 593 | enum pageout_io sync_writeback) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 594 | { |
| 595 | LIST_HEAD(ret_pages); |
| 596 | struct pagevec freed_pvec; |
| 597 | int pgactivate = 0; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 598 | unsigned long nr_reclaimed = 0; |
Wu Fengguang | 6fe6b7e | 2009-06-16 15:33:05 -0700 | [diff] [blame] | 599 | unsigned long vm_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 600 | |
| 601 | cond_resched(); |
| 602 | |
| 603 | pagevec_init(&freed_pvec, 1); |
| 604 | while (!list_empty(page_list)) { |
| 605 | struct address_space *mapping; |
| 606 | struct page *page; |
| 607 | int may_enter_fs; |
| 608 | int referenced; |
| 609 | |
| 610 | cond_resched(); |
| 611 | |
| 612 | page = lru_to_page(page_list); |
| 613 | list_del(&page->lru); |
| 614 | |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 615 | if (!trylock_page(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 616 | goto keep; |
| 617 | |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 618 | VM_BUG_ON(PageActive(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 619 | |
| 620 | sc->nr_scanned++; |
Christoph Lameter | 80e4342 | 2006-02-11 17:55:53 -0800 | [diff] [blame] | 621 | |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 622 | if (unlikely(!page_evictable(page, NULL))) |
| 623 | goto cull_mlocked; |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 624 | |
Johannes Weiner | a6dc60f | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 625 | if (!sc->may_unmap && page_mapped(page)) |
Christoph Lameter | 80e4342 | 2006-02-11 17:55:53 -0800 | [diff] [blame] | 626 | goto keep_locked; |
| 627 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 628 | /* Double the slab pressure for mapped and swapcache pages */ |
| 629 | if (page_mapped(page) || PageSwapCache(page)) |
| 630 | sc->nr_scanned++; |
| 631 | |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 632 | may_enter_fs = (sc->gfp_mask & __GFP_FS) || |
| 633 | (PageSwapCache(page) && (sc->gfp_mask & __GFP_IO)); |
| 634 | |
| 635 | if (PageWriteback(page)) { |
| 636 | /* |
| 637 | * Synchronous reclaim is performed in two passes, |
| 638 | * first an asynchronous pass over the list to |
| 639 | * start parallel writeback, and a second synchronous |
| 640 | * pass to wait for the IO to complete. Wait here |
| 641 | * for any page for which writeback has already |
| 642 | * started. |
| 643 | */ |
| 644 | if (sync_writeback == PAGEOUT_IO_SYNC && may_enter_fs) |
| 645 | wait_on_page_writeback(page); |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 646 | else |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 647 | goto keep_locked; |
| 648 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 649 | |
Wu Fengguang | 6fe6b7e | 2009-06-16 15:33:05 -0700 | [diff] [blame] | 650 | referenced = page_referenced(page, 1, |
| 651 | sc->mem_cgroup, &vm_flags); |
Minchan Kim | 03ef83a | 2009-08-26 14:29:23 -0700 | [diff] [blame] | 652 | /* |
| 653 | * In active use or really unfreeable? Activate it. |
| 654 | * If page which have PG_mlocked lost isoltation race, |
| 655 | * try_to_unmap moves it to unevictable list |
| 656 | */ |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 657 | if (sc->order <= PAGE_ALLOC_COSTLY_ORDER && |
Minchan Kim | 03ef83a | 2009-08-26 14:29:23 -0700 | [diff] [blame] | 658 | referenced && page_mapping_inuse(page) |
| 659 | && !(vm_flags & VM_LOCKED)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 660 | goto activate_locked; |
| 661 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 662 | /* |
| 663 | * Anonymous process memory has backing store? |
| 664 | * Try to allocate it some swap space here. |
| 665 | */ |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 666 | if (PageAnon(page) && !PageSwapCache(page)) { |
Hugh Dickins | 63eb6b9 | 2008-11-19 15:36:37 -0800 | [diff] [blame] | 667 | if (!(sc->gfp_mask & __GFP_IO)) |
| 668 | goto keep_locked; |
Hugh Dickins | ac47b00 | 2009-01-06 14:39:39 -0800 | [diff] [blame] | 669 | if (!add_to_swap(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 670 | goto activate_locked; |
Hugh Dickins | 63eb6b9 | 2008-11-19 15:36:37 -0800 | [diff] [blame] | 671 | may_enter_fs = 1; |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 672 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 673 | |
| 674 | mapping = page_mapping(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 675 | |
| 676 | /* |
| 677 | * The page is mapped into the page tables of one or more |
| 678 | * processes. Try to unmap it here. |
| 679 | */ |
| 680 | if (page_mapped(page) && mapping) { |
Andi Kleen | 14fa31b | 2009-09-16 11:50:10 +0200 | [diff] [blame] | 681 | switch (try_to_unmap(page, TTU_UNMAP)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 682 | case SWAP_FAIL: |
| 683 | goto activate_locked; |
| 684 | case SWAP_AGAIN: |
| 685 | goto keep_locked; |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 686 | case SWAP_MLOCK: |
| 687 | goto cull_mlocked; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 688 | case SWAP_SUCCESS: |
| 689 | ; /* try to free the page below */ |
| 690 | } |
| 691 | } |
| 692 | |
| 693 | if (PageDirty(page)) { |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 694 | if (sc->order <= PAGE_ALLOC_COSTLY_ORDER && referenced) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 695 | goto keep_locked; |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 696 | if (!may_enter_fs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 697 | goto keep_locked; |
Christoph Lameter | 52a8363 | 2006-02-01 03:05:28 -0800 | [diff] [blame] | 698 | if (!sc->may_writepage) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 699 | goto keep_locked; |
| 700 | |
| 701 | /* Page is dirty, try to write it out here */ |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 702 | switch (pageout(page, mapping, sync_writeback)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 703 | case PAGE_KEEP: |
| 704 | goto keep_locked; |
| 705 | case PAGE_ACTIVATE: |
| 706 | goto activate_locked; |
| 707 | case PAGE_SUCCESS: |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 708 | if (PageWriteback(page) || PageDirty(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 709 | goto keep; |
| 710 | /* |
| 711 | * A synchronous write - probably a ramdisk. Go |
| 712 | * ahead and try to reclaim the page. |
| 713 | */ |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 714 | if (!trylock_page(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 715 | goto keep; |
| 716 | if (PageDirty(page) || PageWriteback(page)) |
| 717 | goto keep_locked; |
| 718 | mapping = page_mapping(page); |
| 719 | case PAGE_CLEAN: |
| 720 | ; /* try to free the page below */ |
| 721 | } |
| 722 | } |
| 723 | |
| 724 | /* |
| 725 | * If the page has buffers, try to free the buffer mappings |
| 726 | * associated with this page. If we succeed we try to free |
| 727 | * the page as well. |
| 728 | * |
| 729 | * We do this even if the page is PageDirty(). |
| 730 | * try_to_release_page() does not perform I/O, but it is |
| 731 | * possible for a page to have PageDirty set, but it is actually |
| 732 | * clean (all its buffers are clean). This happens if the |
| 733 | * buffers were written out directly, with submit_bh(). ext3 |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 734 | * will do this, as well as the blockdev mapping. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 735 | * try_to_release_page() will discover that cleanness and will |
| 736 | * drop the buffers and mark the page clean - it can be freed. |
| 737 | * |
| 738 | * Rarely, pages can have buffers and no ->mapping. These are |
| 739 | * the pages which were not successfully invalidated in |
| 740 | * truncate_complete_page(). We try to drop those buffers here |
| 741 | * and if that worked, and the page is no longer mapped into |
| 742 | * process address space (page_count == 1) it can be freed. |
| 743 | * Otherwise, leave the page on the LRU so it is swappable. |
| 744 | */ |
David Howells | 266cf65 | 2009-04-03 16:42:36 +0100 | [diff] [blame] | 745 | if (page_has_private(page)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 746 | if (!try_to_release_page(page, sc->gfp_mask)) |
| 747 | goto activate_locked; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 748 | if (!mapping && page_count(page) == 1) { |
| 749 | unlock_page(page); |
| 750 | if (put_page_testzero(page)) |
| 751 | goto free_it; |
| 752 | else { |
| 753 | /* |
| 754 | * rare race with speculative reference. |
| 755 | * the speculative reference will free |
| 756 | * this page shortly, so we may |
| 757 | * increment nr_reclaimed here (and |
| 758 | * leave it off the LRU). |
| 759 | */ |
| 760 | nr_reclaimed++; |
| 761 | continue; |
| 762 | } |
| 763 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 764 | } |
| 765 | |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 766 | if (!mapping || !__remove_mapping(mapping, page)) |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 767 | goto keep_locked; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 768 | |
Nick Piggin | a978d6f | 2008-10-18 20:26:58 -0700 | [diff] [blame] | 769 | /* |
| 770 | * At this point, we have no other references and there is |
| 771 | * no way to pick any more up (removed from LRU, removed |
| 772 | * from pagecache). Can use non-atomic bitops now (and |
| 773 | * we obviously don't have to worry about waking up a process |
| 774 | * waiting on the page lock, because there are no references. |
| 775 | */ |
| 776 | __clear_page_locked(page); |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 777 | free_it: |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 778 | nr_reclaimed++; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 779 | if (!pagevec_add(&freed_pvec, page)) { |
| 780 | __pagevec_free(&freed_pvec); |
| 781 | pagevec_reinit(&freed_pvec); |
| 782 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 783 | continue; |
| 784 | |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 785 | cull_mlocked: |
Hugh Dickins | 63d6c5a | 2009-01-06 14:39:38 -0800 | [diff] [blame] | 786 | if (PageSwapCache(page)) |
| 787 | try_to_free_swap(page); |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 788 | unlock_page(page); |
| 789 | putback_lru_page(page); |
| 790 | continue; |
| 791 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 792 | activate_locked: |
Rik van Riel | 68a22394 | 2008-10-18 20:26:23 -0700 | [diff] [blame] | 793 | /* Not a candidate for swapping, so reclaim swap space. */ |
| 794 | if (PageSwapCache(page) && vm_swap_full()) |
Hugh Dickins | a2c43ee | 2009-01-06 14:39:36 -0800 | [diff] [blame] | 795 | try_to_free_swap(page); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 796 | VM_BUG_ON(PageActive(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 797 | SetPageActive(page); |
| 798 | pgactivate++; |
| 799 | keep_locked: |
| 800 | unlock_page(page); |
| 801 | keep: |
| 802 | list_add(&page->lru, &ret_pages); |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 803 | VM_BUG_ON(PageLRU(page) || PageUnevictable(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 804 | } |
| 805 | list_splice(&ret_pages, page_list); |
| 806 | if (pagevec_count(&freed_pvec)) |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 807 | __pagevec_free(&freed_pvec); |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 808 | count_vm_events(PGACTIVATE, pgactivate); |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 809 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 810 | } |
| 811 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 812 | /* LRU Isolation modes. */ |
| 813 | #define ISOLATE_INACTIVE 0 /* Isolate inactive pages. */ |
| 814 | #define ISOLATE_ACTIVE 1 /* Isolate active pages. */ |
| 815 | #define ISOLATE_BOTH 2 /* Isolate both active and inactive pages. */ |
| 816 | |
| 817 | /* |
| 818 | * Attempt to remove the specified page from its LRU. Only take this page |
| 819 | * if it is of the appropriate PageActive status. Pages which are being |
| 820 | * freed elsewhere are also ignored. |
| 821 | * |
| 822 | * page: page to consider |
| 823 | * mode: one of the LRU isolation modes defined above |
| 824 | * |
| 825 | * returns 0 on success, -ve errno on failure. |
| 826 | */ |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 827 | int __isolate_lru_page(struct page *page, int mode, int file) |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 828 | { |
| 829 | int ret = -EINVAL; |
| 830 | |
| 831 | /* Only take pages on the LRU. */ |
| 832 | if (!PageLRU(page)) |
| 833 | return ret; |
| 834 | |
| 835 | /* |
| 836 | * When checking the active state, we need to be sure we are |
| 837 | * dealing with comparible boolean values. Take the logical not |
| 838 | * of each. |
| 839 | */ |
| 840 | if (mode != ISOLATE_BOTH && (!PageActive(page) != !mode)) |
| 841 | return ret; |
| 842 | |
Johannes Weiner | 6c0b135 | 2009-09-21 17:02:59 -0700 | [diff] [blame] | 843 | if (mode != ISOLATE_BOTH && page_is_file_cache(page) != file) |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 844 | return ret; |
| 845 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 846 | /* |
| 847 | * When this function is being called for lumpy reclaim, we |
| 848 | * initially look into all LRU pages, active, inactive and |
| 849 | * unevictable; only give shrink_page_list evictable pages. |
| 850 | */ |
| 851 | if (PageUnevictable(page)) |
| 852 | return ret; |
| 853 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 854 | ret = -EBUSY; |
KAMEZAWA Hiroyuki | 08e552c | 2009-01-07 18:08:01 -0800 | [diff] [blame] | 855 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 856 | if (likely(get_page_unless_zero(page))) { |
| 857 | /* |
| 858 | * Be careful not to clear PageLRU until after we're |
| 859 | * sure the page is not being freed elsewhere -- the |
| 860 | * page release code relies on it. |
| 861 | */ |
| 862 | ClearPageLRU(page); |
| 863 | ret = 0; |
| 864 | } |
| 865 | |
| 866 | return ret; |
| 867 | } |
| 868 | |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 869 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 870 | * zone->lru_lock is heavily contended. Some of the functions that |
| 871 | * shrink the lists perform better by taking out a batch of pages |
| 872 | * and working on them outside the LRU lock. |
| 873 | * |
| 874 | * For pagecache intensive workloads, this function is the hottest |
| 875 | * spot in the kernel (apart from copy_*_user functions). |
| 876 | * |
| 877 | * Appropriate locks must be held before calling this function. |
| 878 | * |
| 879 | * @nr_to_scan: The number of pages to look through on the list. |
| 880 | * @src: The LRU list to pull pages off. |
| 881 | * @dst: The temp list to put pages on to. |
| 882 | * @scanned: The number of pages that were scanned. |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 883 | * @order: The caller's attempted allocation order |
| 884 | * @mode: One of the LRU isolation modes |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 885 | * @file: True [1] if isolating file [!anon] pages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 886 | * |
| 887 | * returns how many pages were moved onto *@dst. |
| 888 | */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 889 | static unsigned long isolate_lru_pages(unsigned long nr_to_scan, |
| 890 | struct list_head *src, struct list_head *dst, |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 891 | unsigned long *scanned, int order, int mode, int file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 892 | { |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 893 | unsigned long nr_taken = 0; |
Wu Fengguang | c9b02d9 | 2006-03-22 00:08:23 -0800 | [diff] [blame] | 894 | unsigned long scan; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 895 | |
Wu Fengguang | c9b02d9 | 2006-03-22 00:08:23 -0800 | [diff] [blame] | 896 | for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) { |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 897 | struct page *page; |
| 898 | unsigned long pfn; |
| 899 | unsigned long end_pfn; |
| 900 | unsigned long page_pfn; |
| 901 | int zone_id; |
| 902 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 903 | page = lru_to_page(src); |
| 904 | prefetchw_prev_lru_page(page, src, flags); |
| 905 | |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 906 | VM_BUG_ON(!PageLRU(page)); |
Nick Piggin | 8d438f9 | 2006-03-22 00:07:59 -0800 | [diff] [blame] | 907 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 908 | switch (__isolate_lru_page(page, mode, file)) { |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 909 | case 0: |
| 910 | list_move(&page->lru, dst); |
KAMEZAWA Hiroyuki | 2ffebca | 2009-06-17 16:27:21 -0700 | [diff] [blame] | 911 | mem_cgroup_del_lru(page); |
Nick Piggin | 7c8ee9a | 2006-03-22 00:08:03 -0800 | [diff] [blame] | 912 | nr_taken++; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 913 | break; |
Nick Piggin | 46453a6 | 2006-03-22 00:07:58 -0800 | [diff] [blame] | 914 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 915 | case -EBUSY: |
| 916 | /* else it is being freed elsewhere */ |
| 917 | list_move(&page->lru, src); |
KAMEZAWA Hiroyuki | 2ffebca | 2009-06-17 16:27:21 -0700 | [diff] [blame] | 918 | mem_cgroup_rotate_lru_list(page, page_lru(page)); |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 919 | continue; |
| 920 | |
| 921 | default: |
| 922 | BUG(); |
| 923 | } |
| 924 | |
| 925 | if (!order) |
| 926 | continue; |
| 927 | |
| 928 | /* |
| 929 | * Attempt to take all pages in the order aligned region |
| 930 | * surrounding the tag page. Only take those pages of |
| 931 | * the same active state as that tag page. We may safely |
| 932 | * round the target page pfn down to the requested order |
| 933 | * as the mem_map is guarenteed valid out to MAX_ORDER, |
| 934 | * where that page is in a different zone we will detect |
| 935 | * it from its zone id and abort this block scan. |
| 936 | */ |
| 937 | zone_id = page_zone_id(page); |
| 938 | page_pfn = page_to_pfn(page); |
| 939 | pfn = page_pfn & ~((1 << order) - 1); |
| 940 | end_pfn = pfn + (1 << order); |
| 941 | for (; pfn < end_pfn; pfn++) { |
| 942 | struct page *cursor_page; |
| 943 | |
| 944 | /* The target page is in the block, ignore it. */ |
| 945 | if (unlikely(pfn == page_pfn)) |
| 946 | continue; |
| 947 | |
| 948 | /* Avoid holes within the zone. */ |
| 949 | if (unlikely(!pfn_valid_within(pfn))) |
| 950 | break; |
| 951 | |
| 952 | cursor_page = pfn_to_page(pfn); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 953 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 954 | /* Check that we have not crossed a zone boundary. */ |
| 955 | if (unlikely(page_zone_id(cursor_page) != zone_id)) |
| 956 | continue; |
Minchan Kim | de2e756 | 2009-09-21 17:01:43 -0700 | [diff] [blame] | 957 | |
| 958 | /* |
| 959 | * If we don't have enough swap space, reclaiming of |
| 960 | * anon page which don't already have a swap slot is |
| 961 | * pointless. |
| 962 | */ |
| 963 | if (nr_swap_pages <= 0 && PageAnon(cursor_page) && |
| 964 | !PageSwapCache(cursor_page)) |
| 965 | continue; |
| 966 | |
KAMEZAWA Hiroyuki | ee993b1 | 2009-06-16 15:33:24 -0700 | [diff] [blame] | 967 | if (__isolate_lru_page(cursor_page, mode, file) == 0) { |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 968 | list_move(&cursor_page->lru, dst); |
KAMEZAWA Hiroyuki | cb4cbcf | 2009-06-23 08:57:55 +0900 | [diff] [blame] | 969 | mem_cgroup_del_lru(cursor_page); |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 970 | nr_taken++; |
| 971 | scan++; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 972 | } |
| 973 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 974 | } |
| 975 | |
| 976 | *scanned = scan; |
| 977 | return nr_taken; |
| 978 | } |
| 979 | |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 980 | static unsigned long isolate_pages_global(unsigned long nr, |
| 981 | struct list_head *dst, |
| 982 | unsigned long *scanned, int order, |
| 983 | int mode, struct zone *z, |
| 984 | struct mem_cgroup *mem_cont, |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 985 | int active, int file) |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 986 | { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 987 | int lru = LRU_BASE; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 988 | if (active) |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 989 | lru += LRU_ACTIVE; |
| 990 | if (file) |
| 991 | lru += LRU_FILE; |
| 992 | return isolate_lru_pages(nr, &z->lru[lru].list, dst, scanned, order, |
Johannes Weiner | b7c46d1 | 2009-09-21 17:02:56 -0700 | [diff] [blame] | 993 | mode, file); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 994 | } |
| 995 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 996 | /* |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 997 | * clear_active_flags() is a helper for shrink_active_list(), clearing |
| 998 | * any active bits from the pages in the list. |
| 999 | */ |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1000 | static unsigned long clear_active_flags(struct list_head *page_list, |
| 1001 | unsigned int *count) |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1002 | { |
| 1003 | int nr_active = 0; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1004 | int lru; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1005 | struct page *page; |
| 1006 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1007 | list_for_each_entry(page, page_list, lru) { |
Johannes Weiner | 401a8e1 | 2009-09-21 17:02:58 -0700 | [diff] [blame] | 1008 | lru = page_lru_base_type(page); |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1009 | if (PageActive(page)) { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1010 | lru += LRU_ACTIVE; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1011 | ClearPageActive(page); |
| 1012 | nr_active++; |
| 1013 | } |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1014 | count[lru]++; |
| 1015 | } |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1016 | |
| 1017 | return nr_active; |
| 1018 | } |
| 1019 | |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 1020 | /** |
| 1021 | * isolate_lru_page - tries to isolate a page from its LRU list |
| 1022 | * @page: page to isolate from its LRU list |
| 1023 | * |
| 1024 | * Isolates a @page from an LRU list, clears PageLRU and adjusts the |
| 1025 | * vmstat statistic corresponding to whatever LRU list the page was on. |
| 1026 | * |
| 1027 | * Returns 0 if the page was removed from an LRU list. |
| 1028 | * Returns -EBUSY if the page was not on an LRU list. |
| 1029 | * |
| 1030 | * The returned page will have PageLRU() cleared. If it was found on |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1031 | * the active list, it will have PageActive set. If it was found on |
| 1032 | * the unevictable list, it will have the PageUnevictable bit set. That flag |
| 1033 | * may need to be cleared by the caller before letting the page go. |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 1034 | * |
| 1035 | * The vmstat statistic corresponding to the list on which the page was |
| 1036 | * found will be decremented. |
| 1037 | * |
| 1038 | * Restrictions: |
| 1039 | * (1) Must be called with an elevated refcount on the page. This is a |
| 1040 | * fundamentnal difference from isolate_lru_pages (which is called |
| 1041 | * without a stable reference). |
| 1042 | * (2) the lru_lock must not be held. |
| 1043 | * (3) interrupts must be enabled. |
| 1044 | */ |
| 1045 | int isolate_lru_page(struct page *page) |
| 1046 | { |
| 1047 | int ret = -EBUSY; |
| 1048 | |
| 1049 | if (PageLRU(page)) { |
| 1050 | struct zone *zone = page_zone(page); |
| 1051 | |
| 1052 | spin_lock_irq(&zone->lru_lock); |
| 1053 | if (PageLRU(page) && get_page_unless_zero(page)) { |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1054 | int lru = page_lru(page); |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 1055 | ret = 0; |
| 1056 | ClearPageLRU(page); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1057 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1058 | del_page_from_lru_list(zone, page, lru); |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 1059 | } |
| 1060 | spin_unlock_irq(&zone->lru_lock); |
| 1061 | } |
| 1062 | return ret; |
| 1063 | } |
| 1064 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1065 | /* |
Rik van Riel | 35cd781 | 2009-09-21 17:01:38 -0700 | [diff] [blame] | 1066 | * Are there way too many processes in the direct reclaim path already? |
| 1067 | */ |
| 1068 | static int too_many_isolated(struct zone *zone, int file, |
| 1069 | struct scan_control *sc) |
| 1070 | { |
| 1071 | unsigned long inactive, isolated; |
| 1072 | |
| 1073 | if (current_is_kswapd()) |
| 1074 | return 0; |
| 1075 | |
| 1076 | if (!scanning_global_lru(sc)) |
| 1077 | return 0; |
| 1078 | |
| 1079 | if (file) { |
| 1080 | inactive = zone_page_state(zone, NR_INACTIVE_FILE); |
| 1081 | isolated = zone_page_state(zone, NR_ISOLATED_FILE); |
| 1082 | } else { |
| 1083 | inactive = zone_page_state(zone, NR_INACTIVE_ANON); |
| 1084 | isolated = zone_page_state(zone, NR_ISOLATED_ANON); |
| 1085 | } |
| 1086 | |
| 1087 | return isolated > inactive; |
| 1088 | } |
| 1089 | |
| 1090 | /* |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 1091 | * shrink_inactive_list() is a helper for shrink_zone(). It returns the number |
| 1092 | * of reclaimed pages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1093 | */ |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 1094 | static unsigned long shrink_inactive_list(unsigned long max_scan, |
Rik van Riel | 33c120e | 2008-10-18 20:26:36 -0700 | [diff] [blame] | 1095 | struct zone *zone, struct scan_control *sc, |
| 1096 | int priority, int file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1097 | { |
| 1098 | LIST_HEAD(page_list); |
| 1099 | struct pagevec pvec; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1100 | unsigned long nr_scanned = 0; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1101 | unsigned long nr_reclaimed = 0; |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1102 | struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); |
KOSAKI Motohiro | 78dc583 | 2009-06-16 15:31:40 -0700 | [diff] [blame] | 1103 | int lumpy_reclaim = 0; |
| 1104 | |
Rik van Riel | 35cd781 | 2009-09-21 17:01:38 -0700 | [diff] [blame] | 1105 | while (unlikely(too_many_isolated(zone, file, sc))) { |
KOSAKI Motohiro | 58355c7 | 2009-10-26 16:49:35 -0700 | [diff] [blame] | 1106 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
Rik van Riel | 35cd781 | 2009-09-21 17:01:38 -0700 | [diff] [blame] | 1107 | |
| 1108 | /* We are about to die and free our memory. Return now. */ |
| 1109 | if (fatal_signal_pending(current)) |
| 1110 | return SWAP_CLUSTER_MAX; |
| 1111 | } |
| 1112 | |
KOSAKI Motohiro | 78dc583 | 2009-06-16 15:31:40 -0700 | [diff] [blame] | 1113 | /* |
| 1114 | * If we need a large contiguous chunk of memory, or have |
| 1115 | * trouble getting a small set of contiguous pages, we |
| 1116 | * will reclaim both active and inactive pages. |
| 1117 | * |
| 1118 | * We use the same threshold as pageout congestion_wait below. |
| 1119 | */ |
| 1120 | if (sc->order > PAGE_ALLOC_COSTLY_ORDER) |
| 1121 | lumpy_reclaim = 1; |
| 1122 | else if (sc->order && priority < DEF_PRIORITY - 2) |
| 1123 | lumpy_reclaim = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1124 | |
| 1125 | pagevec_init(&pvec, 1); |
| 1126 | |
| 1127 | lru_add_drain(); |
| 1128 | spin_lock_irq(&zone->lru_lock); |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1129 | do { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1130 | struct page *page; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1131 | unsigned long nr_taken; |
| 1132 | unsigned long nr_scan; |
| 1133 | unsigned long nr_freed; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1134 | unsigned long nr_active; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1135 | unsigned int count[NR_LRU_LISTS] = { 0, }; |
KOSAKI Motohiro | 78dc583 | 2009-06-16 15:31:40 -0700 | [diff] [blame] | 1136 | int mode = lumpy_reclaim ? ISOLATE_BOTH : ISOLATE_INACTIVE; |
KOSAKI Motohiro | a731286 | 2009-09-21 17:01:37 -0700 | [diff] [blame] | 1137 | unsigned long nr_anon; |
| 1138 | unsigned long nr_file; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1139 | |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1140 | nr_taken = sc->isolate_pages(sc->swap_cluster_max, |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1141 | &page_list, &nr_scan, sc->order, mode, |
| 1142 | zone, sc->mem_cgroup, 0, file); |
KOSAKI Motohiro | b35ea17 | 2009-09-21 17:01:36 -0700 | [diff] [blame] | 1143 | |
| 1144 | if (scanning_global_lru(sc)) { |
| 1145 | zone->pages_scanned += nr_scan; |
| 1146 | if (current_is_kswapd()) |
| 1147 | __count_zone_vm_events(PGSCAN_KSWAPD, zone, |
| 1148 | nr_scan); |
| 1149 | else |
| 1150 | __count_zone_vm_events(PGSCAN_DIRECT, zone, |
| 1151 | nr_scan); |
| 1152 | } |
| 1153 | |
| 1154 | if (nr_taken == 0) |
| 1155 | goto done; |
| 1156 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1157 | nr_active = clear_active_flags(&page_list, count); |
Andy Whitcroft | e9187bd | 2007-08-22 14:01:25 -0700 | [diff] [blame] | 1158 | __count_vm_events(PGDEACTIVATE, nr_active); |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1159 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1160 | __mod_zone_page_state(zone, NR_ACTIVE_FILE, |
| 1161 | -count[LRU_ACTIVE_FILE]); |
| 1162 | __mod_zone_page_state(zone, NR_INACTIVE_FILE, |
| 1163 | -count[LRU_INACTIVE_FILE]); |
| 1164 | __mod_zone_page_state(zone, NR_ACTIVE_ANON, |
| 1165 | -count[LRU_ACTIVE_ANON]); |
| 1166 | __mod_zone_page_state(zone, NR_INACTIVE_ANON, |
| 1167 | -count[LRU_INACTIVE_ANON]); |
| 1168 | |
KOSAKI Motohiro | a731286 | 2009-09-21 17:01:37 -0700 | [diff] [blame] | 1169 | nr_anon = count[LRU_ACTIVE_ANON] + count[LRU_INACTIVE_ANON]; |
| 1170 | nr_file = count[LRU_ACTIVE_FILE] + count[LRU_INACTIVE_FILE]; |
| 1171 | __mod_zone_page_state(zone, NR_ISOLATED_ANON, nr_anon); |
| 1172 | __mod_zone_page_state(zone, NR_ISOLATED_FILE, nr_file); |
KOSAKI Motohiro | 3e2f41f | 2009-01-07 18:08:20 -0800 | [diff] [blame] | 1173 | |
| 1174 | reclaim_stat->recent_scanned[0] += count[LRU_INACTIVE_ANON]; |
| 1175 | reclaim_stat->recent_scanned[0] += count[LRU_ACTIVE_ANON]; |
| 1176 | reclaim_stat->recent_scanned[1] += count[LRU_INACTIVE_FILE]; |
| 1177 | reclaim_stat->recent_scanned[1] += count[LRU_ACTIVE_FILE]; |
| 1178 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1179 | spin_unlock_irq(&zone->lru_lock); |
| 1180 | |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1181 | nr_scanned += nr_scan; |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 1182 | nr_freed = shrink_page_list(&page_list, sc, PAGEOUT_IO_ASYNC); |
| 1183 | |
| 1184 | /* |
| 1185 | * If we are direct reclaiming for contiguous pages and we do |
| 1186 | * not reclaim everything in the list, try again and wait |
| 1187 | * for IO to complete. This will stall high-order allocations |
| 1188 | * but that should be acceptable to the caller |
| 1189 | */ |
| 1190 | if (nr_freed < nr_taken && !current_is_kswapd() && |
KOSAKI Motohiro | 78dc583 | 2009-06-16 15:31:40 -0700 | [diff] [blame] | 1191 | lumpy_reclaim) { |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 1192 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 1193 | |
| 1194 | /* |
| 1195 | * The attempt at page out may have made some |
| 1196 | * of the pages active, mark them inactive again. |
| 1197 | */ |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1198 | nr_active = clear_active_flags(&page_list, count); |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 1199 | count_vm_events(PGDEACTIVATE, nr_active); |
| 1200 | |
| 1201 | nr_freed += shrink_page_list(&page_list, sc, |
| 1202 | PAGEOUT_IO_SYNC); |
| 1203 | } |
| 1204 | |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1205 | nr_reclaimed += nr_freed; |
KOSAKI Motohiro | b35ea17 | 2009-09-21 17:01:36 -0700 | [diff] [blame] | 1206 | |
Nick Piggin | a74609f | 2006-01-06 00:11:20 -0800 | [diff] [blame] | 1207 | local_irq_disable(); |
KOSAKI Motohiro | b35ea17 | 2009-09-21 17:01:36 -0700 | [diff] [blame] | 1208 | if (current_is_kswapd()) |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1209 | __count_vm_events(KSWAPD_STEAL, nr_freed); |
Shantanu Goel | 918d3f9 | 2006-12-29 16:48:59 -0800 | [diff] [blame] | 1210 | __count_zone_vm_events(PGSTEAL, zone, nr_freed); |
Nick Piggin | a74609f | 2006-01-06 00:11:20 -0800 | [diff] [blame] | 1211 | |
| 1212 | spin_lock(&zone->lru_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1213 | /* |
| 1214 | * Put back any unfreeable pages. |
| 1215 | */ |
| 1216 | while (!list_empty(&page_list)) { |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1217 | int lru; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1218 | page = lru_to_page(&page_list); |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 1219 | VM_BUG_ON(PageLRU(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1220 | list_del(&page->lru); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1221 | if (unlikely(!page_evictable(page, NULL))) { |
| 1222 | spin_unlock_irq(&zone->lru_lock); |
| 1223 | putback_lru_page(page); |
| 1224 | spin_lock_irq(&zone->lru_lock); |
| 1225 | continue; |
| 1226 | } |
| 1227 | SetPageLRU(page); |
| 1228 | lru = page_lru(page); |
| 1229 | add_page_to_lru_list(zone, page, lru); |
KOSAKI Motohiro | 74a1c48 | 2009-09-21 17:01:45 -0700 | [diff] [blame] | 1230 | if (is_active_lru(lru)) { |
Johannes Weiner | b7c46d1 | 2009-09-21 17:02:56 -0700 | [diff] [blame] | 1231 | int file = is_file_lru(lru); |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1232 | reclaim_stat->recent_rotated[file]++; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1233 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1234 | if (!pagevec_add(&pvec, page)) { |
| 1235 | spin_unlock_irq(&zone->lru_lock); |
| 1236 | __pagevec_release(&pvec); |
| 1237 | spin_lock_irq(&zone->lru_lock); |
| 1238 | } |
| 1239 | } |
KOSAKI Motohiro | a731286 | 2009-09-21 17:01:37 -0700 | [diff] [blame] | 1240 | __mod_zone_page_state(zone, NR_ISOLATED_ANON, -nr_anon); |
| 1241 | __mod_zone_page_state(zone, NR_ISOLATED_FILE, -nr_file); |
| 1242 | |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1243 | } while (nr_scanned < max_scan); |
KOSAKI Motohiro | b35ea17 | 2009-09-21 17:01:36 -0700 | [diff] [blame] | 1244 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1245 | done: |
KOSAKI Motohiro | b35ea17 | 2009-09-21 17:01:36 -0700 | [diff] [blame] | 1246 | spin_unlock_irq(&zone->lru_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1247 | pagevec_release(&pvec); |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1248 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1249 | } |
| 1250 | |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1251 | /* |
| 1252 | * We are about to scan this zone at a certain priority level. If that priority |
| 1253 | * level is smaller (ie: more urgent) than the previous priority, then note |
| 1254 | * that priority level within the zone. This is done so that when the next |
| 1255 | * process comes in to scan this zone, it will immediately start out at this |
| 1256 | * priority level rather than having to build up its own scanning priority. |
| 1257 | * Here, this priority affects only the reclaim-mapped threshold. |
| 1258 | */ |
| 1259 | static inline void note_zone_scanning_priority(struct zone *zone, int priority) |
| 1260 | { |
| 1261 | if (priority < zone->prev_priority) |
| 1262 | zone->prev_priority = priority; |
| 1263 | } |
| 1264 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1265 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1266 | * This moves pages from the active list to the inactive list. |
| 1267 | * |
| 1268 | * We move them the other way if the page is referenced by one or more |
| 1269 | * processes, from rmap. |
| 1270 | * |
| 1271 | * If the pages are mostly unmapped, the processing is fast and it is |
| 1272 | * appropriate to hold zone->lru_lock across the whole operation. But if |
| 1273 | * the pages are mapped, the processing is slow (page_referenced()) so we |
| 1274 | * should drop zone->lru_lock around each page. It's impossible to balance |
| 1275 | * this, so instead we remove the pages from the LRU while processing them. |
| 1276 | * It is safe to rely on PG_active against the non-LRU pages in here because |
| 1277 | * nobody will play with that bit on a non-LRU page. |
| 1278 | * |
| 1279 | * The downside is that we have to touch page->_count against each page. |
| 1280 | * But we had to alter page->flags anyway. |
| 1281 | */ |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1282 | |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1283 | static void move_active_pages_to_lru(struct zone *zone, |
| 1284 | struct list_head *list, |
| 1285 | enum lru_list lru) |
| 1286 | { |
| 1287 | unsigned long pgmoved = 0; |
| 1288 | struct pagevec pvec; |
| 1289 | struct page *page; |
| 1290 | |
| 1291 | pagevec_init(&pvec, 1); |
| 1292 | |
| 1293 | while (!list_empty(list)) { |
| 1294 | page = lru_to_page(list); |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1295 | |
| 1296 | VM_BUG_ON(PageLRU(page)); |
| 1297 | SetPageLRU(page); |
| 1298 | |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1299 | list_move(&page->lru, &zone->lru[lru].list); |
| 1300 | mem_cgroup_add_lru_list(page, lru); |
| 1301 | pgmoved++; |
| 1302 | |
| 1303 | if (!pagevec_add(&pvec, page) || list_empty(list)) { |
| 1304 | spin_unlock_irq(&zone->lru_lock); |
| 1305 | if (buffer_heads_over_limit) |
| 1306 | pagevec_strip(&pvec); |
| 1307 | __pagevec_release(&pvec); |
| 1308 | spin_lock_irq(&zone->lru_lock); |
| 1309 | } |
| 1310 | } |
| 1311 | __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved); |
| 1312 | if (!is_active_lru(lru)) |
| 1313 | __count_vm_events(PGDEACTIVATE, pgmoved); |
| 1314 | } |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1315 | |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 1316 | static void shrink_active_list(unsigned long nr_pages, struct zone *zone, |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1317 | struct scan_control *sc, int priority, int file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1318 | { |
KOSAKI Motohiro | 44c241f | 2009-09-21 17:01:35 -0700 | [diff] [blame] | 1319 | unsigned long nr_taken; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1320 | unsigned long pgscanned; |
Wu Fengguang | 6fe6b7e | 2009-06-16 15:33:05 -0700 | [diff] [blame] | 1321 | unsigned long vm_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1322 | LIST_HEAD(l_hold); /* The pages which were snipped off */ |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1323 | LIST_HEAD(l_active); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1324 | LIST_HEAD(l_inactive); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1325 | struct page *page; |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1326 | struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); |
KOSAKI Motohiro | 44c241f | 2009-09-21 17:01:35 -0700 | [diff] [blame] | 1327 | unsigned long nr_rotated = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1328 | |
| 1329 | lru_add_drain(); |
| 1330 | spin_lock_irq(&zone->lru_lock); |
KOSAKI Motohiro | 44c241f | 2009-09-21 17:01:35 -0700 | [diff] [blame] | 1331 | nr_taken = sc->isolate_pages(nr_pages, &l_hold, &pgscanned, sc->order, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1332 | ISOLATE_ACTIVE, zone, |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1333 | sc->mem_cgroup, 1, file); |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1334 | /* |
| 1335 | * zone->pages_scanned is used for detect zone's oom |
| 1336 | * mem_cgroup remembers nr_scan by itself. |
| 1337 | */ |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1338 | if (scanning_global_lru(sc)) { |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1339 | zone->pages_scanned += pgscanned; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1340 | } |
Johannes Weiner | b7c46d1 | 2009-09-21 17:02:56 -0700 | [diff] [blame] | 1341 | reclaim_stat->recent_scanned[file] += nr_taken; |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1342 | |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1343 | __count_zone_vm_events(PGREFILL, zone, pgscanned); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1344 | if (file) |
KOSAKI Motohiro | 44c241f | 2009-09-21 17:01:35 -0700 | [diff] [blame] | 1345 | __mod_zone_page_state(zone, NR_ACTIVE_FILE, -nr_taken); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1346 | else |
KOSAKI Motohiro | 44c241f | 2009-09-21 17:01:35 -0700 | [diff] [blame] | 1347 | __mod_zone_page_state(zone, NR_ACTIVE_ANON, -nr_taken); |
KOSAKI Motohiro | a731286 | 2009-09-21 17:01:37 -0700 | [diff] [blame] | 1348 | __mod_zone_page_state(zone, NR_ISOLATED_ANON + file, nr_taken); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1349 | spin_unlock_irq(&zone->lru_lock); |
| 1350 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1351 | while (!list_empty(&l_hold)) { |
| 1352 | cond_resched(); |
| 1353 | page = lru_to_page(&l_hold); |
| 1354 | list_del(&page->lru); |
Rik van Riel | 7e9cd48 | 2008-10-18 20:26:35 -0700 | [diff] [blame] | 1355 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1356 | if (unlikely(!page_evictable(page, NULL))) { |
| 1357 | putback_lru_page(page); |
| 1358 | continue; |
| 1359 | } |
| 1360 | |
Rik van Riel | 7e9cd48 | 2008-10-18 20:26:35 -0700 | [diff] [blame] | 1361 | /* page_referenced clears PageReferenced */ |
| 1362 | if (page_mapping_inuse(page) && |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1363 | page_referenced(page, 0, sc->mem_cgroup, &vm_flags)) { |
KOSAKI Motohiro | 44c241f | 2009-09-21 17:01:35 -0700 | [diff] [blame] | 1364 | nr_rotated++; |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1365 | /* |
| 1366 | * Identify referenced, file-backed active pages and |
| 1367 | * give them one more trip around the active list. So |
| 1368 | * that executable code get better chances to stay in |
| 1369 | * memory under moderate memory pressure. Anon pages |
| 1370 | * are not likely to be evicted by use-once streaming |
| 1371 | * IO, plus JVM can create lots of anon VM_EXEC pages, |
| 1372 | * so we ignore them here. |
| 1373 | */ |
Wu Fengguang | 41e2098 | 2009-10-26 16:49:53 -0700 | [diff] [blame] | 1374 | if ((vm_flags & VM_EXEC) && page_is_file_cache(page)) { |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1375 | list_add(&page->lru, &l_active); |
| 1376 | continue; |
| 1377 | } |
| 1378 | } |
Rik van Riel | 7e9cd48 | 2008-10-18 20:26:35 -0700 | [diff] [blame] | 1379 | |
KOSAKI Motohiro | 5205e56 | 2009-09-21 17:01:44 -0700 | [diff] [blame] | 1380 | ClearPageActive(page); /* we are de-activating */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1381 | list_add(&page->lru, &l_inactive); |
| 1382 | } |
| 1383 | |
Andrew Morton | b555749 | 2009-01-06 14:40:13 -0800 | [diff] [blame] | 1384 | /* |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1385 | * Move pages back to the lru list. |
Andrew Morton | b555749 | 2009-01-06 14:40:13 -0800 | [diff] [blame] | 1386 | */ |
Johannes Weiner | 2a1dc50 | 2008-12-01 03:00:35 +0100 | [diff] [blame] | 1387 | spin_lock_irq(&zone->lru_lock); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1388 | /* |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1389 | * Count referenced pages from currently used mappings as rotated, |
| 1390 | * even though only some of them are actually re-activated. This |
| 1391 | * helps balance scan pressure between file and anonymous pages in |
| 1392 | * get_scan_ratio. |
Rik van Riel | 7e9cd48 | 2008-10-18 20:26:35 -0700 | [diff] [blame] | 1393 | */ |
Johannes Weiner | b7c46d1 | 2009-09-21 17:02:56 -0700 | [diff] [blame] | 1394 | reclaim_stat->recent_rotated[file] += nr_rotated; |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1395 | |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1396 | move_active_pages_to_lru(zone, &l_active, |
| 1397 | LRU_ACTIVE + file * LRU_FILE); |
| 1398 | move_active_pages_to_lru(zone, &l_inactive, |
| 1399 | LRU_BASE + file * LRU_FILE); |
KOSAKI Motohiro | a731286 | 2009-09-21 17:01:37 -0700 | [diff] [blame] | 1400 | __mod_zone_page_state(zone, NR_ISOLATED_ANON + file, -nr_taken); |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1401 | spin_unlock_irq(&zone->lru_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1402 | } |
| 1403 | |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1404 | static int inactive_anon_is_low_global(struct zone *zone) |
KOSAKI Motohiro | f89eb90 | 2009-01-07 18:08:14 -0800 | [diff] [blame] | 1405 | { |
| 1406 | unsigned long active, inactive; |
| 1407 | |
| 1408 | active = zone_page_state(zone, NR_ACTIVE_ANON); |
| 1409 | inactive = zone_page_state(zone, NR_INACTIVE_ANON); |
| 1410 | |
| 1411 | if (inactive * zone->inactive_ratio < active) |
| 1412 | return 1; |
| 1413 | |
| 1414 | return 0; |
| 1415 | } |
| 1416 | |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1417 | /** |
| 1418 | * inactive_anon_is_low - check if anonymous pages need to be deactivated |
| 1419 | * @zone: zone to check |
| 1420 | * @sc: scan control of this context |
| 1421 | * |
| 1422 | * Returns true if the zone does not have enough inactive anon pages, |
| 1423 | * meaning some active anon pages need to be deactivated. |
| 1424 | */ |
| 1425 | static int inactive_anon_is_low(struct zone *zone, struct scan_control *sc) |
| 1426 | { |
| 1427 | int low; |
| 1428 | |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1429 | if (scanning_global_lru(sc)) |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1430 | low = inactive_anon_is_low_global(zone); |
| 1431 | else |
KOSAKI Motohiro | c772be9 | 2009-01-07 18:08:25 -0800 | [diff] [blame] | 1432 | low = mem_cgroup_inactive_anon_is_low(sc->mem_cgroup); |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1433 | return low; |
| 1434 | } |
| 1435 | |
Rik van Riel | 56e49d2 | 2009-06-16 15:32:28 -0700 | [diff] [blame] | 1436 | static int inactive_file_is_low_global(struct zone *zone) |
| 1437 | { |
| 1438 | unsigned long active, inactive; |
| 1439 | |
| 1440 | active = zone_page_state(zone, NR_ACTIVE_FILE); |
| 1441 | inactive = zone_page_state(zone, NR_INACTIVE_FILE); |
| 1442 | |
| 1443 | return (active > inactive); |
| 1444 | } |
| 1445 | |
| 1446 | /** |
| 1447 | * inactive_file_is_low - check if file pages need to be deactivated |
| 1448 | * @zone: zone to check |
| 1449 | * @sc: scan control of this context |
| 1450 | * |
| 1451 | * When the system is doing streaming IO, memory pressure here |
| 1452 | * ensures that active file pages get deactivated, until more |
| 1453 | * than half of the file pages are on the inactive list. |
| 1454 | * |
| 1455 | * Once we get to that situation, protect the system's working |
| 1456 | * set from being evicted by disabling active file page aging. |
| 1457 | * |
| 1458 | * This uses a different ratio than the anonymous pages, because |
| 1459 | * the page cache uses a use-once replacement algorithm. |
| 1460 | */ |
| 1461 | static int inactive_file_is_low(struct zone *zone, struct scan_control *sc) |
| 1462 | { |
| 1463 | int low; |
| 1464 | |
| 1465 | if (scanning_global_lru(sc)) |
| 1466 | low = inactive_file_is_low_global(zone); |
| 1467 | else |
| 1468 | low = mem_cgroup_inactive_file_is_low(sc->mem_cgroup); |
| 1469 | return low; |
| 1470 | } |
| 1471 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1472 | static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan, |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1473 | struct zone *zone, struct scan_control *sc, int priority) |
| 1474 | { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1475 | int file = is_file_lru(lru); |
| 1476 | |
Rik van Riel | 56e49d2 | 2009-06-16 15:32:28 -0700 | [diff] [blame] | 1477 | if (lru == LRU_ACTIVE_FILE && inactive_file_is_low(zone, sc)) { |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1478 | shrink_active_list(nr_to_scan, zone, sc, priority, file); |
| 1479 | return 0; |
| 1480 | } |
| 1481 | |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1482 | if (lru == LRU_ACTIVE_ANON && inactive_anon_is_low(zone, sc)) { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1483 | shrink_active_list(nr_to_scan, zone, sc, priority, file); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1484 | return 0; |
| 1485 | } |
Rik van Riel | 33c120e | 2008-10-18 20:26:36 -0700 | [diff] [blame] | 1486 | return shrink_inactive_list(nr_to_scan, zone, sc, priority, file); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1487 | } |
| 1488 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1489 | /* |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1490 | * Determine how aggressively the anon and file LRU lists should be |
| 1491 | * scanned. The relative value of each set of LRU lists is determined |
| 1492 | * by looking at the fraction of the pages scanned we did rotate back |
| 1493 | * onto the active list instead of evict. |
| 1494 | * |
| 1495 | * percent[0] specifies how much pressure to put on ram/swap backed |
| 1496 | * memory, while percent[1] determines pressure on the file LRUs. |
| 1497 | */ |
| 1498 | static void get_scan_ratio(struct zone *zone, struct scan_control *sc, |
| 1499 | unsigned long *percent) |
| 1500 | { |
| 1501 | unsigned long anon, file, free; |
| 1502 | unsigned long anon_prio, file_prio; |
| 1503 | unsigned long ap, fp; |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1504 | struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1505 | |
Vincent Li | 0b21767 | 2009-09-21 17:03:09 -0700 | [diff] [blame] | 1506 | anon = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_ANON) + |
| 1507 | zone_nr_lru_pages(zone, sc, LRU_INACTIVE_ANON); |
| 1508 | file = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_FILE) + |
| 1509 | zone_nr_lru_pages(zone, sc, LRU_INACTIVE_FILE); |
Hugh Dickins | b962716 | 2009-01-06 14:39:41 -0800 | [diff] [blame] | 1510 | |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1511 | if (scanning_global_lru(sc)) { |
KOSAKI Motohiro | eeee9a8 | 2009-01-07 18:08:17 -0800 | [diff] [blame] | 1512 | free = zone_page_state(zone, NR_FREE_PAGES); |
| 1513 | /* If we have very few page cache pages, |
| 1514 | force-scan anon pages. */ |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1515 | if (unlikely(file + free <= high_wmark_pages(zone))) { |
KOSAKI Motohiro | eeee9a8 | 2009-01-07 18:08:17 -0800 | [diff] [blame] | 1516 | percent[0] = 100; |
| 1517 | percent[1] = 0; |
| 1518 | return; |
| 1519 | } |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1520 | } |
| 1521 | |
| 1522 | /* |
| 1523 | * OK, so we have swap space and a fair amount of page cache |
| 1524 | * pages. We use the recently rotated / recently scanned |
| 1525 | * ratios to determine how valuable each cache is. |
| 1526 | * |
| 1527 | * Because workloads change over time (and to avoid overflow) |
| 1528 | * we keep these statistics as a floating average, which ends |
| 1529 | * up weighing recent references more than old ones. |
| 1530 | * |
| 1531 | * anon in [0], file in [1] |
| 1532 | */ |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1533 | if (unlikely(reclaim_stat->recent_scanned[0] > anon / 4)) { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1534 | spin_lock_irq(&zone->lru_lock); |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1535 | reclaim_stat->recent_scanned[0] /= 2; |
| 1536 | reclaim_stat->recent_rotated[0] /= 2; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1537 | spin_unlock_irq(&zone->lru_lock); |
| 1538 | } |
| 1539 | |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1540 | if (unlikely(reclaim_stat->recent_scanned[1] > file / 4)) { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1541 | spin_lock_irq(&zone->lru_lock); |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1542 | reclaim_stat->recent_scanned[1] /= 2; |
| 1543 | reclaim_stat->recent_rotated[1] /= 2; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1544 | spin_unlock_irq(&zone->lru_lock); |
| 1545 | } |
| 1546 | |
| 1547 | /* |
| 1548 | * With swappiness at 100, anonymous and file have the same priority. |
| 1549 | * This scanning priority is essentially the inverse of IO cost. |
| 1550 | */ |
| 1551 | anon_prio = sc->swappiness; |
| 1552 | file_prio = 200 - sc->swappiness; |
| 1553 | |
| 1554 | /* |
Rik van Riel | 00d8089 | 2008-11-19 15:36:44 -0800 | [diff] [blame] | 1555 | * The amount of pressure on anon vs file pages is inversely |
| 1556 | * proportional to the fraction of recently scanned pages on |
| 1557 | * each list that were recently referenced and in active use. |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1558 | */ |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1559 | ap = (anon_prio + 1) * (reclaim_stat->recent_scanned[0] + 1); |
| 1560 | ap /= reclaim_stat->recent_rotated[0] + 1; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1561 | |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1562 | fp = (file_prio + 1) * (reclaim_stat->recent_scanned[1] + 1); |
| 1563 | fp /= reclaim_stat->recent_rotated[1] + 1; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1564 | |
| 1565 | /* Normalize to percentages */ |
| 1566 | percent[0] = 100 * ap / (ap + fp + 1); |
| 1567 | percent[1] = 100 - percent[0]; |
| 1568 | } |
| 1569 | |
Wu Fengguang | 6e08a36 | 2009-06-16 15:32:29 -0700 | [diff] [blame] | 1570 | /* |
| 1571 | * Smallish @nr_to_scan's are deposited in @nr_saved_scan, |
| 1572 | * until we collected @swap_cluster_max pages to scan. |
| 1573 | */ |
| 1574 | static unsigned long nr_scan_try_batch(unsigned long nr_to_scan, |
| 1575 | unsigned long *nr_saved_scan, |
| 1576 | unsigned long swap_cluster_max) |
| 1577 | { |
| 1578 | unsigned long nr; |
| 1579 | |
| 1580 | *nr_saved_scan += nr_to_scan; |
| 1581 | nr = *nr_saved_scan; |
| 1582 | |
| 1583 | if (nr >= swap_cluster_max) |
| 1584 | *nr_saved_scan = 0; |
| 1585 | else |
| 1586 | nr = 0; |
| 1587 | |
| 1588 | return nr; |
| 1589 | } |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1590 | |
| 1591 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1592 | * This is a basic per-zone page freer. Used by both kswapd and direct reclaim. |
| 1593 | */ |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1594 | static void shrink_zone(int priority, struct zone *zone, |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1595 | struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1596 | { |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1597 | unsigned long nr[NR_LRU_LISTS]; |
Christoph Lameter | 8695949 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 1598 | unsigned long nr_to_scan; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1599 | unsigned long percent[2]; /* anon @ 0; file @ 1 */ |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1600 | enum lru_list l; |
KOSAKI Motohiro | 01dbe5c | 2009-01-06 14:40:02 -0800 | [diff] [blame] | 1601 | unsigned long nr_reclaimed = sc->nr_reclaimed; |
| 1602 | unsigned long swap_cluster_max = sc->swap_cluster_max; |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 1603 | unsigned long nr_to_reclaim = sc->nr_to_reclaim; |
Wu Fengguang | f862963 | 2009-09-21 17:03:11 -0700 | [diff] [blame] | 1604 | struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); |
Daisuke Nishimura | 9198e96 | 2009-06-16 15:33:15 -0700 | [diff] [blame] | 1605 | int noswap = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1606 | |
Daisuke Nishimura | 9198e96 | 2009-06-16 15:33:15 -0700 | [diff] [blame] | 1607 | /* If we have no swap space, do not bother scanning anon pages. */ |
| 1608 | if (!sc->may_swap || (nr_swap_pages <= 0)) { |
| 1609 | noswap = 1; |
| 1610 | percent[0] = 0; |
| 1611 | percent[1] = 100; |
| 1612 | } else |
| 1613 | get_scan_ratio(zone, sc, percent); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1614 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1615 | for_each_evictable_lru(l) { |
KOSAKI Motohiro | 9439c1c | 2009-01-07 18:08:21 -0800 | [diff] [blame] | 1616 | int file = is_file_lru(l); |
Andrew Morton | 8713e01 | 2009-04-30 15:08:55 -0700 | [diff] [blame] | 1617 | unsigned long scan; |
Johannes Weiner | e0f79b8 | 2008-10-18 20:26:55 -0700 | [diff] [blame] | 1618 | |
Vincent Li | 0b21767 | 2009-09-21 17:03:09 -0700 | [diff] [blame] | 1619 | scan = zone_nr_lru_pages(zone, sc, l); |
Daisuke Nishimura | 9198e96 | 2009-06-16 15:33:15 -0700 | [diff] [blame] | 1620 | if (priority || noswap) { |
KOSAKI Motohiro | 9439c1c | 2009-01-07 18:08:21 -0800 | [diff] [blame] | 1621 | scan >>= priority; |
| 1622 | scan = (scan * percent[file]) / 100; |
| 1623 | } |
Wu Fengguang | f862963 | 2009-09-21 17:03:11 -0700 | [diff] [blame] | 1624 | nr[l] = nr_scan_try_batch(scan, |
| 1625 | &reclaim_stat->nr_saved_scan[l], |
| 1626 | swap_cluster_max); |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1627 | } |
| 1628 | |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1629 | while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] || |
| 1630 | nr[LRU_INACTIVE_FILE]) { |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1631 | for_each_evictable_lru(l) { |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1632 | if (nr[l]) { |
KOSAKI Motohiro | 01dbe5c | 2009-01-06 14:40:02 -0800 | [diff] [blame] | 1633 | nr_to_scan = min(nr[l], swap_cluster_max); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1634 | nr[l] -= nr_to_scan; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1635 | |
KOSAKI Motohiro | 01dbe5c | 2009-01-06 14:40:02 -0800 | [diff] [blame] | 1636 | nr_reclaimed += shrink_list(l, nr_to_scan, |
| 1637 | zone, sc, priority); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1638 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1639 | } |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1640 | /* |
| 1641 | * On large memory systems, scan >> priority can become |
| 1642 | * really large. This is fine for the starting priority; |
| 1643 | * we want to put equal scanning pressure on each zone. |
| 1644 | * However, if the VM has a harder time of freeing pages, |
| 1645 | * with multiple processes reclaiming pages, the total |
| 1646 | * freeing target can get unreasonably large. |
| 1647 | */ |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 1648 | if (nr_reclaimed > nr_to_reclaim && priority < DEF_PRIORITY) |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1649 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1650 | } |
| 1651 | |
KOSAKI Motohiro | 01dbe5c | 2009-01-06 14:40:02 -0800 | [diff] [blame] | 1652 | sc->nr_reclaimed = nr_reclaimed; |
| 1653 | |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1654 | /* |
| 1655 | * Even if we did not try to evict anon pages at all, we want to |
| 1656 | * rebalance the anon lru active/inactive ratio. |
| 1657 | */ |
MinChan Kim | 69c8548 | 2009-06-16 15:32:44 -0700 | [diff] [blame] | 1658 | if (inactive_anon_is_low(zone, sc) && nr_swap_pages > 0) |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1659 | shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0); |
| 1660 | |
Andrew Morton | 232ea4d | 2007-02-28 20:13:21 -0800 | [diff] [blame] | 1661 | throttle_vm_writeout(sc->gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1662 | } |
| 1663 | |
| 1664 | /* |
| 1665 | * This is the direct reclaim path, for page-allocating processes. We only |
| 1666 | * try to reclaim pages from zones which will satisfy the caller's allocation |
| 1667 | * request. |
| 1668 | * |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1669 | * We reclaim from a zone even if that zone is over high_wmark_pages(zone). |
| 1670 | * Because: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1671 | * a) The caller may be trying to free *extra* pages to satisfy a higher-order |
| 1672 | * allocation or |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1673 | * b) The target zone may be at high_wmark_pages(zone) but the lower zones |
| 1674 | * must go *over* high_wmark_pages(zone) to satisfy the `incremental min' |
| 1675 | * zone defense algorithm. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1676 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1677 | * If a zone is deemed to be full of pinned pages then just give it a light |
| 1678 | * scan then give up on it. |
| 1679 | */ |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1680 | static void shrink_zones(int priority, struct zonelist *zonelist, |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1681 | struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1682 | { |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1683 | enum zone_type high_zoneidx = gfp_zone(sc->gfp_mask); |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1684 | struct zoneref *z; |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1685 | struct zone *zone; |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1686 | |
Nick Piggin | 408d854 | 2006-09-25 23:31:27 -0700 | [diff] [blame] | 1687 | sc->all_unreclaimable = 1; |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 1688 | for_each_zone_zonelist_nodemask(zone, z, zonelist, high_zoneidx, |
| 1689 | sc->nodemask) { |
Con Kolivas | f3fe651 | 2006-01-06 00:11:15 -0800 | [diff] [blame] | 1690 | if (!populated_zone(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1691 | continue; |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1692 | /* |
| 1693 | * Take care memory controller reclaiming has small influence |
| 1694 | * to global LRU. |
| 1695 | */ |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1696 | if (scanning_global_lru(sc)) { |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1697 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
| 1698 | continue; |
| 1699 | note_zone_scanning_priority(zone, priority); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1700 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1701 | if (zone_is_all_unreclaimable(zone) && |
| 1702 | priority != DEF_PRIORITY) |
| 1703 | continue; /* Let kswapd poll it */ |
| 1704 | sc->all_unreclaimable = 0; |
| 1705 | } else { |
| 1706 | /* |
| 1707 | * Ignore cpuset limitation here. We just want to reduce |
| 1708 | * # of used pages by us regardless of memory shortage. |
| 1709 | */ |
| 1710 | sc->all_unreclaimable = 0; |
| 1711 | mem_cgroup_note_reclaim_priority(sc->mem_cgroup, |
| 1712 | priority); |
| 1713 | } |
Nick Piggin | 408d854 | 2006-09-25 23:31:27 -0700 | [diff] [blame] | 1714 | |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1715 | shrink_zone(priority, zone, sc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1716 | } |
| 1717 | } |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1718 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1719 | /* |
| 1720 | * This is the main entry point to direct page reclaim. |
| 1721 | * |
| 1722 | * If a full scan of the inactive list fails to free enough memory then we |
| 1723 | * are "out of memory" and something needs to be killed. |
| 1724 | * |
| 1725 | * If the caller is !__GFP_FS then the probability of a failure is reasonably |
| 1726 | * high - the zone may be full of dirty or under-writeback pages, which this |
Jens Axboe | 5b0830c | 2009-09-23 19:37:09 +0200 | [diff] [blame] | 1727 | * caller can't do much about. We kick the writeback threads and take explicit |
| 1728 | * naps in the hope that some of these pages can be written. But if the |
| 1729 | * allocating task holds filesystem locks which prevent writeout this might not |
| 1730 | * work, and the allocation attempt will fail. |
Nishanth Aravamudan | a41f24e | 2008-04-29 00:58:25 -0700 | [diff] [blame] | 1731 | * |
| 1732 | * returns: 0, if no pages reclaimed |
| 1733 | * else, the number of pages reclaimed |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1734 | */ |
Mel Gorman | dac1d27 | 2008-04-28 02:12:12 -0700 | [diff] [blame] | 1735 | static unsigned long do_try_to_free_pages(struct zonelist *zonelist, |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1736 | struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1737 | { |
| 1738 | int priority; |
kosaki.motohiro@jp.fujitsu.com | c700be3 | 2008-06-12 15:21:27 -0700 | [diff] [blame] | 1739 | unsigned long ret = 0; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1740 | unsigned long total_scanned = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1741 | struct reclaim_state *reclaim_state = current->reclaim_state; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1742 | unsigned long lru_pages = 0; |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1743 | struct zoneref *z; |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1744 | struct zone *zone; |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1745 | enum zone_type high_zoneidx = gfp_zone(sc->gfp_mask); |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 1746 | unsigned long writeback_threshold; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1747 | |
Keika Kobayashi | 873b477 | 2008-07-25 01:48:52 -0700 | [diff] [blame] | 1748 | delayacct_freepages_start(); |
| 1749 | |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1750 | if (scanning_global_lru(sc)) |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1751 | count_vm_event(ALLOCSTALL); |
| 1752 | /* |
| 1753 | * mem_cgroup will not do shrink_slab. |
| 1754 | */ |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1755 | if (scanning_global_lru(sc)) { |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1756 | for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1757 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1758 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
| 1759 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1760 | |
Wu Fengguang | adea02a | 2009-09-21 17:01:42 -0700 | [diff] [blame] | 1761 | lru_pages += zone_reclaimable_pages(zone); |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1762 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1763 | } |
| 1764 | |
| 1765 | for (priority = DEF_PRIORITY; priority >= 0; priority--) { |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1766 | sc->nr_scanned = 0; |
Rik van Riel | f7b7fd8 | 2005-11-28 13:44:07 -0800 | [diff] [blame] | 1767 | if (!priority) |
| 1768 | disable_swap_token(); |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1769 | shrink_zones(priority, zonelist, sc); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1770 | /* |
| 1771 | * Don't shrink slabs when reclaiming memory from |
| 1772 | * over limit cgroups |
| 1773 | */ |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1774 | if (scanning_global_lru(sc)) { |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1775 | shrink_slab(sc->nr_scanned, sc->gfp_mask, lru_pages); |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 1776 | if (reclaim_state) { |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1777 | sc->nr_reclaimed += reclaim_state->reclaimed_slab; |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 1778 | reclaim_state->reclaimed_slab = 0; |
| 1779 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1780 | } |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1781 | total_scanned += sc->nr_scanned; |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 1782 | if (sc->nr_reclaimed >= sc->nr_to_reclaim) { |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1783 | ret = sc->nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1784 | goto out; |
| 1785 | } |
| 1786 | |
| 1787 | /* |
| 1788 | * Try to write back as many pages as we just scanned. This |
| 1789 | * tends to cause slow streaming writers to write data to the |
| 1790 | * disk smoothly, at the dirtying rate, which is nice. But |
| 1791 | * that's undesirable in laptop mode, where we *want* lumpy |
| 1792 | * writeout. So in laptop mode, write out the whole world. |
| 1793 | */ |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 1794 | writeback_threshold = sc->nr_to_reclaim + sc->nr_to_reclaim / 2; |
| 1795 | if (total_scanned > writeback_threshold) { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 1796 | wakeup_flusher_threads(laptop_mode ? 0 : total_scanned); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1797 | sc->may_writepage = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1798 | } |
| 1799 | |
| 1800 | /* Take a nap, wait for some writeback to complete */ |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame^] | 1801 | if (!sc->hibernation_mode && sc->nr_scanned && |
| 1802 | priority < DEF_PRIORITY - 2) |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 1803 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1804 | } |
Fernando Luis Vazquez Cao | 87547ee | 2008-07-29 22:33:42 -0700 | [diff] [blame] | 1805 | /* top priority shrink_zones still had more to do? don't OOM, then */ |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1806 | if (!sc->all_unreclaimable && scanning_global_lru(sc)) |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1807 | ret = sc->nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1808 | out: |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1809 | /* |
| 1810 | * Now that we've scanned all the zones at this priority level, note |
| 1811 | * that level within the zone so that the next thread which performs |
| 1812 | * scanning of this zone will immediately start out at this priority |
| 1813 | * level. This affects only the decision whether or not to bring |
| 1814 | * mapped pages onto the inactive list. |
| 1815 | */ |
| 1816 | if (priority < 0) |
| 1817 | priority = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1818 | |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1819 | if (scanning_global_lru(sc)) { |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1820 | for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1821 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1822 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
| 1823 | continue; |
| 1824 | |
| 1825 | zone->prev_priority = priority; |
| 1826 | } |
| 1827 | } else |
| 1828 | mem_cgroup_record_reclaim_priority(sc->mem_cgroup, priority); |
| 1829 | |
Keika Kobayashi | 873b477 | 2008-07-25 01:48:52 -0700 | [diff] [blame] | 1830 | delayacct_freepages_end(); |
| 1831 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1832 | return ret; |
| 1833 | } |
| 1834 | |
Mel Gorman | dac1d27 | 2008-04-28 02:12:12 -0700 | [diff] [blame] | 1835 | unsigned long try_to_free_pages(struct zonelist *zonelist, int order, |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 1836 | gfp_t gfp_mask, nodemask_t *nodemask) |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1837 | { |
| 1838 | struct scan_control sc = { |
| 1839 | .gfp_mask = gfp_mask, |
| 1840 | .may_writepage = !laptop_mode, |
| 1841 | .swap_cluster_max = SWAP_CLUSTER_MAX, |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 1842 | .nr_to_reclaim = SWAP_CLUSTER_MAX, |
Johannes Weiner | a6dc60f | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 1843 | .may_unmap = 1, |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 1844 | .may_swap = 1, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1845 | .swappiness = vm_swappiness, |
| 1846 | .order = order, |
| 1847 | .mem_cgroup = NULL, |
| 1848 | .isolate_pages = isolate_pages_global, |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 1849 | .nodemask = nodemask, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1850 | }; |
| 1851 | |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1852 | return do_try_to_free_pages(zonelist, &sc); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1853 | } |
| 1854 | |
Balbir Singh | 00f0b82 | 2008-03-04 14:28:39 -0800 | [diff] [blame] | 1855 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1856 | |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 1857 | unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem, |
| 1858 | gfp_t gfp_mask, bool noswap, |
| 1859 | unsigned int swappiness, |
| 1860 | struct zone *zone, int nid) |
| 1861 | { |
| 1862 | struct scan_control sc = { |
| 1863 | .may_writepage = !laptop_mode, |
| 1864 | .may_unmap = 1, |
| 1865 | .may_swap = !noswap, |
| 1866 | .swap_cluster_max = SWAP_CLUSTER_MAX, |
| 1867 | .swappiness = swappiness, |
| 1868 | .order = 0, |
| 1869 | .mem_cgroup = mem, |
| 1870 | .isolate_pages = mem_cgroup_isolate_pages, |
| 1871 | }; |
| 1872 | nodemask_t nm = nodemask_of_node(nid); |
| 1873 | |
| 1874 | sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) | |
| 1875 | (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK); |
| 1876 | sc.nodemask = &nm; |
| 1877 | sc.nr_reclaimed = 0; |
| 1878 | sc.nr_scanned = 0; |
| 1879 | /* |
| 1880 | * NOTE: Although we can get the priority field, using it |
| 1881 | * here is not a good idea, since it limits the pages we can scan. |
| 1882 | * if we don't reclaim here, the shrink_zone from balance_pgdat |
| 1883 | * will pick up pages from other mem cgroup's as well. We hack |
| 1884 | * the priority and make it zero. |
| 1885 | */ |
| 1886 | shrink_zone(0, zone, &sc); |
| 1887 | return sc.nr_reclaimed; |
| 1888 | } |
| 1889 | |
Balbir Singh | e1a1cd5 | 2008-02-07 00:14:02 -0800 | [diff] [blame] | 1890 | unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont, |
KOSAKI Motohiro | a7885eb | 2009-01-07 18:08:24 -0800 | [diff] [blame] | 1891 | gfp_t gfp_mask, |
| 1892 | bool noswap, |
| 1893 | unsigned int swappiness) |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1894 | { |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 1895 | struct zonelist *zonelist; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1896 | struct scan_control sc = { |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1897 | .may_writepage = !laptop_mode, |
Johannes Weiner | a6dc60f | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 1898 | .may_unmap = 1, |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 1899 | .may_swap = !noswap, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1900 | .swap_cluster_max = SWAP_CLUSTER_MAX, |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 1901 | .nr_to_reclaim = SWAP_CLUSTER_MAX, |
KOSAKI Motohiro | a7885eb | 2009-01-07 18:08:24 -0800 | [diff] [blame] | 1902 | .swappiness = swappiness, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1903 | .order = 0, |
| 1904 | .mem_cgroup = mem_cont, |
| 1905 | .isolate_pages = mem_cgroup_isolate_pages, |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 1906 | .nodemask = NULL, /* we don't care the placement */ |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1907 | }; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1908 | |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1909 | sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) | |
| 1910 | (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK); |
| 1911 | zonelist = NODE_DATA(numa_node_id())->node_zonelists; |
| 1912 | return do_try_to_free_pages(zonelist, &sc); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1913 | } |
| 1914 | #endif |
| 1915 | |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 1916 | /* is kswapd sleeping prematurely? */ |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 1917 | static int sleeping_prematurely(pg_data_t *pgdat, int order, long remaining) |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 1918 | { |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 1919 | int i; |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 1920 | |
| 1921 | /* If a direct reclaimer woke kswapd within HZ/10, it's premature */ |
| 1922 | if (remaining) |
| 1923 | return 1; |
| 1924 | |
| 1925 | /* If after HZ/10, a zone is below the high mark, it's premature */ |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 1926 | for (i = 0; i < pgdat->nr_zones; i++) { |
| 1927 | struct zone *zone = pgdat->node_zones + i; |
| 1928 | |
| 1929 | if (!populated_zone(zone)) |
| 1930 | continue; |
| 1931 | |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 1932 | if (!zone_watermark_ok(zone, order, high_wmark_pages(zone), |
| 1933 | 0, 0)) |
| 1934 | return 1; |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 1935 | } |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 1936 | |
| 1937 | return 0; |
| 1938 | } |
| 1939 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1940 | /* |
| 1941 | * For kswapd, balance_pgdat() will work across all this node's zones until |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1942 | * they are all at high_wmark_pages(zone). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1943 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1944 | * Returns the number of pages which were actually freed. |
| 1945 | * |
| 1946 | * There is special handling here for zones which are full of pinned pages. |
| 1947 | * This can happen if the pages are all mlocked, or if they are all used by |
| 1948 | * device drivers (say, ZONE_DMA). Or if they are all in use by hugetlb. |
| 1949 | * What we do is to detect the case where all pages in the zone have been |
| 1950 | * scanned twice and there has been zero successful reclaim. Mark the zone as |
| 1951 | * dead and from now on, only perform a short scan. Basically we're polling |
| 1952 | * the zone for when the problem goes away. |
| 1953 | * |
| 1954 | * kswapd scans the zones in the highmem->normal->dma direction. It skips |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1955 | * zones which have free_pages > high_wmark_pages(zone), but once a zone is |
| 1956 | * found to have free_pages <= high_wmark_pages(zone), we scan that zone and the |
| 1957 | * lower zones regardless of the number of free pages in the lower zones. This |
| 1958 | * interoperates with the page allocator fallback scheme to ensure that aging |
| 1959 | * of pages is balanced across the zones. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1960 | */ |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1961 | static unsigned long balance_pgdat(pg_data_t *pgdat, int order) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1962 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1963 | int all_zones_ok; |
| 1964 | int priority; |
| 1965 | int i; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1966 | unsigned long total_scanned; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1967 | struct reclaim_state *reclaim_state = current->reclaim_state; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 1968 | struct scan_control sc = { |
| 1969 | .gfp_mask = GFP_KERNEL, |
Johannes Weiner | a6dc60f | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 1970 | .may_unmap = 1, |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 1971 | .may_swap = 1, |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1972 | .swap_cluster_max = SWAP_CLUSTER_MAX, |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 1973 | /* |
| 1974 | * kswapd doesn't want to be bailed out while reclaim. because |
| 1975 | * we want to put equal scanning pressure on each zone. |
| 1976 | */ |
| 1977 | .nr_to_reclaim = ULONG_MAX, |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1978 | .swappiness = vm_swappiness, |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1979 | .order = order, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1980 | .mem_cgroup = NULL, |
| 1981 | .isolate_pages = isolate_pages_global, |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 1982 | }; |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1983 | /* |
| 1984 | * temp_priority is used to remember the scanning priority at which |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1985 | * this zone was successfully refilled to |
| 1986 | * free_pages == high_wmark_pages(zone). |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1987 | */ |
| 1988 | int temp_priority[MAX_NR_ZONES]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1989 | |
| 1990 | loop_again: |
| 1991 | total_scanned = 0; |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1992 | sc.nr_reclaimed = 0; |
Christoph Lameter | c0bbbc7 | 2006-06-11 15:22:26 -0700 | [diff] [blame] | 1993 | sc.may_writepage = !laptop_mode; |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1994 | count_vm_event(PAGEOUTRUN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1995 | |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1996 | for (i = 0; i < pgdat->nr_zones; i++) |
| 1997 | temp_priority[i] = DEF_PRIORITY; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1998 | |
| 1999 | for (priority = DEF_PRIORITY; priority >= 0; priority--) { |
| 2000 | int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */ |
| 2001 | unsigned long lru_pages = 0; |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2002 | int has_under_min_watermark_zone = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2003 | |
Rik van Riel | f7b7fd8 | 2005-11-28 13:44:07 -0800 | [diff] [blame] | 2004 | /* The swap token gets in the way of swapout... */ |
| 2005 | if (!priority) |
| 2006 | disable_swap_token(); |
| 2007 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2008 | all_zones_ok = 1; |
| 2009 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2010 | /* |
| 2011 | * Scan in the highmem->dma direction for the highest |
| 2012 | * zone which needs scanning |
| 2013 | */ |
| 2014 | for (i = pgdat->nr_zones - 1; i >= 0; i--) { |
| 2015 | struct zone *zone = pgdat->node_zones + i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2016 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2017 | if (!populated_zone(zone)) |
| 2018 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2019 | |
David Rientjes | e815af9 | 2007-10-16 23:25:54 -0700 | [diff] [blame] | 2020 | if (zone_is_all_unreclaimable(zone) && |
| 2021 | priority != DEF_PRIORITY) |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2022 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2023 | |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 2024 | /* |
| 2025 | * Do some background aging of the anon list, to give |
| 2026 | * pages a chance to be referenced before reclaiming. |
| 2027 | */ |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 2028 | if (inactive_anon_is_low(zone, &sc)) |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 2029 | shrink_active_list(SWAP_CLUSTER_MAX, zone, |
| 2030 | &sc, priority, 0); |
| 2031 | |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 2032 | if (!zone_watermark_ok(zone, order, |
| 2033 | high_wmark_pages(zone), 0, 0)) { |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2034 | end_zone = i; |
Andrew Morton | e1dbeda | 2006-12-06 20:32:01 -0800 | [diff] [blame] | 2035 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2036 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2037 | } |
Andrew Morton | e1dbeda | 2006-12-06 20:32:01 -0800 | [diff] [blame] | 2038 | if (i < 0) |
| 2039 | goto out; |
| 2040 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2041 | for (i = 0; i <= end_zone; i++) { |
| 2042 | struct zone *zone = pgdat->node_zones + i; |
| 2043 | |
Wu Fengguang | adea02a | 2009-09-21 17:01:42 -0700 | [diff] [blame] | 2044 | lru_pages += zone_reclaimable_pages(zone); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2045 | } |
| 2046 | |
| 2047 | /* |
| 2048 | * Now scan the zone in the dma->highmem direction, stopping |
| 2049 | * at the last zone which needs scanning. |
| 2050 | * |
| 2051 | * We do this because the page allocator works in the opposite |
| 2052 | * direction. This prevents the page allocator from allocating |
| 2053 | * pages behind kswapd's direction of progress, which would |
| 2054 | * cause too much scanning of the lower zones. |
| 2055 | */ |
| 2056 | for (i = 0; i <= end_zone; i++) { |
| 2057 | struct zone *zone = pgdat->node_zones + i; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 2058 | int nr_slab; |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 2059 | int nid, zid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2060 | |
Con Kolivas | f3fe651 | 2006-01-06 00:11:15 -0800 | [diff] [blame] | 2061 | if (!populated_zone(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2062 | continue; |
| 2063 | |
David Rientjes | e815af9 | 2007-10-16 23:25:54 -0700 | [diff] [blame] | 2064 | if (zone_is_all_unreclaimable(zone) && |
| 2065 | priority != DEF_PRIORITY) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2066 | continue; |
| 2067 | |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 2068 | if (!zone_watermark_ok(zone, order, |
| 2069 | high_wmark_pages(zone), end_zone, 0)) |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2070 | all_zones_ok = 0; |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 2071 | temp_priority[i] = priority; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2072 | sc.nr_scanned = 0; |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 2073 | note_zone_scanning_priority(zone, priority); |
Balbir Singh | 4e41695 | 2009-09-23 15:56:39 -0700 | [diff] [blame] | 2074 | |
| 2075 | nid = pgdat->node_id; |
| 2076 | zid = zone_idx(zone); |
| 2077 | /* |
| 2078 | * Call soft limit reclaim before calling shrink_zone. |
| 2079 | * For now we ignore the return value |
| 2080 | */ |
| 2081 | mem_cgroup_soft_limit_reclaim(zone, order, sc.gfp_mask, |
| 2082 | nid, zid); |
Rik van Riel | 32a4330 | 2007-10-16 01:24:50 -0700 | [diff] [blame] | 2083 | /* |
| 2084 | * We put equal pressure on every zone, unless one |
| 2085 | * zone has way too many pages free already. |
| 2086 | */ |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 2087 | if (!zone_watermark_ok(zone, order, |
| 2088 | 8*high_wmark_pages(zone), end_zone, 0)) |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2089 | shrink_zone(priority, zone, &sc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2090 | reclaim_state->reclaimed_slab = 0; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 2091 | nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL, |
| 2092 | lru_pages); |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2093 | sc.nr_reclaimed += reclaim_state->reclaimed_slab; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2094 | total_scanned += sc.nr_scanned; |
David Rientjes | e815af9 | 2007-10-16 23:25:54 -0700 | [diff] [blame] | 2095 | if (zone_is_all_unreclaimable(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2096 | continue; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 2097 | if (nr_slab == 0 && zone->pages_scanned >= |
Wu Fengguang | adea02a | 2009-09-21 17:01:42 -0700 | [diff] [blame] | 2098 | (zone_reclaimable_pages(zone) * 6)) |
David Rientjes | e815af9 | 2007-10-16 23:25:54 -0700 | [diff] [blame] | 2099 | zone_set_flag(zone, |
| 2100 | ZONE_ALL_UNRECLAIMABLE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2101 | /* |
| 2102 | * If we've done a decent amount of scanning and |
| 2103 | * the reclaim ratio is low, start doing writepage |
| 2104 | * even in laptop mode |
| 2105 | */ |
| 2106 | if (total_scanned > SWAP_CLUSTER_MAX * 2 && |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2107 | total_scanned > sc.nr_reclaimed + sc.nr_reclaimed / 2) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2108 | sc.may_writepage = 1; |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2109 | |
| 2110 | /* |
| 2111 | * We are still under min water mark. it mean we have |
| 2112 | * GFP_ATOMIC allocation failure risk. Hurry up! |
| 2113 | */ |
| 2114 | if (!zone_watermark_ok(zone, order, min_wmark_pages(zone), |
| 2115 | end_zone, 0)) |
| 2116 | has_under_min_watermark_zone = 1; |
| 2117 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2118 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2119 | if (all_zones_ok) |
| 2120 | break; /* kswapd: all done */ |
| 2121 | /* |
| 2122 | * OK, kswapd is getting into trouble. Take a nap, then take |
| 2123 | * another pass across the zones. |
| 2124 | */ |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2125 | if (total_scanned && (priority < DEF_PRIORITY - 2)) { |
| 2126 | if (has_under_min_watermark_zone) |
| 2127 | count_vm_event(KSWAPD_SKIP_CONGESTION_WAIT); |
| 2128 | else |
| 2129 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
| 2130 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2131 | |
| 2132 | /* |
| 2133 | * We do this so kswapd doesn't build up large priorities for |
| 2134 | * example when it is freeing in parallel with allocators. It |
| 2135 | * matches the direct reclaim path behaviour in terms of impact |
| 2136 | * on zone->*_priority. |
| 2137 | */ |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2138 | if (sc.nr_reclaimed >= SWAP_CLUSTER_MAX) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2139 | break; |
| 2140 | } |
| 2141 | out: |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 2142 | /* |
| 2143 | * Note within each zone the priority level at which this zone was |
| 2144 | * brought into a happy state. So that the next thread which scans this |
| 2145 | * zone will start out at that priority level. |
| 2146 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2147 | for (i = 0; i < pgdat->nr_zones; i++) { |
| 2148 | struct zone *zone = pgdat->node_zones + i; |
| 2149 | |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 2150 | zone->prev_priority = temp_priority[i]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2151 | } |
| 2152 | if (!all_zones_ok) { |
| 2153 | cond_resched(); |
Rafael J. Wysocki | 8357376 | 2006-12-06 20:34:18 -0800 | [diff] [blame] | 2154 | |
| 2155 | try_to_freeze(); |
| 2156 | |
KOSAKI Motohiro | 73ce02e | 2009-01-06 14:40:33 -0800 | [diff] [blame] | 2157 | /* |
| 2158 | * Fragmentation may mean that the system cannot be |
| 2159 | * rebalanced for high-order allocations in all zones. |
| 2160 | * At this point, if nr_reclaimed < SWAP_CLUSTER_MAX, |
| 2161 | * it means the zones have been fully scanned and are still |
| 2162 | * not balanced. For high-order allocations, there is |
| 2163 | * little point trying all over again as kswapd may |
| 2164 | * infinite loop. |
| 2165 | * |
| 2166 | * Instead, recheck all watermarks at order-0 as they |
| 2167 | * are the most important. If watermarks are ok, kswapd will go |
| 2168 | * back to sleep. High-order users can still perform direct |
| 2169 | * reclaim if they wish. |
| 2170 | */ |
| 2171 | if (sc.nr_reclaimed < SWAP_CLUSTER_MAX) |
| 2172 | order = sc.order = 0; |
| 2173 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2174 | goto loop_again; |
| 2175 | } |
| 2176 | |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2177 | return sc.nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2178 | } |
| 2179 | |
| 2180 | /* |
| 2181 | * The background pageout daemon, started as a kernel thread |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 2182 | * from the init process. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2183 | * |
| 2184 | * This basically trickles out pages so that we have _some_ |
| 2185 | * free memory available even if there is no other activity |
| 2186 | * that frees anything up. This is needed for things like routing |
| 2187 | * etc, where we otherwise might have all activity going on in |
| 2188 | * asynchronous contexts that cannot page things out. |
| 2189 | * |
| 2190 | * If there are applications that are active memory-allocators |
| 2191 | * (most normal use), this basically shouldn't matter. |
| 2192 | */ |
| 2193 | static int kswapd(void *p) |
| 2194 | { |
| 2195 | unsigned long order; |
| 2196 | pg_data_t *pgdat = (pg_data_t*)p; |
| 2197 | struct task_struct *tsk = current; |
| 2198 | DEFINE_WAIT(wait); |
| 2199 | struct reclaim_state reclaim_state = { |
| 2200 | .reclaimed_slab = 0, |
| 2201 | }; |
Rusty Russell | a70f730 | 2009-03-13 14:49:46 +1030 | [diff] [blame] | 2202 | const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2203 | |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2204 | lockdep_set_current_reclaim_state(GFP_KERNEL); |
| 2205 | |
Rusty Russell | 174596a | 2009-01-01 10:12:29 +1030 | [diff] [blame] | 2206 | if (!cpumask_empty(cpumask)) |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 2207 | set_cpus_allowed_ptr(tsk, cpumask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2208 | current->reclaim_state = &reclaim_state; |
| 2209 | |
| 2210 | /* |
| 2211 | * Tell the memory management that we're a "memory allocator", |
| 2212 | * and that if we need more memory we should get access to it |
| 2213 | * regardless (see "__alloc_pages()"). "kswapd" should |
| 2214 | * never get caught in the normal page freeing logic. |
| 2215 | * |
| 2216 | * (Kswapd normally doesn't need memory anyway, but sometimes |
| 2217 | * you need a small amount of memory in order to be able to |
| 2218 | * page out something else, and this flag essentially protects |
| 2219 | * us from recursively trying to free more memory as we're |
| 2220 | * trying to free the first piece of memory in the first place). |
| 2221 | */ |
Christoph Lameter | 930d915 | 2006-01-08 01:00:47 -0800 | [diff] [blame] | 2222 | tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD; |
Rafael J. Wysocki | 8314418 | 2007-07-17 04:03:35 -0700 | [diff] [blame] | 2223 | set_freezable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2224 | |
| 2225 | order = 0; |
| 2226 | for ( ; ; ) { |
| 2227 | unsigned long new_order; |
David Rientjes | 8fe23e0 | 2009-12-14 17:58:33 -0800 | [diff] [blame] | 2228 | int ret; |
Christoph Lameter | 3e1d1d2 | 2005-06-24 23:13:50 -0700 | [diff] [blame] | 2229 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2230 | prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); |
| 2231 | new_order = pgdat->kswapd_max_order; |
| 2232 | pgdat->kswapd_max_order = 0; |
| 2233 | if (order < new_order) { |
| 2234 | /* |
| 2235 | * Don't sleep if someone wants a larger 'order' |
| 2236 | * allocation |
| 2237 | */ |
| 2238 | order = new_order; |
| 2239 | } else { |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2240 | if (!freezing(current) && !kthread_should_stop()) { |
| 2241 | long remaining = 0; |
| 2242 | |
| 2243 | /* Try to sleep for a short interval */ |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2244 | if (!sleeping_prematurely(pgdat, order, remaining)) { |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2245 | remaining = schedule_timeout(HZ/10); |
| 2246 | finish_wait(&pgdat->kswapd_wait, &wait); |
| 2247 | prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); |
| 2248 | } |
| 2249 | |
| 2250 | /* |
| 2251 | * After a short sleep, check if it was a |
| 2252 | * premature sleep. If not, then go fully |
| 2253 | * to sleep until explicitly woken up |
| 2254 | */ |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2255 | if (!sleeping_prematurely(pgdat, order, remaining)) |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2256 | schedule(); |
| 2257 | else { |
| 2258 | if (remaining) |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2259 | count_vm_event(KSWAPD_LOW_WMARK_HIT_QUICKLY); |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2260 | else |
KOSAKI Motohiro | bb3ab59 | 2009-12-14 17:58:55 -0800 | [diff] [blame] | 2261 | count_vm_event(KSWAPD_HIGH_WMARK_HIT_QUICKLY); |
Mel Gorman | f50de2d | 2009-12-14 17:58:53 -0800 | [diff] [blame] | 2262 | } |
| 2263 | } |
Rafael J. Wysocki | b1296cc | 2007-05-06 14:50:48 -0700 | [diff] [blame] | 2264 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2265 | order = pgdat->kswapd_max_order; |
| 2266 | } |
| 2267 | finish_wait(&pgdat->kswapd_wait, &wait); |
| 2268 | |
David Rientjes | 8fe23e0 | 2009-12-14 17:58:33 -0800 | [diff] [blame] | 2269 | ret = try_to_freeze(); |
| 2270 | if (kthread_should_stop()) |
| 2271 | break; |
| 2272 | |
| 2273 | /* |
| 2274 | * We can speed up thawing tasks if we don't call balance_pgdat |
| 2275 | * after returning from the refrigerator |
| 2276 | */ |
| 2277 | if (!ret) |
Rafael J. Wysocki | b1296cc | 2007-05-06 14:50:48 -0700 | [diff] [blame] | 2278 | balance_pgdat(pgdat, order); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2279 | } |
| 2280 | return 0; |
| 2281 | } |
| 2282 | |
| 2283 | /* |
| 2284 | * A zone is low on free memory, so wake its kswapd task to service it. |
| 2285 | */ |
| 2286 | void wakeup_kswapd(struct zone *zone, int order) |
| 2287 | { |
| 2288 | pg_data_t *pgdat; |
| 2289 | |
Con Kolivas | f3fe651 | 2006-01-06 00:11:15 -0800 | [diff] [blame] | 2290 | if (!populated_zone(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2291 | return; |
| 2292 | |
| 2293 | pgdat = zone->zone_pgdat; |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 2294 | if (zone_watermark_ok(zone, order, low_wmark_pages(zone), 0, 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2295 | return; |
| 2296 | if (pgdat->kswapd_max_order < order) |
| 2297 | pgdat->kswapd_max_order = order; |
Paul Jackson | 02a0e53 | 2006-12-13 00:34:25 -0800 | [diff] [blame] | 2298 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2299 | return; |
Con Kolivas | 8d0986e | 2005-09-13 01:25:07 -0700 | [diff] [blame] | 2300 | if (!waitqueue_active(&pgdat->kswapd_wait)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2301 | return; |
Con Kolivas | 8d0986e | 2005-09-13 01:25:07 -0700 | [diff] [blame] | 2302 | wake_up_interruptible(&pgdat->kswapd_wait); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2303 | } |
| 2304 | |
Wu Fengguang | adea02a | 2009-09-21 17:01:42 -0700 | [diff] [blame] | 2305 | /* |
| 2306 | * The reclaimable count would be mostly accurate. |
| 2307 | * The less reclaimable pages may be |
| 2308 | * - mlocked pages, which will be moved to unevictable list when encountered |
| 2309 | * - mapped pages, which may require several travels to be reclaimed |
| 2310 | * - dirty pages, which is not "instantly" reclaimable |
| 2311 | */ |
| 2312 | unsigned long global_reclaimable_pages(void) |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 2313 | { |
Wu Fengguang | adea02a | 2009-09-21 17:01:42 -0700 | [diff] [blame] | 2314 | int nr; |
| 2315 | |
| 2316 | nr = global_page_state(NR_ACTIVE_FILE) + |
| 2317 | global_page_state(NR_INACTIVE_FILE); |
| 2318 | |
| 2319 | if (nr_swap_pages > 0) |
| 2320 | nr += global_page_state(NR_ACTIVE_ANON) + |
| 2321 | global_page_state(NR_INACTIVE_ANON); |
| 2322 | |
| 2323 | return nr; |
| 2324 | } |
| 2325 | |
| 2326 | unsigned long zone_reclaimable_pages(struct zone *zone) |
| 2327 | { |
| 2328 | int nr; |
| 2329 | |
| 2330 | nr = zone_page_state(zone, NR_ACTIVE_FILE) + |
| 2331 | zone_page_state(zone, NR_INACTIVE_FILE); |
| 2332 | |
| 2333 | if (nr_swap_pages > 0) |
| 2334 | nr += zone_page_state(zone, NR_ACTIVE_ANON) + |
| 2335 | zone_page_state(zone, NR_INACTIVE_ANON); |
| 2336 | |
| 2337 | return nr; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 2338 | } |
| 2339 | |
Rafael J. Wysocki | c6f37f1 | 2009-05-24 22:16:31 +0200 | [diff] [blame] | 2340 | #ifdef CONFIG_HIBERNATION |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2341 | /* |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame^] | 2342 | * Try to free `nr_to_reclaim' of memory, system-wide, and return the number of |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2343 | * freed pages. |
| 2344 | * |
| 2345 | * Rather than trying to age LRUs the aim is to preserve the overall |
| 2346 | * LRU order by reclaiming preferentially |
| 2347 | * inactive > active > active referenced > active mapped |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2348 | */ |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame^] | 2349 | unsigned long shrink_all_memory(unsigned long nr_to_reclaim) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2350 | { |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2351 | struct reclaim_state reclaim_state; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2352 | struct scan_control sc = { |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame^] | 2353 | .gfp_mask = GFP_HIGHUSER_MOVABLE, |
| 2354 | .may_swap = 1, |
| 2355 | .may_unmap = 1, |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2356 | .may_writepage = 1, |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame^] | 2357 | .swap_cluster_max = SWAP_CLUSTER_MAX, |
| 2358 | .nr_to_reclaim = nr_to_reclaim, |
| 2359 | .hibernation_mode = 1, |
| 2360 | .swappiness = vm_swappiness, |
| 2361 | .order = 0, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2362 | .isolate_pages = isolate_pages_global, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2363 | }; |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame^] | 2364 | struct zonelist * zonelist = node_zonelist(numa_node_id(), sc.gfp_mask); |
| 2365 | struct task_struct *p = current; |
| 2366 | unsigned long nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2367 | |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame^] | 2368 | p->flags |= PF_MEMALLOC; |
| 2369 | lockdep_set_current_reclaim_state(sc.gfp_mask); |
| 2370 | reclaim_state.reclaimed_slab = 0; |
| 2371 | p->reclaim_state = &reclaim_state; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2372 | |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame^] | 2373 | nr_reclaimed = do_try_to_free_pages(zonelist, &sc); |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2374 | |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame^] | 2375 | p->reclaim_state = NULL; |
| 2376 | lockdep_clear_current_reclaim_state(); |
| 2377 | p->flags &= ~PF_MEMALLOC; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2378 | |
KOSAKI Motohiro | 7b51755 | 2009-12-14 17:59:12 -0800 | [diff] [blame^] | 2379 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2380 | } |
Rafael J. Wysocki | c6f37f1 | 2009-05-24 22:16:31 +0200 | [diff] [blame] | 2381 | #endif /* CONFIG_HIBERNATION */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2382 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2383 | /* It's optimal to keep kswapds on the same CPUs as their memory, but |
| 2384 | not required for correctness. So if the last cpu in a node goes |
| 2385 | away, we get changed to run anywhere: as the first one comes back, |
| 2386 | restore their cpu bindings. */ |
Chandra Seetharaman | 9c7b216 | 2006-06-27 02:54:07 -0700 | [diff] [blame] | 2387 | static int __devinit cpu_callback(struct notifier_block *nfb, |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2388 | unsigned long action, void *hcpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2389 | { |
Yasunori Goto | 58c0a4a | 2007-10-16 01:25:40 -0700 | [diff] [blame] | 2390 | int nid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2391 | |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 2392 | if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN) { |
Yasunori Goto | 58c0a4a | 2007-10-16 01:25:40 -0700 | [diff] [blame] | 2393 | for_each_node_state(nid, N_HIGH_MEMORY) { |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 2394 | pg_data_t *pgdat = NODE_DATA(nid); |
Rusty Russell | a70f730 | 2009-03-13 14:49:46 +1030 | [diff] [blame] | 2395 | const struct cpumask *mask; |
| 2396 | |
| 2397 | mask = cpumask_of_node(pgdat->node_id); |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 2398 | |
Rusty Russell | 3e59794 | 2009-01-01 10:12:24 +1030 | [diff] [blame] | 2399 | if (cpumask_any_and(cpu_online_mask, mask) < nr_cpu_ids) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2400 | /* One of our CPUs online: restore mask */ |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 2401 | set_cpus_allowed_ptr(pgdat->kswapd, mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2402 | } |
| 2403 | } |
| 2404 | return NOTIFY_OK; |
| 2405 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2406 | |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 2407 | /* |
| 2408 | * This kswapd start function will be called by init and node-hot-add. |
| 2409 | * On node-hot-add, kswapd will moved to proper cpus if cpus are hot-added. |
| 2410 | */ |
| 2411 | int kswapd_run(int nid) |
| 2412 | { |
| 2413 | pg_data_t *pgdat = NODE_DATA(nid); |
| 2414 | int ret = 0; |
| 2415 | |
| 2416 | if (pgdat->kswapd) |
| 2417 | return 0; |
| 2418 | |
| 2419 | pgdat->kswapd = kthread_run(kswapd, pgdat, "kswapd%d", nid); |
| 2420 | if (IS_ERR(pgdat->kswapd)) { |
| 2421 | /* failure at boot is fatal */ |
| 2422 | BUG_ON(system_state == SYSTEM_BOOTING); |
| 2423 | printk("Failed to start kswapd on node %d\n",nid); |
| 2424 | ret = -1; |
| 2425 | } |
| 2426 | return ret; |
| 2427 | } |
| 2428 | |
David Rientjes | 8fe23e0 | 2009-12-14 17:58:33 -0800 | [diff] [blame] | 2429 | /* |
| 2430 | * Called by memory hotplug when all memory in a node is offlined. |
| 2431 | */ |
| 2432 | void kswapd_stop(int nid) |
| 2433 | { |
| 2434 | struct task_struct *kswapd = NODE_DATA(nid)->kswapd; |
| 2435 | |
| 2436 | if (kswapd) |
| 2437 | kthread_stop(kswapd); |
| 2438 | } |
| 2439 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2440 | static int __init kswapd_init(void) |
| 2441 | { |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 2442 | int nid; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2443 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2444 | swap_setup(); |
Christoph Lameter | 9422ffb | 2007-10-16 01:25:31 -0700 | [diff] [blame] | 2445 | for_each_node_state(nid, N_HIGH_MEMORY) |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 2446 | kswapd_run(nid); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2447 | hotcpu_notifier(cpu_callback, 0); |
| 2448 | return 0; |
| 2449 | } |
| 2450 | |
| 2451 | module_init(kswapd_init) |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2452 | |
| 2453 | #ifdef CONFIG_NUMA |
| 2454 | /* |
| 2455 | * Zone reclaim mode |
| 2456 | * |
| 2457 | * If non-zero call zone_reclaim when the number of free pages falls below |
| 2458 | * the watermarks. |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2459 | */ |
| 2460 | int zone_reclaim_mode __read_mostly; |
| 2461 | |
Christoph Lameter | 1b2ffb7 | 2006-02-01 03:05:34 -0800 | [diff] [blame] | 2462 | #define RECLAIM_OFF 0 |
Fernando Luis Vazquez Cao | 7d03431 | 2008-07-29 22:33:41 -0700 | [diff] [blame] | 2463 | #define RECLAIM_ZONE (1<<0) /* Run shrink_inactive_list on the zone */ |
Christoph Lameter | 1b2ffb7 | 2006-02-01 03:05:34 -0800 | [diff] [blame] | 2464 | #define RECLAIM_WRITE (1<<1) /* Writeout pages during reclaim */ |
| 2465 | #define RECLAIM_SWAP (1<<2) /* Swap pages out during reclaim */ |
| 2466 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2467 | /* |
Christoph Lameter | a92f712 | 2006-02-01 03:05:32 -0800 | [diff] [blame] | 2468 | * Priority for ZONE_RECLAIM. This determines the fraction of pages |
| 2469 | * of a node considered for each zone_reclaim. 4 scans 1/16th of |
| 2470 | * a zone. |
| 2471 | */ |
| 2472 | #define ZONE_RECLAIM_PRIORITY 4 |
| 2473 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2474 | /* |
Christoph Lameter | 9614634 | 2006-07-03 00:24:13 -0700 | [diff] [blame] | 2475 | * Percentage of pages in a zone that must be unmapped for zone_reclaim to |
| 2476 | * occur. |
| 2477 | */ |
| 2478 | int sysctl_min_unmapped_ratio = 1; |
| 2479 | |
| 2480 | /* |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2481 | * If the number of slab pages in a zone grows beyond this percentage then |
| 2482 | * slab reclaim needs to occur. |
| 2483 | */ |
| 2484 | int sysctl_min_slab_ratio = 5; |
| 2485 | |
Mel Gorman | 90afa5d | 2009-06-16 15:33:20 -0700 | [diff] [blame] | 2486 | static inline unsigned long zone_unmapped_file_pages(struct zone *zone) |
| 2487 | { |
| 2488 | unsigned long file_mapped = zone_page_state(zone, NR_FILE_MAPPED); |
| 2489 | unsigned long file_lru = zone_page_state(zone, NR_INACTIVE_FILE) + |
| 2490 | zone_page_state(zone, NR_ACTIVE_FILE); |
| 2491 | |
| 2492 | /* |
| 2493 | * It's possible for there to be more file mapped pages than |
| 2494 | * accounted for by the pages on the file LRU lists because |
| 2495 | * tmpfs pages accounted for as ANON can also be FILE_MAPPED |
| 2496 | */ |
| 2497 | return (file_lru > file_mapped) ? (file_lru - file_mapped) : 0; |
| 2498 | } |
| 2499 | |
| 2500 | /* Work out how many page cache pages we can reclaim in this reclaim_mode */ |
| 2501 | static long zone_pagecache_reclaimable(struct zone *zone) |
| 2502 | { |
| 2503 | long nr_pagecache_reclaimable; |
| 2504 | long delta = 0; |
| 2505 | |
| 2506 | /* |
| 2507 | * If RECLAIM_SWAP is set, then all file pages are considered |
| 2508 | * potentially reclaimable. Otherwise, we have to worry about |
| 2509 | * pages like swapcache and zone_unmapped_file_pages() provides |
| 2510 | * a better estimate |
| 2511 | */ |
| 2512 | if (zone_reclaim_mode & RECLAIM_SWAP) |
| 2513 | nr_pagecache_reclaimable = zone_page_state(zone, NR_FILE_PAGES); |
| 2514 | else |
| 2515 | nr_pagecache_reclaimable = zone_unmapped_file_pages(zone); |
| 2516 | |
| 2517 | /* If we can't clean pages, remove dirty pages from consideration */ |
| 2518 | if (!(zone_reclaim_mode & RECLAIM_WRITE)) |
| 2519 | delta += zone_page_state(zone, NR_FILE_DIRTY); |
| 2520 | |
| 2521 | /* Watch for any possible underflows due to delta */ |
| 2522 | if (unlikely(delta > nr_pagecache_reclaimable)) |
| 2523 | delta = nr_pagecache_reclaimable; |
| 2524 | |
| 2525 | return nr_pagecache_reclaimable - delta; |
| 2526 | } |
| 2527 | |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2528 | /* |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2529 | * Try to free up some pages from this zone through reclaim. |
| 2530 | */ |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2531 | static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2532 | { |
Christoph Lameter | 7fb2d46 | 2006-03-22 00:08:22 -0800 | [diff] [blame] | 2533 | /* Minimum pages needed in order to stay on node */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2534 | const unsigned long nr_pages = 1 << order; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2535 | struct task_struct *p = current; |
| 2536 | struct reclaim_state reclaim_state; |
Christoph Lameter | 8695949 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2537 | int priority; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2538 | struct scan_control sc = { |
| 2539 | .may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE), |
Johannes Weiner | a6dc60f | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 2540 | .may_unmap = !!(zone_reclaim_mode & RECLAIM_SWAP), |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 2541 | .may_swap = 1, |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2542 | .swap_cluster_max = max_t(unsigned long, nr_pages, |
KOSAKI Motohiro | 22fba33 | 2009-12-14 17:59:10 -0800 | [diff] [blame] | 2543 | SWAP_CLUSTER_MAX), |
| 2544 | .nr_to_reclaim = max_t(unsigned long, nr_pages, |
| 2545 | SWAP_CLUSTER_MAX), |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2546 | .gfp_mask = gfp_mask, |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2547 | .swappiness = vm_swappiness, |
Johannes Weiner | bd2f619 | 2009-03-31 15:19:38 -0700 | [diff] [blame] | 2548 | .order = order, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2549 | .isolate_pages = isolate_pages_global, |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2550 | }; |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 2551 | unsigned long slab_reclaimable; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2552 | |
| 2553 | disable_swap_token(); |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2554 | cond_resched(); |
Christoph Lameter | d4f7796 | 2006-02-24 13:04:22 -0800 | [diff] [blame] | 2555 | /* |
| 2556 | * We need to be able to allocate from the reserves for RECLAIM_SWAP |
| 2557 | * and we also need to be able to write out pages for RECLAIM_WRITE |
| 2558 | * and RECLAIM_SWAP. |
| 2559 | */ |
| 2560 | p->flags |= PF_MEMALLOC | PF_SWAPWRITE; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2561 | reclaim_state.reclaimed_slab = 0; |
| 2562 | p->reclaim_state = &reclaim_state; |
Christoph Lameter | c84db23 | 2006-02-01 03:05:29 -0800 | [diff] [blame] | 2563 | |
Mel Gorman | 90afa5d | 2009-06-16 15:33:20 -0700 | [diff] [blame] | 2564 | if (zone_pagecache_reclaimable(zone) > zone->min_unmapped_pages) { |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2565 | /* |
| 2566 | * Free memory by calling shrink zone with increasing |
| 2567 | * priorities until we have enough memory freed. |
| 2568 | */ |
| 2569 | priority = ZONE_RECLAIM_PRIORITY; |
| 2570 | do { |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 2571 | note_zone_scanning_priority(zone, priority); |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2572 | shrink_zone(priority, zone, &sc); |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2573 | priority--; |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2574 | } while (priority >= 0 && sc.nr_reclaimed < nr_pages); |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2575 | } |
Christoph Lameter | c84db23 | 2006-02-01 03:05:29 -0800 | [diff] [blame] | 2576 | |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 2577 | slab_reclaimable = zone_page_state(zone, NR_SLAB_RECLAIMABLE); |
| 2578 | if (slab_reclaimable > zone->min_slab_pages) { |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2579 | /* |
Christoph Lameter | 7fb2d46 | 2006-03-22 00:08:22 -0800 | [diff] [blame] | 2580 | * shrink_slab() does not currently allow us to determine how |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2581 | * many pages were freed in this zone. So we take the current |
| 2582 | * number of slab pages and shake the slab until it is reduced |
| 2583 | * by the same nr_pages that we used for reclaiming unmapped |
| 2584 | * pages. |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2585 | * |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2586 | * Note that shrink_slab will free memory on all zones and may |
| 2587 | * take a long time. |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2588 | */ |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2589 | while (shrink_slab(sc.nr_scanned, gfp_mask, order) && |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 2590 | zone_page_state(zone, NR_SLAB_RECLAIMABLE) > |
| 2591 | slab_reclaimable - nr_pages) |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2592 | ; |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 2593 | |
| 2594 | /* |
| 2595 | * Update nr_reclaimed by the number of slab pages we |
| 2596 | * reclaimed from this zone. |
| 2597 | */ |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2598 | sc.nr_reclaimed += slab_reclaimable - |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 2599 | zone_page_state(zone, NR_SLAB_RECLAIMABLE); |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2600 | } |
| 2601 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2602 | p->reclaim_state = NULL; |
Christoph Lameter | d4f7796 | 2006-02-24 13:04:22 -0800 | [diff] [blame] | 2603 | current->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE); |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2604 | return sc.nr_reclaimed >= nr_pages; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2605 | } |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2606 | |
| 2607 | int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) |
| 2608 | { |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2609 | int node_id; |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2610 | int ret; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2611 | |
| 2612 | /* |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2613 | * Zone reclaim reclaims unmapped file backed pages and |
| 2614 | * slab pages if we are over the defined limits. |
Christoph Lameter | 34aa133 | 2006-06-30 01:55:37 -0700 | [diff] [blame] | 2615 | * |
Christoph Lameter | 9614634 | 2006-07-03 00:24:13 -0700 | [diff] [blame] | 2616 | * A small portion of unmapped file backed pages is needed for |
| 2617 | * file I/O otherwise pages read by file I/O will be immediately |
| 2618 | * thrown out if the zone is overallocated. So we do not reclaim |
| 2619 | * if less than a specified percentage of the zone is used by |
| 2620 | * unmapped file backed pages. |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2621 | */ |
Mel Gorman | 90afa5d | 2009-06-16 15:33:20 -0700 | [diff] [blame] | 2622 | if (zone_pagecache_reclaimable(zone) <= zone->min_unmapped_pages && |
| 2623 | zone_page_state(zone, NR_SLAB_RECLAIMABLE) <= zone->min_slab_pages) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 2624 | return ZONE_RECLAIM_FULL; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2625 | |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2626 | if (zone_is_all_unreclaimable(zone)) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 2627 | return ZONE_RECLAIM_FULL; |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2628 | |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2629 | /* |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2630 | * Do not scan if the allocation should not be delayed. |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2631 | */ |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2632 | if (!(gfp_mask & __GFP_WAIT) || (current->flags & PF_MEMALLOC)) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 2633 | return ZONE_RECLAIM_NOSCAN; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2634 | |
| 2635 | /* |
| 2636 | * Only run zone reclaim on the local zone or on zones that do not |
| 2637 | * have associated processors. This will favor the local processor |
| 2638 | * over remote processors and spread off node memory allocations |
| 2639 | * as wide as possible. |
| 2640 | */ |
Christoph Lameter | 89fa302 | 2006-09-25 23:31:55 -0700 | [diff] [blame] | 2641 | node_id = zone_to_nid(zone); |
Christoph Lameter | 37c0708 | 2007-10-16 01:25:36 -0700 | [diff] [blame] | 2642 | if (node_state(node_id, N_CPU) && node_id != numa_node_id()) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 2643 | return ZONE_RECLAIM_NOSCAN; |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2644 | |
| 2645 | if (zone_test_and_set_flag(zone, ZONE_RECLAIM_LOCKED)) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 2646 | return ZONE_RECLAIM_NOSCAN; |
| 2647 | |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2648 | ret = __zone_reclaim(zone, gfp_mask, order); |
| 2649 | zone_clear_flag(zone, ZONE_RECLAIM_LOCKED); |
| 2650 | |
Mel Gorman | 24cf72518 | 2009-06-16 15:33:23 -0700 | [diff] [blame] | 2651 | if (!ret) |
| 2652 | count_vm_event(PGSCAN_ZONE_RECLAIM_FAILED); |
| 2653 | |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2654 | return ret; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2655 | } |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2656 | #endif |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2657 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2658 | /* |
| 2659 | * page_evictable - test whether a page is evictable |
| 2660 | * @page: the page to test |
| 2661 | * @vma: the VMA in which the page is or will be mapped, may be NULL |
| 2662 | * |
| 2663 | * Test whether page is evictable--i.e., should be placed on active/inactive |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 2664 | * lists vs unevictable list. The vma argument is !NULL when called from the |
| 2665 | * fault path to determine how to instantate a new page. |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2666 | * |
| 2667 | * Reasons page might not be evictable: |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 2668 | * (1) page's mapping marked unevictable |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 2669 | * (2) page is part of an mlocked VMA |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 2670 | * |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2671 | */ |
| 2672 | int page_evictable(struct page *page, struct vm_area_struct *vma) |
| 2673 | { |
| 2674 | |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 2675 | if (mapping_unevictable(page_mapping(page))) |
| 2676 | return 0; |
| 2677 | |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 2678 | if (PageMlocked(page) || (vma && is_mlocked_vma(vma, page))) |
| 2679 | return 0; |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2680 | |
| 2681 | return 1; |
| 2682 | } |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 2683 | |
| 2684 | /** |
| 2685 | * check_move_unevictable_page - check page for evictability and move to appropriate zone lru list |
| 2686 | * @page: page to check evictability and move to appropriate lru list |
| 2687 | * @zone: zone page is in |
| 2688 | * |
| 2689 | * Checks a page for evictability and moves the page to the appropriate |
| 2690 | * zone lru list. |
| 2691 | * |
| 2692 | * Restrictions: zone->lru_lock must be held, page must be on LRU and must |
| 2693 | * have PageUnevictable set. |
| 2694 | */ |
| 2695 | static void check_move_unevictable_page(struct page *page, struct zone *zone) |
| 2696 | { |
| 2697 | VM_BUG_ON(PageActive(page)); |
| 2698 | |
| 2699 | retry: |
| 2700 | ClearPageUnevictable(page); |
| 2701 | if (page_evictable(page, NULL)) { |
Johannes Weiner | 401a8e1 | 2009-09-21 17:02:58 -0700 | [diff] [blame] | 2702 | enum lru_list l = page_lru_base_type(page); |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2703 | |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 2704 | __dec_zone_state(zone, NR_UNEVICTABLE); |
| 2705 | list_move(&page->lru, &zone->lru[l].list); |
KAMEZAWA Hiroyuki | 08e552c | 2009-01-07 18:08:01 -0800 | [diff] [blame] | 2706 | mem_cgroup_move_lists(page, LRU_UNEVICTABLE, l); |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 2707 | __inc_zone_state(zone, NR_INACTIVE_ANON + l); |
| 2708 | __count_vm_event(UNEVICTABLE_PGRESCUED); |
| 2709 | } else { |
| 2710 | /* |
| 2711 | * rotate unevictable list |
| 2712 | */ |
| 2713 | SetPageUnevictable(page); |
| 2714 | list_move(&page->lru, &zone->lru[LRU_UNEVICTABLE].list); |
KAMEZAWA Hiroyuki | 08e552c | 2009-01-07 18:08:01 -0800 | [diff] [blame] | 2715 | mem_cgroup_rotate_lru_list(page, LRU_UNEVICTABLE); |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 2716 | if (page_evictable(page, NULL)) |
| 2717 | goto retry; |
| 2718 | } |
| 2719 | } |
| 2720 | |
| 2721 | /** |
| 2722 | * scan_mapping_unevictable_pages - scan an address space for evictable pages |
| 2723 | * @mapping: struct address_space to scan for evictable pages |
| 2724 | * |
| 2725 | * Scan all pages in mapping. Check unevictable pages for |
| 2726 | * evictability and move them to the appropriate zone lru list. |
| 2727 | */ |
| 2728 | void scan_mapping_unevictable_pages(struct address_space *mapping) |
| 2729 | { |
| 2730 | pgoff_t next = 0; |
| 2731 | pgoff_t end = (i_size_read(mapping->host) + PAGE_CACHE_SIZE - 1) >> |
| 2732 | PAGE_CACHE_SHIFT; |
| 2733 | struct zone *zone; |
| 2734 | struct pagevec pvec; |
| 2735 | |
| 2736 | if (mapping->nrpages == 0) |
| 2737 | return; |
| 2738 | |
| 2739 | pagevec_init(&pvec, 0); |
| 2740 | while (next < end && |
| 2741 | pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { |
| 2742 | int i; |
| 2743 | int pg_scanned = 0; |
| 2744 | |
| 2745 | zone = NULL; |
| 2746 | |
| 2747 | for (i = 0; i < pagevec_count(&pvec); i++) { |
| 2748 | struct page *page = pvec.pages[i]; |
| 2749 | pgoff_t page_index = page->index; |
| 2750 | struct zone *pagezone = page_zone(page); |
| 2751 | |
| 2752 | pg_scanned++; |
| 2753 | if (page_index > next) |
| 2754 | next = page_index; |
| 2755 | next++; |
| 2756 | |
| 2757 | if (pagezone != zone) { |
| 2758 | if (zone) |
| 2759 | spin_unlock_irq(&zone->lru_lock); |
| 2760 | zone = pagezone; |
| 2761 | spin_lock_irq(&zone->lru_lock); |
| 2762 | } |
| 2763 | |
| 2764 | if (PageLRU(page) && PageUnevictable(page)) |
| 2765 | check_move_unevictable_page(page, zone); |
| 2766 | } |
| 2767 | if (zone) |
| 2768 | spin_unlock_irq(&zone->lru_lock); |
| 2769 | pagevec_release(&pvec); |
| 2770 | |
| 2771 | count_vm_events(UNEVICTABLE_PGSCANNED, pg_scanned); |
| 2772 | } |
| 2773 | |
| 2774 | } |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2775 | |
| 2776 | /** |
| 2777 | * scan_zone_unevictable_pages - check unevictable list for evictable pages |
| 2778 | * @zone - zone of which to scan the unevictable list |
| 2779 | * |
| 2780 | * Scan @zone's unevictable LRU lists to check for pages that have become |
| 2781 | * evictable. Move those that have to @zone's inactive list where they |
| 2782 | * become candidates for reclaim, unless shrink_inactive_zone() decides |
| 2783 | * to reactivate them. Pages that are still unevictable are rotated |
| 2784 | * back onto @zone's unevictable list. |
| 2785 | */ |
| 2786 | #define SCAN_UNEVICTABLE_BATCH_SIZE 16UL /* arbitrary lock hold batch size */ |
KOSAKI Motohiro | 14b90b2 | 2009-01-06 14:39:45 -0800 | [diff] [blame] | 2787 | static void scan_zone_unevictable_pages(struct zone *zone) |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2788 | { |
| 2789 | struct list_head *l_unevictable = &zone->lru[LRU_UNEVICTABLE].list; |
| 2790 | unsigned long scan; |
| 2791 | unsigned long nr_to_scan = zone_page_state(zone, NR_UNEVICTABLE); |
| 2792 | |
| 2793 | while (nr_to_scan > 0) { |
| 2794 | unsigned long batch_size = min(nr_to_scan, |
| 2795 | SCAN_UNEVICTABLE_BATCH_SIZE); |
| 2796 | |
| 2797 | spin_lock_irq(&zone->lru_lock); |
| 2798 | for (scan = 0; scan < batch_size; scan++) { |
| 2799 | struct page *page = lru_to_page(l_unevictable); |
| 2800 | |
| 2801 | if (!trylock_page(page)) |
| 2802 | continue; |
| 2803 | |
| 2804 | prefetchw_prev_lru_page(page, l_unevictable, flags); |
| 2805 | |
| 2806 | if (likely(PageLRU(page) && PageUnevictable(page))) |
| 2807 | check_move_unevictable_page(page, zone); |
| 2808 | |
| 2809 | unlock_page(page); |
| 2810 | } |
| 2811 | spin_unlock_irq(&zone->lru_lock); |
| 2812 | |
| 2813 | nr_to_scan -= batch_size; |
| 2814 | } |
| 2815 | } |
| 2816 | |
| 2817 | |
| 2818 | /** |
| 2819 | * scan_all_zones_unevictable_pages - scan all unevictable lists for evictable pages |
| 2820 | * |
| 2821 | * A really big hammer: scan all zones' unevictable LRU lists to check for |
| 2822 | * pages that have become evictable. Move those back to the zones' |
| 2823 | * inactive list where they become candidates for reclaim. |
| 2824 | * This occurs when, e.g., we have unswappable pages on the unevictable lists, |
| 2825 | * and we add swap to the system. As such, it runs in the context of a task |
| 2826 | * that has possibly/probably made some previously unevictable pages |
| 2827 | * evictable. |
| 2828 | */ |
KOSAKI Motohiro | ff30153 | 2009-01-06 14:39:44 -0800 | [diff] [blame] | 2829 | static void scan_all_zones_unevictable_pages(void) |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2830 | { |
| 2831 | struct zone *zone; |
| 2832 | |
| 2833 | for_each_zone(zone) { |
| 2834 | scan_zone_unevictable_pages(zone); |
| 2835 | } |
| 2836 | } |
| 2837 | |
| 2838 | /* |
| 2839 | * scan_unevictable_pages [vm] sysctl handler. On demand re-scan of |
| 2840 | * all nodes' unevictable lists for evictable pages |
| 2841 | */ |
| 2842 | unsigned long scan_unevictable_pages; |
| 2843 | |
| 2844 | int scan_unevictable_handler(struct ctl_table *table, int write, |
Alexey Dobriyan | 8d65af7 | 2009-09-23 15:57:19 -0700 | [diff] [blame] | 2845 | void __user *buffer, |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2846 | size_t *length, loff_t *ppos) |
| 2847 | { |
Alexey Dobriyan | 8d65af7 | 2009-09-23 15:57:19 -0700 | [diff] [blame] | 2848 | proc_doulongvec_minmax(table, write, buffer, length, ppos); |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2849 | |
| 2850 | if (write && *(unsigned long *)table->data) |
| 2851 | scan_all_zones_unevictable_pages(); |
| 2852 | |
| 2853 | scan_unevictable_pages = 0; |
| 2854 | return 0; |
| 2855 | } |
| 2856 | |
| 2857 | /* |
| 2858 | * per node 'scan_unevictable_pages' attribute. On demand re-scan of |
| 2859 | * a specified node's per zone unevictable lists for evictable pages. |
| 2860 | */ |
| 2861 | |
| 2862 | static ssize_t read_scan_unevictable_node(struct sys_device *dev, |
| 2863 | struct sysdev_attribute *attr, |
| 2864 | char *buf) |
| 2865 | { |
| 2866 | return sprintf(buf, "0\n"); /* always zero; should fit... */ |
| 2867 | } |
| 2868 | |
| 2869 | static ssize_t write_scan_unevictable_node(struct sys_device *dev, |
| 2870 | struct sysdev_attribute *attr, |
| 2871 | const char *buf, size_t count) |
| 2872 | { |
| 2873 | struct zone *node_zones = NODE_DATA(dev->id)->node_zones; |
| 2874 | struct zone *zone; |
| 2875 | unsigned long res; |
| 2876 | unsigned long req = strict_strtoul(buf, 10, &res); |
| 2877 | |
| 2878 | if (!req) |
| 2879 | return 1; /* zero is no-op */ |
| 2880 | |
| 2881 | for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) { |
| 2882 | if (!populated_zone(zone)) |
| 2883 | continue; |
| 2884 | scan_zone_unevictable_pages(zone); |
| 2885 | } |
| 2886 | return 1; |
| 2887 | } |
| 2888 | |
| 2889 | |
| 2890 | static SYSDEV_ATTR(scan_unevictable_pages, S_IRUGO | S_IWUSR, |
| 2891 | read_scan_unevictable_node, |
| 2892 | write_scan_unevictable_node); |
| 2893 | |
| 2894 | int scan_unevictable_register_node(struct node *node) |
| 2895 | { |
| 2896 | return sysdev_create_file(&node->sysdev, &attr_scan_unevictable_pages); |
| 2897 | } |
| 2898 | |
| 2899 | void scan_unevictable_unregister_node(struct node *node) |
| 2900 | { |
| 2901 | sysdev_remove_file(&node->sysdev, &attr_scan_unevictable_pages); |
| 2902 | } |
| 2903 | |