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> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | |
| 43 | #include <asm/tlbflush.h> |
| 44 | #include <asm/div64.h> |
| 45 | |
| 46 | #include <linux/swapops.h> |
| 47 | |
Nick Piggin | 0f8053a | 2006-03-22 00:08:33 -0800 | [diff] [blame] | 48 | #include "internal.h" |
| 49 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | struct scan_control { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | /* Incremented by the number of inactive pages that were scanned */ |
| 52 | unsigned long nr_scanned; |
| 53 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | /* This context's GFP mask */ |
Al Viro | 6daa0e2 | 2005-10-21 03:18:50 -0400 | [diff] [blame] | 55 | gfp_t gfp_mask; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 56 | |
| 57 | int may_writepage; |
| 58 | |
Christoph Lameter | f1fd106 | 2006-01-18 17:42:30 -0800 | [diff] [blame] | 59 | /* Can pages be swapped as part of reclaim? */ |
| 60 | int may_swap; |
| 61 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | /* This context's SWAP_CLUSTER_MAX. If freeing memory for |
| 63 | * suspend, we effectively ignore SWAP_CLUSTER_MAX. |
| 64 | * In this context, it doesn't matter that we scan the |
| 65 | * whole list at once. */ |
| 66 | int swap_cluster_max; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 67 | |
| 68 | int swappiness; |
Nick Piggin | 408d854 | 2006-09-25 23:31:27 -0700 | [diff] [blame] | 69 | |
| 70 | int all_unreclaimable; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 71 | |
| 72 | int order; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 73 | |
| 74 | /* Which cgroup do we reclaim from */ |
| 75 | struct mem_cgroup *mem_cgroup; |
| 76 | |
| 77 | /* Pluggable isolate pages callback */ |
| 78 | unsigned long (*isolate_pages)(unsigned long nr, struct list_head *dst, |
| 79 | unsigned long *scanned, int order, int mode, |
| 80 | struct zone *z, struct mem_cgroup *mem_cont, |
| 81 | int active); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | }; |
| 83 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru)) |
| 85 | |
| 86 | #ifdef ARCH_HAS_PREFETCH |
| 87 | #define prefetch_prev_lru_page(_page, _base, _field) \ |
| 88 | do { \ |
| 89 | if ((_page)->lru.prev != _base) { \ |
| 90 | struct page *prev; \ |
| 91 | \ |
| 92 | prev = lru_to_page(&(_page->lru)); \ |
| 93 | prefetch(&prev->_field); \ |
| 94 | } \ |
| 95 | } while (0) |
| 96 | #else |
| 97 | #define prefetch_prev_lru_page(_page, _base, _field) do { } while (0) |
| 98 | #endif |
| 99 | |
| 100 | #ifdef ARCH_HAS_PREFETCHW |
| 101 | #define prefetchw_prev_lru_page(_page, _base, _field) \ |
| 102 | do { \ |
| 103 | if ((_page)->lru.prev != _base) { \ |
| 104 | struct page *prev; \ |
| 105 | \ |
| 106 | prev = lru_to_page(&(_page->lru)); \ |
| 107 | prefetchw(&prev->_field); \ |
| 108 | } \ |
| 109 | } while (0) |
| 110 | #else |
| 111 | #define prefetchw_prev_lru_page(_page, _base, _field) do { } while (0) |
| 112 | #endif |
| 113 | |
| 114 | /* |
| 115 | * From 0 .. 100. Higher means more swappy. |
| 116 | */ |
| 117 | int vm_swappiness = 60; |
Andrew Morton | bd1e22b | 2006-06-23 02:03:47 -0700 | [diff] [blame] | 118 | 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] | 119 | |
| 120 | static LIST_HEAD(shrinker_list); |
| 121 | static DECLARE_RWSEM(shrinker_rwsem); |
| 122 | |
Balbir Singh | 00f0b82 | 2008-03-04 14:28:39 -0800 | [diff] [blame] | 123 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 124 | #define scan_global_lru(sc) (!(sc)->mem_cgroup) |
| 125 | #else |
| 126 | #define scan_global_lru(sc) (1) |
| 127 | #endif |
| 128 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 129 | /* |
| 130 | * Add a shrinker callback to be called from the vm |
| 131 | */ |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 132 | void register_shrinker(struct shrinker *shrinker) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 133 | { |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 134 | shrinker->nr = 0; |
| 135 | down_write(&shrinker_rwsem); |
| 136 | list_add_tail(&shrinker->list, &shrinker_list); |
| 137 | up_write(&shrinker_rwsem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | } |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 139 | EXPORT_SYMBOL(register_shrinker); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | |
| 141 | /* |
| 142 | * Remove one |
| 143 | */ |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 144 | void unregister_shrinker(struct shrinker *shrinker) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 145 | { |
| 146 | down_write(&shrinker_rwsem); |
| 147 | list_del(&shrinker->list); |
| 148 | up_write(&shrinker_rwsem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | } |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 150 | EXPORT_SYMBOL(unregister_shrinker); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 151 | |
| 152 | #define SHRINK_BATCH 128 |
| 153 | /* |
| 154 | * Call the shrink functions to age shrinkable caches |
| 155 | * |
| 156 | * Here we assume it costs one seek to replace a lru page and that it also |
| 157 | * takes a seek to recreate a cache object. With this in mind we age equal |
| 158 | * percentages of the lru and ageable caches. This should balance the seeks |
| 159 | * generated by these structures. |
| 160 | * |
Simon Arlott | 183ff22 | 2007-10-20 01:27:18 +0200 | [diff] [blame] | 161 | * 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] | 162 | * slab to avoid swapping. |
| 163 | * |
| 164 | * We do weird things to avoid (scanned*seeks*entries) overflowing 32 bits. |
| 165 | * |
| 166 | * `lru_pages' represents the number of on-LRU pages in all the zones which |
| 167 | * are eligible for the caller's allocation attempt. It is used for balancing |
| 168 | * slab reclaim versus page reclaim. |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 169 | * |
| 170 | * Returns the number of slab objects which we shrunk. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 171 | */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 172 | unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask, |
| 173 | unsigned long lru_pages) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 174 | { |
| 175 | struct shrinker *shrinker; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 176 | unsigned long ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | |
| 178 | if (scanned == 0) |
| 179 | scanned = SWAP_CLUSTER_MAX; |
| 180 | |
| 181 | if (!down_read_trylock(&shrinker_rwsem)) |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 182 | return 1; /* Assume we'll be able to shrink next time */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 183 | |
| 184 | list_for_each_entry(shrinker, &shrinker_list, list) { |
| 185 | unsigned long long delta; |
| 186 | unsigned long total_scan; |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 187 | unsigned long max_pass = (*shrinker->shrink)(0, gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 188 | |
| 189 | delta = (4 * scanned) / shrinker->seeks; |
Andrea Arcangeli | ea164d7 | 2005-11-28 13:44:15 -0800 | [diff] [blame] | 190 | delta *= max_pass; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 191 | do_div(delta, lru_pages + 1); |
| 192 | shrinker->nr += delta; |
Andrea Arcangeli | ea164d7 | 2005-11-28 13:44:15 -0800 | [diff] [blame] | 193 | if (shrinker->nr < 0) { |
| 194 | printk(KERN_ERR "%s: nr=%ld\n", |
Harvey Harrison | d40cee2 | 2008-04-30 00:55:07 -0700 | [diff] [blame] | 195 | __func__, shrinker->nr); |
Andrea Arcangeli | ea164d7 | 2005-11-28 13:44:15 -0800 | [diff] [blame] | 196 | shrinker->nr = max_pass; |
| 197 | } |
| 198 | |
| 199 | /* |
| 200 | * Avoid risking looping forever due to too large nr value: |
| 201 | * never try to free more than twice the estimate number of |
| 202 | * freeable entries. |
| 203 | */ |
| 204 | if (shrinker->nr > max_pass * 2) |
| 205 | shrinker->nr = max_pass * 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 206 | |
| 207 | total_scan = shrinker->nr; |
| 208 | shrinker->nr = 0; |
| 209 | |
| 210 | while (total_scan >= SHRINK_BATCH) { |
| 211 | long this_scan = SHRINK_BATCH; |
| 212 | int shrink_ret; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 213 | int nr_before; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 214 | |
Rusty Russell | 8e1f936 | 2007-07-17 04:03:17 -0700 | [diff] [blame] | 215 | nr_before = (*shrinker->shrink)(0, gfp_mask); |
| 216 | shrink_ret = (*shrinker->shrink)(this_scan, gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | if (shrink_ret == -1) |
| 218 | break; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 219 | if (shrink_ret < nr_before) |
| 220 | ret += nr_before - shrink_ret; |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 221 | count_vm_events(SLABS_SCANNED, this_scan); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | total_scan -= this_scan; |
| 223 | |
| 224 | cond_resched(); |
| 225 | } |
| 226 | |
| 227 | shrinker->nr += total_scan; |
| 228 | } |
| 229 | up_read(&shrinker_rwsem); |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 230 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 231 | } |
| 232 | |
| 233 | /* Called without lock on whether page is mapped, so answer is unstable */ |
| 234 | static inline int page_mapping_inuse(struct page *page) |
| 235 | { |
| 236 | struct address_space *mapping; |
| 237 | |
| 238 | /* Page is in somebody's page tables. */ |
| 239 | if (page_mapped(page)) |
| 240 | return 1; |
| 241 | |
| 242 | /* Be more reluctant to reclaim swapcache than pagecache */ |
| 243 | if (PageSwapCache(page)) |
| 244 | return 1; |
| 245 | |
| 246 | mapping = page_mapping(page); |
| 247 | if (!mapping) |
| 248 | return 0; |
| 249 | |
| 250 | /* File is mmap'd by somebody? */ |
| 251 | return mapping_mapped(mapping); |
| 252 | } |
| 253 | |
| 254 | static inline int is_page_cache_freeable(struct page *page) |
| 255 | { |
| 256 | return page_count(page) - !!PagePrivate(page) == 2; |
| 257 | } |
| 258 | |
| 259 | static int may_write_to_queue(struct backing_dev_info *bdi) |
| 260 | { |
Christoph Lameter | 930d915 | 2006-01-08 01:00:47 -0800 | [diff] [blame] | 261 | if (current->flags & PF_SWAPWRITE) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 262 | return 1; |
| 263 | if (!bdi_write_congested(bdi)) |
| 264 | return 1; |
| 265 | if (bdi == current->backing_dev_info) |
| 266 | return 1; |
| 267 | return 0; |
| 268 | } |
| 269 | |
| 270 | /* |
| 271 | * We detected a synchronous write error writing a page out. Probably |
| 272 | * -ENOSPC. We need to propagate that into the address_space for a subsequent |
| 273 | * fsync(), msync() or close(). |
| 274 | * |
| 275 | * The tricky part is that after writepage we cannot touch the mapping: nothing |
| 276 | * prevents it from being freed up. But we have a ref on the page and once |
| 277 | * that page is locked, the mapping is pinned. |
| 278 | * |
| 279 | * We're allowed to run sleeping lock_page() here because we know the caller has |
| 280 | * __GFP_FS. |
| 281 | */ |
| 282 | static void handle_write_error(struct address_space *mapping, |
| 283 | struct page *page, int error) |
| 284 | { |
| 285 | lock_page(page); |
Guillaume Chazarain | 3e9f45b | 2007-05-08 00:23:25 -0700 | [diff] [blame] | 286 | if (page_mapping(page) == mapping) |
| 287 | mapping_set_error(mapping, error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | unlock_page(page); |
| 289 | } |
| 290 | |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 291 | /* Request for sync pageout. */ |
| 292 | enum pageout_io { |
| 293 | PAGEOUT_IO_ASYNC, |
| 294 | PAGEOUT_IO_SYNC, |
| 295 | }; |
| 296 | |
Christoph Lameter | 04e62a2 | 2006-06-23 02:03:38 -0700 | [diff] [blame] | 297 | /* possible outcome of pageout() */ |
| 298 | typedef enum { |
| 299 | /* failed to write page out, page is locked */ |
| 300 | PAGE_KEEP, |
| 301 | /* move page to the active list, page is locked */ |
| 302 | PAGE_ACTIVATE, |
| 303 | /* page has been sent to the disk successfully, page is unlocked */ |
| 304 | PAGE_SUCCESS, |
| 305 | /* page is clean and locked */ |
| 306 | PAGE_CLEAN, |
| 307 | } pageout_t; |
| 308 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 309 | /* |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 310 | * pageout is called by shrink_page_list() for each dirty page. |
| 311 | * Calls ->writepage(). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 312 | */ |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 313 | static pageout_t pageout(struct page *page, struct address_space *mapping, |
| 314 | enum pageout_io sync_writeback) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 315 | { |
| 316 | /* |
| 317 | * If the page is dirty, only perform writeback if that write |
| 318 | * will be non-blocking. To prevent this allocation from being |
| 319 | * stalled by pagecache activity. But note that there may be |
| 320 | * stalls if we need to run get_block(). We could test |
| 321 | * PagePrivate for that. |
| 322 | * |
| 323 | * If this process is currently in generic_file_write() against |
| 324 | * this page's queue, we can perform writeback even if that |
| 325 | * will block. |
| 326 | * |
| 327 | * If the page is swapcache, write it back even if that would |
| 328 | * block, for some throttling. This happens by accident, because |
| 329 | * swap_backing_dev_info is bust: it doesn't reflect the |
| 330 | * congestion state of the swapdevs. Easy to fix, if needed. |
| 331 | * See swapfile.c:page_queue_congested(). |
| 332 | */ |
| 333 | if (!is_page_cache_freeable(page)) |
| 334 | return PAGE_KEEP; |
| 335 | if (!mapping) { |
| 336 | /* |
| 337 | * Some data journaling orphaned pages can have |
| 338 | * page->mapping == NULL while being dirty with clean buffers. |
| 339 | */ |
akpm@osdl.org | 323aca6 | 2005-04-16 15:24:06 -0700 | [diff] [blame] | 340 | if (PagePrivate(page)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 341 | if (try_to_free_buffers(page)) { |
| 342 | ClearPageDirty(page); |
Harvey Harrison | d40cee2 | 2008-04-30 00:55:07 -0700 | [diff] [blame] | 343 | printk("%s: orphaned page\n", __func__); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 344 | return PAGE_CLEAN; |
| 345 | } |
| 346 | } |
| 347 | return PAGE_KEEP; |
| 348 | } |
| 349 | if (mapping->a_ops->writepage == NULL) |
| 350 | return PAGE_ACTIVATE; |
| 351 | if (!may_write_to_queue(mapping->backing_dev_info)) |
| 352 | return PAGE_KEEP; |
| 353 | |
| 354 | if (clear_page_dirty_for_io(page)) { |
| 355 | int res; |
| 356 | struct writeback_control wbc = { |
| 357 | .sync_mode = WB_SYNC_NONE, |
| 358 | .nr_to_write = SWAP_CLUSTER_MAX, |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 359 | .range_start = 0, |
| 360 | .range_end = LLONG_MAX, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 361 | .nonblocking = 1, |
| 362 | .for_reclaim = 1, |
| 363 | }; |
| 364 | |
| 365 | SetPageReclaim(page); |
| 366 | res = mapping->a_ops->writepage(page, &wbc); |
| 367 | if (res < 0) |
| 368 | handle_write_error(mapping, page, res); |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 369 | if (res == AOP_WRITEPAGE_ACTIVATE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 370 | ClearPageReclaim(page); |
| 371 | return PAGE_ACTIVATE; |
| 372 | } |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 373 | |
| 374 | /* |
| 375 | * Wait on writeback if requested to. This happens when |
| 376 | * direct reclaiming a large contiguous area and the |
| 377 | * first attempt to free a range of pages fails. |
| 378 | */ |
| 379 | if (PageWriteback(page) && sync_writeback == PAGEOUT_IO_SYNC) |
| 380 | wait_on_page_writeback(page); |
| 381 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 382 | if (!PageWriteback(page)) { |
| 383 | /* synchronous write or broken a_ops? */ |
| 384 | ClearPageReclaim(page); |
| 385 | } |
Andrew Morton | e129b5c | 2006-09-27 01:50:00 -0700 | [diff] [blame] | 386 | inc_zone_page_state(page, NR_VMSCAN_WRITE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 387 | return PAGE_SUCCESS; |
| 388 | } |
| 389 | |
| 390 | return PAGE_CLEAN; |
| 391 | } |
| 392 | |
Andrew Morton | a649fd9 | 2006-10-17 00:09:36 -0700 | [diff] [blame] | 393 | /* |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 394 | * Same as remove_mapping, but if the page is removed from the mapping, it |
| 395 | * gets returned with a refcount of 0. |
Andrew Morton | a649fd9 | 2006-10-17 00:09:36 -0700 | [diff] [blame] | 396 | */ |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 397 | static int __remove_mapping(struct address_space *mapping, struct page *page) |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 398 | { |
Nick Piggin | 28e4d96 | 2006-09-25 23:31:23 -0700 | [diff] [blame] | 399 | BUG_ON(!PageLocked(page)); |
| 400 | BUG_ON(mapping != page_mapping(page)); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 401 | |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 402 | spin_lock_irq(&mapping->tree_lock); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 403 | /* |
Nick Piggin | 0fd0e6b | 2006-09-27 01:50:02 -0700 | [diff] [blame] | 404 | * The non racy check for a busy page. |
| 405 | * |
| 406 | * Must be careful with the order of the tests. When someone has |
| 407 | * a ref to the page, it may be possible that they dirty it then |
| 408 | * drop the reference. So if PageDirty is tested before page_count |
| 409 | * here, then the following race may occur: |
| 410 | * |
| 411 | * get_user_pages(&page); |
| 412 | * [user mapping goes away] |
| 413 | * write_to(page); |
| 414 | * !PageDirty(page) [good] |
| 415 | * SetPageDirty(page); |
| 416 | * put_page(page); |
| 417 | * !page_count(page) [good, discard it] |
| 418 | * |
| 419 | * [oops, our write_to data is lost] |
| 420 | * |
| 421 | * Reversing the order of the tests ensures such a situation cannot |
| 422 | * escape unnoticed. The smp_rmb is needed to ensure the page->flags |
| 423 | * load is not satisfied before that of page->_count. |
| 424 | * |
| 425 | * Note that if SetPageDirty is always performed via set_page_dirty, |
| 426 | * and thus under tree_lock, then this ordering is not required. |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 427 | */ |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 428 | if (!page_freeze_refs(page, 2)) |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 429 | goto cannot_free; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 430 | /* note: atomic_cmpxchg in page_freeze_refs provides the smp_rmb */ |
| 431 | if (unlikely(PageDirty(page))) { |
| 432 | page_unfreeze_refs(page, 2); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 433 | goto cannot_free; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 434 | } |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 435 | |
| 436 | if (PageSwapCache(page)) { |
| 437 | swp_entry_t swap = { .val = page_private(page) }; |
| 438 | __delete_from_swap_cache(page); |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 439 | spin_unlock_irq(&mapping->tree_lock); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 440 | swap_free(swap); |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 441 | } else { |
| 442 | __remove_from_page_cache(page); |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 443 | spin_unlock_irq(&mapping->tree_lock); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 444 | } |
| 445 | |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 446 | return 1; |
| 447 | |
| 448 | cannot_free: |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 449 | spin_unlock_irq(&mapping->tree_lock); |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 450 | return 0; |
| 451 | } |
| 452 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 453 | /* |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 454 | * Attempt to detach a locked page from its ->mapping. If it is dirty or if |
| 455 | * someone else has a ref on the page, abort and return 0. If it was |
| 456 | * successfully detached, return 1. Assumes the caller has a single ref on |
| 457 | * this page. |
| 458 | */ |
| 459 | int remove_mapping(struct address_space *mapping, struct page *page) |
| 460 | { |
| 461 | if (__remove_mapping(mapping, page)) { |
| 462 | /* |
| 463 | * Unfreezing the refcount with 1 rather than 2 effectively |
| 464 | * drops the pagecache ref for us without requiring another |
| 465 | * atomic operation. |
| 466 | */ |
| 467 | page_unfreeze_refs(page, 1); |
| 468 | return 1; |
| 469 | } |
| 470 | return 0; |
| 471 | } |
| 472 | |
| 473 | /* |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 474 | * shrink_page_list() returns the number of reclaimed pages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 475 | */ |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 476 | static unsigned long shrink_page_list(struct list_head *page_list, |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 477 | struct scan_control *sc, |
| 478 | enum pageout_io sync_writeback) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 479 | { |
| 480 | LIST_HEAD(ret_pages); |
| 481 | struct pagevec freed_pvec; |
| 482 | int pgactivate = 0; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 483 | unsigned long nr_reclaimed = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 484 | |
| 485 | cond_resched(); |
| 486 | |
| 487 | pagevec_init(&freed_pvec, 1); |
| 488 | while (!list_empty(page_list)) { |
| 489 | struct address_space *mapping; |
| 490 | struct page *page; |
| 491 | int may_enter_fs; |
| 492 | int referenced; |
| 493 | |
| 494 | cond_resched(); |
| 495 | |
| 496 | page = lru_to_page(page_list); |
| 497 | list_del(&page->lru); |
| 498 | |
| 499 | if (TestSetPageLocked(page)) |
| 500 | goto keep; |
| 501 | |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 502 | VM_BUG_ON(PageActive(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 503 | |
| 504 | sc->nr_scanned++; |
Christoph Lameter | 80e4342 | 2006-02-11 17:55:53 -0800 | [diff] [blame] | 505 | |
| 506 | if (!sc->may_swap && page_mapped(page)) |
| 507 | goto keep_locked; |
| 508 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 509 | /* Double the slab pressure for mapped and swapcache pages */ |
| 510 | if (page_mapped(page) || PageSwapCache(page)) |
| 511 | sc->nr_scanned++; |
| 512 | |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 513 | may_enter_fs = (sc->gfp_mask & __GFP_FS) || |
| 514 | (PageSwapCache(page) && (sc->gfp_mask & __GFP_IO)); |
| 515 | |
| 516 | if (PageWriteback(page)) { |
| 517 | /* |
| 518 | * Synchronous reclaim is performed in two passes, |
| 519 | * first an asynchronous pass over the list to |
| 520 | * start parallel writeback, and a second synchronous |
| 521 | * pass to wait for the IO to complete. Wait here |
| 522 | * for any page for which writeback has already |
| 523 | * started. |
| 524 | */ |
| 525 | if (sync_writeback == PAGEOUT_IO_SYNC && may_enter_fs) |
| 526 | wait_on_page_writeback(page); |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 527 | else |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 528 | goto keep_locked; |
| 529 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 530 | |
Balbir Singh | bed7161 | 2008-02-07 00:14:01 -0800 | [diff] [blame] | 531 | referenced = page_referenced(page, 1, sc->mem_cgroup); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 532 | /* In active use or really unfreeable? Activate it. */ |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 533 | if (sc->order <= PAGE_ALLOC_COSTLY_ORDER && |
| 534 | referenced && page_mapping_inuse(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 535 | goto activate_locked; |
| 536 | |
| 537 | #ifdef CONFIG_SWAP |
| 538 | /* |
| 539 | * Anonymous process memory has backing store? |
| 540 | * Try to allocate it some swap space here. |
| 541 | */ |
Christoph Lameter | 6e5ef1a | 2006-03-22 00:08:45 -0800 | [diff] [blame] | 542 | if (PageAnon(page) && !PageSwapCache(page)) |
Christoph Lameter | 1480a54 | 2006-01-08 01:00:53 -0800 | [diff] [blame] | 543 | if (!add_to_swap(page, GFP_ATOMIC)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 544 | goto activate_locked; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 545 | #endif /* CONFIG_SWAP */ |
| 546 | |
| 547 | mapping = page_mapping(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 548 | |
| 549 | /* |
| 550 | * The page is mapped into the page tables of one or more |
| 551 | * processes. Try to unmap it here. |
| 552 | */ |
| 553 | if (page_mapped(page) && mapping) { |
Christoph Lameter | a48d07a | 2006-02-01 03:05:38 -0800 | [diff] [blame] | 554 | switch (try_to_unmap(page, 0)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 555 | case SWAP_FAIL: |
| 556 | goto activate_locked; |
| 557 | case SWAP_AGAIN: |
| 558 | goto keep_locked; |
| 559 | case SWAP_SUCCESS: |
| 560 | ; /* try to free the page below */ |
| 561 | } |
| 562 | } |
| 563 | |
| 564 | if (PageDirty(page)) { |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 565 | if (sc->order <= PAGE_ALLOC_COSTLY_ORDER && referenced) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 566 | goto keep_locked; |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 567 | if (!may_enter_fs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 568 | goto keep_locked; |
Christoph Lameter | 52a8363 | 2006-02-01 03:05:28 -0800 | [diff] [blame] | 569 | if (!sc->may_writepage) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 570 | goto keep_locked; |
| 571 | |
| 572 | /* Page is dirty, try to write it out here */ |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 573 | switch (pageout(page, mapping, sync_writeback)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 574 | case PAGE_KEEP: |
| 575 | goto keep_locked; |
| 576 | case PAGE_ACTIVATE: |
| 577 | goto activate_locked; |
| 578 | case PAGE_SUCCESS: |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 579 | if (PageWriteback(page) || PageDirty(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 580 | goto keep; |
| 581 | /* |
| 582 | * A synchronous write - probably a ramdisk. Go |
| 583 | * ahead and try to reclaim the page. |
| 584 | */ |
| 585 | if (TestSetPageLocked(page)) |
| 586 | goto keep; |
| 587 | if (PageDirty(page) || PageWriteback(page)) |
| 588 | goto keep_locked; |
| 589 | mapping = page_mapping(page); |
| 590 | case PAGE_CLEAN: |
| 591 | ; /* try to free the page below */ |
| 592 | } |
| 593 | } |
| 594 | |
| 595 | /* |
| 596 | * If the page has buffers, try to free the buffer mappings |
| 597 | * associated with this page. If we succeed we try to free |
| 598 | * the page as well. |
| 599 | * |
| 600 | * We do this even if the page is PageDirty(). |
| 601 | * try_to_release_page() does not perform I/O, but it is |
| 602 | * possible for a page to have PageDirty set, but it is actually |
| 603 | * clean (all its buffers are clean). This happens if the |
| 604 | * buffers were written out directly, with submit_bh(). ext3 |
| 605 | * will do this, as well as the blockdev mapping. |
| 606 | * try_to_release_page() will discover that cleanness and will |
| 607 | * drop the buffers and mark the page clean - it can be freed. |
| 608 | * |
| 609 | * Rarely, pages can have buffers and no ->mapping. These are |
| 610 | * the pages which were not successfully invalidated in |
| 611 | * truncate_complete_page(). We try to drop those buffers here |
| 612 | * and if that worked, and the page is no longer mapped into |
| 613 | * process address space (page_count == 1) it can be freed. |
| 614 | * Otherwise, leave the page on the LRU so it is swappable. |
| 615 | */ |
| 616 | if (PagePrivate(page)) { |
| 617 | if (!try_to_release_page(page, sc->gfp_mask)) |
| 618 | goto activate_locked; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 619 | if (!mapping && page_count(page) == 1) { |
| 620 | unlock_page(page); |
| 621 | if (put_page_testzero(page)) |
| 622 | goto free_it; |
| 623 | else { |
| 624 | /* |
| 625 | * rare race with speculative reference. |
| 626 | * the speculative reference will free |
| 627 | * this page shortly, so we may |
| 628 | * increment nr_reclaimed here (and |
| 629 | * leave it off the LRU). |
| 630 | */ |
| 631 | nr_reclaimed++; |
| 632 | continue; |
| 633 | } |
| 634 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 635 | } |
| 636 | |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 637 | if (!mapping || !__remove_mapping(mapping, page)) |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 638 | goto keep_locked; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 639 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 640 | unlock_page(page); |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 641 | free_it: |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 642 | nr_reclaimed++; |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 643 | if (!pagevec_add(&freed_pvec, page)) { |
| 644 | __pagevec_free(&freed_pvec); |
| 645 | pagevec_reinit(&freed_pvec); |
| 646 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 647 | continue; |
| 648 | |
| 649 | activate_locked: |
| 650 | SetPageActive(page); |
| 651 | pgactivate++; |
| 652 | keep_locked: |
| 653 | unlock_page(page); |
| 654 | keep: |
| 655 | list_add(&page->lru, &ret_pages); |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 656 | VM_BUG_ON(PageLRU(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 657 | } |
| 658 | list_splice(&ret_pages, page_list); |
| 659 | if (pagevec_count(&freed_pvec)) |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 660 | __pagevec_free(&freed_pvec); |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 661 | count_vm_events(PGACTIVATE, pgactivate); |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 662 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 663 | } |
| 664 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 665 | /* LRU Isolation modes. */ |
| 666 | #define ISOLATE_INACTIVE 0 /* Isolate inactive pages. */ |
| 667 | #define ISOLATE_ACTIVE 1 /* Isolate active pages. */ |
| 668 | #define ISOLATE_BOTH 2 /* Isolate both active and inactive pages. */ |
| 669 | |
| 670 | /* |
| 671 | * Attempt to remove the specified page from its LRU. Only take this page |
| 672 | * if it is of the appropriate PageActive status. Pages which are being |
| 673 | * freed elsewhere are also ignored. |
| 674 | * |
| 675 | * page: page to consider |
| 676 | * mode: one of the LRU isolation modes defined above |
| 677 | * |
| 678 | * returns 0 on success, -ve errno on failure. |
| 679 | */ |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 680 | int __isolate_lru_page(struct page *page, int mode) |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 681 | { |
| 682 | int ret = -EINVAL; |
| 683 | |
| 684 | /* Only take pages on the LRU. */ |
| 685 | if (!PageLRU(page)) |
| 686 | return ret; |
| 687 | |
| 688 | /* |
| 689 | * When checking the active state, we need to be sure we are |
| 690 | * dealing with comparible boolean values. Take the logical not |
| 691 | * of each. |
| 692 | */ |
| 693 | if (mode != ISOLATE_BOTH && (!PageActive(page) != !mode)) |
| 694 | return ret; |
| 695 | |
| 696 | ret = -EBUSY; |
| 697 | if (likely(get_page_unless_zero(page))) { |
| 698 | /* |
| 699 | * Be careful not to clear PageLRU until after we're |
| 700 | * sure the page is not being freed elsewhere -- the |
| 701 | * page release code relies on it. |
| 702 | */ |
| 703 | ClearPageLRU(page); |
| 704 | ret = 0; |
| 705 | } |
| 706 | |
| 707 | return ret; |
| 708 | } |
| 709 | |
Christoph Lameter | 49d2e9c | 2006-01-08 01:00:48 -0800 | [diff] [blame] | 710 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 711 | * zone->lru_lock is heavily contended. Some of the functions that |
| 712 | * shrink the lists perform better by taking out a batch of pages |
| 713 | * and working on them outside the LRU lock. |
| 714 | * |
| 715 | * For pagecache intensive workloads, this function is the hottest |
| 716 | * spot in the kernel (apart from copy_*_user functions). |
| 717 | * |
| 718 | * Appropriate locks must be held before calling this function. |
| 719 | * |
| 720 | * @nr_to_scan: The number of pages to look through on the list. |
| 721 | * @src: The LRU list to pull pages off. |
| 722 | * @dst: The temp list to put pages on to. |
| 723 | * @scanned: The number of pages that were scanned. |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 724 | * @order: The caller's attempted allocation order |
| 725 | * @mode: One of the LRU isolation modes |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 726 | * |
| 727 | * returns how many pages were moved onto *@dst. |
| 728 | */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 729 | static unsigned long isolate_lru_pages(unsigned long nr_to_scan, |
| 730 | struct list_head *src, struct list_head *dst, |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 731 | unsigned long *scanned, int order, int mode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 732 | { |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 733 | unsigned long nr_taken = 0; |
Wu Fengguang | c9b02d9 | 2006-03-22 00:08:23 -0800 | [diff] [blame] | 734 | unsigned long scan; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 735 | |
Wu Fengguang | c9b02d9 | 2006-03-22 00:08:23 -0800 | [diff] [blame] | 736 | for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) { |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 737 | struct page *page; |
| 738 | unsigned long pfn; |
| 739 | unsigned long end_pfn; |
| 740 | unsigned long page_pfn; |
| 741 | int zone_id; |
| 742 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 743 | page = lru_to_page(src); |
| 744 | prefetchw_prev_lru_page(page, src, flags); |
| 745 | |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 746 | VM_BUG_ON(!PageLRU(page)); |
Nick Piggin | 8d438f9 | 2006-03-22 00:07:59 -0800 | [diff] [blame] | 747 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 748 | switch (__isolate_lru_page(page, mode)) { |
| 749 | case 0: |
| 750 | list_move(&page->lru, dst); |
Nick Piggin | 7c8ee9a | 2006-03-22 00:08:03 -0800 | [diff] [blame] | 751 | nr_taken++; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 752 | break; |
Nick Piggin | 46453a6 | 2006-03-22 00:07:58 -0800 | [diff] [blame] | 753 | |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 754 | case -EBUSY: |
| 755 | /* else it is being freed elsewhere */ |
| 756 | list_move(&page->lru, src); |
| 757 | continue; |
| 758 | |
| 759 | default: |
| 760 | BUG(); |
| 761 | } |
| 762 | |
| 763 | if (!order) |
| 764 | continue; |
| 765 | |
| 766 | /* |
| 767 | * Attempt to take all pages in the order aligned region |
| 768 | * surrounding the tag page. Only take those pages of |
| 769 | * the same active state as that tag page. We may safely |
| 770 | * round the target page pfn down to the requested order |
| 771 | * as the mem_map is guarenteed valid out to MAX_ORDER, |
| 772 | * where that page is in a different zone we will detect |
| 773 | * it from its zone id and abort this block scan. |
| 774 | */ |
| 775 | zone_id = page_zone_id(page); |
| 776 | page_pfn = page_to_pfn(page); |
| 777 | pfn = page_pfn & ~((1 << order) - 1); |
| 778 | end_pfn = pfn + (1 << order); |
| 779 | for (; pfn < end_pfn; pfn++) { |
| 780 | struct page *cursor_page; |
| 781 | |
| 782 | /* The target page is in the block, ignore it. */ |
| 783 | if (unlikely(pfn == page_pfn)) |
| 784 | continue; |
| 785 | |
| 786 | /* Avoid holes within the zone. */ |
| 787 | if (unlikely(!pfn_valid_within(pfn))) |
| 788 | break; |
| 789 | |
| 790 | cursor_page = pfn_to_page(pfn); |
| 791 | /* Check that we have not crossed a zone boundary. */ |
| 792 | if (unlikely(page_zone_id(cursor_page) != zone_id)) |
| 793 | continue; |
| 794 | switch (__isolate_lru_page(cursor_page, mode)) { |
| 795 | case 0: |
| 796 | list_move(&cursor_page->lru, dst); |
| 797 | nr_taken++; |
| 798 | scan++; |
| 799 | break; |
| 800 | |
| 801 | case -EBUSY: |
| 802 | /* else it is being freed elsewhere */ |
| 803 | list_move(&cursor_page->lru, src); |
| 804 | default: |
| 805 | break; |
| 806 | } |
| 807 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 808 | } |
| 809 | |
| 810 | *scanned = scan; |
| 811 | return nr_taken; |
| 812 | } |
| 813 | |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 814 | static unsigned long isolate_pages_global(unsigned long nr, |
| 815 | struct list_head *dst, |
| 816 | unsigned long *scanned, int order, |
| 817 | int mode, struct zone *z, |
| 818 | struct mem_cgroup *mem_cont, |
| 819 | int active) |
| 820 | { |
| 821 | if (active) |
| 822 | return isolate_lru_pages(nr, &z->active_list, dst, |
| 823 | scanned, order, mode); |
| 824 | else |
| 825 | return isolate_lru_pages(nr, &z->inactive_list, dst, |
| 826 | scanned, order, mode); |
| 827 | } |
| 828 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 829 | /* |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 830 | * clear_active_flags() is a helper for shrink_active_list(), clearing |
| 831 | * any active bits from the pages in the list. |
| 832 | */ |
| 833 | static unsigned long clear_active_flags(struct list_head *page_list) |
| 834 | { |
| 835 | int nr_active = 0; |
| 836 | struct page *page; |
| 837 | |
| 838 | list_for_each_entry(page, page_list, lru) |
| 839 | if (PageActive(page)) { |
| 840 | ClearPageActive(page); |
| 841 | nr_active++; |
| 842 | } |
| 843 | |
| 844 | return nr_active; |
| 845 | } |
| 846 | |
| 847 | /* |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 848 | * shrink_inactive_list() is a helper for shrink_zone(). It returns the number |
| 849 | * of reclaimed pages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 850 | */ |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 851 | static unsigned long shrink_inactive_list(unsigned long max_scan, |
| 852 | struct zone *zone, struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 853 | { |
| 854 | LIST_HEAD(page_list); |
| 855 | struct pagevec pvec; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 856 | unsigned long nr_scanned = 0; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 857 | unsigned long nr_reclaimed = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 858 | |
| 859 | pagevec_init(&pvec, 1); |
| 860 | |
| 861 | lru_add_drain(); |
| 862 | spin_lock_irq(&zone->lru_lock); |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 863 | do { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 864 | struct page *page; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 865 | unsigned long nr_taken; |
| 866 | unsigned long nr_scan; |
| 867 | unsigned long nr_freed; |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 868 | unsigned long nr_active; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 869 | |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 870 | nr_taken = sc->isolate_pages(sc->swap_cluster_max, |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 871 | &page_list, &nr_scan, sc->order, |
| 872 | (sc->order > PAGE_ALLOC_COSTLY_ORDER)? |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 873 | ISOLATE_BOTH : ISOLATE_INACTIVE, |
| 874 | zone, sc->mem_cgroup, 0); |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 875 | nr_active = clear_active_flags(&page_list); |
Andy Whitcroft | e9187bd | 2007-08-22 14:01:25 -0700 | [diff] [blame] | 876 | __count_vm_events(PGDEACTIVATE, nr_active); |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 877 | |
| 878 | __mod_zone_page_state(zone, NR_ACTIVE, -nr_active); |
| 879 | __mod_zone_page_state(zone, NR_INACTIVE, |
| 880 | -(nr_taken - nr_active)); |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 881 | if (scan_global_lru(sc)) |
| 882 | zone->pages_scanned += nr_scan; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 883 | spin_unlock_irq(&zone->lru_lock); |
| 884 | |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 885 | nr_scanned += nr_scan; |
Andy Whitcroft | c661b07 | 2007-08-22 14:01:26 -0700 | [diff] [blame] | 886 | nr_freed = shrink_page_list(&page_list, sc, PAGEOUT_IO_ASYNC); |
| 887 | |
| 888 | /* |
| 889 | * If we are direct reclaiming for contiguous pages and we do |
| 890 | * not reclaim everything in the list, try again and wait |
| 891 | * for IO to complete. This will stall high-order allocations |
| 892 | * but that should be acceptable to the caller |
| 893 | */ |
| 894 | if (nr_freed < nr_taken && !current_is_kswapd() && |
| 895 | sc->order > PAGE_ALLOC_COSTLY_ORDER) { |
| 896 | congestion_wait(WRITE, HZ/10); |
| 897 | |
| 898 | /* |
| 899 | * The attempt at page out may have made some |
| 900 | * of the pages active, mark them inactive again. |
| 901 | */ |
| 902 | nr_active = clear_active_flags(&page_list); |
| 903 | count_vm_events(PGDEACTIVATE, nr_active); |
| 904 | |
| 905 | nr_freed += shrink_page_list(&page_list, sc, |
| 906 | PAGEOUT_IO_SYNC); |
| 907 | } |
| 908 | |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 909 | nr_reclaimed += nr_freed; |
Nick Piggin | a74609f | 2006-01-06 00:11:20 -0800 | [diff] [blame] | 910 | local_irq_disable(); |
| 911 | if (current_is_kswapd()) { |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 912 | __count_zone_vm_events(PGSCAN_KSWAPD, zone, nr_scan); |
| 913 | __count_vm_events(KSWAPD_STEAL, nr_freed); |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 914 | } else if (scan_global_lru(sc)) |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 915 | __count_zone_vm_events(PGSCAN_DIRECT, zone, nr_scan); |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 916 | |
Shantanu Goel | 918d3f9 | 2006-12-29 16:48:59 -0800 | [diff] [blame] | 917 | __count_zone_vm_events(PGSTEAL, zone, nr_freed); |
Nick Piggin | a74609f | 2006-01-06 00:11:20 -0800 | [diff] [blame] | 918 | |
Wu Fengguang | fb8d14e | 2006-03-22 00:08:28 -0800 | [diff] [blame] | 919 | if (nr_taken == 0) |
| 920 | goto done; |
| 921 | |
Nick Piggin | a74609f | 2006-01-06 00:11:20 -0800 | [diff] [blame] | 922 | spin_lock(&zone->lru_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 923 | /* |
| 924 | * Put back any unfreeable pages. |
| 925 | */ |
| 926 | while (!list_empty(&page_list)) { |
| 927 | page = lru_to_page(&page_list); |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 928 | VM_BUG_ON(PageLRU(page)); |
Nick Piggin | 8d438f9 | 2006-03-22 00:07:59 -0800 | [diff] [blame] | 929 | SetPageLRU(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 930 | list_del(&page->lru); |
| 931 | if (PageActive(page)) |
| 932 | add_page_to_active_list(zone, page); |
| 933 | else |
| 934 | add_page_to_inactive_list(zone, page); |
| 935 | if (!pagevec_add(&pvec, page)) { |
| 936 | spin_unlock_irq(&zone->lru_lock); |
| 937 | __pagevec_release(&pvec); |
| 938 | spin_lock_irq(&zone->lru_lock); |
| 939 | } |
| 940 | } |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 941 | } while (nr_scanned < max_scan); |
Wu Fengguang | fb8d14e | 2006-03-22 00:08:28 -0800 | [diff] [blame] | 942 | spin_unlock(&zone->lru_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 943 | done: |
Wu Fengguang | fb8d14e | 2006-03-22 00:08:28 -0800 | [diff] [blame] | 944 | local_irq_enable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 945 | pagevec_release(&pvec); |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 946 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 947 | } |
| 948 | |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 949 | /* |
| 950 | * We are about to scan this zone at a certain priority level. If that priority |
| 951 | * level is smaller (ie: more urgent) than the previous priority, then note |
| 952 | * that priority level within the zone. This is done so that when the next |
| 953 | * process comes in to scan this zone, it will immediately start out at this |
| 954 | * priority level rather than having to build up its own scanning priority. |
| 955 | * Here, this priority affects only the reclaim-mapped threshold. |
| 956 | */ |
| 957 | static inline void note_zone_scanning_priority(struct zone *zone, int priority) |
| 958 | { |
| 959 | if (priority < zone->prev_priority) |
| 960 | zone->prev_priority = priority; |
| 961 | } |
| 962 | |
Nick Piggin | 4ff1ffb | 2006-09-25 23:31:28 -0700 | [diff] [blame] | 963 | static inline int zone_is_near_oom(struct zone *zone) |
| 964 | { |
Christoph Lameter | c878538 | 2007-02-10 01:43:01 -0800 | [diff] [blame] | 965 | return zone->pages_scanned >= (zone_page_state(zone, NR_ACTIVE) |
| 966 | + zone_page_state(zone, NR_INACTIVE))*3; |
Nick Piggin | 4ff1ffb | 2006-09-25 23:31:28 -0700 | [diff] [blame] | 967 | } |
| 968 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 969 | /* |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 970 | * Determine we should try to reclaim mapped pages. |
| 971 | * This is called only when sc->mem_cgroup is NULL. |
| 972 | */ |
| 973 | static int calc_reclaim_mapped(struct scan_control *sc, struct zone *zone, |
| 974 | int priority) |
| 975 | { |
| 976 | long mapped_ratio; |
| 977 | long distress; |
| 978 | long swap_tendency; |
| 979 | long imbalance; |
| 980 | int reclaim_mapped = 0; |
| 981 | int prev_priority; |
| 982 | |
| 983 | if (scan_global_lru(sc) && zone_is_near_oom(zone)) |
| 984 | return 1; |
| 985 | /* |
| 986 | * `distress' is a measure of how much trouble we're having |
| 987 | * reclaiming pages. 0 -> no problems. 100 -> great trouble. |
| 988 | */ |
| 989 | if (scan_global_lru(sc)) |
| 990 | prev_priority = zone->prev_priority; |
| 991 | else |
| 992 | prev_priority = mem_cgroup_get_reclaim_priority(sc->mem_cgroup); |
| 993 | |
| 994 | distress = 100 >> min(prev_priority, priority); |
| 995 | |
| 996 | /* |
| 997 | * The point of this algorithm is to decide when to start |
| 998 | * reclaiming mapped memory instead of just pagecache. Work out |
| 999 | * how much memory |
| 1000 | * is mapped. |
| 1001 | */ |
| 1002 | if (scan_global_lru(sc)) |
| 1003 | mapped_ratio = ((global_page_state(NR_FILE_MAPPED) + |
| 1004 | global_page_state(NR_ANON_PAGES)) * 100) / |
| 1005 | vm_total_pages; |
| 1006 | else |
| 1007 | mapped_ratio = mem_cgroup_calc_mapped_ratio(sc->mem_cgroup); |
| 1008 | |
| 1009 | /* |
| 1010 | * Now decide how much we really want to unmap some pages. The |
| 1011 | * mapped ratio is downgraded - just because there's a lot of |
| 1012 | * mapped memory doesn't necessarily mean that page reclaim |
| 1013 | * isn't succeeding. |
| 1014 | * |
| 1015 | * The distress ratio is important - we don't want to start |
| 1016 | * going oom. |
| 1017 | * |
| 1018 | * A 100% value of vm_swappiness overrides this algorithm |
| 1019 | * altogether. |
| 1020 | */ |
| 1021 | swap_tendency = mapped_ratio / 2 + distress + sc->swappiness; |
| 1022 | |
| 1023 | /* |
| 1024 | * If there's huge imbalance between active and inactive |
| 1025 | * (think active 100 times larger than inactive) we should |
| 1026 | * become more permissive, or the system will take too much |
| 1027 | * cpu before it start swapping during memory pressure. |
| 1028 | * Distress is about avoiding early-oom, this is about |
| 1029 | * making swappiness graceful despite setting it to low |
| 1030 | * values. |
| 1031 | * |
| 1032 | * Avoid div by zero with nr_inactive+1, and max resulting |
| 1033 | * value is vm_total_pages. |
| 1034 | */ |
| 1035 | if (scan_global_lru(sc)) { |
| 1036 | imbalance = zone_page_state(zone, NR_ACTIVE); |
| 1037 | imbalance /= zone_page_state(zone, NR_INACTIVE) + 1; |
| 1038 | } else |
| 1039 | imbalance = mem_cgroup_reclaim_imbalance(sc->mem_cgroup); |
| 1040 | |
| 1041 | /* |
| 1042 | * Reduce the effect of imbalance if swappiness is low, |
| 1043 | * this means for a swappiness very low, the imbalance |
| 1044 | * must be much higher than 100 for this logic to make |
| 1045 | * the difference. |
| 1046 | * |
| 1047 | * Max temporary value is vm_total_pages*100. |
| 1048 | */ |
| 1049 | imbalance *= (vm_swappiness + 1); |
| 1050 | imbalance /= 100; |
| 1051 | |
| 1052 | /* |
| 1053 | * If not much of the ram is mapped, makes the imbalance |
| 1054 | * less relevant, it's high priority we refill the inactive |
| 1055 | * list with mapped pages only in presence of high ratio of |
| 1056 | * mapped pages. |
| 1057 | * |
| 1058 | * Max temporary value is vm_total_pages*100. |
| 1059 | */ |
| 1060 | imbalance *= mapped_ratio; |
| 1061 | imbalance /= 100; |
| 1062 | |
| 1063 | /* apply imbalance feedback to swap_tendency */ |
| 1064 | swap_tendency += imbalance; |
| 1065 | |
| 1066 | /* |
| 1067 | * Now use this metric to decide whether to start moving mapped |
| 1068 | * memory onto the inactive list. |
| 1069 | */ |
| 1070 | if (swap_tendency >= 100) |
| 1071 | reclaim_mapped = 1; |
| 1072 | |
| 1073 | return reclaim_mapped; |
| 1074 | } |
| 1075 | |
| 1076 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1077 | * This moves pages from the active list to the inactive list. |
| 1078 | * |
| 1079 | * We move them the other way if the page is referenced by one or more |
| 1080 | * processes, from rmap. |
| 1081 | * |
| 1082 | * If the pages are mostly unmapped, the processing is fast and it is |
| 1083 | * appropriate to hold zone->lru_lock across the whole operation. But if |
| 1084 | * the pages are mapped, the processing is slow (page_referenced()) so we |
| 1085 | * should drop zone->lru_lock around each page. It's impossible to balance |
| 1086 | * this, so instead we remove the pages from the LRU while processing them. |
| 1087 | * It is safe to rely on PG_active against the non-LRU pages in here because |
| 1088 | * nobody will play with that bit on a non-LRU page. |
| 1089 | * |
| 1090 | * The downside is that we have to touch page->_count against each page. |
| 1091 | * But we had to alter page->flags anyway. |
| 1092 | */ |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1093 | |
| 1094 | |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 1095 | static void shrink_active_list(unsigned long nr_pages, struct zone *zone, |
Martin Bligh | bbdb396 | 2006-10-28 10:38:25 -0700 | [diff] [blame] | 1096 | struct scan_control *sc, int priority) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1097 | { |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1098 | unsigned long pgmoved; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1099 | int pgdeactivate = 0; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1100 | unsigned long pgscanned; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1101 | LIST_HEAD(l_hold); /* The pages which were snipped off */ |
| 1102 | LIST_HEAD(l_inactive); /* Pages to go onto the inactive_list */ |
| 1103 | LIST_HEAD(l_active); /* Pages to go onto the active_list */ |
| 1104 | struct page *page; |
| 1105 | struct pagevec pvec; |
| 1106 | int reclaim_mapped = 0; |
Christoph Lameter | 2903fb1 | 2006-02-11 17:55:55 -0800 | [diff] [blame] | 1107 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1108 | if (sc->may_swap) |
| 1109 | reclaim_mapped = calc_reclaim_mapped(sc, zone, priority); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1110 | |
| 1111 | lru_add_drain(); |
| 1112 | spin_lock_irq(&zone->lru_lock); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1113 | pgmoved = sc->isolate_pages(nr_pages, &l_hold, &pgscanned, sc->order, |
| 1114 | ISOLATE_ACTIVE, zone, |
| 1115 | sc->mem_cgroup, 1); |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1116 | /* |
| 1117 | * zone->pages_scanned is used for detect zone's oom |
| 1118 | * mem_cgroup remembers nr_scan by itself. |
| 1119 | */ |
| 1120 | if (scan_global_lru(sc)) |
| 1121 | zone->pages_scanned += pgscanned; |
| 1122 | |
Christoph Lameter | c878538 | 2007-02-10 01:43:01 -0800 | [diff] [blame] | 1123 | __mod_zone_page_state(zone, NR_ACTIVE, -pgmoved); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1124 | spin_unlock_irq(&zone->lru_lock); |
| 1125 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1126 | while (!list_empty(&l_hold)) { |
| 1127 | cond_resched(); |
| 1128 | page = lru_to_page(&l_hold); |
| 1129 | list_del(&page->lru); |
| 1130 | if (page_mapped(page)) { |
| 1131 | if (!reclaim_mapped || |
| 1132 | (total_swap_pages == 0 && PageAnon(page)) || |
Balbir Singh | bed7161 | 2008-02-07 00:14:01 -0800 | [diff] [blame] | 1133 | page_referenced(page, 0, sc->mem_cgroup)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1134 | list_add(&page->lru, &l_active); |
| 1135 | continue; |
| 1136 | } |
| 1137 | } |
| 1138 | list_add(&page->lru, &l_inactive); |
| 1139 | } |
| 1140 | |
| 1141 | pagevec_init(&pvec, 1); |
| 1142 | pgmoved = 0; |
| 1143 | spin_lock_irq(&zone->lru_lock); |
| 1144 | while (!list_empty(&l_inactive)) { |
| 1145 | page = lru_to_page(&l_inactive); |
| 1146 | prefetchw_prev_lru_page(page, &l_inactive, flags); |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 1147 | VM_BUG_ON(PageLRU(page)); |
Nick Piggin | 8d438f9 | 2006-03-22 00:07:59 -0800 | [diff] [blame] | 1148 | SetPageLRU(page); |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 1149 | VM_BUG_ON(!PageActive(page)); |
Nick Piggin | 4c84cac | 2006-03-22 00:08:00 -0800 | [diff] [blame] | 1150 | ClearPageActive(page); |
| 1151 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1152 | list_move(&page->lru, &zone->inactive_list); |
Hugh Dickins | 427d541 | 2008-03-04 14:29:03 -0800 | [diff] [blame] | 1153 | mem_cgroup_move_lists(page, false); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1154 | pgmoved++; |
| 1155 | if (!pagevec_add(&pvec, page)) { |
Christoph Lameter | c878538 | 2007-02-10 01:43:01 -0800 | [diff] [blame] | 1156 | __mod_zone_page_state(zone, NR_INACTIVE, pgmoved); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1157 | spin_unlock_irq(&zone->lru_lock); |
| 1158 | pgdeactivate += pgmoved; |
| 1159 | pgmoved = 0; |
| 1160 | if (buffer_heads_over_limit) |
| 1161 | pagevec_strip(&pvec); |
| 1162 | __pagevec_release(&pvec); |
| 1163 | spin_lock_irq(&zone->lru_lock); |
| 1164 | } |
| 1165 | } |
Christoph Lameter | c878538 | 2007-02-10 01:43:01 -0800 | [diff] [blame] | 1166 | __mod_zone_page_state(zone, NR_INACTIVE, pgmoved); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1167 | pgdeactivate += pgmoved; |
| 1168 | if (buffer_heads_over_limit) { |
| 1169 | spin_unlock_irq(&zone->lru_lock); |
| 1170 | pagevec_strip(&pvec); |
| 1171 | spin_lock_irq(&zone->lru_lock); |
| 1172 | } |
| 1173 | |
| 1174 | pgmoved = 0; |
| 1175 | while (!list_empty(&l_active)) { |
| 1176 | page = lru_to_page(&l_active); |
| 1177 | prefetchw_prev_lru_page(page, &l_active, flags); |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 1178 | VM_BUG_ON(PageLRU(page)); |
Nick Piggin | 8d438f9 | 2006-03-22 00:07:59 -0800 | [diff] [blame] | 1179 | SetPageLRU(page); |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 1180 | VM_BUG_ON(!PageActive(page)); |
Hugh Dickins | 427d541 | 2008-03-04 14:29:03 -0800 | [diff] [blame] | 1181 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1182 | list_move(&page->lru, &zone->active_list); |
Hugh Dickins | 427d541 | 2008-03-04 14:29:03 -0800 | [diff] [blame] | 1183 | mem_cgroup_move_lists(page, true); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1184 | pgmoved++; |
| 1185 | if (!pagevec_add(&pvec, page)) { |
Christoph Lameter | c878538 | 2007-02-10 01:43:01 -0800 | [diff] [blame] | 1186 | __mod_zone_page_state(zone, NR_ACTIVE, pgmoved); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1187 | pgmoved = 0; |
| 1188 | spin_unlock_irq(&zone->lru_lock); |
| 1189 | __pagevec_release(&pvec); |
| 1190 | spin_lock_irq(&zone->lru_lock); |
| 1191 | } |
| 1192 | } |
Christoph Lameter | c878538 | 2007-02-10 01:43:01 -0800 | [diff] [blame] | 1193 | __mod_zone_page_state(zone, NR_ACTIVE, pgmoved); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1194 | |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1195 | __count_zone_vm_events(PGREFILL, zone, pgscanned); |
| 1196 | __count_vm_events(PGDEACTIVATE, pgdeactivate); |
| 1197 | spin_unlock_irq(&zone->lru_lock); |
Nick Piggin | a74609f | 2006-01-06 00:11:20 -0800 | [diff] [blame] | 1198 | |
| 1199 | pagevec_release(&pvec); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1200 | } |
| 1201 | |
| 1202 | /* |
| 1203 | * This is a basic per-zone page freer. Used by both kswapd and direct reclaim. |
| 1204 | */ |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1205 | static unsigned long shrink_zone(int priority, struct zone *zone, |
| 1206 | struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1207 | { |
| 1208 | unsigned long nr_active; |
| 1209 | unsigned long nr_inactive; |
Christoph Lameter | 8695949 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 1210 | unsigned long nr_to_scan; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1211 | unsigned long nr_reclaimed = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1212 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1213 | if (scan_global_lru(sc)) { |
| 1214 | /* |
| 1215 | * Add one to nr_to_scan just to make sure that the kernel |
| 1216 | * will slowly sift through the active list. |
| 1217 | */ |
| 1218 | zone->nr_scan_active += |
| 1219 | (zone_page_state(zone, NR_ACTIVE) >> priority) + 1; |
| 1220 | nr_active = zone->nr_scan_active; |
| 1221 | zone->nr_scan_inactive += |
| 1222 | (zone_page_state(zone, NR_INACTIVE) >> priority) + 1; |
| 1223 | nr_inactive = zone->nr_scan_inactive; |
| 1224 | if (nr_inactive >= sc->swap_cluster_max) |
| 1225 | zone->nr_scan_inactive = 0; |
| 1226 | else |
| 1227 | nr_inactive = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1228 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1229 | if (nr_active >= sc->swap_cluster_max) |
| 1230 | zone->nr_scan_active = 0; |
| 1231 | else |
| 1232 | nr_active = 0; |
| 1233 | } else { |
| 1234 | /* |
| 1235 | * This reclaim occurs not because zone memory shortage but |
| 1236 | * because memory controller hits its limit. |
| 1237 | * Then, don't modify zone reclaim related data. |
| 1238 | */ |
| 1239 | nr_active = mem_cgroup_calc_reclaim_active(sc->mem_cgroup, |
| 1240 | zone, priority); |
| 1241 | |
| 1242 | nr_inactive = mem_cgroup_calc_reclaim_inactive(sc->mem_cgroup, |
| 1243 | zone, priority); |
| 1244 | } |
| 1245 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1246 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1247 | while (nr_active || nr_inactive) { |
| 1248 | if (nr_active) { |
Christoph Lameter | 8695949 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 1249 | nr_to_scan = min(nr_active, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1250 | (unsigned long)sc->swap_cluster_max); |
Christoph Lameter | 8695949 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 1251 | nr_active -= nr_to_scan; |
Martin Bligh | bbdb396 | 2006-10-28 10:38:25 -0700 | [diff] [blame] | 1252 | shrink_active_list(nr_to_scan, zone, sc, priority); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1253 | } |
| 1254 | |
| 1255 | if (nr_inactive) { |
Christoph Lameter | 8695949 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 1256 | nr_to_scan = min(nr_inactive, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1257 | (unsigned long)sc->swap_cluster_max); |
Christoph Lameter | 8695949 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 1258 | nr_inactive -= nr_to_scan; |
Andrew Morton | 1742f19 | 2006-03-22 00:08:21 -0800 | [diff] [blame] | 1259 | nr_reclaimed += shrink_inactive_list(nr_to_scan, zone, |
| 1260 | sc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1261 | } |
| 1262 | } |
| 1263 | |
Andrew Morton | 232ea4d | 2007-02-28 20:13:21 -0800 | [diff] [blame] | 1264 | throttle_vm_writeout(sc->gfp_mask); |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1265 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1266 | } |
| 1267 | |
| 1268 | /* |
| 1269 | * This is the direct reclaim path, for page-allocating processes. We only |
| 1270 | * try to reclaim pages from zones which will satisfy the caller's allocation |
| 1271 | * request. |
| 1272 | * |
| 1273 | * We reclaim from a zone even if that zone is over pages_high. Because: |
| 1274 | * a) The caller may be trying to free *extra* pages to satisfy a higher-order |
| 1275 | * allocation or |
| 1276 | * b) The zones may be over pages_high but they must go *over* pages_high to |
| 1277 | * satisfy the `incremental min' zone defense algorithm. |
| 1278 | * |
| 1279 | * Returns the number of reclaimed pages. |
| 1280 | * |
| 1281 | * If a zone is deemed to be full of pinned pages then just give it a light |
| 1282 | * scan then give up on it. |
| 1283 | */ |
Mel Gorman | dac1d27 | 2008-04-28 02:12:12 -0700 | [diff] [blame] | 1284 | static unsigned long shrink_zones(int priority, struct zonelist *zonelist, |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1285 | struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1286 | { |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1287 | enum zone_type high_zoneidx = gfp_zone(sc->gfp_mask); |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1288 | unsigned long nr_reclaimed = 0; |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1289 | struct zoneref *z; |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1290 | struct zone *zone; |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1291 | |
Nick Piggin | 408d854 | 2006-09-25 23:31:27 -0700 | [diff] [blame] | 1292 | sc->all_unreclaimable = 1; |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1293 | for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { |
Con Kolivas | f3fe651 | 2006-01-06 00:11:15 -0800 | [diff] [blame] | 1294 | if (!populated_zone(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1295 | continue; |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1296 | /* |
| 1297 | * Take care memory controller reclaiming has small influence |
| 1298 | * to global LRU. |
| 1299 | */ |
| 1300 | if (scan_global_lru(sc)) { |
| 1301 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
| 1302 | continue; |
| 1303 | note_zone_scanning_priority(zone, priority); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1304 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1305 | if (zone_is_all_unreclaimable(zone) && |
| 1306 | priority != DEF_PRIORITY) |
| 1307 | continue; /* Let kswapd poll it */ |
| 1308 | sc->all_unreclaimable = 0; |
| 1309 | } else { |
| 1310 | /* |
| 1311 | * Ignore cpuset limitation here. We just want to reduce |
| 1312 | * # of used pages by us regardless of memory shortage. |
| 1313 | */ |
| 1314 | sc->all_unreclaimable = 0; |
| 1315 | mem_cgroup_note_reclaim_priority(sc->mem_cgroup, |
| 1316 | priority); |
| 1317 | } |
Nick Piggin | 408d854 | 2006-09-25 23:31:27 -0700 | [diff] [blame] | 1318 | |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1319 | nr_reclaimed += shrink_zone(priority, zone, sc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1320 | } |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1321 | |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1322 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1323 | } |
| 1324 | |
| 1325 | /* |
| 1326 | * This is the main entry point to direct page reclaim. |
| 1327 | * |
| 1328 | * If a full scan of the inactive list fails to free enough memory then we |
| 1329 | * are "out of memory" and something needs to be killed. |
| 1330 | * |
| 1331 | * If the caller is !__GFP_FS then the probability of a failure is reasonably |
| 1332 | * high - the zone may be full of dirty or under-writeback pages, which this |
| 1333 | * caller can't do much about. We kick pdflush and take explicit naps in the |
| 1334 | * hope that some of these pages can be written. But if the allocating task |
| 1335 | * holds filesystem locks which prevent writeout this might not work, and the |
| 1336 | * allocation attempt will fail. |
Nishanth Aravamudan | a41f24e | 2008-04-29 00:58:25 -0700 | [diff] [blame] | 1337 | * |
| 1338 | * returns: 0, if no pages reclaimed |
| 1339 | * else, the number of pages reclaimed |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1340 | */ |
Mel Gorman | dac1d27 | 2008-04-28 02:12:12 -0700 | [diff] [blame] | 1341 | static unsigned long do_try_to_free_pages(struct zonelist *zonelist, |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1342 | struct scan_control *sc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1343 | { |
| 1344 | int priority; |
kosaki.motohiro@jp.fujitsu.com | c700be3 | 2008-06-12 15:21:27 -0700 | [diff] [blame] | 1345 | unsigned long ret = 0; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1346 | unsigned long total_scanned = 0; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1347 | unsigned long nr_reclaimed = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1348 | struct reclaim_state *reclaim_state = current->reclaim_state; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1349 | unsigned long lru_pages = 0; |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1350 | struct zoneref *z; |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1351 | struct zone *zone; |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1352 | enum zone_type high_zoneidx = gfp_zone(sc->gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1353 | |
Keika Kobayashi | 873b477 | 2008-07-25 01:48:52 -0700 | [diff] [blame] | 1354 | delayacct_freepages_start(); |
| 1355 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1356 | if (scan_global_lru(sc)) |
| 1357 | count_vm_event(ALLOCSTALL); |
| 1358 | /* |
| 1359 | * mem_cgroup will not do shrink_slab. |
| 1360 | */ |
| 1361 | if (scan_global_lru(sc)) { |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1362 | for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1363 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1364 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
| 1365 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1366 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1367 | lru_pages += zone_page_state(zone, NR_ACTIVE) |
| 1368 | + zone_page_state(zone, NR_INACTIVE); |
| 1369 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1370 | } |
| 1371 | |
| 1372 | for (priority = DEF_PRIORITY; priority >= 0; priority--) { |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1373 | sc->nr_scanned = 0; |
Rik van Riel | f7b7fd8 | 2005-11-28 13:44:07 -0800 | [diff] [blame] | 1374 | if (!priority) |
| 1375 | disable_swap_token(); |
Mel Gorman | dac1d27 | 2008-04-28 02:12:12 -0700 | [diff] [blame] | 1376 | nr_reclaimed += shrink_zones(priority, zonelist, sc); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1377 | /* |
| 1378 | * Don't shrink slabs when reclaiming memory from |
| 1379 | * over limit cgroups |
| 1380 | */ |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 1381 | if (scan_global_lru(sc)) { |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1382 | shrink_slab(sc->nr_scanned, sc->gfp_mask, lru_pages); |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 1383 | if (reclaim_state) { |
| 1384 | nr_reclaimed += reclaim_state->reclaimed_slab; |
| 1385 | reclaim_state->reclaimed_slab = 0; |
| 1386 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1387 | } |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1388 | total_scanned += sc->nr_scanned; |
| 1389 | if (nr_reclaimed >= sc->swap_cluster_max) { |
Nishanth Aravamudan | a41f24e | 2008-04-29 00:58:25 -0700 | [diff] [blame] | 1390 | ret = nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1391 | goto out; |
| 1392 | } |
| 1393 | |
| 1394 | /* |
| 1395 | * Try to write back as many pages as we just scanned. This |
| 1396 | * tends to cause slow streaming writers to write data to the |
| 1397 | * disk smoothly, at the dirtying rate, which is nice. But |
| 1398 | * that's undesirable in laptop mode, where we *want* lumpy |
| 1399 | * writeout. So in laptop mode, write out the whole world. |
| 1400 | */ |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1401 | if (total_scanned > sc->swap_cluster_max + |
| 1402 | sc->swap_cluster_max / 2) { |
Pekka J Enberg | 687a21c | 2005-06-28 20:44:55 -0700 | [diff] [blame] | 1403 | wakeup_pdflush(laptop_mode ? 0 : total_scanned); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1404 | sc->may_writepage = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1405 | } |
| 1406 | |
| 1407 | /* Take a nap, wait for some writeback to complete */ |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 1408 | if (sc->nr_scanned && priority < DEF_PRIORITY - 2) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 1409 | congestion_wait(WRITE, HZ/10); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1410 | } |
Fernando Luis Vazquez Cao | 87547ee | 2008-07-29 22:33:42 -0700 | [diff] [blame^] | 1411 | /* top priority shrink_zones still had more to do? don't OOM, then */ |
KAMEZAWA Hiroyuki | 91a4547 | 2008-02-07 00:14:29 -0800 | [diff] [blame] | 1412 | if (!sc->all_unreclaimable && scan_global_lru(sc)) |
Nishanth Aravamudan | a41f24e | 2008-04-29 00:58:25 -0700 | [diff] [blame] | 1413 | ret = nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1414 | out: |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1415 | /* |
| 1416 | * Now that we've scanned all the zones at this priority level, note |
| 1417 | * that level within the zone so that the next thread which performs |
| 1418 | * scanning of this zone will immediately start out at this priority |
| 1419 | * level. This affects only the decision whether or not to bring |
| 1420 | * mapped pages onto the inactive list. |
| 1421 | */ |
| 1422 | if (priority < 0) |
| 1423 | priority = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1424 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1425 | if (scan_global_lru(sc)) { |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 1426 | for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1427 | |
KAMEZAWA Hiroyuki | 1cfb419 | 2008-02-07 00:14:37 -0800 | [diff] [blame] | 1428 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
| 1429 | continue; |
| 1430 | |
| 1431 | zone->prev_priority = priority; |
| 1432 | } |
| 1433 | } else |
| 1434 | mem_cgroup_record_reclaim_priority(sc->mem_cgroup, priority); |
| 1435 | |
Keika Kobayashi | 873b477 | 2008-07-25 01:48:52 -0700 | [diff] [blame] | 1436 | delayacct_freepages_end(); |
| 1437 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1438 | return ret; |
| 1439 | } |
| 1440 | |
Mel Gorman | dac1d27 | 2008-04-28 02:12:12 -0700 | [diff] [blame] | 1441 | unsigned long try_to_free_pages(struct zonelist *zonelist, int order, |
| 1442 | gfp_t gfp_mask) |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1443 | { |
| 1444 | struct scan_control sc = { |
| 1445 | .gfp_mask = gfp_mask, |
| 1446 | .may_writepage = !laptop_mode, |
| 1447 | .swap_cluster_max = SWAP_CLUSTER_MAX, |
| 1448 | .may_swap = 1, |
| 1449 | .swappiness = vm_swappiness, |
| 1450 | .order = order, |
| 1451 | .mem_cgroup = NULL, |
| 1452 | .isolate_pages = isolate_pages_global, |
| 1453 | }; |
| 1454 | |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1455 | return do_try_to_free_pages(zonelist, &sc); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1456 | } |
| 1457 | |
Balbir Singh | 00f0b82 | 2008-03-04 14:28:39 -0800 | [diff] [blame] | 1458 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1459 | |
Balbir Singh | e1a1cd5 | 2008-02-07 00:14:02 -0800 | [diff] [blame] | 1460 | unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont, |
| 1461 | gfp_t gfp_mask) |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1462 | { |
| 1463 | struct scan_control sc = { |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1464 | .may_writepage = !laptop_mode, |
| 1465 | .may_swap = 1, |
| 1466 | .swap_cluster_max = SWAP_CLUSTER_MAX, |
| 1467 | .swappiness = vm_swappiness, |
| 1468 | .order = 0, |
| 1469 | .mem_cgroup = mem_cont, |
| 1470 | .isolate_pages = mem_cgroup_isolate_pages, |
| 1471 | }; |
Mel Gorman | dac1d27 | 2008-04-28 02:12:12 -0700 | [diff] [blame] | 1472 | struct zonelist *zonelist; |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1473 | |
Mel Gorman | dd1a239 | 2008-04-28 02:12:17 -0700 | [diff] [blame] | 1474 | sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) | |
| 1475 | (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK); |
| 1476 | zonelist = NODE_DATA(numa_node_id())->node_zonelists; |
| 1477 | return do_try_to_free_pages(zonelist, &sc); |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1478 | } |
| 1479 | #endif |
| 1480 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1481 | /* |
| 1482 | * For kswapd, balance_pgdat() will work across all this node's zones until |
| 1483 | * they are all at pages_high. |
| 1484 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1485 | * Returns the number of pages which were actually freed. |
| 1486 | * |
| 1487 | * There is special handling here for zones which are full of pinned pages. |
| 1488 | * This can happen if the pages are all mlocked, or if they are all used by |
| 1489 | * device drivers (say, ZONE_DMA). Or if they are all in use by hugetlb. |
| 1490 | * What we do is to detect the case where all pages in the zone have been |
| 1491 | * scanned twice and there has been zero successful reclaim. Mark the zone as |
| 1492 | * dead and from now on, only perform a short scan. Basically we're polling |
| 1493 | * the zone for when the problem goes away. |
| 1494 | * |
| 1495 | * kswapd scans the zones in the highmem->normal->dma direction. It skips |
| 1496 | * zones which have free_pages > pages_high, but once a zone is found to have |
| 1497 | * free_pages <= pages_high, we scan that zone and the lower zones regardless |
| 1498 | * of the number of free pages in the lower zones. This interoperates with |
| 1499 | * the page allocator fallback scheme to ensure that aging of pages is balanced |
| 1500 | * across the zones. |
| 1501 | */ |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1502 | static unsigned long balance_pgdat(pg_data_t *pgdat, int order) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1503 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1504 | int all_zones_ok; |
| 1505 | int priority; |
| 1506 | int i; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1507 | unsigned long total_scanned; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1508 | unsigned long nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1509 | struct reclaim_state *reclaim_state = current->reclaim_state; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 1510 | struct scan_control sc = { |
| 1511 | .gfp_mask = GFP_KERNEL, |
| 1512 | .may_swap = 1, |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1513 | .swap_cluster_max = SWAP_CLUSTER_MAX, |
| 1514 | .swappiness = vm_swappiness, |
Andy Whitcroft | 5ad333e | 2007-07-17 04:03:16 -0700 | [diff] [blame] | 1515 | .order = order, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1516 | .mem_cgroup = NULL, |
| 1517 | .isolate_pages = isolate_pages_global, |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 1518 | }; |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1519 | /* |
| 1520 | * temp_priority is used to remember the scanning priority at which |
| 1521 | * this zone was successfully refilled to free_pages == pages_high. |
| 1522 | */ |
| 1523 | int temp_priority[MAX_NR_ZONES]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1524 | |
| 1525 | loop_again: |
| 1526 | total_scanned = 0; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1527 | nr_reclaimed = 0; |
Christoph Lameter | c0bbbc7 | 2006-06-11 15:22:26 -0700 | [diff] [blame] | 1528 | sc.may_writepage = !laptop_mode; |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1529 | count_vm_event(PAGEOUTRUN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1530 | |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1531 | for (i = 0; i < pgdat->nr_zones; i++) |
| 1532 | temp_priority[i] = DEF_PRIORITY; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1533 | |
| 1534 | for (priority = DEF_PRIORITY; priority >= 0; priority--) { |
| 1535 | int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */ |
| 1536 | unsigned long lru_pages = 0; |
| 1537 | |
Rik van Riel | f7b7fd8 | 2005-11-28 13:44:07 -0800 | [diff] [blame] | 1538 | /* The swap token gets in the way of swapout... */ |
| 1539 | if (!priority) |
| 1540 | disable_swap_token(); |
| 1541 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1542 | all_zones_ok = 1; |
| 1543 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1544 | /* |
| 1545 | * Scan in the highmem->dma direction for the highest |
| 1546 | * zone which needs scanning |
| 1547 | */ |
| 1548 | for (i = pgdat->nr_zones - 1; i >= 0; i--) { |
| 1549 | struct zone *zone = pgdat->node_zones + i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1550 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1551 | if (!populated_zone(zone)) |
| 1552 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1553 | |
David Rientjes | e815af9 | 2007-10-16 23:25:54 -0700 | [diff] [blame] | 1554 | if (zone_is_all_unreclaimable(zone) && |
| 1555 | priority != DEF_PRIORITY) |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1556 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1557 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1558 | if (!zone_watermark_ok(zone, order, zone->pages_high, |
| 1559 | 0, 0)) { |
| 1560 | end_zone = i; |
Andrew Morton | e1dbeda | 2006-12-06 20:32:01 -0800 | [diff] [blame] | 1561 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1562 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1563 | } |
Andrew Morton | e1dbeda | 2006-12-06 20:32:01 -0800 | [diff] [blame] | 1564 | if (i < 0) |
| 1565 | goto out; |
| 1566 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1567 | for (i = 0; i <= end_zone; i++) { |
| 1568 | struct zone *zone = pgdat->node_zones + i; |
| 1569 | |
Christoph Lameter | c878538 | 2007-02-10 01:43:01 -0800 | [diff] [blame] | 1570 | lru_pages += zone_page_state(zone, NR_ACTIVE) |
| 1571 | + zone_page_state(zone, NR_INACTIVE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1572 | } |
| 1573 | |
| 1574 | /* |
| 1575 | * Now scan the zone in the dma->highmem direction, stopping |
| 1576 | * at the last zone which needs scanning. |
| 1577 | * |
| 1578 | * We do this because the page allocator works in the opposite |
| 1579 | * direction. This prevents the page allocator from allocating |
| 1580 | * pages behind kswapd's direction of progress, which would |
| 1581 | * cause too much scanning of the lower zones. |
| 1582 | */ |
| 1583 | for (i = 0; i <= end_zone; i++) { |
| 1584 | struct zone *zone = pgdat->node_zones + i; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 1585 | int nr_slab; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1586 | |
Con Kolivas | f3fe651 | 2006-01-06 00:11:15 -0800 | [diff] [blame] | 1587 | if (!populated_zone(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1588 | continue; |
| 1589 | |
David Rientjes | e815af9 | 2007-10-16 23:25:54 -0700 | [diff] [blame] | 1590 | if (zone_is_all_unreclaimable(zone) && |
| 1591 | priority != DEF_PRIORITY) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1592 | continue; |
| 1593 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1594 | if (!zone_watermark_ok(zone, order, zone->pages_high, |
| 1595 | end_zone, 0)) |
| 1596 | all_zones_ok = 0; |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1597 | temp_priority[i] = priority; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1598 | sc.nr_scanned = 0; |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1599 | note_zone_scanning_priority(zone, priority); |
Rik van Riel | 32a4330 | 2007-10-16 01:24:50 -0700 | [diff] [blame] | 1600 | /* |
| 1601 | * We put equal pressure on every zone, unless one |
| 1602 | * zone has way too many pages free already. |
| 1603 | */ |
| 1604 | if (!zone_watermark_ok(zone, order, 8*zone->pages_high, |
| 1605 | end_zone, 0)) |
| 1606 | nr_reclaimed += shrink_zone(priority, zone, &sc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1607 | reclaim_state->reclaimed_slab = 0; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 1608 | nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL, |
| 1609 | lru_pages); |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1610 | nr_reclaimed += reclaim_state->reclaimed_slab; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1611 | total_scanned += sc.nr_scanned; |
David Rientjes | e815af9 | 2007-10-16 23:25:54 -0700 | [diff] [blame] | 1612 | if (zone_is_all_unreclaimable(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1613 | continue; |
akpm@osdl.org | b15e090 | 2005-06-21 17:14:35 -0700 | [diff] [blame] | 1614 | if (nr_slab == 0 && zone->pages_scanned >= |
Christoph Lameter | c878538 | 2007-02-10 01:43:01 -0800 | [diff] [blame] | 1615 | (zone_page_state(zone, NR_ACTIVE) |
| 1616 | + zone_page_state(zone, NR_INACTIVE)) * 6) |
David Rientjes | e815af9 | 2007-10-16 23:25:54 -0700 | [diff] [blame] | 1617 | zone_set_flag(zone, |
| 1618 | ZONE_ALL_UNRECLAIMABLE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1619 | /* |
| 1620 | * If we've done a decent amount of scanning and |
| 1621 | * the reclaim ratio is low, start doing writepage |
| 1622 | * even in laptop mode |
| 1623 | */ |
| 1624 | if (total_scanned > SWAP_CLUSTER_MAX * 2 && |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1625 | total_scanned > nr_reclaimed + nr_reclaimed / 2) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1626 | sc.may_writepage = 1; |
| 1627 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1628 | if (all_zones_ok) |
| 1629 | break; /* kswapd: all done */ |
| 1630 | /* |
| 1631 | * OK, kswapd is getting into trouble. Take a nap, then take |
| 1632 | * another pass across the zones. |
| 1633 | */ |
Andrew Morton | 4dd4b92 | 2008-03-24 12:29:52 -0700 | [diff] [blame] | 1634 | if (total_scanned && priority < DEF_PRIORITY - 2) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 1635 | congestion_wait(WRITE, HZ/10); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1636 | |
| 1637 | /* |
| 1638 | * We do this so kswapd doesn't build up large priorities for |
| 1639 | * example when it is freeing in parallel with allocators. It |
| 1640 | * matches the direct reclaim path behaviour in terms of impact |
| 1641 | * on zone->*_priority. |
| 1642 | */ |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1643 | if (nr_reclaimed >= SWAP_CLUSTER_MAX) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1644 | break; |
| 1645 | } |
| 1646 | out: |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1647 | /* |
| 1648 | * Note within each zone the priority level at which this zone was |
| 1649 | * brought into a happy state. So that the next thread which scans this |
| 1650 | * zone will start out at that priority level. |
| 1651 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1652 | for (i = 0; i < pgdat->nr_zones; i++) { |
| 1653 | struct zone *zone = pgdat->node_zones + i; |
| 1654 | |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 1655 | zone->prev_priority = temp_priority[i]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1656 | } |
| 1657 | if (!all_zones_ok) { |
| 1658 | cond_resched(); |
Rafael J. Wysocki | 8357376 | 2006-12-06 20:34:18 -0800 | [diff] [blame] | 1659 | |
| 1660 | try_to_freeze(); |
| 1661 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1662 | goto loop_again; |
| 1663 | } |
| 1664 | |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 1665 | return nr_reclaimed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1666 | } |
| 1667 | |
| 1668 | /* |
| 1669 | * The background pageout daemon, started as a kernel thread |
| 1670 | * from the init process. |
| 1671 | * |
| 1672 | * This basically trickles out pages so that we have _some_ |
| 1673 | * free memory available even if there is no other activity |
| 1674 | * that frees anything up. This is needed for things like routing |
| 1675 | * etc, where we otherwise might have all activity going on in |
| 1676 | * asynchronous contexts that cannot page things out. |
| 1677 | * |
| 1678 | * If there are applications that are active memory-allocators |
| 1679 | * (most normal use), this basically shouldn't matter. |
| 1680 | */ |
| 1681 | static int kswapd(void *p) |
| 1682 | { |
| 1683 | unsigned long order; |
| 1684 | pg_data_t *pgdat = (pg_data_t*)p; |
| 1685 | struct task_struct *tsk = current; |
| 1686 | DEFINE_WAIT(wait); |
| 1687 | struct reclaim_state reclaim_state = { |
| 1688 | .reclaimed_slab = 0, |
| 1689 | }; |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 1690 | node_to_cpumask_ptr(cpumask, pgdat->node_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1691 | |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 1692 | if (!cpus_empty(*cpumask)) |
| 1693 | set_cpus_allowed_ptr(tsk, cpumask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1694 | current->reclaim_state = &reclaim_state; |
| 1695 | |
| 1696 | /* |
| 1697 | * Tell the memory management that we're a "memory allocator", |
| 1698 | * and that if we need more memory we should get access to it |
| 1699 | * regardless (see "__alloc_pages()"). "kswapd" should |
| 1700 | * never get caught in the normal page freeing logic. |
| 1701 | * |
| 1702 | * (Kswapd normally doesn't need memory anyway, but sometimes |
| 1703 | * you need a small amount of memory in order to be able to |
| 1704 | * page out something else, and this flag essentially protects |
| 1705 | * us from recursively trying to free more memory as we're |
| 1706 | * trying to free the first piece of memory in the first place). |
| 1707 | */ |
Christoph Lameter | 930d915 | 2006-01-08 01:00:47 -0800 | [diff] [blame] | 1708 | tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD; |
Rafael J. Wysocki | 8314418 | 2007-07-17 04:03:35 -0700 | [diff] [blame] | 1709 | set_freezable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1710 | |
| 1711 | order = 0; |
| 1712 | for ( ; ; ) { |
| 1713 | unsigned long new_order; |
Christoph Lameter | 3e1d1d2 | 2005-06-24 23:13:50 -0700 | [diff] [blame] | 1714 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1715 | prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); |
| 1716 | new_order = pgdat->kswapd_max_order; |
| 1717 | pgdat->kswapd_max_order = 0; |
| 1718 | if (order < new_order) { |
| 1719 | /* |
| 1720 | * Don't sleep if someone wants a larger 'order' |
| 1721 | * allocation |
| 1722 | */ |
| 1723 | order = new_order; |
| 1724 | } else { |
Rafael J. Wysocki | b1296cc | 2007-05-06 14:50:48 -0700 | [diff] [blame] | 1725 | if (!freezing(current)) |
| 1726 | schedule(); |
| 1727 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1728 | order = pgdat->kswapd_max_order; |
| 1729 | } |
| 1730 | finish_wait(&pgdat->kswapd_wait, &wait); |
| 1731 | |
Rafael J. Wysocki | b1296cc | 2007-05-06 14:50:48 -0700 | [diff] [blame] | 1732 | if (!try_to_freeze()) { |
| 1733 | /* We can speed up thawing tasks if we don't call |
| 1734 | * balance_pgdat after returning from the refrigerator |
| 1735 | */ |
| 1736 | balance_pgdat(pgdat, order); |
| 1737 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1738 | } |
| 1739 | return 0; |
| 1740 | } |
| 1741 | |
| 1742 | /* |
| 1743 | * A zone is low on free memory, so wake its kswapd task to service it. |
| 1744 | */ |
| 1745 | void wakeup_kswapd(struct zone *zone, int order) |
| 1746 | { |
| 1747 | pg_data_t *pgdat; |
| 1748 | |
Con Kolivas | f3fe651 | 2006-01-06 00:11:15 -0800 | [diff] [blame] | 1749 | if (!populated_zone(zone)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1750 | return; |
| 1751 | |
| 1752 | pgdat = zone->zone_pgdat; |
Rohit Seth | 7fb1d9f | 2005-11-13 16:06:43 -0800 | [diff] [blame] | 1753 | if (zone_watermark_ok(zone, order, zone->pages_low, 0, 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1754 | return; |
| 1755 | if (pgdat->kswapd_max_order < order) |
| 1756 | pgdat->kswapd_max_order = order; |
Paul Jackson | 02a0e53 | 2006-12-13 00:34:25 -0800 | [diff] [blame] | 1757 | if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1758 | return; |
Con Kolivas | 8d0986e | 2005-09-13 01:25:07 -0700 | [diff] [blame] | 1759 | if (!waitqueue_active(&pgdat->kswapd_wait)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1760 | return; |
Con Kolivas | 8d0986e | 2005-09-13 01:25:07 -0700 | [diff] [blame] | 1761 | wake_up_interruptible(&pgdat->kswapd_wait); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1762 | } |
| 1763 | |
| 1764 | #ifdef CONFIG_PM |
| 1765 | /* |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1766 | * Helper function for shrink_all_memory(). Tries to reclaim 'nr_pages' pages |
| 1767 | * from LRU lists system-wide, for given pass and priority, and returns the |
| 1768 | * number of reclaimed pages |
| 1769 | * |
| 1770 | * For pass > 3 we also try to shrink the LRU lists that contain a few pages |
| 1771 | */ |
Nigel Cunningham | e07aa05 | 2006-12-22 01:07:21 -0800 | [diff] [blame] | 1772 | static unsigned long shrink_all_zones(unsigned long nr_pages, int prio, |
| 1773 | int pass, struct scan_control *sc) |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1774 | { |
| 1775 | struct zone *zone; |
| 1776 | unsigned long nr_to_scan, ret = 0; |
| 1777 | |
| 1778 | for_each_zone(zone) { |
| 1779 | |
| 1780 | if (!populated_zone(zone)) |
| 1781 | continue; |
| 1782 | |
David Rientjes | e815af9 | 2007-10-16 23:25:54 -0700 | [diff] [blame] | 1783 | if (zone_is_all_unreclaimable(zone) && prio != DEF_PRIORITY) |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1784 | continue; |
| 1785 | |
| 1786 | /* For pass = 0 we don't shrink the active list */ |
| 1787 | if (pass > 0) { |
Christoph Lameter | c878538 | 2007-02-10 01:43:01 -0800 | [diff] [blame] | 1788 | zone->nr_scan_active += |
| 1789 | (zone_page_state(zone, NR_ACTIVE) >> prio) + 1; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1790 | if (zone->nr_scan_active >= nr_pages || pass > 3) { |
| 1791 | zone->nr_scan_active = 0; |
Christoph Lameter | c878538 | 2007-02-10 01:43:01 -0800 | [diff] [blame] | 1792 | nr_to_scan = min(nr_pages, |
| 1793 | zone_page_state(zone, NR_ACTIVE)); |
Martin Bligh | bbdb396 | 2006-10-28 10:38:25 -0700 | [diff] [blame] | 1794 | shrink_active_list(nr_to_scan, zone, sc, prio); |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1795 | } |
| 1796 | } |
| 1797 | |
Christoph Lameter | c878538 | 2007-02-10 01:43:01 -0800 | [diff] [blame] | 1798 | zone->nr_scan_inactive += |
| 1799 | (zone_page_state(zone, NR_INACTIVE) >> prio) + 1; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1800 | if (zone->nr_scan_inactive >= nr_pages || pass > 3) { |
| 1801 | zone->nr_scan_inactive = 0; |
Christoph Lameter | c878538 | 2007-02-10 01:43:01 -0800 | [diff] [blame] | 1802 | nr_to_scan = min(nr_pages, |
| 1803 | zone_page_state(zone, NR_INACTIVE)); |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1804 | ret += shrink_inactive_list(nr_to_scan, zone, sc); |
| 1805 | if (ret >= nr_pages) |
| 1806 | return ret; |
| 1807 | } |
| 1808 | } |
| 1809 | |
| 1810 | return ret; |
| 1811 | } |
| 1812 | |
Andrew Morton | 76395d3 | 2007-01-05 16:37:05 -0800 | [diff] [blame] | 1813 | static unsigned long count_lru_pages(void) |
| 1814 | { |
Christoph Lameter | c878538 | 2007-02-10 01:43:01 -0800 | [diff] [blame] | 1815 | return global_page_state(NR_ACTIVE) + global_page_state(NR_INACTIVE); |
Andrew Morton | 76395d3 | 2007-01-05 16:37:05 -0800 | [diff] [blame] | 1816 | } |
| 1817 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1818 | /* |
| 1819 | * Try to free `nr_pages' of memory, system-wide, and return the number of |
| 1820 | * freed pages. |
| 1821 | * |
| 1822 | * Rather than trying to age LRUs the aim is to preserve the overall |
| 1823 | * LRU order by reclaiming preferentially |
| 1824 | * inactive > active > active referenced > active mapped |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1825 | */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1826 | unsigned long shrink_all_memory(unsigned long nr_pages) |
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 | unsigned long lru_pages, nr_slab; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1829 | unsigned long ret = 0; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1830 | int pass; |
| 1831 | struct reclaim_state reclaim_state; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1832 | struct scan_control sc = { |
| 1833 | .gfp_mask = GFP_KERNEL, |
| 1834 | .may_swap = 0, |
| 1835 | .swap_cluster_max = nr_pages, |
| 1836 | .may_writepage = 1, |
| 1837 | .swappiness = vm_swappiness, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 1838 | .isolate_pages = isolate_pages_global, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1839 | }; |
| 1840 | |
| 1841 | current->reclaim_state = &reclaim_state; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1842 | |
Andrew Morton | 76395d3 | 2007-01-05 16:37:05 -0800 | [diff] [blame] | 1843 | lru_pages = count_lru_pages(); |
Christoph Lameter | 972d1a7 | 2006-09-25 23:31:51 -0700 | [diff] [blame] | 1844 | nr_slab = global_page_state(NR_SLAB_RECLAIMABLE); |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1845 | /* If slab caches are huge, it's better to hit them first */ |
| 1846 | while (nr_slab >= lru_pages) { |
| 1847 | reclaim_state.reclaimed_slab = 0; |
| 1848 | shrink_slab(nr_pages, sc.gfp_mask, lru_pages); |
| 1849 | if (!reclaim_state.reclaimed_slab) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1850 | break; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1851 | |
| 1852 | ret += reclaim_state.reclaimed_slab; |
| 1853 | if (ret >= nr_pages) |
| 1854 | goto out; |
| 1855 | |
| 1856 | nr_slab -= reclaim_state.reclaimed_slab; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1857 | } |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1858 | |
| 1859 | /* |
| 1860 | * We try to shrink LRUs in 5 passes: |
| 1861 | * 0 = Reclaim from inactive_list only |
| 1862 | * 1 = Reclaim from active list but don't reclaim mapped |
| 1863 | * 2 = 2nd pass of type 1 |
| 1864 | * 3 = Reclaim mapped (normal reclaim) |
| 1865 | * 4 = 2nd pass of type 3 |
| 1866 | */ |
| 1867 | for (pass = 0; pass < 5; pass++) { |
| 1868 | int prio; |
| 1869 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1870 | /* Force reclaiming mapped pages in the passes #3 and #4 */ |
| 1871 | if (pass > 2) { |
| 1872 | sc.may_swap = 1; |
| 1873 | sc.swappiness = 100; |
| 1874 | } |
| 1875 | |
| 1876 | for (prio = DEF_PRIORITY; prio >= 0; prio--) { |
| 1877 | unsigned long nr_to_scan = nr_pages - ret; |
| 1878 | |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1879 | sc.nr_scanned = 0; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1880 | ret += shrink_all_zones(nr_to_scan, prio, pass, &sc); |
| 1881 | if (ret >= nr_pages) |
| 1882 | goto out; |
| 1883 | |
| 1884 | reclaim_state.reclaimed_slab = 0; |
Andrew Morton | 76395d3 | 2007-01-05 16:37:05 -0800 | [diff] [blame] | 1885 | shrink_slab(sc.nr_scanned, sc.gfp_mask, |
| 1886 | count_lru_pages()); |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1887 | ret += reclaim_state.reclaimed_slab; |
| 1888 | if (ret >= nr_pages) |
| 1889 | goto out; |
| 1890 | |
| 1891 | if (sc.nr_scanned && prio < DEF_PRIORITY - 2) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 1892 | congestion_wait(WRITE, HZ / 10); |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1893 | } |
Rafael J. Wysocki | 248a030 | 2006-03-22 00:09:04 -0800 | [diff] [blame] | 1894 | } |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1895 | |
| 1896 | /* |
| 1897 | * If ret = 0, we could not shrink LRUs, but there may be something |
| 1898 | * in slab caches |
| 1899 | */ |
Andrew Morton | 76395d3 | 2007-01-05 16:37:05 -0800 | [diff] [blame] | 1900 | if (!ret) { |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1901 | do { |
| 1902 | reclaim_state.reclaimed_slab = 0; |
Andrew Morton | 76395d3 | 2007-01-05 16:37:05 -0800 | [diff] [blame] | 1903 | shrink_slab(nr_pages, sc.gfp_mask, count_lru_pages()); |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1904 | ret += reclaim_state.reclaimed_slab; |
| 1905 | } while (ret < nr_pages && reclaim_state.reclaimed_slab > 0); |
Andrew Morton | 76395d3 | 2007-01-05 16:37:05 -0800 | [diff] [blame] | 1906 | } |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1907 | |
| 1908 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1909 | current->reclaim_state = NULL; |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 1910 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1911 | return ret; |
| 1912 | } |
| 1913 | #endif |
| 1914 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1915 | /* It's optimal to keep kswapds on the same CPUs as their memory, but |
| 1916 | not required for correctness. So if the last cpu in a node goes |
| 1917 | away, we get changed to run anywhere: as the first one comes back, |
| 1918 | restore their cpu bindings. */ |
Chandra Seetharaman | 9c7b216 | 2006-06-27 02:54:07 -0700 | [diff] [blame] | 1919 | static int __devinit cpu_callback(struct notifier_block *nfb, |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1920 | unsigned long action, void *hcpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1921 | { |
Yasunori Goto | 58c0a4a | 2007-10-16 01:25:40 -0700 | [diff] [blame] | 1922 | int nid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1923 | |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 1924 | if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN) { |
Yasunori Goto | 58c0a4a | 2007-10-16 01:25:40 -0700 | [diff] [blame] | 1925 | for_each_node_state(nid, N_HIGH_MEMORY) { |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 1926 | pg_data_t *pgdat = NODE_DATA(nid); |
| 1927 | node_to_cpumask_ptr(mask, pgdat->node_id); |
| 1928 | |
| 1929 | if (any_online_cpu(*mask) < nr_cpu_ids) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1930 | /* One of our CPUs online: restore mask */ |
Mike Travis | c5f59f0 | 2008-04-04 18:11:10 -0700 | [diff] [blame] | 1931 | set_cpus_allowed_ptr(pgdat->kswapd, mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1932 | } |
| 1933 | } |
| 1934 | return NOTIFY_OK; |
| 1935 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1936 | |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 1937 | /* |
| 1938 | * This kswapd start function will be called by init and node-hot-add. |
| 1939 | * On node-hot-add, kswapd will moved to proper cpus if cpus are hot-added. |
| 1940 | */ |
| 1941 | int kswapd_run(int nid) |
| 1942 | { |
| 1943 | pg_data_t *pgdat = NODE_DATA(nid); |
| 1944 | int ret = 0; |
| 1945 | |
| 1946 | if (pgdat->kswapd) |
| 1947 | return 0; |
| 1948 | |
| 1949 | pgdat->kswapd = kthread_run(kswapd, pgdat, "kswapd%d", nid); |
| 1950 | if (IS_ERR(pgdat->kswapd)) { |
| 1951 | /* failure at boot is fatal */ |
| 1952 | BUG_ON(system_state == SYSTEM_BOOTING); |
| 1953 | printk("Failed to start kswapd on node %d\n",nid); |
| 1954 | ret = -1; |
| 1955 | } |
| 1956 | return ret; |
| 1957 | } |
| 1958 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1959 | static int __init kswapd_init(void) |
| 1960 | { |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 1961 | int nid; |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 1962 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1963 | swap_setup(); |
Christoph Lameter | 9422ffb | 2007-10-16 01:25:31 -0700 | [diff] [blame] | 1964 | for_each_node_state(nid, N_HIGH_MEMORY) |
Yasunori Goto | 3218ae1 | 2006-06-27 02:53:33 -0700 | [diff] [blame] | 1965 | kswapd_run(nid); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1966 | hotcpu_notifier(cpu_callback, 0); |
| 1967 | return 0; |
| 1968 | } |
| 1969 | |
| 1970 | module_init(kswapd_init) |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 1971 | |
| 1972 | #ifdef CONFIG_NUMA |
| 1973 | /* |
| 1974 | * Zone reclaim mode |
| 1975 | * |
| 1976 | * If non-zero call zone_reclaim when the number of free pages falls below |
| 1977 | * the watermarks. |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 1978 | */ |
| 1979 | int zone_reclaim_mode __read_mostly; |
| 1980 | |
Christoph Lameter | 1b2ffb7 | 2006-02-01 03:05:34 -0800 | [diff] [blame] | 1981 | #define RECLAIM_OFF 0 |
Fernando Luis Vazquez Cao | 7d03431 | 2008-07-29 22:33:41 -0700 | [diff] [blame] | 1982 | #define RECLAIM_ZONE (1<<0) /* Run shrink_inactive_list on the zone */ |
Christoph Lameter | 1b2ffb7 | 2006-02-01 03:05:34 -0800 | [diff] [blame] | 1983 | #define RECLAIM_WRITE (1<<1) /* Writeout pages during reclaim */ |
| 1984 | #define RECLAIM_SWAP (1<<2) /* Swap pages out during reclaim */ |
| 1985 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 1986 | /* |
Christoph Lameter | a92f712 | 2006-02-01 03:05:32 -0800 | [diff] [blame] | 1987 | * Priority for ZONE_RECLAIM. This determines the fraction of pages |
| 1988 | * of a node considered for each zone_reclaim. 4 scans 1/16th of |
| 1989 | * a zone. |
| 1990 | */ |
| 1991 | #define ZONE_RECLAIM_PRIORITY 4 |
| 1992 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 1993 | /* |
Christoph Lameter | 9614634 | 2006-07-03 00:24:13 -0700 | [diff] [blame] | 1994 | * Percentage of pages in a zone that must be unmapped for zone_reclaim to |
| 1995 | * occur. |
| 1996 | */ |
| 1997 | int sysctl_min_unmapped_ratio = 1; |
| 1998 | |
| 1999 | /* |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2000 | * If the number of slab pages in a zone grows beyond this percentage then |
| 2001 | * slab reclaim needs to occur. |
| 2002 | */ |
| 2003 | int sysctl_min_slab_ratio = 5; |
| 2004 | |
| 2005 | /* |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2006 | * Try to free up some pages from this zone through reclaim. |
| 2007 | */ |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2008 | 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] | 2009 | { |
Christoph Lameter | 7fb2d46 | 2006-03-22 00:08:22 -0800 | [diff] [blame] | 2010 | /* Minimum pages needed in order to stay on node */ |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2011 | const unsigned long nr_pages = 1 << order; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2012 | struct task_struct *p = current; |
| 2013 | struct reclaim_state reclaim_state; |
Christoph Lameter | 8695949 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2014 | int priority; |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 2015 | unsigned long nr_reclaimed = 0; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2016 | struct scan_control sc = { |
| 2017 | .may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE), |
| 2018 | .may_swap = !!(zone_reclaim_mode & RECLAIM_SWAP), |
Andrew Morton | 69e0594 | 2006-03-22 00:08:19 -0800 | [diff] [blame] | 2019 | .swap_cluster_max = max_t(unsigned long, nr_pages, |
| 2020 | SWAP_CLUSTER_MAX), |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2021 | .gfp_mask = gfp_mask, |
Rafael J. Wysocki | d6277db | 2006-06-23 02:03:18 -0700 | [diff] [blame] | 2022 | .swappiness = vm_swappiness, |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 2023 | .isolate_pages = isolate_pages_global, |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2024 | }; |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 2025 | unsigned long slab_reclaimable; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2026 | |
| 2027 | disable_swap_token(); |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2028 | cond_resched(); |
Christoph Lameter | d4f7796 | 2006-02-24 13:04:22 -0800 | [diff] [blame] | 2029 | /* |
| 2030 | * We need to be able to allocate from the reserves for RECLAIM_SWAP |
| 2031 | * and we also need to be able to write out pages for RECLAIM_WRITE |
| 2032 | * and RECLAIM_SWAP. |
| 2033 | */ |
| 2034 | p->flags |= PF_MEMALLOC | PF_SWAPWRITE; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2035 | reclaim_state.reclaimed_slab = 0; |
| 2036 | p->reclaim_state = &reclaim_state; |
Christoph Lameter | c84db23 | 2006-02-01 03:05:29 -0800 | [diff] [blame] | 2037 | |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2038 | if (zone_page_state(zone, NR_FILE_PAGES) - |
| 2039 | zone_page_state(zone, NR_FILE_MAPPED) > |
| 2040 | zone->min_unmapped_pages) { |
| 2041 | /* |
| 2042 | * Free memory by calling shrink zone with increasing |
| 2043 | * priorities until we have enough memory freed. |
| 2044 | */ |
| 2045 | priority = ZONE_RECLAIM_PRIORITY; |
| 2046 | do { |
Martin Bligh | 3bb1a85 | 2006-10-28 10:38:24 -0700 | [diff] [blame] | 2047 | note_zone_scanning_priority(zone, priority); |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2048 | nr_reclaimed += shrink_zone(priority, zone, &sc); |
| 2049 | priority--; |
| 2050 | } while (priority >= 0 && nr_reclaimed < nr_pages); |
| 2051 | } |
Christoph Lameter | c84db23 | 2006-02-01 03:05:29 -0800 | [diff] [blame] | 2052 | |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 2053 | slab_reclaimable = zone_page_state(zone, NR_SLAB_RECLAIMABLE); |
| 2054 | if (slab_reclaimable > zone->min_slab_pages) { |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2055 | /* |
Christoph Lameter | 7fb2d46 | 2006-03-22 00:08:22 -0800 | [diff] [blame] | 2056 | * shrink_slab() does not currently allow us to determine how |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2057 | * many pages were freed in this zone. So we take the current |
| 2058 | * number of slab pages and shake the slab until it is reduced |
| 2059 | * by the same nr_pages that we used for reclaiming unmapped |
| 2060 | * pages. |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2061 | * |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2062 | * Note that shrink_slab will free memory on all zones and may |
| 2063 | * take a long time. |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2064 | */ |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2065 | while (shrink_slab(sc.nr_scanned, gfp_mask, order) && |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 2066 | zone_page_state(zone, NR_SLAB_RECLAIMABLE) > |
| 2067 | slab_reclaimable - nr_pages) |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2068 | ; |
Christoph Lameter | 83e33a4 | 2006-09-25 23:31:53 -0700 | [diff] [blame] | 2069 | |
| 2070 | /* |
| 2071 | * Update nr_reclaimed by the number of slab pages we |
| 2072 | * reclaimed from this zone. |
| 2073 | */ |
| 2074 | nr_reclaimed += slab_reclaimable - |
| 2075 | zone_page_state(zone, NR_SLAB_RECLAIMABLE); |
Christoph Lameter | 2a16e3f | 2006-02-01 03:05:35 -0800 | [diff] [blame] | 2076 | } |
| 2077 | |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2078 | p->reclaim_state = NULL; |
Christoph Lameter | d4f7796 | 2006-02-24 13:04:22 -0800 | [diff] [blame] | 2079 | current->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE); |
Andrew Morton | 05ff513 | 2006-03-22 00:08:20 -0800 | [diff] [blame] | 2080 | return nr_reclaimed >= nr_pages; |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2081 | } |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2082 | |
| 2083 | int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) |
| 2084 | { |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2085 | int node_id; |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2086 | int ret; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2087 | |
| 2088 | /* |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2089 | * Zone reclaim reclaims unmapped file backed pages and |
| 2090 | * slab pages if we are over the defined limits. |
Christoph Lameter | 34aa133 | 2006-06-30 01:55:37 -0700 | [diff] [blame] | 2091 | * |
Christoph Lameter | 9614634 | 2006-07-03 00:24:13 -0700 | [diff] [blame] | 2092 | * A small portion of unmapped file backed pages is needed for |
| 2093 | * file I/O otherwise pages read by file I/O will be immediately |
| 2094 | * thrown out if the zone is overallocated. So we do not reclaim |
| 2095 | * if less than a specified percentage of the zone is used by |
| 2096 | * unmapped file backed pages. |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2097 | */ |
Christoph Lameter | 34aa133 | 2006-06-30 01:55:37 -0700 | [diff] [blame] | 2098 | if (zone_page_state(zone, NR_FILE_PAGES) - |
Christoph Lameter | 0ff3849 | 2006-09-25 23:31:52 -0700 | [diff] [blame] | 2099 | zone_page_state(zone, NR_FILE_MAPPED) <= zone->min_unmapped_pages |
| 2100 | && zone_page_state(zone, NR_SLAB_RECLAIMABLE) |
| 2101 | <= zone->min_slab_pages) |
Christoph Lameter | 9614634 | 2006-07-03 00:24:13 -0700 | [diff] [blame] | 2102 | return 0; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2103 | |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2104 | if (zone_is_all_unreclaimable(zone)) |
| 2105 | return 0; |
| 2106 | |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2107 | /* |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2108 | * Do not scan if the allocation should not be delayed. |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2109 | */ |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2110 | if (!(gfp_mask & __GFP_WAIT) || (current->flags & PF_MEMALLOC)) |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2111 | return 0; |
| 2112 | |
| 2113 | /* |
| 2114 | * Only run zone reclaim on the local zone or on zones that do not |
| 2115 | * have associated processors. This will favor the local processor |
| 2116 | * over remote processors and spread off node memory allocations |
| 2117 | * as wide as possible. |
| 2118 | */ |
Christoph Lameter | 89fa302 | 2006-09-25 23:31:55 -0700 | [diff] [blame] | 2119 | node_id = zone_to_nid(zone); |
Christoph Lameter | 37c0708 | 2007-10-16 01:25:36 -0700 | [diff] [blame] | 2120 | if (node_state(node_id, N_CPU) && node_id != numa_node_id()) |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2121 | return 0; |
David Rientjes | d773ed6 | 2007-10-16 23:26:01 -0700 | [diff] [blame] | 2122 | |
| 2123 | if (zone_test_and_set_flag(zone, ZONE_RECLAIM_LOCKED)) |
| 2124 | return 0; |
| 2125 | ret = __zone_reclaim(zone, gfp_mask, order); |
| 2126 | zone_clear_flag(zone, ZONE_RECLAIM_LOCKED); |
| 2127 | |
| 2128 | return ret; |
Andrew Morton | 179e963 | 2006-03-22 00:08:18 -0800 | [diff] [blame] | 2129 | } |
Christoph Lameter | 9eeff23 | 2006-01-18 17:42:31 -0800 | [diff] [blame] | 2130 | #endif |