Blame view
mm/swap_state.c
10.4 KB
1da177e4c Linux-2.6.12-rc2 |
1 2 3 4 5 6 7 8 9 10 11 12 |
/* * linux/mm/swap_state.c * * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds * Swap reorganised 29.12.95, Stephen Tweedie * * Rewritten to use page cache, (C) 1998 Stephen Tweedie */ #include <linux/module.h> #include <linux/mm.h> #include <linux/kernel_stat.h> #include <linux/swap.h> |
46017e954 swapin_readahead:... |
13 |
#include <linux/swapops.h> |
1da177e4c Linux-2.6.12-rc2 |
14 15 16 17 |
#include <linux/init.h> #include <linux/pagemap.h> #include <linux/buffer_head.h> #include <linux/backing-dev.h> |
c484d4104 [PATCH] mm: free_... |
18 |
#include <linux/pagevec.h> |
b20a35035 [PATCH] page migr... |
19 |
#include <linux/migrate.h> |
8c7c6e34a memcg: mem+swap c... |
20 |
#include <linux/page_cgroup.h> |
1da177e4c Linux-2.6.12-rc2 |
21 22 23 24 25 |
#include <asm/pgtable.h> /* * swapper_space is a fiction, retained to simplify the path through |
2706a1b89 vmscan: fix comme... |
26 |
* vmscan's shrink_page_list, to make sync_page look nicer, and to allow |
1da177e4c Linux-2.6.12-rc2 |
27 28 |
* future use of radix_tree tags in the swap cache. */ |
f5e54d6e5 [PATCH] mark addr... |
29 |
static const struct address_space_operations swap_aops = { |
1da177e4c Linux-2.6.12-rc2 |
30 31 32 |
.writepage = swap_writepage, .sync_page = block_sync_page, .set_page_dirty = __set_page_dirty_nobuffers, |
e965f9630 [PATCH] Direct Mi... |
33 |
.migratepage = migrate_page, |
1da177e4c Linux-2.6.12-rc2 |
34 35 36 |
}; static struct backing_dev_info swap_backing_dev_info = { |
d993831fa writeback: add na... |
37 |
.name = "swap", |
4f98a2fee vmscan: split LRU... |
38 |
.capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED, |
1da177e4c Linux-2.6.12-rc2 |
39 40 41 42 43 |
.unplug_io_fn = swap_unplug_io_fn, }; struct address_space swapper_space = { .page_tree = RADIX_TREE_INIT(GFP_ATOMIC|__GFP_NOWARN), |
19fd62312 mm: spinlock tree... |
44 |
.tree_lock = __SPIN_LOCK_UNLOCKED(swapper_space.tree_lock), |
1da177e4c Linux-2.6.12-rc2 |
45 46 47 48 |
.a_ops = &swap_aops, .i_mmap_nonlinear = LIST_HEAD_INIT(swapper_space.i_mmap_nonlinear), .backing_dev_info = &swap_backing_dev_info, }; |
1da177e4c Linux-2.6.12-rc2 |
49 50 51 52 53 54 55 56 |
#define INC_CACHE_INFO(x) do { swap_cache_info.x++; } while (0) static struct { unsigned long add_total; unsigned long del_total; unsigned long find_success; unsigned long find_total; |
1da177e4c Linux-2.6.12-rc2 |
57 58 59 60 |
} swap_cache_info; void show_swap_cache_info(void) { |
2c97b7fc0 mm: print swapcac... |
61 62 63 64 |
printk("%lu pages in swap cache ", total_swapcache_pages); printk("Swap cache stats: add %lu, delete %lu, find %lu/%lu ", |
1da177e4c Linux-2.6.12-rc2 |
65 |
swap_cache_info.add_total, swap_cache_info.del_total, |
bb63be0a0 tmpfs: move swap_... |
66 |
swap_cache_info.find_success, swap_cache_info.find_total); |
07279cdfd mm: show free swa... |
67 68 |
printk("Free swap = %ldkB ", nr_swap_pages << (PAGE_SHIFT - 10)); |
1da177e4c Linux-2.6.12-rc2 |
69 70 71 72 73 |
printk("Total swap = %lukB ", total_swap_pages << (PAGE_SHIFT - 10)); } /* |
31a563962 mm: add_to_swap_c... |
74 |
* __add_to_swap_cache resembles add_to_page_cache_locked on swapper_space, |
1da177e4c Linux-2.6.12-rc2 |
75 76 |
* but sets SwapCache flag and private instead of mapping and index. */ |
31a563962 mm: add_to_swap_c... |
77 |
static int __add_to_swap_cache(struct page *page, swp_entry_t entry) |
1da177e4c Linux-2.6.12-rc2 |
78 79 |
{ int error; |
51726b122 mm: replace some ... |
80 81 82 |
VM_BUG_ON(!PageLocked(page)); VM_BUG_ON(PageSwapCache(page)); VM_BUG_ON(!PageSwapBacked(page)); |
31a563962 mm: add_to_swap_c... |
83 84 85 86 87 88 89 90 91 92 93 94 95 96 |
page_cache_get(page); SetPageSwapCache(page); set_page_private(page, entry.val); spin_lock_irq(&swapper_space.tree_lock); error = radix_tree_insert(&swapper_space.page_tree, entry.val, page); if (likely(!error)) { total_swapcache_pages++; __inc_zone_page_state(page, NR_FILE_PAGES); INC_CACHE_INFO(add_total); } spin_unlock_irq(&swapper_space.tree_lock); if (unlikely(error)) { |
2ca4532a4 mm: add_to_swap_c... |
97 98 99 100 101 102 |
/* * Only the context which have set SWAP_HAS_CACHE flag * would call add_to_swap_cache(). * So add_to_swap_cache() doesn't returns -EEXIST. */ VM_BUG_ON(error == -EEXIST); |
31a563962 mm: add_to_swap_c... |
103 104 105 106 107 108 109 110 111 112 113 114 |
set_page_private(page, 0UL); ClearPageSwapCache(page); page_cache_release(page); } return error; } int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask) { int error; |
35c754d79 memory controller... |
115 116 |
error = radix_tree_preload(gfp_mask); if (!error) { |
31a563962 mm: add_to_swap_c... |
117 |
error = __add_to_swap_cache(page, entry); |
1da177e4c Linux-2.6.12-rc2 |
118 |
radix_tree_preload_end(); |
fa1de9008 memcgroup: revert... |
119 |
} |
1da177e4c Linux-2.6.12-rc2 |
120 121 |
return error; } |
1da177e4c Linux-2.6.12-rc2 |
122 123 124 125 126 127 |
/* * This must be called only on pages that have * been verified to be in the swap cache. */ void __delete_from_swap_cache(struct page *page) { |
51726b122 mm: replace some ... |
128 129 130 |
VM_BUG_ON(!PageLocked(page)); VM_BUG_ON(!PageSwapCache(page)); VM_BUG_ON(PageWriteback(page)); |
1da177e4c Linux-2.6.12-rc2 |
131 |
|
4c21e2f24 [PATCH] mm: split... |
132 133 |
radix_tree_delete(&swapper_space.page_tree, page_private(page)); set_page_private(page, 0); |
1da177e4c Linux-2.6.12-rc2 |
134 135 |
ClearPageSwapCache(page); total_swapcache_pages--; |
347ce434d [PATCH] zoned vm ... |
136 |
__dec_zone_page_state(page, NR_FILE_PAGES); |
1da177e4c Linux-2.6.12-rc2 |
137 138 139 140 141 142 143 144 145 146 |
INC_CACHE_INFO(del_total); } /** * add_to_swap - allocate swap space for a page * @page: page we want to move to swap * * Allocate swap space for the page and add the page to the * swap cache. Caller needs to hold the page lock. */ |
ac47b003d mm: remove gfp_ma... |
147 |
int add_to_swap(struct page *page) |
1da177e4c Linux-2.6.12-rc2 |
148 149 |
{ swp_entry_t entry; |
1da177e4c Linux-2.6.12-rc2 |
150 |
int err; |
51726b122 mm: replace some ... |
151 152 |
VM_BUG_ON(!PageLocked(page)); VM_BUG_ON(!PageUptodate(page)); |
1da177e4c Linux-2.6.12-rc2 |
153 |
|
2ca4532a4 mm: add_to_swap_c... |
154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 |
entry = get_swap_page(); if (!entry.val) return 0; /* * Radix-tree node allocations from PF_MEMALLOC contexts could * completely exhaust the page allocator. __GFP_NOMEMALLOC * stops emergency reserves from being allocated. * * TODO: this could cause a theoretical memory reclaim * deadlock in the swap out path. */ /* * Add it to the swap cache and mark it dirty */ err = add_to_swap_cache(page, entry, __GFP_HIGH|__GFP_NOMEMALLOC|__GFP_NOWARN); if (!err) { /* Success */ SetPageDirty(page); return 1; } else { /* -ENOMEM radix-tree allocation failure */ |
bd53b714d [PATCH] mm: use _... |
176 |
/* |
2ca4532a4 mm: add_to_swap_c... |
177 178 |
* add_to_swap_cache() doesn't return -EEXIST, so we can safely * clear SWAP_HAS_CACHE flag. |
1da177e4c Linux-2.6.12-rc2 |
179 |
*/ |
2ca4532a4 mm: add_to_swap_c... |
180 181 |
swapcache_free(entry, NULL); return 0; |
1da177e4c Linux-2.6.12-rc2 |
182 183 184 185 186 187 188 189 190 191 192 193 |
} } /* * This must be called only on pages that have * been verified to be in the swap cache and locked. * It will never put the page into the free list, * the caller has a reference on the page. */ void delete_from_swap_cache(struct page *page) { swp_entry_t entry; |
4c21e2f24 [PATCH] mm: split... |
194 |
entry.val = page_private(page); |
1da177e4c Linux-2.6.12-rc2 |
195 |
|
19fd62312 mm: spinlock tree... |
196 |
spin_lock_irq(&swapper_space.tree_lock); |
1da177e4c Linux-2.6.12-rc2 |
197 |
__delete_from_swap_cache(page); |
19fd62312 mm: spinlock tree... |
198 |
spin_unlock_irq(&swapper_space.tree_lock); |
1da177e4c Linux-2.6.12-rc2 |
199 |
|
cb4b86ba4 mm: add swap cach... |
200 |
swapcache_free(entry, page); |
1da177e4c Linux-2.6.12-rc2 |
201 202 |
page_cache_release(page); } |
1da177e4c Linux-2.6.12-rc2 |
203 204 205 206 |
/* * If we are the only user, then try to free up the swap cache. * * Its ok to check for PageSwapCache without the page lock |
a2c43eed8 mm: try_to_free_s... |
207 208 |
* here because we are going to recheck again inside * try_to_free_swap() _with_ the lock. |
1da177e4c Linux-2.6.12-rc2 |
209 210 211 212 |
* - Marcelo */ static inline void free_swap_cache(struct page *page) { |
a2c43eed8 mm: try_to_free_s... |
213 214 |
if (PageSwapCache(page) && !page_mapped(page) && trylock_page(page)) { try_to_free_swap(page); |
1da177e4c Linux-2.6.12-rc2 |
215 216 217 218 219 220 |
unlock_page(page); } } /* * Perform a free_page(), also freeing any swap cache associated with |
b8072f099 [PATCH] mm: updat... |
221 |
* this page if it is the last user of the page. |
1da177e4c Linux-2.6.12-rc2 |
222 223 224 225 226 227 228 229 230 231 232 233 234 |
*/ void free_page_and_swap_cache(struct page *page) { free_swap_cache(page); page_cache_release(page); } /* * Passed an array of pages, drop them all from swapcache and then release * them. They are removed from the LRU and freed if this is their last use. */ void free_pages_and_swap_cache(struct page **pages, int nr) { |
1da177e4c Linux-2.6.12-rc2 |
235 236 237 238 |
struct page **pagep = pages; lru_add_drain(); while (nr) { |
c484d4104 [PATCH] mm: free_... |
239 |
int todo = min(nr, PAGEVEC_SIZE); |
1da177e4c Linux-2.6.12-rc2 |
240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 |
int i; for (i = 0; i < todo; i++) free_swap_cache(pagep[i]); release_pages(pagep, todo, 0); pagep += todo; nr -= todo; } } /* * Lookup a swap entry in the swap cache. A found page will be returned * unlocked and with its refcount incremented - we rely on the kernel * lock getting page table operations atomic even if we drop the page * lock before returning. */ struct page * lookup_swap_cache(swp_entry_t entry) { struct page *page; page = find_get_page(&swapper_space, entry.val); if (page) INC_CACHE_INFO(find_success); INC_CACHE_INFO(find_total); return page; } /* * Locate a page of swap in physical memory, reserving swap cache space * and reading the disk if it is not already cached. * A failure return means that either the page allocation failed or that * the swap entry is no longer in use. */ |
02098feaa swapin needs gfp_... |
275 |
struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, |
1da177e4c Linux-2.6.12-rc2 |
276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 |
struct vm_area_struct *vma, unsigned long addr) { struct page *found_page, *new_page = NULL; int err; do { /* * First check the swap cache. Since this is normally * called after lookup_swap_cache() failed, re-calling * that would confuse statistics. */ found_page = find_get_page(&swapper_space, entry.val); if (found_page) break; /* * Get a new page to read into from swap. */ if (!new_page) { |
02098feaa swapin needs gfp_... |
295 |
new_page = alloc_page_vma(gfp_mask, vma, addr); |
1da177e4c Linux-2.6.12-rc2 |
296 297 298 299 300 |
if (!new_page) break; /* Out of memory */ } /* |
31a563962 mm: add_to_swap_c... |
301 302 303 304 305 306 307 |
* call radix_tree_preload() while we can wait. */ err = radix_tree_preload(gfp_mask & GFP_KERNEL); if (err) break; /* |
f000944d0 tmpfs: shuffle ad... |
308 309 |
* Swap entry may have been freed since our caller observed it. */ |
355cfa73d mm: modify swap_m... |
310 |
err = swapcache_prepare(entry); |
31a563962 mm: add_to_swap_c... |
311 312 |
if (err == -EEXIST) { /* seems racy */ radix_tree_preload_end(); |
355cfa73d mm: modify swap_m... |
313 |
continue; |
31a563962 mm: add_to_swap_c... |
314 315 316 |
} if (err) { /* swp entry is obsolete ? */ radix_tree_preload_end(); |
f000944d0 tmpfs: shuffle ad... |
317 |
break; |
31a563962 mm: add_to_swap_c... |
318 |
} |
f000944d0 tmpfs: shuffle ad... |
319 |
|
2ca4532a4 mm: add_to_swap_c... |
320 |
/* May fail (-ENOMEM) if radix-tree node allocation failed. */ |
f45840b5c mm: pagecache ins... |
321 |
__set_page_locked(new_page); |
b2e185384 define page_file_... |
322 |
SetPageSwapBacked(new_page); |
31a563962 mm: add_to_swap_c... |
323 |
err = __add_to_swap_cache(new_page, entry); |
529ae9aaa mm: rename page t... |
324 |
if (likely(!err)) { |
31a563962 mm: add_to_swap_c... |
325 |
radix_tree_preload_end(); |
1da177e4c Linux-2.6.12-rc2 |
326 327 328 |
/* * Initiate read into locked page and return. */ |
c5fdae469 vmscan: add newly... |
329 |
lru_cache_add_anon(new_page); |
aca8bf323 mm: remove file a... |
330 |
swap_readpage(new_page); |
1da177e4c Linux-2.6.12-rc2 |
331 332 |
return new_page; } |
31a563962 mm: add_to_swap_c... |
333 |
radix_tree_preload_end(); |
b2e185384 define page_file_... |
334 |
ClearPageSwapBacked(new_page); |
f45840b5c mm: pagecache ins... |
335 |
__clear_page_locked(new_page); |
2ca4532a4 mm: add_to_swap_c... |
336 337 338 339 |
/* * add_to_swap_cache() doesn't return -EEXIST, so we can safely * clear SWAP_HAS_CACHE flag. */ |
cb4b86ba4 mm: add swap cach... |
340 |
swapcache_free(entry, NULL); |
f000944d0 tmpfs: shuffle ad... |
341 |
} while (err != -ENOMEM); |
1da177e4c Linux-2.6.12-rc2 |
342 343 344 345 346 |
if (new_page) page_cache_release(new_page); return found_page; } |
46017e954 swapin_readahead:... |
347 348 349 350 |
/** * swapin_readahead - swap in pages in hope we need them soon * @entry: swap entry of this memory |
7682486b3 mm: fix various k... |
351 |
* @gfp_mask: memory allocation flags |
46017e954 swapin_readahead:... |
352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 |
* @vma: user vma this address belongs to * @addr: target address for mempolicy * * Returns the struct page for entry and addr, after queueing swapin. * * Primitive swap readahead code. We simply read an aligned block of * (1 << page_cluster) entries in the swap area. This method is chosen * because it doesn't cost us any seek time. We also make sure to queue * the 'original' request together with the readahead ones... * * This has been extended to use the NUMA policies from the mm triggering * the readahead. * * Caller must hold down_read on the vma->vm_mm if vma is not NULL. */ |
02098feaa swapin needs gfp_... |
367 |
struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask, |
46017e954 swapin_readahead:... |
368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 |
struct vm_area_struct *vma, unsigned long addr) { int nr_pages; struct page *page; unsigned long offset; unsigned long end_offset; /* * Get starting offset for readaround, and number of pages to read. * Adjust starting address by readbehind (for NUMA interleave case)? * No, it's very unlikely that swap layout would follow vma layout, * more likely that neighbouring swap pages came from the same node: * so use the same "addr" to choose the same node for each swap read. */ nr_pages = valid_swaphandles(entry, &offset); for (end_offset = offset + nr_pages; offset < end_offset; offset++) { /* Ok, do the async read-ahead now */ page = read_swap_cache_async(swp_entry(swp_type(entry), offset), |
02098feaa swapin needs gfp_... |
386 |
gfp_mask, vma, addr); |
46017e954 swapin_readahead:... |
387 388 389 390 391 |
if (!page) break; page_cache_release(page); } lru_add_drain(); /* Push any new pages onto the LRU now */ |
02098feaa swapin needs gfp_... |
392 |
return read_swap_cache_async(entry, gfp_mask, vma, addr); |
46017e954 swapin_readahead:... |
393 |
} |