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 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | /* This context's GFP mask */ |
Al Viro | 6daa0e2 | 2005-10-21 03:18:50 -0400 | [diff] [blame] | 59 | gfp_t gfp_mask; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 60 | |
| 61 | int may_writepage; |
| 62 | |
Johannes Weiner | a6dc60f | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 63 | /* Can mapped pages be reclaimed? */ |
| 64 | int may_unmap; |
Christoph Lameter | f1fd106 | 2006-01-18 17:42:30 -0800 | [diff] [blame] | 65 | |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 66 | /* Can pages be swapped as part of reclaim? */ |
| 67 | int may_swap; |
| 68 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 69 | /* This context's SWAP_CLUSTER_MAX. If freeing memory for |
| 70 | * suspend, we effectively ignore SWAP_CLUSTER_MAX. |
| 71 | * In this context, it doesn't matter that we scan the |
| 72 | * whole list at once. */ |
| 73 | int swap_cluster_max; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 74 | |
| 75 | int swappiness; |
Nick Piggin | 408d854 | 2006-09-25 23:31:27 -0700 | [diff] [blame] | 76 | |
| 77 | int all_unreclaimable; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 78 | |
| 79 | int order; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 80 | |
| 81 | /* Which cgroup do we reclaim from */ |
| 82 | struct mem_cgroup *mem_cgroup; |
| 83 | |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 84 | /* |
| 85 | * Nodemask of nodes allowed by the caller. If NULL, all nodes |
| 86 | * are scanned. |
| 87 | */ |
| 88 | nodemask_t *nodemask; |
| 89 | |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 90 | /* Pluggable isolate pages callback */ |
| 91 | unsigned long (*isolate_pages)(unsigned long nr, struct list_head *dst, |
| 92 | unsigned long *scanned, int order, int mode, |
| 93 | struct zone *z, struct mem_cgroup *mem_cont, |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 94 | int active, int file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | }; |
| 96 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 97 | #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru)) |
| 98 | |
| 99 | #ifdef ARCH_HAS_PREFETCH |
| 100 | #define prefetch_prev_lru_page(_page, _base, _field) \ |
| 101 | do { \ |
| 102 | if ((_page)->lru.prev != _base) { \ |
| 103 | struct page *prev; \ |
| 104 | \ |
| 105 | prev = lru_to_page(&(_page->lru)); \ |
| 106 | prefetch(&prev->_field); \ |
| 107 | } \ |
| 108 | } while (0) |
| 109 | #else |
| 110 | #define prefetch_prev_lru_page(_page, _base, _field) do { } while (0) |
| 111 | #endif |
| 112 | |
| 113 | #ifdef ARCH_HAS_PREFETCHW |
| 114 | #define prefetchw_prev_lru_page(_page, _base, _field) \ |
| 115 | do { \ |
| 116 | if ((_page)->lru.prev != _base) { \ |
| 117 | struct page *prev; \ |
| 118 | \ |
| 119 | prev = lru_to_page(&(_page->lru)); \ |
| 120 | prefetchw(&prev->_field); \ |
| 121 | } \ |
| 122 | } while (0) |
| 123 | #else |
| 124 | #define prefetchw_prev_lru_page(_page, _base, _field) do { } while (0) |
| 125 | #endif |
| 126 | |
| 127 | /* |
| 128 | * From 0 .. 100. Higher means more swappy. |
| 129 | */ |
| 130 | int vm_swappiness = 60; |
Andrew Morton | bd1e22b | 2006-06-23 02:03:47 -0700 | [diff] [blame] | 131 | 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] | 132 | |
| 133 | static LIST_HEAD(shrinker_list); |
| 134 | static DECLARE_RWSEM(shrinker_rwsem); |
| 135 | |
Balbir Singh | 00f0b82 | 2008-03-04 14:28:39 -0800 | [diff] [blame] | 136 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 137 | #define scanning_global_lru(sc) (!(sc)->mem_cgroup) |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 138 | #else |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 139 | #define scanning_global_lru(sc) (1) |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 140 | #endif |
| 141 | |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 142 | static struct zone_reclaim_stat *get_reclaim_stat(struct zone *zone, |
| 143 | struct scan_control *sc) |
| 144 | { |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 145 | if (!scanning_global_lru(sc)) |
KOSAKI Motohiro | 3e2f41f | 2009-01-07 18:08:20 -0800 | [diff] [blame] | 146 | return mem_cgroup_get_reclaim_stat(sc->mem_cgroup, zone); |
| 147 | |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 148 | return &zone->reclaim_stat; |
| 149 | } |
| 150 | |
KOSAKI Motohiro | c9f299d | 2009-01-07 18:08:16 -0800 | [diff] [blame] | 151 | static unsigned long zone_nr_pages(struct zone *zone, struct scan_control *sc, |
| 152 | enum lru_list lru) |
| 153 | { |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 154 | if (!scanning_global_lru(sc)) |
KOSAKI Motohiro | a3d8e05 | 2009-01-07 18:08:19 -0800 | [diff] [blame] | 155 | return mem_cgroup_zone_nr_pages(sc->mem_cgroup, zone, lru); |
| 156 | |
KOSAKI Motohiro | c9f299d | 2009-01-07 18:08:16 -0800 | [diff] [blame] | 157 | return zone_page_state(zone, NR_LRU_BASE + lru); |
| 158 | } |
| 159 | |
| 160 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | /* |
| 162 | * Add a shrinker callback to be called from the vm |
| 163 | */ |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 164 | void register_shrinker(struct shrinker *shrinker) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | { |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 166 | shrinker->nr = 0; |
| 167 | down_write(&shrinker_rwsem); |
| 168 | list_add_tail(&shrinker->list, &shrinker_list); |
| 169 | up_write(&shrinker_rwsem); |
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 | EXPORT_SYMBOL(register_shrinker); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 172 | |
| 173 | /* |
| 174 | * Remove one |
| 175 | */ |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 176 | void unregister_shrinker(struct shrinker *shrinker) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | { |
| 178 | down_write(&shrinker_rwsem); |
| 179 | list_del(&shrinker->list); |
| 180 | up_write(&shrinker_rwsem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | } |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 182 | EXPORT_SYMBOL(unregister_shrinker); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 183 | |
| 184 | #define SHRINK_BATCH 128 |
| 185 | /* |
| 186 | * Call the shrink functions to age shrinkable caches |
| 187 | * |
| 188 | * Here we assume it costs one seek to replace a lru page and that it also |
| 189 | * takes a seek to recreate a cache object. With this in mind we age equal |
| 190 | * percentages of the lru and ageable caches. This should balance the seeks |
| 191 | * generated by these structures. |
| 192 | * |
Simon Arlott | 183ff22 | 2007-10-20 01:27:18 +0200 | [diff] [blame] | 193 | * 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] | 194 | * slab to avoid swapping. |
| 195 | * |
| 196 | * We do weird things to avoid (scanned*seeks*entries) overflowing 32 bits. |
| 197 | * |
| 198 | * `lru_pages' represents the number of on-LRU pages in all the zones which |
| 199 | * are eligible for the caller's allocation attempt. It is used for balancing |
| 200 | * slab reclaim versus page reclaim. |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 201 | * |
| 202 | * Returns the number of slab objects which we shrunk. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 204 | unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask, |
| 205 | unsigned long lru_pages) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 206 | { |
| 207 | struct shrinker *shrinker; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 208 | unsigned long ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | |
| 210 | if (scanned == 0) |
| 211 | scanned = SWAP_CLUSTER_MAX; |
| 212 | |
| 213 | if (!down_read_trylock(&shrinker_rwsem)) |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 214 | return 1; /* Assume we'll be able to shrink next time */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 215 | |
| 216 | list_for_each_entry(shrinker, &shrinker_list, list) { |
| 217 | unsigned long long delta; |
| 218 | unsigned long total_scan; |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 219 | unsigned long max_pass = (*shrinker->shrink)(0, gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | |
| 221 | delta = (4 * scanned) / shrinker->seeks; |
Andrea Arcangeli | ea164d7 | 2005-11-28 13:44:15 -0800 | [diff] [blame] | 222 | delta *= max_pass; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | do_div(delta, lru_pages + 1); |
| 224 | shrinker->nr += delta; |
Andrea Arcangeli | ea164d7 | 2005-11-28 13:44:15 -0800 | [diff] [blame] | 225 | if (shrinker->nr < 0) { |
David Rientjes | 88c3bd7 | 2009-03-31 15:23:29 -0700 | [diff] [blame] | 226 | printk(KERN_ERR "shrink_slab: %pF negative objects to " |
| 227 | "delete nr=%ld\n", |
| 228 | shrinker->shrink, shrinker->nr); |
Andrea Arcangeli | ea164d7 | 2005-11-28 13:44:15 -0800 | [diff] [blame] | 229 | shrinker->nr = max_pass; |
| 230 | } |
| 231 | |
| 232 | /* |
| 233 | * Avoid risking looping forever due to too large nr value: |
| 234 | * never try to free more than twice the estimate number of |
| 235 | * freeable entries. |
| 236 | */ |
| 237 | if (shrinker->nr > max_pass * 2) |
| 238 | shrinker->nr = max_pass * 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | |
| 240 | total_scan = shrinker->nr; |
| 241 | shrinker->nr = 0; |
| 242 | |
| 243 | while (total_scan >= SHRINK_BATCH) { |
| 244 | long this_scan = SHRINK_BATCH; |
| 245 | int shrink_ret; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 246 | int nr_before; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 247 | |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 248 | nr_before = (*shrinker->shrink)(0, gfp_mask); |
| 249 | shrink_ret = (*shrinker->shrink)(this_scan, gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 250 | if (shrink_ret == -1) |
| 251 | break; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 252 | if (shrink_ret < nr_before) |
| 253 | ret += nr_before - shrink_ret; |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 254 | count_vm_events(SLABS_SCANNED, this_scan); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 255 | total_scan -= this_scan; |
| 256 | |
| 257 | cond_resched(); |
| 258 | } |
| 259 | |
| 260 | shrinker->nr += total_scan; |
| 261 | } |
| 262 | up_read(&shrinker_rwsem); |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 263 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 264 | } |
| 265 | |
| 266 | /* Called without lock on whether page is mapped, so answer is unstable */ |
| 267 | static inline int page_mapping_inuse(struct page *page) |
| 268 | { |
| 269 | struct address_space *mapping; |
| 270 | |
| 271 | /* Page is in somebody's page tables. */ |
| 272 | if (page_mapped(page)) |
| 273 | return 1; |
| 274 | |
| 275 | /* Be more reluctant to reclaim swapcache than pagecache */ |
| 276 | if (PageSwapCache(page)) |
| 277 | return 1; |
| 278 | |
| 279 | mapping = page_mapping(page); |
| 280 | if (!mapping) |
| 281 | return 0; |
| 282 | |
| 283 | /* File is mmap'd by somebody? */ |
| 284 | return mapping_mapped(mapping); |
| 285 | } |
| 286 | |
| 287 | static inline int is_page_cache_freeable(struct page *page) |
| 288 | { |
David Howells | 266cf65 | 2009-04-03 16:42:36 +0100 | [diff] [blame] | 289 | return page_count(page) - !!page_has_private(page) == 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | } |
| 291 | |
| 292 | static int may_write_to_queue(struct backing_dev_info *bdi) |
| 293 | { |
Christoph Lameter | 930d915 | 2006-01-08 01:00:47 -0800 | [diff] [blame] | 294 | if (current->flags & PF_SWAPWRITE) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 295 | return 1; |
| 296 | if (!bdi_write_congested(bdi)) |
| 297 | return 1; |
| 298 | if (bdi == current->backing_dev_info) |
| 299 | return 1; |
| 300 | return 0; |
| 301 | } |
| 302 | |
| 303 | /* |
| 304 | * We detected a synchronous write error writing a page out. Probably |
| 305 | * -ENOSPC. We need to propagate that into the address_space for a subsequent |
| 306 | * fsync(), msync() or close(). |
| 307 | * |
| 308 | * The tricky part is that after writepage we cannot touch the mapping: nothing |
| 309 | * prevents it from being freed up. But we have a ref on the page and once |
| 310 | * that page is locked, the mapping is pinned. |
| 311 | * |
| 312 | * We're allowed to run sleeping lock_page() here because we know the caller has |
| 313 | * __GFP_FS. |
| 314 | */ |
| 315 | static void handle_write_error(struct address_space *mapping, |
| 316 | struct page *page, int error) |
| 317 | { |
| 318 | lock_page(page); |
Guillaume Chazarain | 3e9f45b | 2007-05-08 00:23:25 -0700 | [diff] [blame] | 319 | if (page_mapping(page) == mapping) |
| 320 | mapping_set_error(mapping, error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | unlock_page(page); |
| 322 | } |
| 323 | |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 324 | /* Request for sync pageout. */ |
| 325 | enum pageout_io { |
| 326 | PAGEOUT_IO_ASYNC, |
| 327 | PAGEOUT_IO_SYNC, |
| 328 | }; |
| 329 | |
Christoph Lameter | 04e62a2 | 2006-06-23 02:03:38 -0700 | [diff] [blame] | 330 | /* possible outcome of pageout() */ |
| 331 | typedef enum { |
| 332 | /* failed to write page out, page is locked */ |
| 333 | PAGE_KEEP, |
| 334 | /* move page to the active list, page is locked */ |
| 335 | PAGE_ACTIVATE, |
| 336 | /* page has been sent to the disk successfully, page is unlocked */ |
| 337 | PAGE_SUCCESS, |
| 338 | /* page is clean and locked */ |
| 339 | PAGE_CLEAN, |
| 340 | } pageout_t; |
| 341 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 342 | /* |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 343 | * pageout is called by shrink_page_list() for each dirty page. |
| 344 | * Calls ->writepage(). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 345 | */ |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 346 | static pageout_t pageout(struct page *page, struct address_space *mapping, |
| 347 | enum pageout_io sync_writeback) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 348 | { |
| 349 | /* |
| 350 | * If the page is dirty, only perform writeback if that write |
| 351 | * will be non-blocking. To prevent this allocation from being |
| 352 | * stalled by pagecache activity. But note that there may be |
| 353 | * stalls if we need to run get_block(). We could test |
| 354 | * PagePrivate for that. |
| 355 | * |
| 356 | * If this process is currently in generic_file_write() against |
| 357 | * this page's queue, we can perform writeback even if that |
| 358 | * will block. |
| 359 | * |
| 360 | * If the page is swapcache, write it back even if that would |
| 361 | * block, for some throttling. This happens by accident, because |
| 362 | * swap_backing_dev_info is bust: it doesn't reflect the |
| 363 | * congestion state of the swapdevs. Easy to fix, if needed. |
| 364 | * See swapfile.c:page_queue_congested(). |
| 365 | */ |
| 366 | if (!is_page_cache_freeable(page)) |
| 367 | return PAGE_KEEP; |
| 368 | if (!mapping) { |
| 369 | /* |
| 370 | * Some data journaling orphaned pages can have |
| 371 | * page->mapping == NULL while being dirty with clean buffers. |
| 372 | */ |
David Howells | 266cf65 | 2009-04-03 16:42:36 +0100 | [diff] [blame] | 373 | if (page_has_private(page)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 374 | if (try_to_free_buffers(page)) { |
| 375 | ClearPageDirty(page); |
Harvey Harrison | d40cee2 | 2008-04-30 00:55:07 -0700 | [diff] [blame] | 376 | printk("%s: orphaned page\n", __func__); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 377 | return PAGE_CLEAN; |
| 378 | } |
| 379 | } |
| 380 | return PAGE_KEEP; |
| 381 | } |
| 382 | if (mapping->a_ops->writepage == NULL) |
| 383 | return PAGE_ACTIVATE; |
| 384 | if (!may_write_to_queue(mapping->backing_dev_info)) |
| 385 | return PAGE_KEEP; |
| 386 | |
| 387 | if (clear_page_dirty_for_io(page)) { |
| 388 | int res; |
| 389 | struct writeback_control wbc = { |
| 390 | .sync_mode = WB_SYNC_NONE, |
| 391 | .nr_to_write = SWAP_CLUSTER_MAX, |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 392 | .range_start = 0, |
| 393 | .range_end = LLONG_MAX, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 394 | .nonblocking = 1, |
| 395 | .for_reclaim = 1, |
| 396 | }; |
| 397 | |
| 398 | SetPageReclaim(page); |
| 399 | res = mapping->a_ops->writepage(page, &wbc); |
| 400 | if (res < 0) |
| 401 | handle_write_error(mapping, page, res); |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 402 | if (res == AOP_WRITEPAGE_ACTIVATE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 403 | ClearPageReclaim(page); |
| 404 | return PAGE_ACTIVATE; |
| 405 | } |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 406 | |
| 407 | /* |
| 408 | * Wait on writeback if requested to. This happens when |
| 409 | * direct reclaiming a large contiguous area and the |
| 410 | * first attempt to free a range of pages fails. |
| 411 | */ |
| 412 | if (PageWriteback(page) && sync_writeback == PAGEOUT_IO_SYNC) |
| 413 | wait_on_page_writeback(page); |
| 414 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | if (!PageWriteback(page)) { |
| 416 | /* synchronous write or broken a_ops? */ |
| 417 | ClearPageReclaim(page); |
| 418 | } |
Andrew Morton | e129b5c | 2006-09-27 01:50:00 -0700 | [diff] [blame] | 419 | inc_zone_page_state(page, NR_VMSCAN_WRITE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 420 | return PAGE_SUCCESS; |
| 421 | } |
| 422 | |
| 423 | return PAGE_CLEAN; |
| 424 | } |
| 425 | |
Andrew Morton | a649fd9 | 2006-10-17 00:09:36 -0700 | [diff] [blame] | 426 | /* |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 427 | * Same as remove_mapping, but if the page is removed from the mapping, it |
| 428 | * gets returned with a refcount of 0. |
Andrew Morton | a649fd9 | 2006-10-17 00:09:36 -0700 | [diff] [blame] | 429 | */ |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 430 | static int __remove_mapping(struct address_space *mapping, struct page *page) |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 431 | { |
Nick Piggin | 28e4d96 | 2006-09-25 23:31:23 -0700 | [diff] [blame] | 432 | BUG_ON(!PageLocked(page)); |
| 433 | BUG_ON(mapping != page_mapping(page)); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 434 | |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 435 | spin_lock_irq(&mapping->tree_lock); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 436 | /* |
Nick Piggin | 0fd0e6b | 2006-09-27 01:50:02 -0700 | [diff] [blame] | 437 | * The non racy check for a busy page. |
| 438 | * |
| 439 | * Must be careful with the order of the tests. When someone has |
| 440 | * a ref to the page, it may be possible that they dirty it then |
| 441 | * drop the reference. So if PageDirty is tested before page_count |
| 442 | * here, then the following race may occur: |
| 443 | * |
| 444 | * get_user_pages(&page); |
| 445 | * [user mapping goes away] |
| 446 | * write_to(page); |
| 447 | * !PageDirty(page) [good] |
| 448 | * SetPageDirty(page); |
| 449 | * put_page(page); |
| 450 | * !page_count(page) [good, discard it] |
| 451 | * |
| 452 | * [oops, our write_to data is lost] |
| 453 | * |
| 454 | * Reversing the order of the tests ensures such a situation cannot |
| 455 | * escape unnoticed. The smp_rmb is needed to ensure the page->flags |
| 456 | * load is not satisfied before that of page->_count. |
| 457 | * |
| 458 | * Note that if SetPageDirty is always performed via set_page_dirty, |
| 459 | * and thus under tree_lock, then this ordering is not required. |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 460 | */ |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 461 | if (!page_freeze_refs(page, 2)) |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 462 | goto cannot_free; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 463 | /* note: atomic_cmpxchg in page_freeze_refs provides the smp_rmb */ |
| 464 | if (unlikely(PageDirty(page))) { |
| 465 | page_unfreeze_refs(page, 2); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 466 | goto cannot_free; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 467 | } |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 468 | |
| 469 | if (PageSwapCache(page)) { |
| 470 | swp_entry_t swap = { .val = page_private(page) }; |
| 471 | __delete_from_swap_cache(page); |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 472 | spin_unlock_irq(&mapping->tree_lock); |
KAMEZAWA Hiroyuki | cb4b86b | 2009-06-16 15:32:52 -0700 | [diff] [blame] | 473 | swapcache_free(swap, page); |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 474 | } else { |
| 475 | __remove_from_page_cache(page); |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 476 | spin_unlock_irq(&mapping->tree_lock); |
Daisuke Nishimura | e767e05 | 2009-05-28 14:34:28 -0700 | [diff] [blame] | 477 | mem_cgroup_uncharge_cache_page(page); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 478 | } |
| 479 | |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 480 | return 1; |
| 481 | |
| 482 | cannot_free: |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 483 | spin_unlock_irq(&mapping->tree_lock); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 484 | return 0; |
| 485 | } |
| 486 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 487 | /* |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 488 | * Attempt to detach a locked page from its ->mapping. If it is dirty or if |
| 489 | * someone else has a ref on the page, abort and return 0. If it was |
| 490 | * successfully detached, return 1. Assumes the caller has a single ref on |
| 491 | * this page. |
| 492 | */ |
| 493 | int remove_mapping(struct address_space *mapping, struct page *page) |
| 494 | { |
| 495 | if (__remove_mapping(mapping, page)) { |
| 496 | /* |
| 497 | * Unfreezing the refcount with 1 rather than 2 effectively |
| 498 | * drops the pagecache ref for us without requiring another |
| 499 | * atomic operation. |
| 500 | */ |
| 501 | page_unfreeze_refs(page, 1); |
| 502 | return 1; |
| 503 | } |
| 504 | return 0; |
| 505 | } |
| 506 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 507 | /** |
| 508 | * putback_lru_page - put previously isolated page onto appropriate LRU list |
| 509 | * @page: page to be put back to appropriate lru list |
| 510 | * |
| 511 | * Add previously isolated @page to appropriate LRU list. |
| 512 | * Page may still be unevictable for other reasons. |
| 513 | * |
| 514 | * lru_lock must not be held, interrupts must be enabled. |
| 515 | */ |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 516 | void putback_lru_page(struct page *page) |
| 517 | { |
| 518 | int lru; |
| 519 | int active = !!TestClearPageActive(page); |
Lee Schermerhorn | bbfd28e | 2008-10-18 20:26:40 -0700 | [diff] [blame] | 520 | int was_unevictable = PageUnevictable(page); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 521 | |
| 522 | VM_BUG_ON(PageLRU(page)); |
| 523 | |
| 524 | redo: |
| 525 | ClearPageUnevictable(page); |
| 526 | |
| 527 | if (page_evictable(page, NULL)) { |
| 528 | /* |
| 529 | * For evictable pages, we can use the cache. |
| 530 | * In event of a race, worst case is we end up with an |
| 531 | * unevictable page on [in]active list. |
| 532 | * We know how to handle that. |
| 533 | */ |
| 534 | lru = active + page_is_file_cache(page); |
| 535 | lru_cache_add_lru(page, lru); |
| 536 | } else { |
| 537 | /* |
| 538 | * Put unevictable pages directly on zone's unevictable |
| 539 | * list. |
| 540 | */ |
| 541 | lru = LRU_UNEVICTABLE; |
| 542 | add_page_to_unevictable_list(page); |
| 543 | } |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 544 | |
| 545 | /* |
| 546 | * page's status can change while we move it among lru. If an evictable |
| 547 | * page is on unevictable list, it never be freed. To avoid that, |
| 548 | * check after we added it to the list, again. |
| 549 | */ |
| 550 | if (lru == LRU_UNEVICTABLE && page_evictable(page, NULL)) { |
| 551 | if (!isolate_lru_page(page)) { |
| 552 | put_page(page); |
| 553 | goto redo; |
| 554 | } |
| 555 | /* This means someone else dropped this page from LRU |
| 556 | * So, it will be freed or putback to LRU again. There is |
| 557 | * nothing to do here. |
| 558 | */ |
| 559 | } |
| 560 | |
Lee Schermerhorn | bbfd28e | 2008-10-18 20:26:40 -0700 | [diff] [blame] | 561 | if (was_unevictable && lru != LRU_UNEVICTABLE) |
| 562 | count_vm_event(UNEVICTABLE_PGRESCUED); |
| 563 | else if (!was_unevictable && lru == LRU_UNEVICTABLE) |
| 564 | count_vm_event(UNEVICTABLE_PGCULLED); |
| 565 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 566 | put_page(page); /* drop ref from isolate */ |
| 567 | } |
| 568 | |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 569 | /* |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 570 | * shrink_page_list() returns the number of reclaimed pages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 571 | */ |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 572 | static unsigned long shrink_page_list(struct list_head *page_list, |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 573 | struct scan_control *sc, |
| 574 | enum pageout_io sync_writeback) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 575 | { |
| 576 | LIST_HEAD(ret_pages); |
| 577 | struct pagevec freed_pvec; |
| 578 | int pgactivate = 0; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 579 | unsigned long nr_reclaimed = 0; |
Wu Fengguang | 6fe6b7e | 2009-06-16 15:33:05 -0700 | [diff] [blame] | 580 | unsigned long vm_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 581 | |
| 582 | cond_resched(); |
| 583 | |
| 584 | pagevec_init(&freed_pvec, 1); |
| 585 | while (!list_empty(page_list)) { |
| 586 | struct address_space *mapping; |
| 587 | struct page *page; |
| 588 | int may_enter_fs; |
| 589 | int referenced; |
| 590 | |
| 591 | cond_resched(); |
| 592 | |
| 593 | page = lru_to_page(page_list); |
| 594 | list_del(&page->lru); |
| 595 | |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 596 | if (!trylock_page(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 597 | goto keep; |
| 598 | |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 599 | VM_BUG_ON(PageActive(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 600 | |
| 601 | sc->nr_scanned++; |
Christoph Lameter | 80e4342 | 2006-02-11 17:55:53 -0800 | [diff] [blame] | 602 | |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 603 | if (unlikely(!page_evictable(page, NULL))) |
| 604 | goto cull_mlocked; |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 605 | |
Johannes Weiner | a6dc60f | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 606 | if (!sc->may_unmap && page_mapped(page)) |
Christoph Lameter | 80e4342 | 2006-02-11 17:55:53 -0800 | [diff] [blame] | 607 | goto keep_locked; |
| 608 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 609 | /* Double the slab pressure for mapped and swapcache pages */ |
| 610 | if (page_mapped(page) || PageSwapCache(page)) |
| 611 | sc->nr_scanned++; |
| 612 | |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 613 | may_enter_fs = (sc->gfp_mask & __GFP_FS) || |
| 614 | (PageSwapCache(page) && (sc->gfp_mask & __GFP_IO)); |
| 615 | |
| 616 | if (PageWriteback(page)) { |
| 617 | /* |
| 618 | * Synchronous reclaim is performed in two passes, |
| 619 | * first an asynchronous pass over the list to |
| 620 | * start parallel writeback, and a second synchronous |
| 621 | * pass to wait for the IO to complete. Wait here |
| 622 | * for any page for which writeback has already |
| 623 | * started. |
| 624 | */ |
| 625 | if (sync_writeback == PAGEOUT_IO_SYNC && may_enter_fs) |
| 626 | wait_on_page_writeback(page); |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 627 | else |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 628 | goto keep_locked; |
| 629 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 630 | |
Wu Fengguang | 6fe6b7e | 2009-06-16 15:33:05 -0700 | [diff] [blame] | 631 | referenced = page_referenced(page, 1, |
| 632 | sc->mem_cgroup, &vm_flags); |
Minchan Kim | 03ef83a | 2009-08-26 14:29:23 -0700 | [diff] [blame] | 633 | /* |
| 634 | * In active use or really unfreeable? Activate it. |
| 635 | * If page which have PG_mlocked lost isoltation race, |
| 636 | * try_to_unmap moves it to unevictable list |
| 637 | */ |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 638 | if (sc->order <= PAGE_ALLOC_COSTLY_ORDER && |
Minchan Kim | 03ef83a | 2009-08-26 14:29:23 -0700 | [diff] [blame] | 639 | referenced && page_mapping_inuse(page) |
| 640 | && !(vm_flags & VM_LOCKED)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 641 | goto activate_locked; |
| 642 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 643 | /* |
| 644 | * Anonymous process memory has backing store? |
| 645 | * Try to allocate it some swap space here. |
| 646 | */ |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 647 | if (PageAnon(page) && !PageSwapCache(page)) { |
Hugh Dickins | 63eb6b9 | 2008-11-19 15:36:37 -0800 | [diff] [blame] | 648 | if (!(sc->gfp_mask & __GFP_IO)) |
| 649 | goto keep_locked; |
Hugh Dickins | ac47b00 | 2009-01-06 14:39:39 -0800 | [diff] [blame] | 650 | if (!add_to_swap(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 651 | goto activate_locked; |
Hugh Dickins | 63eb6b9 | 2008-11-19 15:36:37 -0800 | [diff] [blame] | 652 | may_enter_fs = 1; |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 653 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 654 | |
| 655 | mapping = page_mapping(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 656 | |
| 657 | /* |
| 658 | * The page is mapped into the page tables of one or more |
| 659 | * processes. Try to unmap it here. |
| 660 | */ |
| 661 | if (page_mapped(page) && mapping) { |
Christoph Lameter | a48d07a | 2006-02-01 03:05:38 -0800 | [diff] [blame] | 662 | switch (try_to_unmap(page, 0)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 663 | case SWAP_FAIL: |
| 664 | goto activate_locked; |
| 665 | case SWAP_AGAIN: |
| 666 | goto keep_locked; |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 667 | case SWAP_MLOCK: |
| 668 | goto cull_mlocked; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 669 | case SWAP_SUCCESS: |
| 670 | ; /* try to free the page below */ |
| 671 | } |
| 672 | } |
| 673 | |
| 674 | if (PageDirty(page)) { |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 675 | if (sc->order <= PAGE_ALLOC_COSTLY_ORDER && referenced) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 676 | goto keep_locked; |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 677 | if (!may_enter_fs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 678 | goto keep_locked; |
Christoph Lameter | 52a8363 | 2006-02-01 03:05:28 -0800 | [diff] [blame] | 679 | if (!sc->may_writepage) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 680 | goto keep_locked; |
| 681 | |
| 682 | /* Page is dirty, try to write it out here */ |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 683 | switch (pageout(page, mapping, sync_writeback)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 684 | case PAGE_KEEP: |
| 685 | goto keep_locked; |
| 686 | case PAGE_ACTIVATE: |
| 687 | goto activate_locked; |
| 688 | case PAGE_SUCCESS: |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 689 | if (PageWriteback(page) || PageDirty(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 690 | goto keep; |
| 691 | /* |
| 692 | * A synchronous write - probably a ramdisk. Go |
| 693 | * ahead and try to reclaim the page. |
| 694 | */ |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 695 | if (!trylock_page(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 696 | goto keep; |
| 697 | if (PageDirty(page) || PageWriteback(page)) |
| 698 | goto keep_locked; |
| 699 | mapping = page_mapping(page); |
| 700 | case PAGE_CLEAN: |
| 701 | ; /* try to free the page below */ |
| 702 | } |
| 703 | } |
| 704 | |
| 705 | /* |
| 706 | * If the page has buffers, try to free the buffer mappings |
| 707 | * associated with this page. If we succeed we try to free |
| 708 | * the page as well. |
| 709 | * |
| 710 | * We do this even if the page is PageDirty(). |
| 711 | * try_to_release_page() does not perform I/O, but it is |
| 712 | * possible for a page to have PageDirty set, but it is actually |
| 713 | * clean (all its buffers are clean). This happens if the |
| 714 | * buffers were written out directly, with submit_bh(). ext3 |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 715 | * will do this, as well as the blockdev mapping. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 716 | * try_to_release_page() will discover that cleanness and will |
| 717 | * drop the buffers and mark the page clean - it can be freed. |
| 718 | * |
| 719 | * Rarely, pages can have buffers and no ->mapping. These are |
| 720 | * the pages which were not successfully invalidated in |
| 721 | * truncate_complete_page(). We try to drop those buffers here |
| 722 | * and if that worked, and the page is no longer mapped into |
| 723 | * process address space (page_count == 1) it can be freed. |
| 724 | * Otherwise, leave the page on the LRU so it is swappable. |
| 725 | */ |
David Howells | 266cf65 | 2009-04-03 16:42:36 +0100 | [diff] [blame] | 726 | if (page_has_private(page)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 727 | if (!try_to_release_page(page, sc->gfp_mask)) |
| 728 | goto activate_locked; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 729 | if (!mapping && page_count(page) == 1) { |
| 730 | unlock_page(page); |
| 731 | if (put_page_testzero(page)) |
| 732 | goto free_it; |
| 733 | else { |
| 734 | /* |
| 735 | * rare race with speculative reference. |
| 736 | * the speculative reference will free |
| 737 | * this page shortly, so we may |
| 738 | * increment nr_reclaimed here (and |
| 739 | * leave it off the LRU). |
| 740 | */ |
| 741 | nr_reclaimed++; |
| 742 | continue; |
| 743 | } |
| 744 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 745 | } |
| 746 | |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 747 | if (!mapping || !__remove_mapping(mapping, page)) |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 748 | goto keep_locked; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 749 | |
Nick Piggin | a978d6f | 2008-10-18 20:26:58 -0700 | [diff] [blame] | 750 | /* |
| 751 | * At this point, we have no other references and there is |
| 752 | * no way to pick any more up (removed from LRU, removed |
| 753 | * from pagecache). Can use non-atomic bitops now (and |
| 754 | * we obviously don't have to worry about waking up a process |
| 755 | * waiting on the page lock, because there are no references. |
| 756 | */ |
| 757 | __clear_page_locked(page); |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 758 | free_it: |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 759 | nr_reclaimed++; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 760 | if (!pagevec_add(&freed_pvec, page)) { |
| 761 | __pagevec_free(&freed_pvec); |
| 762 | pagevec_reinit(&freed_pvec); |
| 763 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 764 | continue; |
| 765 | |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 766 | cull_mlocked: |
Hugh Dickins | 63d6c5a | 2009-01-06 14:39:38 -0800 | [diff] [blame] | 767 | if (PageSwapCache(page)) |
| 768 | try_to_free_swap(page); |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 769 | unlock_page(page); |
| 770 | putback_lru_page(page); |
| 771 | continue; |
| 772 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 773 | activate_locked: |
Rik van Riel | 68a22394 | 2008-10-18 20:26:23 -0700 | [diff] [blame] | 774 | /* Not a candidate for swapping, so reclaim swap space. */ |
| 775 | if (PageSwapCache(page) && vm_swap_full()) |
Hugh Dickins | a2c43ee | 2009-01-06 14:39:36 -0800 | [diff] [blame] | 776 | try_to_free_swap(page); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 777 | VM_BUG_ON(PageActive(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 778 | SetPageActive(page); |
| 779 | pgactivate++; |
| 780 | keep_locked: |
| 781 | unlock_page(page); |
| 782 | keep: |
| 783 | list_add(&page->lru, &ret_pages); |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 784 | VM_BUG_ON(PageLRU(page) || PageUnevictable(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 785 | } |
| 786 | list_splice(&ret_pages, page_list); |
| 787 | if (pagevec_count(&freed_pvec)) |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 788 | __pagevec_free(&freed_pvec); |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 789 | count_vm_events(PGACTIVATE, pgactivate); |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 790 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 791 | } |
| 792 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 793 | /* LRU Isolation modes. */ |
| 794 | #define ISOLATE_INACTIVE 0 /* Isolate inactive pages. */ |
| 795 | #define ISOLATE_ACTIVE 1 /* Isolate active pages. */ |
| 796 | #define ISOLATE_BOTH 2 /* Isolate both active and inactive pages. */ |
| 797 | |
| 798 | /* |
| 799 | * Attempt to remove the specified page from its LRU. Only take this page |
| 800 | * if it is of the appropriate PageActive status. Pages which are being |
| 801 | * freed elsewhere are also ignored. |
| 802 | * |
| 803 | * page: page to consider |
| 804 | * mode: one of the LRU isolation modes defined above |
| 805 | * |
| 806 | * returns 0 on success, -ve errno on failure. |
| 807 | */ |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 808 | int __isolate_lru_page(struct page *page, int mode, int file) |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 809 | { |
| 810 | int ret = -EINVAL; |
| 811 | |
| 812 | /* Only take pages on the LRU. */ |
| 813 | if (!PageLRU(page)) |
| 814 | return ret; |
| 815 | |
| 816 | /* |
| 817 | * When checking the active state, we need to be sure we are |
| 818 | * dealing with comparible boolean values. Take the logical not |
| 819 | * of each. |
| 820 | */ |
| 821 | if (mode != ISOLATE_BOTH && (!PageActive(page) != !mode)) |
| 822 | return ret; |
| 823 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 824 | if (mode != ISOLATE_BOTH && (!page_is_file_cache(page) != !file)) |
| 825 | return ret; |
| 826 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 827 | /* |
| 828 | * When this function is being called for lumpy reclaim, we |
| 829 | * initially look into all LRU pages, active, inactive and |
| 830 | * unevictable; only give shrink_page_list evictable pages. |
| 831 | */ |
| 832 | if (PageUnevictable(page)) |
| 833 | return ret; |
| 834 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 835 | ret = -EBUSY; |
KAMEZAWA Hiroyuki | 08e552c | 2009-01-07 18:08:01 -0800 | [diff] [blame] | 836 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 837 | if (likely(get_page_unless_zero(page))) { |
| 838 | /* |
| 839 | * Be careful not to clear PageLRU until after we're |
| 840 | * sure the page is not being freed elsewhere -- the |
| 841 | * page release code relies on it. |
| 842 | */ |
| 843 | ClearPageLRU(page); |
| 844 | ret = 0; |
| 845 | } |
| 846 | |
| 847 | return ret; |
| 848 | } |
| 849 | |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 850 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 851 | * zone->lru_lock is heavily contended. Some of the functions that |
| 852 | * shrink the lists perform better by taking out a batch of pages |
| 853 | * and working on them outside the LRU lock. |
| 854 | * |
| 855 | * For pagecache intensive workloads, this function is the hottest |
| 856 | * spot in the kernel (apart from copy_*_user functions). |
| 857 | * |
| 858 | * Appropriate locks must be held before calling this function. |
| 859 | * |
| 860 | * @nr_to_scan: The number of pages to look through on the list. |
| 861 | * @src: The LRU list to pull pages off. |
| 862 | * @dst: The temp list to put pages on to. |
| 863 | * @scanned: The number of pages that were scanned. |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 864 | * @order: The caller's attempted allocation order |
| 865 | * @mode: One of the LRU isolation modes |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 866 | * @file: True [1] if isolating file [!anon] pages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 867 | * |
| 868 | * returns how many pages were moved onto *@dst. |
| 869 | */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 870 | static unsigned long isolate_lru_pages(unsigned long nr_to_scan, |
| 871 | struct list_head *src, struct list_head *dst, |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 872 | unsigned long *scanned, int order, int mode, int file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 873 | { |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 874 | unsigned long nr_taken = 0; |
Wu Fengguang | c9b02d9 | 2006-03-22 00:08:23 -0800 | [diff] [blame] | 875 | unsigned long scan; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 876 | |
Wu Fengguang | c9b02d9 | 2006-03-22 00:08:23 -0800 | [diff] [blame] | 877 | for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) { |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 878 | struct page *page; |
| 879 | unsigned long pfn; |
| 880 | unsigned long end_pfn; |
| 881 | unsigned long page_pfn; |
| 882 | int zone_id; |
| 883 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 884 | page = lru_to_page(src); |
| 885 | prefetchw_prev_lru_page(page, src, flags); |
| 886 | |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 887 | VM_BUG_ON(!PageLRU(page)); |
Nick Piggin | 8d438f9 | 2006-03-22 00:07:59 -0800 | [diff] [blame] | 888 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 889 | switch (__isolate_lru_page(page, mode, file)) { |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 890 | case 0: |
| 891 | list_move(&page->lru, dst); |
KAMEZAWA Hiroyuki | 2ffebca | 2009-06-17 16:27:21 -0700 | [diff] [blame] | 892 | mem_cgroup_del_lru(page); |
Nick Piggin | 7c8ee9a | 2006-03-22 00:08:03 -0800 | [diff] [blame] | 893 | nr_taken++; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 894 | break; |
Nick Piggin | 46453a6 | 2006-03-22 00:07:58 -0800 | [diff] [blame] | 895 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 896 | case -EBUSY: |
| 897 | /* else it is being freed elsewhere */ |
| 898 | list_move(&page->lru, src); |
KAMEZAWA Hiroyuki | 2ffebca | 2009-06-17 16:27:21 -0700 | [diff] [blame] | 899 | mem_cgroup_rotate_lru_list(page, page_lru(page)); |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 900 | continue; |
| 901 | |
| 902 | default: |
| 903 | BUG(); |
| 904 | } |
| 905 | |
| 906 | if (!order) |
| 907 | continue; |
| 908 | |
| 909 | /* |
| 910 | * Attempt to take all pages in the order aligned region |
| 911 | * surrounding the tag page. Only take those pages of |
| 912 | * the same active state as that tag page. We may safely |
| 913 | * round the target page pfn down to the requested order |
| 914 | * as the mem_map is guarenteed valid out to MAX_ORDER, |
| 915 | * where that page is in a different zone we will detect |
| 916 | * it from its zone id and abort this block scan. |
| 917 | */ |
| 918 | zone_id = page_zone_id(page); |
| 919 | page_pfn = page_to_pfn(page); |
| 920 | pfn = page_pfn & ~((1 << order) - 1); |
| 921 | end_pfn = pfn + (1 << order); |
| 922 | for (; pfn < end_pfn; pfn++) { |
| 923 | struct page *cursor_page; |
| 924 | |
| 925 | /* The target page is in the block, ignore it. */ |
| 926 | if (unlikely(pfn == page_pfn)) |
| 927 | continue; |
| 928 | |
| 929 | /* Avoid holes within the zone. */ |
| 930 | if (unlikely(!pfn_valid_within(pfn))) |
| 931 | break; |
| 932 | |
| 933 | cursor_page = pfn_to_page(pfn); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 934 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 935 | /* Check that we have not crossed a zone boundary. */ |
| 936 | if (unlikely(page_zone_id(cursor_page) != zone_id)) |
| 937 | continue; |
KAMEZAWA Hiroyuki | ee993b1 | 2009-06-16 15:33:24 -0700 | [diff] [blame] | 938 | if (__isolate_lru_page(cursor_page, mode, file) == 0) { |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 939 | list_move(&cursor_page->lru, dst); |
KAMEZAWA Hiroyuki | cb4cbcf | 2009-06-23 08:57:55 +0900 | [diff] [blame] | 940 | mem_cgroup_del_lru(cursor_page); |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 941 | nr_taken++; |
| 942 | scan++; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 943 | } |
| 944 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 945 | } |
| 946 | |
| 947 | *scanned = scan; |
| 948 | return nr_taken; |
| 949 | } |
| 950 | |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 951 | static unsigned long isolate_pages_global(unsigned long nr, |
| 952 | struct list_head *dst, |
| 953 | unsigned long *scanned, int order, |
| 954 | int mode, struct zone *z, |
| 955 | struct mem_cgroup *mem_cont, |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 956 | int active, int file) |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 957 | { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 958 | int lru = LRU_BASE; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 959 | if (active) |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 960 | lru += LRU_ACTIVE; |
| 961 | if (file) |
| 962 | lru += LRU_FILE; |
| 963 | return isolate_lru_pages(nr, &z->lru[lru].list, dst, scanned, order, |
| 964 | mode, !!file); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 965 | } |
| 966 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 967 | /* |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 968 | * clear_active_flags() is a helper for shrink_active_list(), clearing |
| 969 | * any active bits from the pages in the list. |
| 970 | */ |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 971 | static unsigned long clear_active_flags(struct list_head *page_list, |
| 972 | unsigned int *count) |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 973 | { |
| 974 | int nr_active = 0; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 975 | int lru; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 976 | struct page *page; |
| 977 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 978 | list_for_each_entry(page, page_list, lru) { |
| 979 | lru = page_is_file_cache(page); |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 980 | if (PageActive(page)) { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 981 | lru += LRU_ACTIVE; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 982 | ClearPageActive(page); |
| 983 | nr_active++; |
| 984 | } |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 985 | count[lru]++; |
| 986 | } |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 987 | |
| 988 | return nr_active; |
| 989 | } |
| 990 | |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 991 | /** |
| 992 | * isolate_lru_page - tries to isolate a page from its LRU list |
| 993 | * @page: page to isolate from its LRU list |
| 994 | * |
| 995 | * Isolates a @page from an LRU list, clears PageLRU and adjusts the |
| 996 | * vmstat statistic corresponding to whatever LRU list the page was on. |
| 997 | * |
| 998 | * Returns 0 if the page was removed from an LRU list. |
| 999 | * Returns -EBUSY if the page was not on an LRU list. |
| 1000 | * |
| 1001 | * The returned page will have PageLRU() cleared. If it was found on |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1002 | * the active list, it will have PageActive set. If it was found on |
| 1003 | * the unevictable list, it will have the PageUnevictable bit set. That flag |
| 1004 | * 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] | 1005 | * |
| 1006 | * The vmstat statistic corresponding to the list on which the page was |
| 1007 | * found will be decremented. |
| 1008 | * |
| 1009 | * Restrictions: |
| 1010 | * (1) Must be called with an elevated refcount on the page. This is a |
| 1011 | * fundamentnal difference from isolate_lru_pages (which is called |
| 1012 | * without a stable reference). |
| 1013 | * (2) the lru_lock must not be held. |
| 1014 | * (3) interrupts must be enabled. |
| 1015 | */ |
| 1016 | int isolate_lru_page(struct page *page) |
| 1017 | { |
| 1018 | int ret = -EBUSY; |
| 1019 | |
| 1020 | if (PageLRU(page)) { |
| 1021 | struct zone *zone = page_zone(page); |
| 1022 | |
| 1023 | spin_lock_irq(&zone->lru_lock); |
| 1024 | if (PageLRU(page) && get_page_unless_zero(page)) { |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1025 | int lru = page_lru(page); |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 1026 | ret = 0; |
| 1027 | ClearPageLRU(page); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1028 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1029 | del_page_from_lru_list(zone, page, lru); |
Nick Piggin | 62695a8 | 2008-10-18 20:26:09 -0700 | [diff] [blame] | 1030 | } |
| 1031 | spin_unlock_irq(&zone->lru_lock); |
| 1032 | } |
| 1033 | return ret; |
| 1034 | } |
| 1035 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1036 | /* |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 1037 | * shrink_inactive_list() is a helper for shrink_zone(). It returns the number |
| 1038 | * of reclaimed pages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1039 | */ |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 1040 | static unsigned long shrink_inactive_list(unsigned long max_scan, |
Rik van Riel | 33c120e | 2008-10-18 20:26:36 -0700 | [diff] [blame] | 1041 | struct zone *zone, struct scan_control *sc, |
| 1042 | int priority, int file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1043 | { |
| 1044 | LIST_HEAD(page_list); |
| 1045 | struct pagevec pvec; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1046 | unsigned long nr_scanned = 0; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1047 | unsigned long nr_reclaimed = 0; |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1048 | struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); |
KOSAKI Motohiro | 78dc583 | 2009-06-16 15:31:40 -0700 | [diff] [blame] | 1049 | int lumpy_reclaim = 0; |
| 1050 | |
| 1051 | /* |
| 1052 | * If we need a large contiguous chunk of memory, or have |
| 1053 | * trouble getting a small set of contiguous pages, we |
| 1054 | * will reclaim both active and inactive pages. |
| 1055 | * |
| 1056 | * We use the same threshold as pageout congestion_wait below. |
| 1057 | */ |
| 1058 | if (sc->order > PAGE_ALLOC_COSTLY_ORDER) |
| 1059 | lumpy_reclaim = 1; |
| 1060 | else if (sc->order && priority < DEF_PRIORITY - 2) |
| 1061 | lumpy_reclaim = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1062 | |
| 1063 | pagevec_init(&pvec, 1); |
| 1064 | |
| 1065 | lru_add_drain(); |
| 1066 | spin_lock_irq(&zone->lru_lock); |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1067 | do { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1068 | struct page *page; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1069 | unsigned long nr_taken; |
| 1070 | unsigned long nr_scan; |
| 1071 | unsigned long nr_freed; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1072 | unsigned long nr_active; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1073 | unsigned int count[NR_LRU_LISTS] = { 0, }; |
KOSAKI Motohiro | 78dc583 | 2009-06-16 15:31:40 -0700 | [diff] [blame] | 1074 | int mode = lumpy_reclaim ? ISOLATE_BOTH : ISOLATE_INACTIVE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1075 | |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1076 | nr_taken = sc->isolate_pages(sc->swap_cluster_max, |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1077 | &page_list, &nr_scan, sc->order, mode, |
| 1078 | zone, sc->mem_cgroup, 0, file); |
| 1079 | nr_active = clear_active_flags(&page_list, count); |
Andy Whitcroft | e9187bd | 2007-08-22 14:01:25 -0700 | [diff] [blame] | 1080 | __count_vm_events(PGDEACTIVATE, nr_active); |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1081 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1082 | __mod_zone_page_state(zone, NR_ACTIVE_FILE, |
| 1083 | -count[LRU_ACTIVE_FILE]); |
| 1084 | __mod_zone_page_state(zone, NR_INACTIVE_FILE, |
| 1085 | -count[LRU_INACTIVE_FILE]); |
| 1086 | __mod_zone_page_state(zone, NR_ACTIVE_ANON, |
| 1087 | -count[LRU_ACTIVE_ANON]); |
| 1088 | __mod_zone_page_state(zone, NR_INACTIVE_ANON, |
| 1089 | -count[LRU_INACTIVE_ANON]); |
| 1090 | |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1091 | if (scanning_global_lru(sc)) |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1092 | zone->pages_scanned += nr_scan; |
KOSAKI Motohiro | 3e2f41f | 2009-01-07 18:08:20 -0800 | [diff] [blame] | 1093 | |
| 1094 | reclaim_stat->recent_scanned[0] += count[LRU_INACTIVE_ANON]; |
| 1095 | reclaim_stat->recent_scanned[0] += count[LRU_ACTIVE_ANON]; |
| 1096 | reclaim_stat->recent_scanned[1] += count[LRU_INACTIVE_FILE]; |
| 1097 | reclaim_stat->recent_scanned[1] += count[LRU_ACTIVE_FILE]; |
| 1098 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1099 | spin_unlock_irq(&zone->lru_lock); |
| 1100 | |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1101 | nr_scanned += nr_scan; |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 1102 | nr_freed = shrink_page_list(&page_list, sc, PAGEOUT_IO_ASYNC); |
| 1103 | |
| 1104 | /* |
| 1105 | * If we are direct reclaiming for contiguous pages and we do |
| 1106 | * not reclaim everything in the list, try again and wait |
| 1107 | * for IO to complete. This will stall high-order allocations |
| 1108 | * but that should be acceptable to the caller |
| 1109 | */ |
| 1110 | if (nr_freed < nr_taken && !current_is_kswapd() && |
KOSAKI Motohiro | 78dc583 | 2009-06-16 15:31:40 -0700 | [diff] [blame] | 1111 | lumpy_reclaim) { |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 1112 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 1113 | |
| 1114 | /* |
| 1115 | * The attempt at page out may have made some |
| 1116 | * of the pages active, mark them inactive again. |
| 1117 | */ |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1118 | nr_active = clear_active_flags(&page_list, count); |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 1119 | count_vm_events(PGDEACTIVATE, nr_active); |
| 1120 | |
| 1121 | nr_freed += shrink_page_list(&page_list, sc, |
| 1122 | PAGEOUT_IO_SYNC); |
| 1123 | } |
| 1124 | |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1125 | nr_reclaimed += nr_freed; |
Nick Piggin | a74609f | 2006-01-06 00:11:20 -0800 | [diff] [blame] | 1126 | local_irq_disable(); |
| 1127 | if (current_is_kswapd()) { |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1128 | __count_zone_vm_events(PGSCAN_KSWAPD, zone, nr_scan); |
| 1129 | __count_vm_events(KSWAPD_STEAL, nr_freed); |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1130 | } else if (scanning_global_lru(sc)) |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1131 | __count_zone_vm_events(PGSCAN_DIRECT, zone, nr_scan); |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1132 | |
Shantanu Goel | 918d3f9 | 2006-12-29 16:48:59 -0800 | [diff] [blame] | 1133 | __count_zone_vm_events(PGSTEAL, zone, nr_freed); |
Nick Piggin | a74609f | 2006-01-06 00:11:20 -0800 | [diff] [blame] | 1134 | |
Wu Fengguang | fb8d14e | 2006-03-22 00:08:28 -0800 | [diff] [blame] | 1135 | if (nr_taken == 0) |
| 1136 | goto done; |
| 1137 | |
Nick Piggin | a74609f | 2006-01-06 00:11:20 -0800 | [diff] [blame] | 1138 | spin_lock(&zone->lru_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1139 | /* |
| 1140 | * Put back any unfreeable pages. |
| 1141 | */ |
| 1142 | while (!list_empty(&page_list)) { |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1143 | int lru; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1144 | page = lru_to_page(&page_list); |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 1145 | VM_BUG_ON(PageLRU(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1146 | list_del(&page->lru); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1147 | if (unlikely(!page_evictable(page, NULL))) { |
| 1148 | spin_unlock_irq(&zone->lru_lock); |
| 1149 | putback_lru_page(page); |
| 1150 | spin_lock_irq(&zone->lru_lock); |
| 1151 | continue; |
| 1152 | } |
| 1153 | SetPageLRU(page); |
| 1154 | lru = page_lru(page); |
| 1155 | add_page_to_lru_list(zone, page, lru); |
KOSAKI Motohiro | 3e2f41f | 2009-01-07 18:08:20 -0800 | [diff] [blame] | 1156 | if (PageActive(page)) { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1157 | int file = !!page_is_file_cache(page); |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1158 | reclaim_stat->recent_rotated[file]++; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1159 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1160 | if (!pagevec_add(&pvec, page)) { |
| 1161 | spin_unlock_irq(&zone->lru_lock); |
| 1162 | __pagevec_release(&pvec); |
| 1163 | spin_lock_irq(&zone->lru_lock); |
| 1164 | } |
| 1165 | } |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1166 | } while (nr_scanned < max_scan); |
Wu Fengguang | fb8d14e | 2006-03-22 00:08:28 -0800 | [diff] [blame] | 1167 | spin_unlock(&zone->lru_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1168 | done: |
Wu Fengguang | fb8d14e | 2006-03-22 00:08:28 -0800 | [diff] [blame] | 1169 | local_irq_enable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1170 | pagevec_release(&pvec); |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1171 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1172 | } |
| 1173 | |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1174 | /* |
| 1175 | * We are about to scan this zone at a certain priority level. If that priority |
| 1176 | * level is smaller (ie: more urgent) than the previous priority, then note |
| 1177 | * that priority level within the zone. This is done so that when the next |
| 1178 | * process comes in to scan this zone, it will immediately start out at this |
| 1179 | * priority level rather than having to build up its own scanning priority. |
| 1180 | * Here, this priority affects only the reclaim-mapped threshold. |
| 1181 | */ |
| 1182 | static inline void note_zone_scanning_priority(struct zone *zone, int priority) |
| 1183 | { |
| 1184 | if (priority < zone->prev_priority) |
| 1185 | zone->prev_priority = priority; |
| 1186 | } |
| 1187 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1188 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1189 | * This moves pages from the active list to the inactive list. |
| 1190 | * |
| 1191 | * We move them the other way if the page is referenced by one or more |
| 1192 | * processes, from rmap. |
| 1193 | * |
| 1194 | * If the pages are mostly unmapped, the processing is fast and it is |
| 1195 | * appropriate to hold zone->lru_lock across the whole operation. But if |
| 1196 | * the pages are mapped, the processing is slow (page_referenced()) so we |
| 1197 | * should drop zone->lru_lock around each page. It's impossible to balance |
| 1198 | * this, so instead we remove the pages from the LRU while processing them. |
| 1199 | * It is safe to rely on PG_active against the non-LRU pages in here because |
| 1200 | * nobody will play with that bit on a non-LRU page. |
| 1201 | * |
| 1202 | * The downside is that we have to touch page->_count against each page. |
| 1203 | * But we had to alter page->flags anyway. |
| 1204 | */ |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1205 | |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1206 | static void move_active_pages_to_lru(struct zone *zone, |
| 1207 | struct list_head *list, |
| 1208 | enum lru_list lru) |
| 1209 | { |
| 1210 | unsigned long pgmoved = 0; |
| 1211 | struct pagevec pvec; |
| 1212 | struct page *page; |
| 1213 | |
| 1214 | pagevec_init(&pvec, 1); |
| 1215 | |
| 1216 | while (!list_empty(list)) { |
| 1217 | page = lru_to_page(list); |
| 1218 | prefetchw_prev_lru_page(page, list, flags); |
| 1219 | |
| 1220 | VM_BUG_ON(PageLRU(page)); |
| 1221 | SetPageLRU(page); |
| 1222 | |
| 1223 | VM_BUG_ON(!PageActive(page)); |
| 1224 | if (!is_active_lru(lru)) |
| 1225 | ClearPageActive(page); /* we are de-activating */ |
| 1226 | |
| 1227 | list_move(&page->lru, &zone->lru[lru].list); |
| 1228 | mem_cgroup_add_lru_list(page, lru); |
| 1229 | pgmoved++; |
| 1230 | |
| 1231 | if (!pagevec_add(&pvec, page) || list_empty(list)) { |
| 1232 | spin_unlock_irq(&zone->lru_lock); |
| 1233 | if (buffer_heads_over_limit) |
| 1234 | pagevec_strip(&pvec); |
| 1235 | __pagevec_release(&pvec); |
| 1236 | spin_lock_irq(&zone->lru_lock); |
| 1237 | } |
| 1238 | } |
| 1239 | __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved); |
| 1240 | if (!is_active_lru(lru)) |
| 1241 | __count_vm_events(PGDEACTIVATE, pgmoved); |
| 1242 | } |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1243 | |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 1244 | 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] | 1245 | struct scan_control *sc, int priority, int file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1246 | { |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1247 | unsigned long pgmoved; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1248 | unsigned long pgscanned; |
Wu Fengguang | 6fe6b7e | 2009-06-16 15:33:05 -0700 | [diff] [blame] | 1249 | unsigned long vm_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1250 | LIST_HEAD(l_hold); /* The pages which were snipped off */ |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1251 | LIST_HEAD(l_active); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1252 | LIST_HEAD(l_inactive); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1253 | struct page *page; |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1254 | struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1255 | |
| 1256 | lru_add_drain(); |
| 1257 | spin_lock_irq(&zone->lru_lock); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1258 | pgmoved = sc->isolate_pages(nr_pages, &l_hold, &pgscanned, sc->order, |
| 1259 | ISOLATE_ACTIVE, zone, |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1260 | sc->mem_cgroup, 1, file); |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1261 | /* |
| 1262 | * zone->pages_scanned is used for detect zone's oom |
| 1263 | * mem_cgroup remembers nr_scan by itself. |
| 1264 | */ |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1265 | if (scanning_global_lru(sc)) { |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1266 | zone->pages_scanned += pgscanned; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1267 | } |
KOSAKI Motohiro | 3e2f41f | 2009-01-07 18:08:20 -0800 | [diff] [blame] | 1268 | reclaim_stat->recent_scanned[!!file] += pgmoved; |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1269 | |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1270 | __count_zone_vm_events(PGREFILL, zone, pgscanned); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1271 | if (file) |
| 1272 | __mod_zone_page_state(zone, NR_ACTIVE_FILE, -pgmoved); |
| 1273 | else |
| 1274 | __mod_zone_page_state(zone, NR_ACTIVE_ANON, -pgmoved); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1275 | spin_unlock_irq(&zone->lru_lock); |
| 1276 | |
Wu Fengguang | af16677 | 2009-06-16 15:32:31 -0700 | [diff] [blame] | 1277 | pgmoved = 0; /* count referenced (mapping) mapped pages */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1278 | while (!list_empty(&l_hold)) { |
| 1279 | cond_resched(); |
| 1280 | page = lru_to_page(&l_hold); |
| 1281 | list_del(&page->lru); |
Rik van Riel | 7e9cd48 | 2008-10-18 20:26:35 -0700 | [diff] [blame] | 1282 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1283 | if (unlikely(!page_evictable(page, NULL))) { |
| 1284 | putback_lru_page(page); |
| 1285 | continue; |
| 1286 | } |
| 1287 | |
Rik van Riel | 7e9cd48 | 2008-10-18 20:26:35 -0700 | [diff] [blame] | 1288 | /* page_referenced clears PageReferenced */ |
| 1289 | if (page_mapping_inuse(page) && |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1290 | page_referenced(page, 0, sc->mem_cgroup, &vm_flags)) { |
Rik van Riel | 7e9cd48 | 2008-10-18 20:26:35 -0700 | [diff] [blame] | 1291 | pgmoved++; |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1292 | /* |
| 1293 | * Identify referenced, file-backed active pages and |
| 1294 | * give them one more trip around the active list. So |
| 1295 | * that executable code get better chances to stay in |
| 1296 | * memory under moderate memory pressure. Anon pages |
| 1297 | * are not likely to be evicted by use-once streaming |
| 1298 | * IO, plus JVM can create lots of anon VM_EXEC pages, |
| 1299 | * so we ignore them here. |
| 1300 | */ |
| 1301 | if ((vm_flags & VM_EXEC) && !PageAnon(page)) { |
| 1302 | list_add(&page->lru, &l_active); |
| 1303 | continue; |
| 1304 | } |
| 1305 | } |
Rik van Riel | 7e9cd48 | 2008-10-18 20:26:35 -0700 | [diff] [blame] | 1306 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1307 | list_add(&page->lru, &l_inactive); |
| 1308 | } |
| 1309 | |
Andrew Morton | b555749 | 2009-01-06 14:40:13 -0800 | [diff] [blame] | 1310 | /* |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1311 | * Move pages back to the lru list. |
Andrew Morton | b555749 | 2009-01-06 14:40:13 -0800 | [diff] [blame] | 1312 | */ |
Johannes Weiner | 2a1dc50 | 2008-12-01 03:00:35 +0100 | [diff] [blame] | 1313 | spin_lock_irq(&zone->lru_lock); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1314 | /* |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1315 | * Count referenced pages from currently used mappings as rotated, |
| 1316 | * even though only some of them are actually re-activated. This |
| 1317 | * helps balance scan pressure between file and anonymous pages in |
| 1318 | * get_scan_ratio. |
Rik van Riel | 7e9cd48 | 2008-10-18 20:26:35 -0700 | [diff] [blame] | 1319 | */ |
KOSAKI Motohiro | 3e2f41f | 2009-01-07 18:08:20 -0800 | [diff] [blame] | 1320 | reclaim_stat->recent_rotated[!!file] += pgmoved; |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1321 | |
Wu Fengguang | 3eb4140 | 2009-06-16 15:33:13 -0700 | [diff] [blame] | 1322 | move_active_pages_to_lru(zone, &l_active, |
| 1323 | LRU_ACTIVE + file * LRU_FILE); |
| 1324 | move_active_pages_to_lru(zone, &l_inactive, |
| 1325 | LRU_BASE + file * LRU_FILE); |
Wu Fengguang | 8cab475 | 2009-06-16 15:33:12 -0700 | [diff] [blame] | 1326 | |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1327 | spin_unlock_irq(&zone->lru_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1328 | } |
| 1329 | |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1330 | static int inactive_anon_is_low_global(struct zone *zone) |
KOSAKI Motohiro | f89eb90 | 2009-01-07 18:08:14 -0800 | [diff] [blame] | 1331 | { |
| 1332 | unsigned long active, inactive; |
| 1333 | |
| 1334 | active = zone_page_state(zone, NR_ACTIVE_ANON); |
| 1335 | inactive = zone_page_state(zone, NR_INACTIVE_ANON); |
| 1336 | |
| 1337 | if (inactive * zone->inactive_ratio < active) |
| 1338 | return 1; |
| 1339 | |
| 1340 | return 0; |
| 1341 | } |
| 1342 | |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1343 | /** |
| 1344 | * inactive_anon_is_low - check if anonymous pages need to be deactivated |
| 1345 | * @zone: zone to check |
| 1346 | * @sc: scan control of this context |
| 1347 | * |
| 1348 | * Returns true if the zone does not have enough inactive anon pages, |
| 1349 | * meaning some active anon pages need to be deactivated. |
| 1350 | */ |
| 1351 | static int inactive_anon_is_low(struct zone *zone, struct scan_control *sc) |
| 1352 | { |
| 1353 | int low; |
| 1354 | |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1355 | if (scanning_global_lru(sc)) |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1356 | low = inactive_anon_is_low_global(zone); |
| 1357 | else |
KOSAKI Motohiro | c772be9 | 2009-01-07 18:08:25 -0800 | [diff] [blame] | 1358 | low = mem_cgroup_inactive_anon_is_low(sc->mem_cgroup); |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1359 | return low; |
| 1360 | } |
| 1361 | |
Rik van Riel | 56e49d2 | 2009-06-16 15:32:28 -0700 | [diff] [blame] | 1362 | static int inactive_file_is_low_global(struct zone *zone) |
| 1363 | { |
| 1364 | unsigned long active, inactive; |
| 1365 | |
| 1366 | active = zone_page_state(zone, NR_ACTIVE_FILE); |
| 1367 | inactive = zone_page_state(zone, NR_INACTIVE_FILE); |
| 1368 | |
| 1369 | return (active > inactive); |
| 1370 | } |
| 1371 | |
| 1372 | /** |
| 1373 | * inactive_file_is_low - check if file pages need to be deactivated |
| 1374 | * @zone: zone to check |
| 1375 | * @sc: scan control of this context |
| 1376 | * |
| 1377 | * When the system is doing streaming IO, memory pressure here |
| 1378 | * ensures that active file pages get deactivated, until more |
| 1379 | * than half of the file pages are on the inactive list. |
| 1380 | * |
| 1381 | * Once we get to that situation, protect the system's working |
| 1382 | * set from being evicted by disabling active file page aging. |
| 1383 | * |
| 1384 | * This uses a different ratio than the anonymous pages, because |
| 1385 | * the page cache uses a use-once replacement algorithm. |
| 1386 | */ |
| 1387 | static int inactive_file_is_low(struct zone *zone, struct scan_control *sc) |
| 1388 | { |
| 1389 | int low; |
| 1390 | |
| 1391 | if (scanning_global_lru(sc)) |
| 1392 | low = inactive_file_is_low_global(zone); |
| 1393 | else |
| 1394 | low = mem_cgroup_inactive_file_is_low(sc->mem_cgroup); |
| 1395 | return low; |
| 1396 | } |
| 1397 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1398 | 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] | 1399 | struct zone *zone, struct scan_control *sc, int priority) |
| 1400 | { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1401 | int file = is_file_lru(lru); |
| 1402 | |
Rik van Riel | 56e49d2 | 2009-06-16 15:32:28 -0700 | [diff] [blame] | 1403 | if (lru == LRU_ACTIVE_FILE && inactive_file_is_low(zone, sc)) { |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1404 | shrink_active_list(nr_to_scan, zone, sc, priority, file); |
| 1405 | return 0; |
| 1406 | } |
| 1407 | |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1408 | if (lru == LRU_ACTIVE_ANON && inactive_anon_is_low(zone, sc)) { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1409 | shrink_active_list(nr_to_scan, zone, sc, priority, file); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1410 | return 0; |
| 1411 | } |
Rik van Riel | 33c120e | 2008-10-18 20:26:36 -0700 | [diff] [blame] | 1412 | return shrink_inactive_list(nr_to_scan, zone, sc, priority, file); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1413 | } |
| 1414 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1415 | /* |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1416 | * Determine how aggressively the anon and file LRU lists should be |
| 1417 | * scanned. The relative value of each set of LRU lists is determined |
| 1418 | * by looking at the fraction of the pages scanned we did rotate back |
| 1419 | * onto the active list instead of evict. |
| 1420 | * |
| 1421 | * percent[0] specifies how much pressure to put on ram/swap backed |
| 1422 | * memory, while percent[1] determines pressure on the file LRUs. |
| 1423 | */ |
| 1424 | static void get_scan_ratio(struct zone *zone, struct scan_control *sc, |
| 1425 | unsigned long *percent) |
| 1426 | { |
| 1427 | unsigned long anon, file, free; |
| 1428 | unsigned long anon_prio, file_prio; |
| 1429 | unsigned long ap, fp; |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1430 | struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1431 | |
KOSAKI Motohiro | c9f299d | 2009-01-07 18:08:16 -0800 | [diff] [blame] | 1432 | anon = zone_nr_pages(zone, sc, LRU_ACTIVE_ANON) + |
| 1433 | zone_nr_pages(zone, sc, LRU_INACTIVE_ANON); |
| 1434 | file = zone_nr_pages(zone, sc, LRU_ACTIVE_FILE) + |
| 1435 | zone_nr_pages(zone, sc, LRU_INACTIVE_FILE); |
Hugh Dickins | b962716 | 2009-01-06 14:39:41 -0800 | [diff] [blame] | 1436 | |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1437 | if (scanning_global_lru(sc)) { |
KOSAKI Motohiro | eeee9a8 | 2009-01-07 18:08:17 -0800 | [diff] [blame] | 1438 | free = zone_page_state(zone, NR_FREE_PAGES); |
| 1439 | /* If we have very few page cache pages, |
| 1440 | force-scan anon pages. */ |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1441 | if (unlikely(file + free <= high_wmark_pages(zone))) { |
KOSAKI Motohiro | eeee9a8 | 2009-01-07 18:08:17 -0800 | [diff] [blame] | 1442 | percent[0] = 100; |
| 1443 | percent[1] = 0; |
| 1444 | return; |
| 1445 | } |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1446 | } |
| 1447 | |
| 1448 | /* |
| 1449 | * OK, so we have swap space and a fair amount of page cache |
| 1450 | * pages. We use the recently rotated / recently scanned |
| 1451 | * ratios to determine how valuable each cache is. |
| 1452 | * |
| 1453 | * Because workloads change over time (and to avoid overflow) |
| 1454 | * we keep these statistics as a floating average, which ends |
| 1455 | * up weighing recent references more than old ones. |
| 1456 | * |
| 1457 | * anon in [0], file in [1] |
| 1458 | */ |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1459 | if (unlikely(reclaim_stat->recent_scanned[0] > anon / 4)) { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1460 | spin_lock_irq(&zone->lru_lock); |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1461 | reclaim_stat->recent_scanned[0] /= 2; |
| 1462 | reclaim_stat->recent_rotated[0] /= 2; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1463 | spin_unlock_irq(&zone->lru_lock); |
| 1464 | } |
| 1465 | |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1466 | if (unlikely(reclaim_stat->recent_scanned[1] > file / 4)) { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1467 | spin_lock_irq(&zone->lru_lock); |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1468 | reclaim_stat->recent_scanned[1] /= 2; |
| 1469 | reclaim_stat->recent_rotated[1] /= 2; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1470 | spin_unlock_irq(&zone->lru_lock); |
| 1471 | } |
| 1472 | |
| 1473 | /* |
| 1474 | * With swappiness at 100, anonymous and file have the same priority. |
| 1475 | * This scanning priority is essentially the inverse of IO cost. |
| 1476 | */ |
| 1477 | anon_prio = sc->swappiness; |
| 1478 | file_prio = 200 - sc->swappiness; |
| 1479 | |
| 1480 | /* |
Rik van Riel | 00d8089 | 2008-11-19 15:36:44 -0800 | [diff] [blame] | 1481 | * The amount of pressure on anon vs file pages is inversely |
| 1482 | * proportional to the fraction of recently scanned pages on |
| 1483 | * each list that were recently referenced and in active use. |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1484 | */ |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1485 | ap = (anon_prio + 1) * (reclaim_stat->recent_scanned[0] + 1); |
| 1486 | ap /= reclaim_stat->recent_rotated[0] + 1; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1487 | |
KOSAKI Motohiro | 6e90157 | 2009-01-07 18:08:15 -0800 | [diff] [blame] | 1488 | fp = (file_prio + 1) * (reclaim_stat->recent_scanned[1] + 1); |
| 1489 | fp /= reclaim_stat->recent_rotated[1] + 1; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1490 | |
| 1491 | /* Normalize to percentages */ |
| 1492 | percent[0] = 100 * ap / (ap + fp + 1); |
| 1493 | percent[1] = 100 - percent[0]; |
| 1494 | } |
| 1495 | |
Wu Fengguang | 6e08a36 | 2009-06-16 15:32:29 -0700 | [diff] [blame] | 1496 | /* |
| 1497 | * Smallish @nr_to_scan's are deposited in @nr_saved_scan, |
| 1498 | * until we collected @swap_cluster_max pages to scan. |
| 1499 | */ |
| 1500 | static unsigned long nr_scan_try_batch(unsigned long nr_to_scan, |
| 1501 | unsigned long *nr_saved_scan, |
| 1502 | unsigned long swap_cluster_max) |
| 1503 | { |
| 1504 | unsigned long nr; |
| 1505 | |
| 1506 | *nr_saved_scan += nr_to_scan; |
| 1507 | nr = *nr_saved_scan; |
| 1508 | |
| 1509 | if (nr >= swap_cluster_max) |
| 1510 | *nr_saved_scan = 0; |
| 1511 | else |
| 1512 | nr = 0; |
| 1513 | |
| 1514 | return nr; |
| 1515 | } |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1516 | |
| 1517 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1518 | * This is a basic per-zone page freer. Used by both kswapd and direct reclaim. |
| 1519 | */ |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1520 | static void shrink_zone(int priority, struct zone *zone, |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1521 | struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1522 | { |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1523 | unsigned long nr[NR_LRU_LISTS]; |
Christoph Lameter | 8695949 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 1524 | unsigned long nr_to_scan; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1525 | unsigned long percent[2]; /* anon @ 0; file @ 1 */ |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1526 | enum lru_list l; |
KOSAKI Motohiro | 01dbe5c | 2009-01-06 14:40:02 -0800 | [diff] [blame] | 1527 | unsigned long nr_reclaimed = sc->nr_reclaimed; |
| 1528 | unsigned long swap_cluster_max = sc->swap_cluster_max; |
Daisuke Nishimura | 9198e96 | 2009-06-16 15:33:15 -0700 | [diff] [blame] | 1529 | int noswap = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1530 | |
Daisuke Nishimura | 9198e96 | 2009-06-16 15:33:15 -0700 | [diff] [blame] | 1531 | /* If we have no swap space, do not bother scanning anon pages. */ |
| 1532 | if (!sc->may_swap || (nr_swap_pages <= 0)) { |
| 1533 | noswap = 1; |
| 1534 | percent[0] = 0; |
| 1535 | percent[1] = 100; |
| 1536 | } else |
| 1537 | get_scan_ratio(zone, sc, percent); |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1538 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1539 | for_each_evictable_lru(l) { |
KOSAKI Motohiro | 9439c1c | 2009-01-07 18:08:21 -0800 | [diff] [blame] | 1540 | int file = is_file_lru(l); |
Andrew Morton | 8713e01 | 2009-04-30 15:08:55 -0700 | [diff] [blame] | 1541 | unsigned long scan; |
Johannes Weiner | e0f79b8 | 2008-10-18 20:26:55 -0700 | [diff] [blame] | 1542 | |
KOSAKI Motohiro | f272b7b | 2009-03-12 14:31:36 -0700 | [diff] [blame] | 1543 | scan = zone_nr_pages(zone, sc, l); |
Daisuke Nishimura | 9198e96 | 2009-06-16 15:33:15 -0700 | [diff] [blame] | 1544 | if (priority || noswap) { |
KOSAKI Motohiro | 9439c1c | 2009-01-07 18:08:21 -0800 | [diff] [blame] | 1545 | scan >>= priority; |
| 1546 | scan = (scan * percent[file]) / 100; |
| 1547 | } |
Wu Fengguang | 6e08a36 | 2009-06-16 15:32:29 -0700 | [diff] [blame] | 1548 | if (scanning_global_lru(sc)) |
| 1549 | nr[l] = nr_scan_try_batch(scan, |
| 1550 | &zone->lru[l].nr_saved_scan, |
| 1551 | swap_cluster_max); |
| 1552 | else |
KOSAKI Motohiro | 9439c1c | 2009-01-07 18:08:21 -0800 | [diff] [blame] | 1553 | nr[l] = scan; |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1554 | } |
| 1555 | |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1556 | while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] || |
| 1557 | nr[LRU_INACTIVE_FILE]) { |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 1558 | for_each_evictable_lru(l) { |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1559 | if (nr[l]) { |
KOSAKI Motohiro | 01dbe5c | 2009-01-06 14:40:02 -0800 | [diff] [blame] | 1560 | nr_to_scan = min(nr[l], swap_cluster_max); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1561 | nr[l] -= nr_to_scan; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1562 | |
KOSAKI Motohiro | 01dbe5c | 2009-01-06 14:40:02 -0800 | [diff] [blame] | 1563 | nr_reclaimed += shrink_list(l, nr_to_scan, |
| 1564 | zone, sc, priority); |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 1565 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1566 | } |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1567 | /* |
| 1568 | * On large memory systems, scan >> priority can become |
| 1569 | * really large. This is fine for the starting priority; |
| 1570 | * we want to put equal scanning pressure on each zone. |
| 1571 | * However, if the VM has a harder time of freeing pages, |
| 1572 | * with multiple processes reclaiming pages, the total |
| 1573 | * freeing target can get unreasonably large. |
| 1574 | */ |
KOSAKI Motohiro | 01dbe5c | 2009-01-06 14:40:02 -0800 | [diff] [blame] | 1575 | if (nr_reclaimed > swap_cluster_max && |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1576 | priority < DEF_PRIORITY && !current_is_kswapd()) |
| 1577 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1578 | } |
| 1579 | |
KOSAKI Motohiro | 01dbe5c | 2009-01-06 14:40:02 -0800 | [diff] [blame] | 1580 | sc->nr_reclaimed = nr_reclaimed; |
| 1581 | |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1582 | /* |
| 1583 | * Even if we did not try to evict anon pages at all, we want to |
| 1584 | * rebalance the anon lru active/inactive ratio. |
| 1585 | */ |
MinChan Kim | 69c8548 | 2009-06-16 15:32:44 -0700 | [diff] [blame] | 1586 | if (inactive_anon_is_low(zone, sc) && nr_swap_pages > 0) |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1587 | shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0); |
| 1588 | |
Andrew Morton | 232ea4d | 2007-02-28 20:13:21 -0800 | [diff] [blame] | 1589 | throttle_vm_writeout(sc->gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1590 | } |
| 1591 | |
| 1592 | /* |
| 1593 | * This is the direct reclaim path, for page-allocating processes. We only |
| 1594 | * try to reclaim pages from zones which will satisfy the caller's allocation |
| 1595 | * request. |
| 1596 | * |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1597 | * We reclaim from a zone even if that zone is over high_wmark_pages(zone). |
| 1598 | * Because: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1599 | * a) The caller may be trying to free *extra* pages to satisfy a higher-order |
| 1600 | * allocation or |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1601 | * b) The target zone may be at high_wmark_pages(zone) but the lower zones |
| 1602 | * must go *over* high_wmark_pages(zone) to satisfy the `incremental min' |
| 1603 | * zone defense algorithm. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1604 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1605 | * If a zone is deemed to be full of pinned pages then just give it a light |
| 1606 | * scan then give up on it. |
| 1607 | */ |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1608 | static void shrink_zones(int priority, struct zonelist *zonelist, |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1609 | struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1610 | { |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1611 | enum zone_type high_zoneidx = gfp_zone(sc->gfp_mask); |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1612 | struct zoneref *z; |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1613 | struct zone *zone; |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1614 | |
Nick Piggin | 408d854 | 2006-09-25 23:31:27 -0700 | [diff] [blame] | 1615 | sc->all_unreclaimable = 1; |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 1616 | for_each_zone_zonelist_nodemask(zone, z, zonelist, high_zoneidx, |
| 1617 | sc->nodemask) { |
Con Kolivas | f3fe651 | 2006-01-06 00:11:15 -0800 | [diff] [blame] | 1618 | if (!populated_zone(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1619 | continue; |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1620 | /* |
| 1621 | * Take care memory controller reclaiming has small influence |
| 1622 | * to global LRU. |
| 1623 | */ |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1624 | if (scanning_global_lru(sc)) { |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1625 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
| 1626 | continue; |
| 1627 | note_zone_scanning_priority(zone, priority); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1628 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1629 | if (zone_is_all_unreclaimable(zone) && |
| 1630 | priority != DEF_PRIORITY) |
| 1631 | continue; /* Let kswapd poll it */ |
| 1632 | sc->all_unreclaimable = 0; |
| 1633 | } else { |
| 1634 | /* |
| 1635 | * Ignore cpuset limitation here. We just want to reduce |
| 1636 | * # of used pages by us regardless of memory shortage. |
| 1637 | */ |
| 1638 | sc->all_unreclaimable = 0; |
| 1639 | mem_cgroup_note_reclaim_priority(sc->mem_cgroup, |
| 1640 | priority); |
| 1641 | } |
Nick Piggin | 408d854 | 2006-09-25 23:31:27 -0700 | [diff] [blame] | 1642 | |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1643 | shrink_zone(priority, zone, sc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1644 | } |
| 1645 | } |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1646 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1647 | /* |
| 1648 | * This is the main entry point to direct page reclaim. |
| 1649 | * |
| 1650 | * If a full scan of the inactive list fails to free enough memory then we |
| 1651 | * are "out of memory" and something needs to be killed. |
| 1652 | * |
| 1653 | * If the caller is !__GFP_FS then the probability of a failure is reasonably |
| 1654 | * high - the zone may be full of dirty or under-writeback pages, which this |
| 1655 | * caller can't do much about. We kick pdflush and take explicit naps in the |
| 1656 | * hope that some of these pages can be written. But if the allocating task |
| 1657 | * holds filesystem locks which prevent writeout this might not work, and the |
| 1658 | * allocation attempt will fail. |
Nishanth Aravamudan | a41f24e | 2008-04-29 00:58:25 -0700 | [diff] [blame] | 1659 | * |
| 1660 | * returns: 0, if no pages reclaimed |
| 1661 | * else, the number of pages reclaimed |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1662 | */ |
Mel Gorman | dac1d27 | 2008-04-28 02:12:12 -0700 | [diff] [blame] | 1663 | static unsigned long do_try_to_free_pages(struct zonelist *zonelist, |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1664 | struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1665 | { |
| 1666 | int priority; |
kosaki.motohiro@jp.fujitsu.com | c700be3 | 2008-06-12 15:21:27 -0700 | [diff] [blame] | 1667 | unsigned long ret = 0; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1668 | unsigned long total_scanned = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1669 | struct reclaim_state *reclaim_state = current->reclaim_state; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1670 | unsigned long lru_pages = 0; |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1671 | struct zoneref *z; |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1672 | struct zone *zone; |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1673 | enum zone_type high_zoneidx = gfp_zone(sc->gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1674 | |
Keika Kobayashi | 873b477 | 2008-07-25 01:48:52 -0700 | [diff] [blame] | 1675 | delayacct_freepages_start(); |
| 1676 | |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1677 | if (scanning_global_lru(sc)) |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1678 | count_vm_event(ALLOCSTALL); |
| 1679 | /* |
| 1680 | * mem_cgroup will not do shrink_slab. |
| 1681 | */ |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1682 | if (scanning_global_lru(sc)) { |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1683 | for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1684 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1685 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
| 1686 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1687 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1688 | lru_pages += zone_lru_pages(zone); |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1689 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1690 | } |
| 1691 | |
| 1692 | for (priority = DEF_PRIORITY; priority >= 0; priority--) { |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1693 | sc->nr_scanned = 0; |
Rik van Riel | f7b7fd8 | 2005-11-28 13:44:07 -0800 | [diff] [blame] | 1694 | if (!priority) |
| 1695 | disable_swap_token(); |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1696 | shrink_zones(priority, zonelist, sc); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1697 | /* |
| 1698 | * Don't shrink slabs when reclaiming memory from |
| 1699 | * over limit cgroups |
| 1700 | */ |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1701 | if (scanning_global_lru(sc)) { |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1702 | shrink_slab(sc->nr_scanned, sc->gfp_mask, lru_pages); |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 1703 | if (reclaim_state) { |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1704 | sc->nr_reclaimed += reclaim_state->reclaimed_slab; |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 1705 | reclaim_state->reclaimed_slab = 0; |
| 1706 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1707 | } |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1708 | total_scanned += sc->nr_scanned; |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1709 | if (sc->nr_reclaimed >= sc->swap_cluster_max) { |
| 1710 | ret = sc->nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1711 | goto out; |
| 1712 | } |
| 1713 | |
| 1714 | /* |
| 1715 | * Try to write back as many pages as we just scanned. This |
| 1716 | * tends to cause slow streaming writers to write data to the |
| 1717 | * disk smoothly, at the dirtying rate, which is nice. But |
| 1718 | * that's undesirable in laptop mode, where we *want* lumpy |
| 1719 | * writeout. So in laptop mode, write out the whole world. |
| 1720 | */ |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1721 | if (total_scanned > sc->swap_cluster_max + |
| 1722 | sc->swap_cluster_max / 2) { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame^] | 1723 | wakeup_flusher_threads(laptop_mode ? 0 : total_scanned); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1724 | sc->may_writepage = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1725 | } |
| 1726 | |
| 1727 | /* Take a nap, wait for some writeback to complete */ |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 1728 | if (sc->nr_scanned && priority < DEF_PRIORITY - 2) |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 1729 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1730 | } |
Fernando Luis Vazquez Cao | 87547ee | 2008-07-29 22:33:42 -0700 | [diff] [blame] | 1731 | /* 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] | 1732 | if (!sc->all_unreclaimable && scanning_global_lru(sc)) |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1733 | ret = sc->nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1734 | out: |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1735 | /* |
| 1736 | * Now that we've scanned all the zones at this priority level, note |
| 1737 | * that level within the zone so that the next thread which performs |
| 1738 | * scanning of this zone will immediately start out at this priority |
| 1739 | * level. This affects only the decision whether or not to bring |
| 1740 | * mapped pages onto the inactive list. |
| 1741 | */ |
| 1742 | if (priority < 0) |
| 1743 | priority = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1744 | |
KAMEZAWA Hiroyuki | e72e2bd | 2009-01-07 18:08:23 -0800 | [diff] [blame] | 1745 | if (scanning_global_lru(sc)) { |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1746 | for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1747 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1748 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
| 1749 | continue; |
| 1750 | |
| 1751 | zone->prev_priority = priority; |
| 1752 | } |
| 1753 | } else |
| 1754 | mem_cgroup_record_reclaim_priority(sc->mem_cgroup, priority); |
| 1755 | |
Keika Kobayashi | 873b477 | 2008-07-25 01:48:52 -0700 | [diff] [blame] | 1756 | delayacct_freepages_end(); |
| 1757 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1758 | return ret; |
| 1759 | } |
| 1760 | |
Mel Gorman | dac1d27 | 2008-04-28 02:12:12 -0700 | [diff] [blame] | 1761 | unsigned long try_to_free_pages(struct zonelist *zonelist, int order, |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 1762 | gfp_t gfp_mask, nodemask_t *nodemask) |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1763 | { |
| 1764 | struct scan_control sc = { |
| 1765 | .gfp_mask = gfp_mask, |
| 1766 | .may_writepage = !laptop_mode, |
| 1767 | .swap_cluster_max = SWAP_CLUSTER_MAX, |
Johannes Weiner | a6dc60f | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 1768 | .may_unmap = 1, |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 1769 | .may_swap = 1, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1770 | .swappiness = vm_swappiness, |
| 1771 | .order = order, |
| 1772 | .mem_cgroup = NULL, |
| 1773 | .isolate_pages = isolate_pages_global, |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 1774 | .nodemask = nodemask, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1775 | }; |
| 1776 | |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1777 | return do_try_to_free_pages(zonelist, &sc); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1778 | } |
| 1779 | |
Balbir Singh | 00f0b82 | 2008-03-04 14:28:39 -0800 | [diff] [blame] | 1780 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1781 | |
Balbir Singh | e1a1cd5 | 2008-02-07 00:14:02 -0800 | [diff] [blame] | 1782 | 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] | 1783 | gfp_t gfp_mask, |
| 1784 | bool noswap, |
| 1785 | unsigned int swappiness) |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1786 | { |
| 1787 | struct scan_control sc = { |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1788 | .may_writepage = !laptop_mode, |
Johannes Weiner | a6dc60f | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 1789 | .may_unmap = 1, |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 1790 | .may_swap = !noswap, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1791 | .swap_cluster_max = SWAP_CLUSTER_MAX, |
KOSAKI Motohiro | a7885eb | 2009-01-07 18:08:24 -0800 | [diff] [blame] | 1792 | .swappiness = swappiness, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1793 | .order = 0, |
| 1794 | .mem_cgroup = mem_cont, |
| 1795 | .isolate_pages = mem_cgroup_isolate_pages, |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 1796 | .nodemask = NULL, /* we don't care the placement */ |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1797 | }; |
Mel Gorman | dac1d27 | 2008-04-28 02:12:12 -0700 | [diff] [blame] | 1798 | struct zonelist *zonelist; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1799 | |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1800 | sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) | |
| 1801 | (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK); |
| 1802 | zonelist = NODE_DATA(numa_node_id())->node_zonelists; |
| 1803 | return do_try_to_free_pages(zonelist, &sc); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1804 | } |
| 1805 | #endif |
| 1806 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1807 | /* |
| 1808 | * 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] | 1809 | * they are all at high_wmark_pages(zone). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1810 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1811 | * Returns the number of pages which were actually freed. |
| 1812 | * |
| 1813 | * There is special handling here for zones which are full of pinned pages. |
| 1814 | * This can happen if the pages are all mlocked, or if they are all used by |
| 1815 | * device drivers (say, ZONE_DMA). Or if they are all in use by hugetlb. |
| 1816 | * What we do is to detect the case where all pages in the zone have been |
| 1817 | * scanned twice and there has been zero successful reclaim. Mark the zone as |
| 1818 | * dead and from now on, only perform a short scan. Basically we're polling |
| 1819 | * the zone for when the problem goes away. |
| 1820 | * |
| 1821 | * kswapd scans the zones in the highmem->normal->dma direction. It skips |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1822 | * zones which have free_pages > high_wmark_pages(zone), but once a zone is |
| 1823 | * found to have free_pages <= high_wmark_pages(zone), we scan that zone and the |
| 1824 | * lower zones regardless of the number of free pages in the lower zones. This |
| 1825 | * interoperates with the page allocator fallback scheme to ensure that aging |
| 1826 | * of pages is balanced across the zones. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1827 | */ |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1828 | static unsigned long balance_pgdat(pg_data_t *pgdat, int order) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1829 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1830 | int all_zones_ok; |
| 1831 | int priority; |
| 1832 | int i; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1833 | unsigned long total_scanned; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1834 | struct reclaim_state *reclaim_state = current->reclaim_state; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 1835 | struct scan_control sc = { |
| 1836 | .gfp_mask = GFP_KERNEL, |
Johannes Weiner | a6dc60f | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 1837 | .may_unmap = 1, |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 1838 | .may_swap = 1, |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1839 | .swap_cluster_max = SWAP_CLUSTER_MAX, |
| 1840 | .swappiness = vm_swappiness, |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1841 | .order = order, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1842 | .mem_cgroup = NULL, |
| 1843 | .isolate_pages = isolate_pages_global, |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 1844 | }; |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1845 | /* |
| 1846 | * temp_priority is used to remember the scanning priority at which |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1847 | * this zone was successfully refilled to |
| 1848 | * free_pages == high_wmark_pages(zone). |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1849 | */ |
| 1850 | int temp_priority[MAX_NR_ZONES]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1851 | |
| 1852 | loop_again: |
| 1853 | total_scanned = 0; |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1854 | sc.nr_reclaimed = 0; |
Christoph Lameter | c0bbbc7 | 2006-06-11 15:22:26 -0700 | [diff] [blame] | 1855 | sc.may_writepage = !laptop_mode; |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1856 | count_vm_event(PAGEOUTRUN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1857 | |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1858 | for (i = 0; i < pgdat->nr_zones; i++) |
| 1859 | temp_priority[i] = DEF_PRIORITY; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1860 | |
| 1861 | for (priority = DEF_PRIORITY; priority >= 0; priority--) { |
| 1862 | int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */ |
| 1863 | unsigned long lru_pages = 0; |
| 1864 | |
Rik van Riel | f7b7fd8 | 2005-11-28 13:44:07 -0800 | [diff] [blame] | 1865 | /* The swap token gets in the way of swapout... */ |
| 1866 | if (!priority) |
| 1867 | disable_swap_token(); |
| 1868 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1869 | all_zones_ok = 1; |
| 1870 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1871 | /* |
| 1872 | * Scan in the highmem->dma direction for the highest |
| 1873 | * zone which needs scanning |
| 1874 | */ |
| 1875 | for (i = pgdat->nr_zones - 1; i >= 0; i--) { |
| 1876 | struct zone *zone = pgdat->node_zones + i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1877 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1878 | if (!populated_zone(zone)) |
| 1879 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1880 | |
David Rientjes | e815af9 | 2007-10-16 23:25:54 -0700 | [diff] [blame] | 1881 | if (zone_is_all_unreclaimable(zone) && |
| 1882 | priority != DEF_PRIORITY) |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1883 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1884 | |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1885 | /* |
| 1886 | * Do some background aging of the anon list, to give |
| 1887 | * pages a chance to be referenced before reclaiming. |
| 1888 | */ |
KOSAKI Motohiro | 14797e2 | 2009-01-07 18:08:18 -0800 | [diff] [blame] | 1889 | if (inactive_anon_is_low(zone, &sc)) |
Rik van Riel | 556adec | 2008-10-18 20:26:34 -0700 | [diff] [blame] | 1890 | shrink_active_list(SWAP_CLUSTER_MAX, zone, |
| 1891 | &sc, priority, 0); |
| 1892 | |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1893 | if (!zone_watermark_ok(zone, order, |
| 1894 | high_wmark_pages(zone), 0, 0)) { |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1895 | end_zone = i; |
Andrew Morton | e1dbeda | 2006-12-06 20:32:01 -0800 | [diff] [blame] | 1896 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1897 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1898 | } |
Andrew Morton | e1dbeda | 2006-12-06 20:32:01 -0800 | [diff] [blame] | 1899 | if (i < 0) |
| 1900 | goto out; |
| 1901 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1902 | for (i = 0; i <= end_zone; i++) { |
| 1903 | struct zone *zone = pgdat->node_zones + i; |
| 1904 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1905 | lru_pages += zone_lru_pages(zone); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1906 | } |
| 1907 | |
| 1908 | /* |
| 1909 | * Now scan the zone in the dma->highmem direction, stopping |
| 1910 | * at the last zone which needs scanning. |
| 1911 | * |
| 1912 | * We do this because the page allocator works in the opposite |
| 1913 | * direction. This prevents the page allocator from allocating |
| 1914 | * pages behind kswapd's direction of progress, which would |
| 1915 | * cause too much scanning of the lower zones. |
| 1916 | */ |
| 1917 | for (i = 0; i <= end_zone; i++) { |
| 1918 | struct zone *zone = pgdat->node_zones + i; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 1919 | int nr_slab; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1920 | |
Con Kolivas | f3fe651 | 2006-01-06 00:11:15 -0800 | [diff] [blame] | 1921 | if (!populated_zone(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1922 | continue; |
| 1923 | |
David Rientjes | e815af9 | 2007-10-16 23:25:54 -0700 | [diff] [blame] | 1924 | if (zone_is_all_unreclaimable(zone) && |
| 1925 | priority != DEF_PRIORITY) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1926 | continue; |
| 1927 | |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1928 | if (!zone_watermark_ok(zone, order, |
| 1929 | high_wmark_pages(zone), end_zone, 0)) |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1930 | all_zones_ok = 0; |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1931 | temp_priority[i] = priority; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1932 | sc.nr_scanned = 0; |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1933 | note_zone_scanning_priority(zone, priority); |
Rik van Riel | 32a4330 | 2007-10-16 01:24:50 -0700 | [diff] [blame] | 1934 | /* |
| 1935 | * We put equal pressure on every zone, unless one |
| 1936 | * zone has way too many pages free already. |
| 1937 | */ |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 1938 | if (!zone_watermark_ok(zone, order, |
| 1939 | 8*high_wmark_pages(zone), end_zone, 0)) |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1940 | shrink_zone(priority, zone, &sc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1941 | reclaim_state->reclaimed_slab = 0; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 1942 | nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL, |
| 1943 | lru_pages); |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1944 | sc.nr_reclaimed += reclaim_state->reclaimed_slab; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1945 | total_scanned += sc.nr_scanned; |
David Rientjes | e815af9 | 2007-10-16 23:25:54 -0700 | [diff] [blame] | 1946 | if (zone_is_all_unreclaimable(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1947 | continue; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 1948 | if (nr_slab == 0 && zone->pages_scanned >= |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 1949 | (zone_lru_pages(zone) * 6)) |
David Rientjes | e815af9 | 2007-10-16 23:25:54 -0700 | [diff] [blame] | 1950 | zone_set_flag(zone, |
| 1951 | ZONE_ALL_UNRECLAIMABLE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1952 | /* |
| 1953 | * If we've done a decent amount of scanning and |
| 1954 | * the reclaim ratio is low, start doing writepage |
| 1955 | * even in laptop mode |
| 1956 | */ |
| 1957 | if (total_scanned > SWAP_CLUSTER_MAX * 2 && |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1958 | total_scanned > sc.nr_reclaimed + sc.nr_reclaimed / 2) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1959 | sc.may_writepage = 1; |
| 1960 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1961 | if (all_zones_ok) |
| 1962 | break; /* kswapd: all done */ |
| 1963 | /* |
| 1964 | * OK, kswapd is getting into trouble. Take a nap, then take |
| 1965 | * another pass across the zones. |
| 1966 | */ |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 1967 | if (total_scanned && priority < DEF_PRIORITY - 2) |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 1968 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1969 | |
| 1970 | /* |
| 1971 | * We do this so kswapd doesn't build up large priorities for |
| 1972 | * example when it is freeing in parallel with allocators. It |
| 1973 | * matches the direct reclaim path behaviour in terms of impact |
| 1974 | * on zone->*_priority. |
| 1975 | */ |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 1976 | if (sc.nr_reclaimed >= SWAP_CLUSTER_MAX) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1977 | break; |
| 1978 | } |
| 1979 | out: |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1980 | /* |
| 1981 | * Note within each zone the priority level at which this zone was |
| 1982 | * brought into a happy state. So that the next thread which scans this |
| 1983 | * zone will start out at that priority level. |
| 1984 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1985 | for (i = 0; i < pgdat->nr_zones; i++) { |
| 1986 | struct zone *zone = pgdat->node_zones + i; |
| 1987 | |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1988 | zone->prev_priority = temp_priority[i]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1989 | } |
| 1990 | if (!all_zones_ok) { |
| 1991 | cond_resched(); |
Rafael J. Wysocki | 8357376 | 2006-12-06 20:34:18 -0800 | [diff] [blame] | 1992 | |
| 1993 | try_to_freeze(); |
| 1994 | |
KOSAKI Motohiro | 73ce02e | 2009-01-06 14:40:33 -0800 | [diff] [blame] | 1995 | /* |
| 1996 | * Fragmentation may mean that the system cannot be |
| 1997 | * rebalanced for high-order allocations in all zones. |
| 1998 | * At this point, if nr_reclaimed < SWAP_CLUSTER_MAX, |
| 1999 | * it means the zones have been fully scanned and are still |
| 2000 | * not balanced. For high-order allocations, there is |
| 2001 | * little point trying all over again as kswapd may |
| 2002 | * infinite loop. |
| 2003 | * |
| 2004 | * Instead, recheck all watermarks at order-0 as they |
| 2005 | * are the most important. If watermarks are ok, kswapd will go |
| 2006 | * back to sleep. High-order users can still perform direct |
| 2007 | * reclaim if they wish. |
| 2008 | */ |
| 2009 | if (sc.nr_reclaimed < SWAP_CLUSTER_MAX) |
| 2010 | order = sc.order = 0; |
| 2011 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2012 | goto loop_again; |
| 2013 | } |
| 2014 | |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2015 | return sc.nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2016 | } |
| 2017 | |
| 2018 | /* |
| 2019 | * The background pageout daemon, started as a kernel thread |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 2020 | * from the init process. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2021 | * |
| 2022 | * This basically trickles out pages so that we have _some_ |
| 2023 | * free memory available even if there is no other activity |
| 2024 | * that frees anything up. This is needed for things like routing |
| 2025 | * etc, where we otherwise might have all activity going on in |
| 2026 | * asynchronous contexts that cannot page things out. |
| 2027 | * |
| 2028 | * If there are applications that are active memory-allocators |
| 2029 | * (most normal use), this basically shouldn't matter. |
| 2030 | */ |
| 2031 | static int kswapd(void *p) |
| 2032 | { |
| 2033 | unsigned long order; |
| 2034 | pg_data_t *pgdat = (pg_data_t*)p; |
| 2035 | struct task_struct *tsk = current; |
| 2036 | DEFINE_WAIT(wait); |
| 2037 | struct reclaim_state reclaim_state = { |
| 2038 | .reclaimed_slab = 0, |
| 2039 | }; |
Rusty Russell | a70f730 | 2009-03-13 14:49:46 +1030 | [diff] [blame] | 2040 | const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2041 | |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2042 | lockdep_set_current_reclaim_state(GFP_KERNEL); |
| 2043 | |
Rusty Russell | 174596a | 2009-01-01 10:12:29 +1030 | [diff] [blame] | 2044 | if (!cpumask_empty(cpumask)) |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 2045 | set_cpus_allowed_ptr(tsk, cpumask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2046 | current->reclaim_state = &reclaim_state; |
| 2047 | |
| 2048 | /* |
| 2049 | * Tell the memory management that we're a "memory allocator", |
| 2050 | * and that if we need more memory we should get access to it |
| 2051 | * regardless (see "__alloc_pages()"). "kswapd" should |
| 2052 | * never get caught in the normal page freeing logic. |
| 2053 | * |
| 2054 | * (Kswapd normally doesn't need memory anyway, but sometimes |
| 2055 | * you need a small amount of memory in order to be able to |
| 2056 | * page out something else, and this flag essentially protects |
| 2057 | * us from recursively trying to free more memory as we're |
| 2058 | * trying to free the first piece of memory in the first place). |
| 2059 | */ |
Christoph Lameter | 930d915 | 2006-01-08 01:00:47 -0800 | [diff] [blame] | 2060 | tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD; |
Rafael J. Wysocki | 8314418 | 2007-07-17 04:03:35 -0700 | [diff] [blame] | 2061 | set_freezable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2062 | |
| 2063 | order = 0; |
| 2064 | for ( ; ; ) { |
| 2065 | unsigned long new_order; |
Christoph Lameter | 3e1d1d2 | 2005-06-24 23:13:50 -0700 | [diff] [blame] | 2066 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2067 | prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); |
| 2068 | new_order = pgdat->kswapd_max_order; |
| 2069 | pgdat->kswapd_max_order = 0; |
| 2070 | if (order < new_order) { |
| 2071 | /* |
| 2072 | * Don't sleep if someone wants a larger 'order' |
| 2073 | * allocation |
| 2074 | */ |
| 2075 | order = new_order; |
| 2076 | } else { |
Rafael J. Wysocki | b1296cc | 2007-05-06 14:50:48 -0700 | [diff] [blame] | 2077 | if (!freezing(current)) |
| 2078 | schedule(); |
| 2079 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2080 | order = pgdat->kswapd_max_order; |
| 2081 | } |
| 2082 | finish_wait(&pgdat->kswapd_wait, &wait); |
| 2083 | |
Rafael J. Wysocki | b1296cc | 2007-05-06 14:50:48 -0700 | [diff] [blame] | 2084 | if (!try_to_freeze()) { |
| 2085 | /* We can speed up thawing tasks if we don't call |
| 2086 | * balance_pgdat after returning from the refrigerator |
| 2087 | */ |
| 2088 | balance_pgdat(pgdat, order); |
| 2089 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2090 | } |
| 2091 | return 0; |
| 2092 | } |
| 2093 | |
| 2094 | /* |
| 2095 | * A zone is low on free memory, so wake its kswapd task to service it. |
| 2096 | */ |
| 2097 | void wakeup_kswapd(struct zone *zone, int order) |
| 2098 | { |
| 2099 | pg_data_t *pgdat; |
| 2100 | |
Con Kolivas | f3fe651 | 2006-01-06 00:11:15 -0800 | [diff] [blame] | 2101 | if (!populated_zone(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2102 | return; |
| 2103 | |
| 2104 | pgdat = zone->zone_pgdat; |
Mel Gorman | 4185896 | 2009-06-16 15:32:12 -0700 | [diff] [blame] | 2105 | if (zone_watermark_ok(zone, order, low_wmark_pages(zone), 0, 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2106 | return; |
| 2107 | if (pgdat->kswapd_max_order < order) |
| 2108 | pgdat->kswapd_max_order = order; |
Paul Jackson | 02a0e53 | 2006-12-13 00:34:25 -0800 | [diff] [blame] | 2109 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2110 | return; |
Con Kolivas | 8d0986e | 2005-09-13 01:25:07 -0700 | [diff] [blame] | 2111 | if (!waitqueue_active(&pgdat->kswapd_wait)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2112 | return; |
Con Kolivas | 8d0986e | 2005-09-13 01:25:07 -0700 | [diff] [blame] | 2113 | wake_up_interruptible(&pgdat->kswapd_wait); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2114 | } |
| 2115 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 2116 | unsigned long global_lru_pages(void) |
| 2117 | { |
| 2118 | return global_page_state(NR_ACTIVE_ANON) |
| 2119 | + global_page_state(NR_ACTIVE_FILE) |
| 2120 | + global_page_state(NR_INACTIVE_ANON) |
| 2121 | + global_page_state(NR_INACTIVE_FILE); |
| 2122 | } |
| 2123 | |
Rafael J. Wysocki | c6f37f1 | 2009-05-24 22:16:31 +0200 | [diff] [blame] | 2124 | #ifdef CONFIG_HIBERNATION |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2125 | /* |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2126 | * Helper function for shrink_all_memory(). Tries to reclaim 'nr_pages' pages |
MinChan Kim | d979677 | 2009-03-31 15:19:34 -0700 | [diff] [blame] | 2127 | * from LRU lists system-wide, for given pass and priority. |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2128 | * |
| 2129 | * For pass > 3 we also try to shrink the LRU lists that contain a few pages |
| 2130 | */ |
MinChan Kim | d979677 | 2009-03-31 15:19:34 -0700 | [diff] [blame] | 2131 | static void shrink_all_zones(unsigned long nr_pages, int prio, |
Nigel Cunningham | e07aa05 | 2006-12-22 01:07:21 -0800 | [diff] [blame] | 2132 | int pass, struct scan_control *sc) |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2133 | { |
| 2134 | struct zone *zone; |
MinChan Kim | d979677 | 2009-03-31 15:19:34 -0700 | [diff] [blame] | 2135 | unsigned long nr_reclaimed = 0; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2136 | |
KOSAKI Motohiro | ee99c71 | 2009-03-31 15:19:31 -0700 | [diff] [blame] | 2137 | for_each_populated_zone(zone) { |
Johannes Weiner | 0cb5725 | 2009-02-14 02:04:10 +0100 | [diff] [blame] | 2138 | enum lru_list l; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2139 | |
David Rientjes | e815af9 | 2007-10-16 23:25:54 -0700 | [diff] [blame] | 2140 | if (zone_is_all_unreclaimable(zone) && prio != DEF_PRIORITY) |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2141 | continue; |
| 2142 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2143 | for_each_evictable_lru(l) { |
Johannes Weiner | 0cb5725 | 2009-02-14 02:04:10 +0100 | [diff] [blame] | 2144 | enum zone_stat_item ls = NR_LRU_BASE + l; |
| 2145 | unsigned long lru_pages = zone_page_state(zone, ls); |
| 2146 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2147 | /* For pass = 0, we don't shrink the active list */ |
Johannes Weiner | 0cb5725 | 2009-02-14 02:04:10 +0100 | [diff] [blame] | 2148 | if (pass == 0 && (l == LRU_ACTIVE_ANON || |
| 2149 | l == LRU_ACTIVE_FILE)) |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 2150 | continue; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2151 | |
Wu Fengguang | 6e08a36 | 2009-06-16 15:32:29 -0700 | [diff] [blame] | 2152 | zone->lru[l].nr_saved_scan += (lru_pages >> prio) + 1; |
| 2153 | if (zone->lru[l].nr_saved_scan >= nr_pages || pass > 3) { |
Johannes Weiner | 0cb5725 | 2009-02-14 02:04:10 +0100 | [diff] [blame] | 2154 | unsigned long nr_to_scan; |
| 2155 | |
Wu Fengguang | 6e08a36 | 2009-06-16 15:32:29 -0700 | [diff] [blame] | 2156 | zone->lru[l].nr_saved_scan = 0; |
Johannes Weiner | 0cb5725 | 2009-02-14 02:04:10 +0100 | [diff] [blame] | 2157 | nr_to_scan = min(nr_pages, lru_pages); |
MinChan Kim | d979677 | 2009-03-31 15:19:34 -0700 | [diff] [blame] | 2158 | nr_reclaimed += shrink_list(l, nr_to_scan, zone, |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 2159 | sc, prio); |
MinChan Kim | d979677 | 2009-03-31 15:19:34 -0700 | [diff] [blame] | 2160 | if (nr_reclaimed >= nr_pages) { |
Rafael J. Wysocki | a21e255 | 2009-04-18 17:23:41 +0200 | [diff] [blame] | 2161 | sc->nr_reclaimed += nr_reclaimed; |
MinChan Kim | d979677 | 2009-03-31 15:19:34 -0700 | [diff] [blame] | 2162 | return; |
| 2163 | } |
Christoph Lameter | b69408e | 2008-10-18 20:26:14 -0700 | [diff] [blame] | 2164 | } |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2165 | } |
| 2166 | } |
Rafael J. Wysocki | a21e255 | 2009-04-18 17:23:41 +0200 | [diff] [blame] | 2167 | sc->nr_reclaimed += nr_reclaimed; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2168 | } |
| 2169 | |
| 2170 | /* |
| 2171 | * Try to free `nr_pages' of memory, system-wide, and return the number of |
| 2172 | * freed pages. |
| 2173 | * |
| 2174 | * Rather than trying to age LRUs the aim is to preserve the overall |
| 2175 | * LRU order by reclaiming preferentially |
| 2176 | * inactive > active > active referenced > active mapped |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2177 | */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2178 | unsigned long shrink_all_memory(unsigned long nr_pages) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2179 | { |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2180 | unsigned long lru_pages, nr_slab; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2181 | int pass; |
| 2182 | struct reclaim_state reclaim_state; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2183 | struct scan_control sc = { |
| 2184 | .gfp_mask = GFP_KERNEL, |
Johannes Weiner | a6dc60f | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 2185 | .may_unmap = 0, |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2186 | .may_writepage = 1, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2187 | .isolate_pages = isolate_pages_global, |
Rafael J. Wysocki | a21e255 | 2009-04-18 17:23:41 +0200 | [diff] [blame] | 2188 | .nr_reclaimed = 0, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2189 | }; |
| 2190 | |
| 2191 | current->reclaim_state = &reclaim_state; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2192 | |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 2193 | lru_pages = global_lru_pages(); |
Christoph Lameter | 972d1a7 | 2006-09-25 23:31:51 -0700 | [diff] [blame] | 2194 | nr_slab = global_page_state(NR_SLAB_RECLAIMABLE); |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2195 | /* If slab caches are huge, it's better to hit them first */ |
| 2196 | while (nr_slab >= lru_pages) { |
| 2197 | reclaim_state.reclaimed_slab = 0; |
| 2198 | shrink_slab(nr_pages, sc.gfp_mask, lru_pages); |
| 2199 | if (!reclaim_state.reclaimed_slab) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2200 | break; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2201 | |
MinChan Kim | d979677 | 2009-03-31 15:19:34 -0700 | [diff] [blame] | 2202 | sc.nr_reclaimed += reclaim_state.reclaimed_slab; |
| 2203 | if (sc.nr_reclaimed >= nr_pages) |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2204 | goto out; |
| 2205 | |
| 2206 | nr_slab -= reclaim_state.reclaimed_slab; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2207 | } |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2208 | |
| 2209 | /* |
| 2210 | * We try to shrink LRUs in 5 passes: |
| 2211 | * 0 = Reclaim from inactive_list only |
| 2212 | * 1 = Reclaim from active list but don't reclaim mapped |
| 2213 | * 2 = 2nd pass of type 1 |
| 2214 | * 3 = Reclaim mapped (normal reclaim) |
| 2215 | * 4 = 2nd pass of type 3 |
| 2216 | */ |
| 2217 | for (pass = 0; pass < 5; pass++) { |
| 2218 | int prio; |
| 2219 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2220 | /* Force reclaiming mapped pages in the passes #3 and #4 */ |
Johannes Weiner | 3049103 | 2009-02-14 02:03:08 +0100 | [diff] [blame] | 2221 | if (pass > 2) |
Johannes Weiner | a6dc60f | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 2222 | sc.may_unmap = 1; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2223 | |
| 2224 | for (prio = DEF_PRIORITY; prio >= 0; prio--) { |
MinChan Kim | d979677 | 2009-03-31 15:19:34 -0700 | [diff] [blame] | 2225 | unsigned long nr_to_scan = nr_pages - sc.nr_reclaimed; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2226 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2227 | sc.nr_scanned = 0; |
Johannes Weiner | 9786bf8 | 2009-03-31 15:19:35 -0700 | [diff] [blame] | 2228 | sc.swap_cluster_max = nr_to_scan; |
MinChan Kim | d979677 | 2009-03-31 15:19:34 -0700 | [diff] [blame] | 2229 | shrink_all_zones(nr_to_scan, prio, pass, &sc); |
| 2230 | if (sc.nr_reclaimed >= nr_pages) |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2231 | goto out; |
| 2232 | |
| 2233 | reclaim_state.reclaimed_slab = 0; |
Andrew Morton | 76395d3 | 2007-01-05 16:37:05 -0800 | [diff] [blame] | 2234 | shrink_slab(sc.nr_scanned, sc.gfp_mask, |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 2235 | global_lru_pages()); |
MinChan Kim | d979677 | 2009-03-31 15:19:34 -0700 | [diff] [blame] | 2236 | sc.nr_reclaimed += reclaim_state.reclaimed_slab; |
| 2237 | if (sc.nr_reclaimed >= nr_pages) |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2238 | goto out; |
| 2239 | |
| 2240 | if (sc.nr_scanned && prio < DEF_PRIORITY - 2) |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 2241 | congestion_wait(BLK_RW_ASYNC, HZ / 10); |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2242 | } |
Rafael J. Wysocki | 248a030 | 2006-03-22 00:09:04 -0800 | [diff] [blame] | 2243 | } |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2244 | |
| 2245 | /* |
MinChan Kim | d979677 | 2009-03-31 15:19:34 -0700 | [diff] [blame] | 2246 | * If sc.nr_reclaimed = 0, we could not shrink LRUs, but there may be |
| 2247 | * something in slab caches |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2248 | */ |
MinChan Kim | d979677 | 2009-03-31 15:19:34 -0700 | [diff] [blame] | 2249 | if (!sc.nr_reclaimed) { |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2250 | do { |
| 2251 | reclaim_state.reclaimed_slab = 0; |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 2252 | shrink_slab(nr_pages, sc.gfp_mask, global_lru_pages()); |
MinChan Kim | d979677 | 2009-03-31 15:19:34 -0700 | [diff] [blame] | 2253 | sc.nr_reclaimed += reclaim_state.reclaimed_slab; |
| 2254 | } while (sc.nr_reclaimed < nr_pages && |
| 2255 | reclaim_state.reclaimed_slab > 0); |
Andrew Morton | 76395d3 | 2007-01-05 16:37:05 -0800 | [diff] [blame] | 2256 | } |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2257 | |
MinChan Kim | d979677 | 2009-03-31 15:19:34 -0700 | [diff] [blame] | 2258 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2259 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2260 | current->reclaim_state = NULL; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2261 | |
MinChan Kim | d979677 | 2009-03-31 15:19:34 -0700 | [diff] [blame] | 2262 | return sc.nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2263 | } |
Rafael J. Wysocki | c6f37f1 | 2009-05-24 22:16:31 +0200 | [diff] [blame] | 2264 | #endif /* CONFIG_HIBERNATION */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2265 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2266 | /* It's optimal to keep kswapds on the same CPUs as their memory, but |
| 2267 | not required for correctness. So if the last cpu in a node goes |
| 2268 | away, we get changed to run anywhere: as the first one comes back, |
| 2269 | restore their cpu bindings. */ |
Chandra Seetharaman | 9c7b216 | 2006-06-27 02:54:07 -0700 | [diff] [blame] | 2270 | static int __devinit cpu_callback(struct notifier_block *nfb, |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2271 | unsigned long action, void *hcpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2272 | { |
Yasunori Goto | 58c0a4a | 2007-10-16 01:25:40 -0700 | [diff] [blame] | 2273 | int nid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2274 | |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 2275 | if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN) { |
Yasunori Goto | 58c0a4a | 2007-10-16 01:25:40 -0700 | [diff] [blame] | 2276 | for_each_node_state(nid, N_HIGH_MEMORY) { |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 2277 | pg_data_t *pgdat = NODE_DATA(nid); |
Rusty Russell | a70f730 | 2009-03-13 14:49:46 +1030 | [diff] [blame] | 2278 | const struct cpumask *mask; |
| 2279 | |
| 2280 | mask = cpumask_of_node(pgdat->node_id); |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 2281 | |
Rusty Russell | 3e59794 | 2009-01-01 10:12:24 +1030 | [diff] [blame] | 2282 | if (cpumask_any_and(cpu_online_mask, mask) < nr_cpu_ids) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2283 | /* One of our CPUs online: restore mask */ |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 2284 | set_cpus_allowed_ptr(pgdat->kswapd, mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2285 | } |
| 2286 | } |
| 2287 | return NOTIFY_OK; |
| 2288 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2289 | |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 2290 | /* |
| 2291 | * This kswapd start function will be called by init and node-hot-add. |
| 2292 | * On node-hot-add, kswapd will moved to proper cpus if cpus are hot-added. |
| 2293 | */ |
| 2294 | int kswapd_run(int nid) |
| 2295 | { |
| 2296 | pg_data_t *pgdat = NODE_DATA(nid); |
| 2297 | int ret = 0; |
| 2298 | |
| 2299 | if (pgdat->kswapd) |
| 2300 | return 0; |
| 2301 | |
| 2302 | pgdat->kswapd = kthread_run(kswapd, pgdat, "kswapd%d", nid); |
| 2303 | if (IS_ERR(pgdat->kswapd)) { |
| 2304 | /* failure at boot is fatal */ |
| 2305 | BUG_ON(system_state == SYSTEM_BOOTING); |
| 2306 | printk("Failed to start kswapd on node %d\n",nid); |
| 2307 | ret = -1; |
| 2308 | } |
| 2309 | return ret; |
| 2310 | } |
| 2311 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2312 | static int __init kswapd_init(void) |
| 2313 | { |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 2314 | int nid; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2315 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2316 | swap_setup(); |
Christoph Lameter | 9422ffb | 2007-10-16 01:25:31 -0700 | [diff] [blame] | 2317 | for_each_node_state(nid, N_HIGH_MEMORY) |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 2318 | kswapd_run(nid); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2319 | hotcpu_notifier(cpu_callback, 0); |
| 2320 | return 0; |
| 2321 | } |
| 2322 | |
| 2323 | module_init(kswapd_init) |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2324 | |
| 2325 | #ifdef CONFIG_NUMA |
| 2326 | /* |
| 2327 | * Zone reclaim mode |
| 2328 | * |
| 2329 | * If non-zero call zone_reclaim when the number of free pages falls below |
| 2330 | * the watermarks. |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2331 | */ |
| 2332 | int zone_reclaim_mode __read_mostly; |
| 2333 | |
Christoph Lameter | 1b2ffb7 | 2006-02-01 03:05:34 -0800 | [diff] [blame] | 2334 | #define RECLAIM_OFF 0 |
Fernando Luis Vazquez Cao | 7d03431 | 2008-07-29 22:33:41 -0700 | [diff] [blame] | 2335 | #define RECLAIM_ZONE (1<<0) /* Run shrink_inactive_list on the zone */ |
Christoph Lameter | 1b2ffb7 | 2006-02-01 03:05:34 -0800 | [diff] [blame] | 2336 | #define RECLAIM_WRITE (1<<1) /* Writeout pages during reclaim */ |
| 2337 | #define RECLAIM_SWAP (1<<2) /* Swap pages out during reclaim */ |
| 2338 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2339 | /* |
Christoph Lameter | a92f712 | 2006-02-01 03:05:32 -0800 | [diff] [blame] | 2340 | * Priority for ZONE_RECLAIM. This determines the fraction of pages |
| 2341 | * of a node considered for each zone_reclaim. 4 scans 1/16th of |
| 2342 | * a zone. |
| 2343 | */ |
| 2344 | #define ZONE_RECLAIM_PRIORITY 4 |
| 2345 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2346 | /* |
Christoph Lameter | 9614634 | 2006-07-03 00:24:13 -0700 | [diff] [blame] | 2347 | * Percentage of pages in a zone that must be unmapped for zone_reclaim to |
| 2348 | * occur. |
| 2349 | */ |
| 2350 | int sysctl_min_unmapped_ratio = 1; |
| 2351 | |
| 2352 | /* |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2353 | * If the number of slab pages in a zone grows beyond this percentage then |
| 2354 | * slab reclaim needs to occur. |
| 2355 | */ |
| 2356 | int sysctl_min_slab_ratio = 5; |
| 2357 | |
Mel Gorman | 90afa5d | 2009-06-16 15:33:20 -0700 | [diff] [blame] | 2358 | static inline unsigned long zone_unmapped_file_pages(struct zone *zone) |
| 2359 | { |
| 2360 | unsigned long file_mapped = zone_page_state(zone, NR_FILE_MAPPED); |
| 2361 | unsigned long file_lru = zone_page_state(zone, NR_INACTIVE_FILE) + |
| 2362 | zone_page_state(zone, NR_ACTIVE_FILE); |
| 2363 | |
| 2364 | /* |
| 2365 | * It's possible for there to be more file mapped pages than |
| 2366 | * accounted for by the pages on the file LRU lists because |
| 2367 | * tmpfs pages accounted for as ANON can also be FILE_MAPPED |
| 2368 | */ |
| 2369 | return (file_lru > file_mapped) ? (file_lru - file_mapped) : 0; |
| 2370 | } |
| 2371 | |
| 2372 | /* Work out how many page cache pages we can reclaim in this reclaim_mode */ |
| 2373 | static long zone_pagecache_reclaimable(struct zone *zone) |
| 2374 | { |
| 2375 | long nr_pagecache_reclaimable; |
| 2376 | long delta = 0; |
| 2377 | |
| 2378 | /* |
| 2379 | * If RECLAIM_SWAP is set, then all file pages are considered |
| 2380 | * potentially reclaimable. Otherwise, we have to worry about |
| 2381 | * pages like swapcache and zone_unmapped_file_pages() provides |
| 2382 | * a better estimate |
| 2383 | */ |
| 2384 | if (zone_reclaim_mode & RECLAIM_SWAP) |
| 2385 | nr_pagecache_reclaimable = zone_page_state(zone, NR_FILE_PAGES); |
| 2386 | else |
| 2387 | nr_pagecache_reclaimable = zone_unmapped_file_pages(zone); |
| 2388 | |
| 2389 | /* If we can't clean pages, remove dirty pages from consideration */ |
| 2390 | if (!(zone_reclaim_mode & RECLAIM_WRITE)) |
| 2391 | delta += zone_page_state(zone, NR_FILE_DIRTY); |
| 2392 | |
| 2393 | /* Watch for any possible underflows due to delta */ |
| 2394 | if (unlikely(delta > nr_pagecache_reclaimable)) |
| 2395 | delta = nr_pagecache_reclaimable; |
| 2396 | |
| 2397 | return nr_pagecache_reclaimable - delta; |
| 2398 | } |
| 2399 | |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2400 | /* |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2401 | * Try to free up some pages from this zone through reclaim. |
| 2402 | */ |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2403 | 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] | 2404 | { |
Christoph Lameter | 7fb2d46 | 2006-03-22 00:08:22 -0800 | [diff] [blame] | 2405 | /* Minimum pages needed in order to stay on node */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2406 | const unsigned long nr_pages = 1 << order; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2407 | struct task_struct *p = current; |
| 2408 | struct reclaim_state reclaim_state; |
Christoph Lameter | 8695949 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2409 | int priority; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2410 | struct scan_control sc = { |
| 2411 | .may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE), |
Johannes Weiner | a6dc60f | 2009-03-31 15:19:30 -0700 | [diff] [blame] | 2412 | .may_unmap = !!(zone_reclaim_mode & RECLAIM_SWAP), |
KOSAKI Motohiro | 2e2e425 | 2009-04-21 12:24:57 -0700 | [diff] [blame] | 2413 | .may_swap = 1, |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2414 | .swap_cluster_max = max_t(unsigned long, nr_pages, |
| 2415 | SWAP_CLUSTER_MAX), |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2416 | .gfp_mask = gfp_mask, |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2417 | .swappiness = vm_swappiness, |
Johannes Weiner | bd2f619 | 2009-03-31 15:19:38 -0700 | [diff] [blame] | 2418 | .order = order, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2419 | .isolate_pages = isolate_pages_global, |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2420 | }; |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 2421 | unsigned long slab_reclaimable; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2422 | |
| 2423 | disable_swap_token(); |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2424 | cond_resched(); |
Christoph Lameter | d4f7796 | 2006-02-24 13:04:22 -0800 | [diff] [blame] | 2425 | /* |
| 2426 | * We need to be able to allocate from the reserves for RECLAIM_SWAP |
| 2427 | * and we also need to be able to write out pages for RECLAIM_WRITE |
| 2428 | * and RECLAIM_SWAP. |
| 2429 | */ |
| 2430 | p->flags |= PF_MEMALLOC | PF_SWAPWRITE; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2431 | reclaim_state.reclaimed_slab = 0; |
| 2432 | p->reclaim_state = &reclaim_state; |
Christoph Lameter | c84db23 | 2006-02-01 03:05:29 -0800 | [diff] [blame] | 2433 | |
Mel Gorman | 90afa5d | 2009-06-16 15:33:20 -0700 | [diff] [blame] | 2434 | if (zone_pagecache_reclaimable(zone) > zone->min_unmapped_pages) { |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2435 | /* |
| 2436 | * Free memory by calling shrink zone with increasing |
| 2437 | * priorities until we have enough memory freed. |
| 2438 | */ |
| 2439 | priority = ZONE_RECLAIM_PRIORITY; |
| 2440 | do { |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 2441 | note_zone_scanning_priority(zone, priority); |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2442 | shrink_zone(priority, zone, &sc); |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2443 | priority--; |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2444 | } while (priority >= 0 && sc.nr_reclaimed < nr_pages); |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2445 | } |
Christoph Lameter | c84db23 | 2006-02-01 03:05:29 -0800 | [diff] [blame] | 2446 | |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 2447 | slab_reclaimable = zone_page_state(zone, NR_SLAB_RECLAIMABLE); |
| 2448 | if (slab_reclaimable > zone->min_slab_pages) { |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2449 | /* |
Christoph Lameter | 7fb2d46 | 2006-03-22 00:08:22 -0800 | [diff] [blame] | 2450 | * shrink_slab() does not currently allow us to determine how |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2451 | * many pages were freed in this zone. So we take the current |
| 2452 | * number of slab pages and shake the slab until it is reduced |
| 2453 | * by the same nr_pages that we used for reclaiming unmapped |
| 2454 | * pages. |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2455 | * |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2456 | * Note that shrink_slab will free memory on all zones and may |
| 2457 | * take a long time. |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2458 | */ |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2459 | while (shrink_slab(sc.nr_scanned, gfp_mask, order) && |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 2460 | zone_page_state(zone, NR_SLAB_RECLAIMABLE) > |
| 2461 | slab_reclaimable - nr_pages) |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2462 | ; |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 2463 | |
| 2464 | /* |
| 2465 | * Update nr_reclaimed by the number of slab pages we |
| 2466 | * reclaimed from this zone. |
| 2467 | */ |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2468 | sc.nr_reclaimed += slab_reclaimable - |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 2469 | zone_page_state(zone, NR_SLAB_RECLAIMABLE); |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2470 | } |
| 2471 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2472 | p->reclaim_state = NULL; |
Christoph Lameter | d4f7796 | 2006-02-24 13:04:22 -0800 | [diff] [blame] | 2473 | current->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE); |
Rik van Riel | a79311c | 2009-01-06 14:40:01 -0800 | [diff] [blame] | 2474 | return sc.nr_reclaimed >= nr_pages; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2475 | } |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2476 | |
| 2477 | int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) |
| 2478 | { |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2479 | int node_id; |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2480 | int ret; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2481 | |
| 2482 | /* |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2483 | * Zone reclaim reclaims unmapped file backed pages and |
| 2484 | * slab pages if we are over the defined limits. |
Christoph Lameter | 34aa133 | 2006-06-30 01:55:37 -0700 | [diff] [blame] | 2485 | * |
Christoph Lameter | 9614634 | 2006-07-03 00:24:13 -0700 | [diff] [blame] | 2486 | * A small portion of unmapped file backed pages is needed for |
| 2487 | * file I/O otherwise pages read by file I/O will be immediately |
| 2488 | * thrown out if the zone is overallocated. So we do not reclaim |
| 2489 | * if less than a specified percentage of the zone is used by |
| 2490 | * unmapped file backed pages. |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2491 | */ |
Mel Gorman | 90afa5d | 2009-06-16 15:33:20 -0700 | [diff] [blame] | 2492 | if (zone_pagecache_reclaimable(zone) <= zone->min_unmapped_pages && |
| 2493 | zone_page_state(zone, NR_SLAB_RECLAIMABLE) <= zone->min_slab_pages) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 2494 | return ZONE_RECLAIM_FULL; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2495 | |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2496 | if (zone_is_all_unreclaimable(zone)) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 2497 | return ZONE_RECLAIM_FULL; |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2498 | |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2499 | /* |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2500 | * Do not scan if the allocation should not be delayed. |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2501 | */ |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2502 | if (!(gfp_mask & __GFP_WAIT) || (current->flags & PF_MEMALLOC)) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 2503 | return ZONE_RECLAIM_NOSCAN; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2504 | |
| 2505 | /* |
| 2506 | * Only run zone reclaim on the local zone or on zones that do not |
| 2507 | * have associated processors. This will favor the local processor |
| 2508 | * over remote processors and spread off node memory allocations |
| 2509 | * as wide as possible. |
| 2510 | */ |
Christoph Lameter | 89fa302 | 2006-09-25 23:31:55 -0700 | [diff] [blame] | 2511 | node_id = zone_to_nid(zone); |
Christoph Lameter | 37c0708 | 2007-10-16 01:25:36 -0700 | [diff] [blame] | 2512 | if (node_state(node_id, N_CPU) && node_id != numa_node_id()) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 2513 | return ZONE_RECLAIM_NOSCAN; |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2514 | |
| 2515 | if (zone_test_and_set_flag(zone, ZONE_RECLAIM_LOCKED)) |
Mel Gorman | fa5e084 | 2009-06-16 15:33:22 -0700 | [diff] [blame] | 2516 | return ZONE_RECLAIM_NOSCAN; |
| 2517 | |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2518 | ret = __zone_reclaim(zone, gfp_mask, order); |
| 2519 | zone_clear_flag(zone, ZONE_RECLAIM_LOCKED); |
| 2520 | |
Mel Gorman | 24cf72518 | 2009-06-16 15:33:23 -0700 | [diff] [blame] | 2521 | if (!ret) |
| 2522 | count_vm_event(PGSCAN_ZONE_RECLAIM_FAILED); |
| 2523 | |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2524 | return ret; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2525 | } |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2526 | #endif |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2527 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2528 | /* |
| 2529 | * page_evictable - test whether a page is evictable |
| 2530 | * @page: the page to test |
| 2531 | * @vma: the VMA in which the page is or will be mapped, may be NULL |
| 2532 | * |
| 2533 | * 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] | 2534 | * lists vs unevictable list. The vma argument is !NULL when called from the |
| 2535 | * fault path to determine how to instantate a new page. |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2536 | * |
| 2537 | * Reasons page might not be evictable: |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 2538 | * (1) page's mapping marked unevictable |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 2539 | * (2) page is part of an mlocked VMA |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 2540 | * |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2541 | */ |
| 2542 | int page_evictable(struct page *page, struct vm_area_struct *vma) |
| 2543 | { |
| 2544 | |
Lee Schermerhorn | ba9ddf4 | 2008-10-18 20:26:42 -0700 | [diff] [blame] | 2545 | if (mapping_unevictable(page_mapping(page))) |
| 2546 | return 0; |
| 2547 | |
Nick Piggin | b291f00 | 2008-10-18 20:26:44 -0700 | [diff] [blame] | 2548 | if (PageMlocked(page) || (vma && is_mlocked_vma(vma, page))) |
| 2549 | return 0; |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 2550 | |
| 2551 | return 1; |
| 2552 | } |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 2553 | |
| 2554 | /** |
| 2555 | * check_move_unevictable_page - check page for evictability and move to appropriate zone lru list |
| 2556 | * @page: page to check evictability and move to appropriate lru list |
| 2557 | * @zone: zone page is in |
| 2558 | * |
| 2559 | * Checks a page for evictability and moves the page to the appropriate |
| 2560 | * zone lru list. |
| 2561 | * |
| 2562 | * Restrictions: zone->lru_lock must be held, page must be on LRU and must |
| 2563 | * have PageUnevictable set. |
| 2564 | */ |
| 2565 | static void check_move_unevictable_page(struct page *page, struct zone *zone) |
| 2566 | { |
| 2567 | VM_BUG_ON(PageActive(page)); |
| 2568 | |
| 2569 | retry: |
| 2570 | ClearPageUnevictable(page); |
| 2571 | if (page_evictable(page, NULL)) { |
| 2572 | enum lru_list l = LRU_INACTIVE_ANON + page_is_file_cache(page); |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2573 | |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 2574 | __dec_zone_state(zone, NR_UNEVICTABLE); |
| 2575 | list_move(&page->lru, &zone->lru[l].list); |
KAMEZAWA Hiroyuki | 08e552c | 2009-01-07 18:08:01 -0800 | [diff] [blame] | 2576 | mem_cgroup_move_lists(page, LRU_UNEVICTABLE, l); |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 2577 | __inc_zone_state(zone, NR_INACTIVE_ANON + l); |
| 2578 | __count_vm_event(UNEVICTABLE_PGRESCUED); |
| 2579 | } else { |
| 2580 | /* |
| 2581 | * rotate unevictable list |
| 2582 | */ |
| 2583 | SetPageUnevictable(page); |
| 2584 | list_move(&page->lru, &zone->lru[LRU_UNEVICTABLE].list); |
KAMEZAWA Hiroyuki | 08e552c | 2009-01-07 18:08:01 -0800 | [diff] [blame] | 2585 | mem_cgroup_rotate_lru_list(page, LRU_UNEVICTABLE); |
Lee Schermerhorn | 89e004ea | 2008-10-18 20:26:43 -0700 | [diff] [blame] | 2586 | if (page_evictable(page, NULL)) |
| 2587 | goto retry; |
| 2588 | } |
| 2589 | } |
| 2590 | |
| 2591 | /** |
| 2592 | * scan_mapping_unevictable_pages - scan an address space for evictable pages |
| 2593 | * @mapping: struct address_space to scan for evictable pages |
| 2594 | * |
| 2595 | * Scan all pages in mapping. Check unevictable pages for |
| 2596 | * evictability and move them to the appropriate zone lru list. |
| 2597 | */ |
| 2598 | void scan_mapping_unevictable_pages(struct address_space *mapping) |
| 2599 | { |
| 2600 | pgoff_t next = 0; |
| 2601 | pgoff_t end = (i_size_read(mapping->host) + PAGE_CACHE_SIZE - 1) >> |
| 2602 | PAGE_CACHE_SHIFT; |
| 2603 | struct zone *zone; |
| 2604 | struct pagevec pvec; |
| 2605 | |
| 2606 | if (mapping->nrpages == 0) |
| 2607 | return; |
| 2608 | |
| 2609 | pagevec_init(&pvec, 0); |
| 2610 | while (next < end && |
| 2611 | pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { |
| 2612 | int i; |
| 2613 | int pg_scanned = 0; |
| 2614 | |
| 2615 | zone = NULL; |
| 2616 | |
| 2617 | for (i = 0; i < pagevec_count(&pvec); i++) { |
| 2618 | struct page *page = pvec.pages[i]; |
| 2619 | pgoff_t page_index = page->index; |
| 2620 | struct zone *pagezone = page_zone(page); |
| 2621 | |
| 2622 | pg_scanned++; |
| 2623 | if (page_index > next) |
| 2624 | next = page_index; |
| 2625 | next++; |
| 2626 | |
| 2627 | if (pagezone != zone) { |
| 2628 | if (zone) |
| 2629 | spin_unlock_irq(&zone->lru_lock); |
| 2630 | zone = pagezone; |
| 2631 | spin_lock_irq(&zone->lru_lock); |
| 2632 | } |
| 2633 | |
| 2634 | if (PageLRU(page) && PageUnevictable(page)) |
| 2635 | check_move_unevictable_page(page, zone); |
| 2636 | } |
| 2637 | if (zone) |
| 2638 | spin_unlock_irq(&zone->lru_lock); |
| 2639 | pagevec_release(&pvec); |
| 2640 | |
| 2641 | count_vm_events(UNEVICTABLE_PGSCANNED, pg_scanned); |
| 2642 | } |
| 2643 | |
| 2644 | } |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2645 | |
| 2646 | /** |
| 2647 | * scan_zone_unevictable_pages - check unevictable list for evictable pages |
| 2648 | * @zone - zone of which to scan the unevictable list |
| 2649 | * |
| 2650 | * Scan @zone's unevictable LRU lists to check for pages that have become |
| 2651 | * evictable. Move those that have to @zone's inactive list where they |
| 2652 | * become candidates for reclaim, unless shrink_inactive_zone() decides |
| 2653 | * to reactivate them. Pages that are still unevictable are rotated |
| 2654 | * back onto @zone's unevictable list. |
| 2655 | */ |
| 2656 | #define SCAN_UNEVICTABLE_BATCH_SIZE 16UL /* arbitrary lock hold batch size */ |
KOSAKI Motohiro | 14b90b2 | 2009-01-06 14:39:45 -0800 | [diff] [blame] | 2657 | static void scan_zone_unevictable_pages(struct zone *zone) |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2658 | { |
| 2659 | struct list_head *l_unevictable = &zone->lru[LRU_UNEVICTABLE].list; |
| 2660 | unsigned long scan; |
| 2661 | unsigned long nr_to_scan = zone_page_state(zone, NR_UNEVICTABLE); |
| 2662 | |
| 2663 | while (nr_to_scan > 0) { |
| 2664 | unsigned long batch_size = min(nr_to_scan, |
| 2665 | SCAN_UNEVICTABLE_BATCH_SIZE); |
| 2666 | |
| 2667 | spin_lock_irq(&zone->lru_lock); |
| 2668 | for (scan = 0; scan < batch_size; scan++) { |
| 2669 | struct page *page = lru_to_page(l_unevictable); |
| 2670 | |
| 2671 | if (!trylock_page(page)) |
| 2672 | continue; |
| 2673 | |
| 2674 | prefetchw_prev_lru_page(page, l_unevictable, flags); |
| 2675 | |
| 2676 | if (likely(PageLRU(page) && PageUnevictable(page))) |
| 2677 | check_move_unevictable_page(page, zone); |
| 2678 | |
| 2679 | unlock_page(page); |
| 2680 | } |
| 2681 | spin_unlock_irq(&zone->lru_lock); |
| 2682 | |
| 2683 | nr_to_scan -= batch_size; |
| 2684 | } |
| 2685 | } |
| 2686 | |
| 2687 | |
| 2688 | /** |
| 2689 | * scan_all_zones_unevictable_pages - scan all unevictable lists for evictable pages |
| 2690 | * |
| 2691 | * A really big hammer: scan all zones' unevictable LRU lists to check for |
| 2692 | * pages that have become evictable. Move those back to the zones' |
| 2693 | * inactive list where they become candidates for reclaim. |
| 2694 | * This occurs when, e.g., we have unswappable pages on the unevictable lists, |
| 2695 | * and we add swap to the system. As such, it runs in the context of a task |
| 2696 | * that has possibly/probably made some previously unevictable pages |
| 2697 | * evictable. |
| 2698 | */ |
KOSAKI Motohiro | ff30153 | 2009-01-06 14:39:44 -0800 | [diff] [blame] | 2699 | static void scan_all_zones_unevictable_pages(void) |
Lee Schermerhorn | af936a1 | 2008-10-18 20:26:53 -0700 | [diff] [blame] | 2700 | { |
| 2701 | struct zone *zone; |
| 2702 | |
| 2703 | for_each_zone(zone) { |
| 2704 | scan_zone_unevictable_pages(zone); |
| 2705 | } |
| 2706 | } |
| 2707 | |
| 2708 | /* |
| 2709 | * scan_unevictable_pages [vm] sysctl handler. On demand re-scan of |
| 2710 | * all nodes' unevictable lists for evictable pages |
| 2711 | */ |
| 2712 | unsigned long scan_unevictable_pages; |
| 2713 | |
| 2714 | int scan_unevictable_handler(struct ctl_table *table, int write, |
| 2715 | struct file *file, void __user *buffer, |
| 2716 | size_t *length, loff_t *ppos) |
| 2717 | { |
| 2718 | proc_doulongvec_minmax(table, write, file, buffer, length, ppos); |
| 2719 | |
| 2720 | if (write && *(unsigned long *)table->data) |
| 2721 | scan_all_zones_unevictable_pages(); |
| 2722 | |
| 2723 | scan_unevictable_pages = 0; |
| 2724 | return 0; |
| 2725 | } |
| 2726 | |
| 2727 | /* |
| 2728 | * per node 'scan_unevictable_pages' attribute. On demand re-scan of |
| 2729 | * a specified node's per zone unevictable lists for evictable pages. |
| 2730 | */ |
| 2731 | |
| 2732 | static ssize_t read_scan_unevictable_node(struct sys_device *dev, |
| 2733 | struct sysdev_attribute *attr, |
| 2734 | char *buf) |
| 2735 | { |
| 2736 | return sprintf(buf, "0\n"); /* always zero; should fit... */ |
| 2737 | } |
| 2738 | |
| 2739 | static ssize_t write_scan_unevictable_node(struct sys_device *dev, |
| 2740 | struct sysdev_attribute *attr, |
| 2741 | const char *buf, size_t count) |
| 2742 | { |
| 2743 | struct zone *node_zones = NODE_DATA(dev->id)->node_zones; |
| 2744 | struct zone *zone; |
| 2745 | unsigned long res; |
| 2746 | unsigned long req = strict_strtoul(buf, 10, &res); |
| 2747 | |
| 2748 | if (!req) |
| 2749 | return 1; /* zero is no-op */ |
| 2750 | |
| 2751 | for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) { |
| 2752 | if (!populated_zone(zone)) |
| 2753 | continue; |
| 2754 | scan_zone_unevictable_pages(zone); |
| 2755 | } |
| 2756 | return 1; |
| 2757 | } |
| 2758 | |
| 2759 | |
| 2760 | static SYSDEV_ATTR(scan_unevictable_pages, S_IRUGO | S_IWUSR, |
| 2761 | read_scan_unevictable_node, |
| 2762 | write_scan_unevictable_node); |
| 2763 | |
| 2764 | int scan_unevictable_register_node(struct node *node) |
| 2765 | { |
| 2766 | return sysdev_create_file(&node->sysdev, &attr_scan_unevictable_pages); |
| 2767 | } |
| 2768 | |
| 2769 | void scan_unevictable_unregister_node(struct node *node) |
| 2770 | { |
| 2771 | sysdev_remove_file(&node->sysdev, &attr_scan_unevictable_pages); |
| 2772 | } |
| 2773 | |