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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/mm/swapfile.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds | |
5 | * Swap reorganised 29.12.95, Stephen Tweedie | |
6 | */ | |
7 | ||
1da177e4 | 8 | #include <linux/mm.h> |
6e84f315 | 9 | #include <linux/sched/mm.h> |
29930025 | 10 | #include <linux/sched/task.h> |
1da177e4 LT |
11 | #include <linux/hugetlb.h> |
12 | #include <linux/mman.h> | |
13 | #include <linux/slab.h> | |
14 | #include <linux/kernel_stat.h> | |
15 | #include <linux/swap.h> | |
16 | #include <linux/vmalloc.h> | |
17 | #include <linux/pagemap.h> | |
18 | #include <linux/namei.h> | |
072441e2 | 19 | #include <linux/shmem_fs.h> |
1da177e4 | 20 | #include <linux/blkdev.h> |
20137a49 | 21 | #include <linux/random.h> |
1da177e4 LT |
22 | #include <linux/writeback.h> |
23 | #include <linux/proc_fs.h> | |
24 | #include <linux/seq_file.h> | |
25 | #include <linux/init.h> | |
5ad64688 | 26 | #include <linux/ksm.h> |
1da177e4 LT |
27 | #include <linux/rmap.h> |
28 | #include <linux/security.h> | |
29 | #include <linux/backing-dev.h> | |
fc0abb14 | 30 | #include <linux/mutex.h> |
c59ede7b | 31 | #include <linux/capability.h> |
1da177e4 | 32 | #include <linux/syscalls.h> |
8a9f3ccd | 33 | #include <linux/memcontrol.h> |
66d7dd51 | 34 | #include <linux/poll.h> |
72788c38 | 35 | #include <linux/oom.h> |
38b5faf4 DM |
36 | #include <linux/frontswap.h> |
37 | #include <linux/swapfile.h> | |
f981c595 | 38 | #include <linux/export.h> |
67afa38e | 39 | #include <linux/swap_slots.h> |
155b5f88 | 40 | #include <linux/sort.h> |
1da177e4 LT |
41 | |
42 | #include <asm/pgtable.h> | |
43 | #include <asm/tlbflush.h> | |
44 | #include <linux/swapops.h> | |
5d1ea48b | 45 | #include <linux/swap_cgroup.h> |
1da177e4 | 46 | |
570a335b HD |
47 | static bool swap_count_continued(struct swap_info_struct *, pgoff_t, |
48 | unsigned char); | |
49 | static void free_swap_count_continuations(struct swap_info_struct *); | |
d4906e1a | 50 | static sector_t map_swap_entry(swp_entry_t, struct block_device**); |
570a335b | 51 | |
38b5faf4 | 52 | DEFINE_SPINLOCK(swap_lock); |
7c363b8c | 53 | static unsigned int nr_swapfiles; |
ec8acf20 | 54 | atomic_long_t nr_swap_pages; |
fb0fec50 CW |
55 | /* |
56 | * Some modules use swappable objects and may try to swap them out under | |
57 | * memory pressure (via the shrinker). Before doing so, they may wish to | |
58 | * check to see if any swap space is available. | |
59 | */ | |
60 | EXPORT_SYMBOL_GPL(nr_swap_pages); | |
ec8acf20 | 61 | /* protected with swap_lock. reading in vm_swap_full() doesn't need lock */ |
1da177e4 | 62 | long total_swap_pages; |
a2468cc9 | 63 | static int least_priority = -1; |
1da177e4 | 64 | |
1da177e4 LT |
65 | static const char Bad_file[] = "Bad swap file entry "; |
66 | static const char Unused_file[] = "Unused swap file entry "; | |
67 | static const char Bad_offset[] = "Bad swap offset entry "; | |
68 | static const char Unused_offset[] = "Unused swap offset entry "; | |
69 | ||
adfab836 DS |
70 | /* |
71 | * all active swap_info_structs | |
72 | * protected with swap_lock, and ordered by priority. | |
73 | */ | |
18ab4d4c DS |
74 | PLIST_HEAD(swap_active_head); |
75 | ||
76 | /* | |
77 | * all available (active, not full) swap_info_structs | |
78 | * protected with swap_avail_lock, ordered by priority. | |
79 | * This is used by get_swap_page() instead of swap_active_head | |
80 | * because swap_active_head includes all swap_info_structs, | |
81 | * but get_swap_page() doesn't need to look at full ones. | |
82 | * This uses its own lock instead of swap_lock because when a | |
83 | * swap_info_struct changes between not-full/full, it needs to | |
84 | * add/remove itself to/from this list, but the swap_info_struct->lock | |
85 | * is held and the locking order requires swap_lock to be taken | |
86 | * before any swap_info_struct->lock. | |
87 | */ | |
bfc6b1ca | 88 | static struct plist_head *swap_avail_heads; |
18ab4d4c | 89 | static DEFINE_SPINLOCK(swap_avail_lock); |
1da177e4 | 90 | |
38b5faf4 | 91 | struct swap_info_struct *swap_info[MAX_SWAPFILES]; |
1da177e4 | 92 | |
fc0abb14 | 93 | static DEFINE_MUTEX(swapon_mutex); |
1da177e4 | 94 | |
66d7dd51 KS |
95 | static DECLARE_WAIT_QUEUE_HEAD(proc_poll_wait); |
96 | /* Activity counter to indicate that a swapon or swapoff has occurred */ | |
97 | static atomic_t proc_poll_event = ATOMIC_INIT(0); | |
98 | ||
81a0298b HY |
99 | atomic_t nr_rotate_swap = ATOMIC_INIT(0); |
100 | ||
c10d38cc DJ |
101 | static struct swap_info_struct *swap_type_to_swap_info(int type) |
102 | { | |
103 | if (type >= READ_ONCE(nr_swapfiles)) | |
104 | return NULL; | |
105 | ||
106 | smp_rmb(); /* Pairs with smp_wmb in alloc_swap_info. */ | |
107 | return READ_ONCE(swap_info[type]); | |
108 | } | |
109 | ||
8d69aaee | 110 | static inline unsigned char swap_count(unsigned char ent) |
355cfa73 | 111 | { |
955c97f0 | 112 | return ent & ~SWAP_HAS_CACHE; /* may include COUNT_CONTINUED flag */ |
355cfa73 KH |
113 | } |
114 | ||
bcd49e86 HY |
115 | /* Reclaim the swap entry anyway if possible */ |
116 | #define TTRS_ANYWAY 0x1 | |
117 | /* | |
118 | * Reclaim the swap entry if there are no more mappings of the | |
119 | * corresponding page | |
120 | */ | |
121 | #define TTRS_UNMAPPED 0x2 | |
122 | /* Reclaim the swap entry if swap is getting full*/ | |
123 | #define TTRS_FULL 0x4 | |
124 | ||
efa90a98 | 125 | /* returns 1 if swap entry is freed */ |
bcd49e86 HY |
126 | static int __try_to_reclaim_swap(struct swap_info_struct *si, |
127 | unsigned long offset, unsigned long flags) | |
c9e44410 | 128 | { |
efa90a98 | 129 | swp_entry_t entry = swp_entry(si->type, offset); |
c9e44410 KH |
130 | struct page *page; |
131 | int ret = 0; | |
132 | ||
bcd49e86 | 133 | page = find_get_page(swap_address_space(entry), offset); |
c9e44410 KH |
134 | if (!page) |
135 | return 0; | |
136 | /* | |
bcd49e86 HY |
137 | * When this function is called from scan_swap_map_slots() and it's |
138 | * called by vmscan.c at reclaiming pages. So, we hold a lock on a page, | |
139 | * here. We have to use trylock for avoiding deadlock. This is a special | |
c9e44410 KH |
140 | * case and you should use try_to_free_swap() with explicit lock_page() |
141 | * in usual operations. | |
142 | */ | |
143 | if (trylock_page(page)) { | |
bcd49e86 HY |
144 | if ((flags & TTRS_ANYWAY) || |
145 | ((flags & TTRS_UNMAPPED) && !page_mapped(page)) || | |
146 | ((flags & TTRS_FULL) && mem_cgroup_swap_full(page))) | |
147 | ret = try_to_free_swap(page); | |
c9e44410 KH |
148 | unlock_page(page); |
149 | } | |
09cbfeaf | 150 | put_page(page); |
c9e44410 KH |
151 | return ret; |
152 | } | |
355cfa73 | 153 | |
6a6ba831 HD |
154 | /* |
155 | * swapon tell device that all the old swap contents can be discarded, | |
156 | * to allow the swap device to optimize its wear-levelling. | |
157 | */ | |
158 | static int discard_swap(struct swap_info_struct *si) | |
159 | { | |
160 | struct swap_extent *se; | |
9625a5f2 HD |
161 | sector_t start_block; |
162 | sector_t nr_blocks; | |
6a6ba831 HD |
163 | int err = 0; |
164 | ||
9625a5f2 HD |
165 | /* Do not discard the swap header page! */ |
166 | se = &si->first_swap_extent; | |
167 | start_block = (se->start_block + 1) << (PAGE_SHIFT - 9); | |
168 | nr_blocks = ((sector_t)se->nr_pages - 1) << (PAGE_SHIFT - 9); | |
169 | if (nr_blocks) { | |
170 | err = blkdev_issue_discard(si->bdev, start_block, | |
dd3932ed | 171 | nr_blocks, GFP_KERNEL, 0); |
9625a5f2 HD |
172 | if (err) |
173 | return err; | |
174 | cond_resched(); | |
175 | } | |
6a6ba831 | 176 | |
9625a5f2 HD |
177 | list_for_each_entry(se, &si->first_swap_extent.list, list) { |
178 | start_block = se->start_block << (PAGE_SHIFT - 9); | |
179 | nr_blocks = (sector_t)se->nr_pages << (PAGE_SHIFT - 9); | |
6a6ba831 HD |
180 | |
181 | err = blkdev_issue_discard(si->bdev, start_block, | |
dd3932ed | 182 | nr_blocks, GFP_KERNEL, 0); |
6a6ba831 HD |
183 | if (err) |
184 | break; | |
185 | ||
186 | cond_resched(); | |
187 | } | |
188 | return err; /* That will often be -EOPNOTSUPP */ | |
189 | } | |
190 | ||
7992fde7 HD |
191 | /* |
192 | * swap allocation tell device that a cluster of swap can now be discarded, | |
193 | * to allow the swap device to optimize its wear-levelling. | |
194 | */ | |
195 | static void discard_swap_cluster(struct swap_info_struct *si, | |
196 | pgoff_t start_page, pgoff_t nr_pages) | |
197 | { | |
198 | struct swap_extent *se = si->curr_swap_extent; | |
199 | int found_extent = 0; | |
200 | ||
201 | while (nr_pages) { | |
7992fde7 HD |
202 | if (se->start_page <= start_page && |
203 | start_page < se->start_page + se->nr_pages) { | |
204 | pgoff_t offset = start_page - se->start_page; | |
205 | sector_t start_block = se->start_block + offset; | |
858a2990 | 206 | sector_t nr_blocks = se->nr_pages - offset; |
7992fde7 HD |
207 | |
208 | if (nr_blocks > nr_pages) | |
209 | nr_blocks = nr_pages; | |
210 | start_page += nr_blocks; | |
211 | nr_pages -= nr_blocks; | |
212 | ||
213 | if (!found_extent++) | |
214 | si->curr_swap_extent = se; | |
215 | ||
216 | start_block <<= PAGE_SHIFT - 9; | |
217 | nr_blocks <<= PAGE_SHIFT - 9; | |
218 | if (blkdev_issue_discard(si->bdev, start_block, | |
dd3932ed | 219 | nr_blocks, GFP_NOIO, 0)) |
7992fde7 HD |
220 | break; |
221 | } | |
222 | ||
a8ae4991 | 223 | se = list_next_entry(se, list); |
7992fde7 HD |
224 | } |
225 | } | |
226 | ||
38d8b4e6 HY |
227 | #ifdef CONFIG_THP_SWAP |
228 | #define SWAPFILE_CLUSTER HPAGE_PMD_NR | |
a448f2d0 HY |
229 | |
230 | #define swap_entry_size(size) (size) | |
38d8b4e6 | 231 | #else |
048c27fd | 232 | #define SWAPFILE_CLUSTER 256 |
a448f2d0 HY |
233 | |
234 | /* | |
235 | * Define swap_entry_size() as constant to let compiler to optimize | |
236 | * out some code if !CONFIG_THP_SWAP | |
237 | */ | |
238 | #define swap_entry_size(size) 1 | |
38d8b4e6 | 239 | #endif |
048c27fd HD |
240 | #define LATENCY_LIMIT 256 |
241 | ||
2a8f9449 SL |
242 | static inline void cluster_set_flag(struct swap_cluster_info *info, |
243 | unsigned int flag) | |
244 | { | |
245 | info->flags = flag; | |
246 | } | |
247 | ||
248 | static inline unsigned int cluster_count(struct swap_cluster_info *info) | |
249 | { | |
250 | return info->data; | |
251 | } | |
252 | ||
253 | static inline void cluster_set_count(struct swap_cluster_info *info, | |
254 | unsigned int c) | |
255 | { | |
256 | info->data = c; | |
257 | } | |
258 | ||
259 | static inline void cluster_set_count_flag(struct swap_cluster_info *info, | |
260 | unsigned int c, unsigned int f) | |
261 | { | |
262 | info->flags = f; | |
263 | info->data = c; | |
264 | } | |
265 | ||
266 | static inline unsigned int cluster_next(struct swap_cluster_info *info) | |
267 | { | |
268 | return info->data; | |
269 | } | |
270 | ||
271 | static inline void cluster_set_next(struct swap_cluster_info *info, | |
272 | unsigned int n) | |
273 | { | |
274 | info->data = n; | |
275 | } | |
276 | ||
277 | static inline void cluster_set_next_flag(struct swap_cluster_info *info, | |
278 | unsigned int n, unsigned int f) | |
279 | { | |
280 | info->flags = f; | |
281 | info->data = n; | |
282 | } | |
283 | ||
284 | static inline bool cluster_is_free(struct swap_cluster_info *info) | |
285 | { | |
286 | return info->flags & CLUSTER_FLAG_FREE; | |
287 | } | |
288 | ||
289 | static inline bool cluster_is_null(struct swap_cluster_info *info) | |
290 | { | |
291 | return info->flags & CLUSTER_FLAG_NEXT_NULL; | |
292 | } | |
293 | ||
294 | static inline void cluster_set_null(struct swap_cluster_info *info) | |
295 | { | |
296 | info->flags = CLUSTER_FLAG_NEXT_NULL; | |
297 | info->data = 0; | |
298 | } | |
299 | ||
e0709829 HY |
300 | static inline bool cluster_is_huge(struct swap_cluster_info *info) |
301 | { | |
33ee011e HY |
302 | if (IS_ENABLED(CONFIG_THP_SWAP)) |
303 | return info->flags & CLUSTER_FLAG_HUGE; | |
304 | return false; | |
e0709829 HY |
305 | } |
306 | ||
307 | static inline void cluster_clear_huge(struct swap_cluster_info *info) | |
308 | { | |
309 | info->flags &= ~CLUSTER_FLAG_HUGE; | |
310 | } | |
311 | ||
235b6217 HY |
312 | static inline struct swap_cluster_info *lock_cluster(struct swap_info_struct *si, |
313 | unsigned long offset) | |
314 | { | |
315 | struct swap_cluster_info *ci; | |
316 | ||
317 | ci = si->cluster_info; | |
318 | if (ci) { | |
319 | ci += offset / SWAPFILE_CLUSTER; | |
320 | spin_lock(&ci->lock); | |
321 | } | |
322 | return ci; | |
323 | } | |
324 | ||
325 | static inline void unlock_cluster(struct swap_cluster_info *ci) | |
326 | { | |
327 | if (ci) | |
328 | spin_unlock(&ci->lock); | |
329 | } | |
330 | ||
59d98bf3 HY |
331 | /* |
332 | * Determine the locking method in use for this device. Return | |
333 | * swap_cluster_info if SSD-style cluster-based locking is in place. | |
334 | */ | |
235b6217 | 335 | static inline struct swap_cluster_info *lock_cluster_or_swap_info( |
59d98bf3 | 336 | struct swap_info_struct *si, unsigned long offset) |
235b6217 HY |
337 | { |
338 | struct swap_cluster_info *ci; | |
339 | ||
59d98bf3 | 340 | /* Try to use fine-grained SSD-style locking if available: */ |
235b6217 | 341 | ci = lock_cluster(si, offset); |
59d98bf3 | 342 | /* Otherwise, fall back to traditional, coarse locking: */ |
235b6217 HY |
343 | if (!ci) |
344 | spin_lock(&si->lock); | |
345 | ||
346 | return ci; | |
347 | } | |
348 | ||
349 | static inline void unlock_cluster_or_swap_info(struct swap_info_struct *si, | |
350 | struct swap_cluster_info *ci) | |
351 | { | |
352 | if (ci) | |
353 | unlock_cluster(ci); | |
354 | else | |
355 | spin_unlock(&si->lock); | |
356 | } | |
357 | ||
6b534915 HY |
358 | static inline bool cluster_list_empty(struct swap_cluster_list *list) |
359 | { | |
360 | return cluster_is_null(&list->head); | |
361 | } | |
362 | ||
363 | static inline unsigned int cluster_list_first(struct swap_cluster_list *list) | |
364 | { | |
365 | return cluster_next(&list->head); | |
366 | } | |
367 | ||
368 | static void cluster_list_init(struct swap_cluster_list *list) | |
369 | { | |
370 | cluster_set_null(&list->head); | |
371 | cluster_set_null(&list->tail); | |
372 | } | |
373 | ||
374 | static void cluster_list_add_tail(struct swap_cluster_list *list, | |
375 | struct swap_cluster_info *ci, | |
376 | unsigned int idx) | |
377 | { | |
378 | if (cluster_list_empty(list)) { | |
379 | cluster_set_next_flag(&list->head, idx, 0); | |
380 | cluster_set_next_flag(&list->tail, idx, 0); | |
381 | } else { | |
235b6217 | 382 | struct swap_cluster_info *ci_tail; |
6b534915 HY |
383 | unsigned int tail = cluster_next(&list->tail); |
384 | ||
235b6217 HY |
385 | /* |
386 | * Nested cluster lock, but both cluster locks are | |
387 | * only acquired when we held swap_info_struct->lock | |
388 | */ | |
389 | ci_tail = ci + tail; | |
390 | spin_lock_nested(&ci_tail->lock, SINGLE_DEPTH_NESTING); | |
391 | cluster_set_next(ci_tail, idx); | |
0ef017d1 | 392 | spin_unlock(&ci_tail->lock); |
6b534915 HY |
393 | cluster_set_next_flag(&list->tail, idx, 0); |
394 | } | |
395 | } | |
396 | ||
397 | static unsigned int cluster_list_del_first(struct swap_cluster_list *list, | |
398 | struct swap_cluster_info *ci) | |
399 | { | |
400 | unsigned int idx; | |
401 | ||
402 | idx = cluster_next(&list->head); | |
403 | if (cluster_next(&list->tail) == idx) { | |
404 | cluster_set_null(&list->head); | |
405 | cluster_set_null(&list->tail); | |
406 | } else | |
407 | cluster_set_next_flag(&list->head, | |
408 | cluster_next(&ci[idx]), 0); | |
409 | ||
410 | return idx; | |
411 | } | |
412 | ||
815c2c54 SL |
413 | /* Add a cluster to discard list and schedule it to do discard */ |
414 | static void swap_cluster_schedule_discard(struct swap_info_struct *si, | |
415 | unsigned int idx) | |
416 | { | |
417 | /* | |
418 | * If scan_swap_map() can't find a free cluster, it will check | |
419 | * si->swap_map directly. To make sure the discarding cluster isn't | |
420 | * taken by scan_swap_map(), mark the swap entries bad (occupied). It | |
421 | * will be cleared after discard | |
422 | */ | |
423 | memset(si->swap_map + idx * SWAPFILE_CLUSTER, | |
424 | SWAP_MAP_BAD, SWAPFILE_CLUSTER); | |
425 | ||
6b534915 | 426 | cluster_list_add_tail(&si->discard_clusters, si->cluster_info, idx); |
815c2c54 SL |
427 | |
428 | schedule_work(&si->discard_work); | |
429 | } | |
430 | ||
38d8b4e6 HY |
431 | static void __free_cluster(struct swap_info_struct *si, unsigned long idx) |
432 | { | |
433 | struct swap_cluster_info *ci = si->cluster_info; | |
434 | ||
435 | cluster_set_flag(ci + idx, CLUSTER_FLAG_FREE); | |
436 | cluster_list_add_tail(&si->free_clusters, ci, idx); | |
437 | } | |
438 | ||
815c2c54 SL |
439 | /* |
440 | * Doing discard actually. After a cluster discard is finished, the cluster | |
441 | * will be added to free cluster list. caller should hold si->lock. | |
442 | */ | |
443 | static void swap_do_scheduled_discard(struct swap_info_struct *si) | |
444 | { | |
235b6217 | 445 | struct swap_cluster_info *info, *ci; |
815c2c54 SL |
446 | unsigned int idx; |
447 | ||
448 | info = si->cluster_info; | |
449 | ||
6b534915 HY |
450 | while (!cluster_list_empty(&si->discard_clusters)) { |
451 | idx = cluster_list_del_first(&si->discard_clusters, info); | |
815c2c54 SL |
452 | spin_unlock(&si->lock); |
453 | ||
454 | discard_swap_cluster(si, idx * SWAPFILE_CLUSTER, | |
455 | SWAPFILE_CLUSTER); | |
456 | ||
457 | spin_lock(&si->lock); | |
235b6217 | 458 | ci = lock_cluster(si, idx * SWAPFILE_CLUSTER); |
38d8b4e6 | 459 | __free_cluster(si, idx); |
815c2c54 SL |
460 | memset(si->swap_map + idx * SWAPFILE_CLUSTER, |
461 | 0, SWAPFILE_CLUSTER); | |
235b6217 | 462 | unlock_cluster(ci); |
815c2c54 SL |
463 | } |
464 | } | |
465 | ||
466 | static void swap_discard_work(struct work_struct *work) | |
467 | { | |
468 | struct swap_info_struct *si; | |
469 | ||
470 | si = container_of(work, struct swap_info_struct, discard_work); | |
471 | ||
472 | spin_lock(&si->lock); | |
473 | swap_do_scheduled_discard(si); | |
474 | spin_unlock(&si->lock); | |
475 | } | |
476 | ||
38d8b4e6 HY |
477 | static void alloc_cluster(struct swap_info_struct *si, unsigned long idx) |
478 | { | |
479 | struct swap_cluster_info *ci = si->cluster_info; | |
480 | ||
481 | VM_BUG_ON(cluster_list_first(&si->free_clusters) != idx); | |
482 | cluster_list_del_first(&si->free_clusters, ci); | |
483 | cluster_set_count_flag(ci + idx, 0, 0); | |
484 | } | |
485 | ||
486 | static void free_cluster(struct swap_info_struct *si, unsigned long idx) | |
487 | { | |
488 | struct swap_cluster_info *ci = si->cluster_info + idx; | |
489 | ||
490 | VM_BUG_ON(cluster_count(ci) != 0); | |
491 | /* | |
492 | * If the swap is discardable, prepare discard the cluster | |
493 | * instead of free it immediately. The cluster will be freed | |
494 | * after discard. | |
495 | */ | |
496 | if ((si->flags & (SWP_WRITEOK | SWP_PAGE_DISCARD)) == | |
497 | (SWP_WRITEOK | SWP_PAGE_DISCARD)) { | |
498 | swap_cluster_schedule_discard(si, idx); | |
499 | return; | |
500 | } | |
501 | ||
502 | __free_cluster(si, idx); | |
503 | } | |
504 | ||
2a8f9449 SL |
505 | /* |
506 | * The cluster corresponding to page_nr will be used. The cluster will be | |
507 | * removed from free cluster list and its usage counter will be increased. | |
508 | */ | |
509 | static void inc_cluster_info_page(struct swap_info_struct *p, | |
510 | struct swap_cluster_info *cluster_info, unsigned long page_nr) | |
511 | { | |
512 | unsigned long idx = page_nr / SWAPFILE_CLUSTER; | |
513 | ||
514 | if (!cluster_info) | |
515 | return; | |
38d8b4e6 HY |
516 | if (cluster_is_free(&cluster_info[idx])) |
517 | alloc_cluster(p, idx); | |
2a8f9449 SL |
518 | |
519 | VM_BUG_ON(cluster_count(&cluster_info[idx]) >= SWAPFILE_CLUSTER); | |
520 | cluster_set_count(&cluster_info[idx], | |
521 | cluster_count(&cluster_info[idx]) + 1); | |
522 | } | |
523 | ||
524 | /* | |
525 | * The cluster corresponding to page_nr decreases one usage. If the usage | |
526 | * counter becomes 0, which means no page in the cluster is in using, we can | |
527 | * optionally discard the cluster and add it to free cluster list. | |
528 | */ | |
529 | static void dec_cluster_info_page(struct swap_info_struct *p, | |
530 | struct swap_cluster_info *cluster_info, unsigned long page_nr) | |
531 | { | |
532 | unsigned long idx = page_nr / SWAPFILE_CLUSTER; | |
533 | ||
534 | if (!cluster_info) | |
535 | return; | |
536 | ||
537 | VM_BUG_ON(cluster_count(&cluster_info[idx]) == 0); | |
538 | cluster_set_count(&cluster_info[idx], | |
539 | cluster_count(&cluster_info[idx]) - 1); | |
540 | ||
38d8b4e6 HY |
541 | if (cluster_count(&cluster_info[idx]) == 0) |
542 | free_cluster(p, idx); | |
2a8f9449 SL |
543 | } |
544 | ||
545 | /* | |
546 | * It's possible scan_swap_map() uses a free cluster in the middle of free | |
547 | * cluster list. Avoiding such abuse to avoid list corruption. | |
548 | */ | |
ebc2a1a6 SL |
549 | static bool |
550 | scan_swap_map_ssd_cluster_conflict(struct swap_info_struct *si, | |
2a8f9449 SL |
551 | unsigned long offset) |
552 | { | |
ebc2a1a6 SL |
553 | struct percpu_cluster *percpu_cluster; |
554 | bool conflict; | |
555 | ||
2a8f9449 | 556 | offset /= SWAPFILE_CLUSTER; |
6b534915 HY |
557 | conflict = !cluster_list_empty(&si->free_clusters) && |
558 | offset != cluster_list_first(&si->free_clusters) && | |
2a8f9449 | 559 | cluster_is_free(&si->cluster_info[offset]); |
ebc2a1a6 SL |
560 | |
561 | if (!conflict) | |
562 | return false; | |
563 | ||
564 | percpu_cluster = this_cpu_ptr(si->percpu_cluster); | |
565 | cluster_set_null(&percpu_cluster->index); | |
566 | return true; | |
567 | } | |
568 | ||
569 | /* | |
570 | * Try to get a swap entry from current cpu's swap entry pool (a cluster). This | |
571 | * might involve allocating a new cluster for current CPU too. | |
572 | */ | |
36005bae | 573 | static bool scan_swap_map_try_ssd_cluster(struct swap_info_struct *si, |
ebc2a1a6 SL |
574 | unsigned long *offset, unsigned long *scan_base) |
575 | { | |
576 | struct percpu_cluster *cluster; | |
235b6217 | 577 | struct swap_cluster_info *ci; |
ebc2a1a6 | 578 | bool found_free; |
235b6217 | 579 | unsigned long tmp, max; |
ebc2a1a6 SL |
580 | |
581 | new_cluster: | |
582 | cluster = this_cpu_ptr(si->percpu_cluster); | |
583 | if (cluster_is_null(&cluster->index)) { | |
6b534915 HY |
584 | if (!cluster_list_empty(&si->free_clusters)) { |
585 | cluster->index = si->free_clusters.head; | |
ebc2a1a6 SL |
586 | cluster->next = cluster_next(&cluster->index) * |
587 | SWAPFILE_CLUSTER; | |
6b534915 | 588 | } else if (!cluster_list_empty(&si->discard_clusters)) { |
ebc2a1a6 SL |
589 | /* |
590 | * we don't have free cluster but have some clusters in | |
591 | * discarding, do discard now and reclaim them | |
592 | */ | |
593 | swap_do_scheduled_discard(si); | |
594 | *scan_base = *offset = si->cluster_next; | |
595 | goto new_cluster; | |
596 | } else | |
36005bae | 597 | return false; |
ebc2a1a6 SL |
598 | } |
599 | ||
600 | found_free = false; | |
601 | ||
602 | /* | |
603 | * Other CPUs can use our cluster if they can't find a free cluster, | |
604 | * check if there is still free entry in the cluster | |
605 | */ | |
606 | tmp = cluster->next; | |
235b6217 HY |
607 | max = min_t(unsigned long, si->max, |
608 | (cluster_next(&cluster->index) + 1) * SWAPFILE_CLUSTER); | |
609 | if (tmp >= max) { | |
610 | cluster_set_null(&cluster->index); | |
611 | goto new_cluster; | |
612 | } | |
613 | ci = lock_cluster(si, tmp); | |
614 | while (tmp < max) { | |
ebc2a1a6 SL |
615 | if (!si->swap_map[tmp]) { |
616 | found_free = true; | |
617 | break; | |
618 | } | |
619 | tmp++; | |
620 | } | |
235b6217 | 621 | unlock_cluster(ci); |
ebc2a1a6 SL |
622 | if (!found_free) { |
623 | cluster_set_null(&cluster->index); | |
624 | goto new_cluster; | |
625 | } | |
626 | cluster->next = tmp + 1; | |
627 | *offset = tmp; | |
628 | *scan_base = tmp; | |
36005bae | 629 | return found_free; |
2a8f9449 SL |
630 | } |
631 | ||
a2468cc9 AL |
632 | static void __del_from_avail_list(struct swap_info_struct *p) |
633 | { | |
634 | int nid; | |
635 | ||
636 | for_each_node(nid) | |
637 | plist_del(&p->avail_lists[nid], &swap_avail_heads[nid]); | |
638 | } | |
639 | ||
640 | static void del_from_avail_list(struct swap_info_struct *p) | |
641 | { | |
642 | spin_lock(&swap_avail_lock); | |
643 | __del_from_avail_list(p); | |
644 | spin_unlock(&swap_avail_lock); | |
645 | } | |
646 | ||
38d8b4e6 HY |
647 | static void swap_range_alloc(struct swap_info_struct *si, unsigned long offset, |
648 | unsigned int nr_entries) | |
649 | { | |
650 | unsigned int end = offset + nr_entries - 1; | |
651 | ||
652 | if (offset == si->lowest_bit) | |
653 | si->lowest_bit += nr_entries; | |
654 | if (end == si->highest_bit) | |
655 | si->highest_bit -= nr_entries; | |
656 | si->inuse_pages += nr_entries; | |
657 | if (si->inuse_pages == si->pages) { | |
658 | si->lowest_bit = si->max; | |
659 | si->highest_bit = 0; | |
a2468cc9 | 660 | del_from_avail_list(si); |
38d8b4e6 HY |
661 | } |
662 | } | |
663 | ||
a2468cc9 AL |
664 | static void add_to_avail_list(struct swap_info_struct *p) |
665 | { | |
666 | int nid; | |
667 | ||
668 | spin_lock(&swap_avail_lock); | |
669 | for_each_node(nid) { | |
670 | WARN_ON(!plist_node_empty(&p->avail_lists[nid])); | |
671 | plist_add(&p->avail_lists[nid], &swap_avail_heads[nid]); | |
672 | } | |
673 | spin_unlock(&swap_avail_lock); | |
674 | } | |
675 | ||
38d8b4e6 HY |
676 | static void swap_range_free(struct swap_info_struct *si, unsigned long offset, |
677 | unsigned int nr_entries) | |
678 | { | |
679 | unsigned long end = offset + nr_entries - 1; | |
680 | void (*swap_slot_free_notify)(struct block_device *, unsigned long); | |
681 | ||
682 | if (offset < si->lowest_bit) | |
683 | si->lowest_bit = offset; | |
684 | if (end > si->highest_bit) { | |
685 | bool was_full = !si->highest_bit; | |
686 | ||
687 | si->highest_bit = end; | |
a2468cc9 AL |
688 | if (was_full && (si->flags & SWP_WRITEOK)) |
689 | add_to_avail_list(si); | |
38d8b4e6 HY |
690 | } |
691 | atomic_long_add(nr_entries, &nr_swap_pages); | |
692 | si->inuse_pages -= nr_entries; | |
693 | if (si->flags & SWP_BLKDEV) | |
694 | swap_slot_free_notify = | |
695 | si->bdev->bd_disk->fops->swap_slot_free_notify; | |
696 | else | |
697 | swap_slot_free_notify = NULL; | |
698 | while (offset <= end) { | |
699 | frontswap_invalidate_page(si->type, offset); | |
700 | if (swap_slot_free_notify) | |
701 | swap_slot_free_notify(si->bdev, offset); | |
702 | offset++; | |
703 | } | |
704 | } | |
705 | ||
36005bae TC |
706 | static int scan_swap_map_slots(struct swap_info_struct *si, |
707 | unsigned char usage, int nr, | |
708 | swp_entry_t slots[]) | |
1da177e4 | 709 | { |
235b6217 | 710 | struct swap_cluster_info *ci; |
ebebbbe9 | 711 | unsigned long offset; |
c60aa176 | 712 | unsigned long scan_base; |
7992fde7 | 713 | unsigned long last_in_cluster = 0; |
048c27fd | 714 | int latency_ration = LATENCY_LIMIT; |
36005bae TC |
715 | int n_ret = 0; |
716 | ||
717 | if (nr > SWAP_BATCH) | |
718 | nr = SWAP_BATCH; | |
7dfad418 | 719 | |
886bb7e9 | 720 | /* |
7dfad418 HD |
721 | * We try to cluster swap pages by allocating them sequentially |
722 | * in swap. Once we've allocated SWAPFILE_CLUSTER pages this | |
723 | * way, however, we resort to first-free allocation, starting | |
724 | * a new cluster. This prevents us from scattering swap pages | |
725 | * all over the entire swap partition, so that we reduce | |
726 | * overall disk seek times between swap pages. -- sct | |
727 | * But we do now try to find an empty cluster. -Andrea | |
c60aa176 | 728 | * And we let swap pages go all over an SSD partition. Hugh |
7dfad418 HD |
729 | */ |
730 | ||
52b7efdb | 731 | si->flags += SWP_SCANNING; |
c60aa176 | 732 | scan_base = offset = si->cluster_next; |
ebebbbe9 | 733 | |
ebc2a1a6 SL |
734 | /* SSD algorithm */ |
735 | if (si->cluster_info) { | |
36005bae TC |
736 | if (scan_swap_map_try_ssd_cluster(si, &offset, &scan_base)) |
737 | goto checks; | |
738 | else | |
739 | goto scan; | |
ebc2a1a6 SL |
740 | } |
741 | ||
ebebbbe9 HD |
742 | if (unlikely(!si->cluster_nr--)) { |
743 | if (si->pages - si->inuse_pages < SWAPFILE_CLUSTER) { | |
744 | si->cluster_nr = SWAPFILE_CLUSTER - 1; | |
745 | goto checks; | |
746 | } | |
2a8f9449 | 747 | |
ec8acf20 | 748 | spin_unlock(&si->lock); |
7dfad418 | 749 | |
c60aa176 HD |
750 | /* |
751 | * If seek is expensive, start searching for new cluster from | |
752 | * start of partition, to minimize the span of allocated swap. | |
50088c44 CY |
753 | * If seek is cheap, that is the SWP_SOLIDSTATE si->cluster_info |
754 | * case, just handled by scan_swap_map_try_ssd_cluster() above. | |
c60aa176 | 755 | */ |
50088c44 | 756 | scan_base = offset = si->lowest_bit; |
7dfad418 HD |
757 | last_in_cluster = offset + SWAPFILE_CLUSTER - 1; |
758 | ||
759 | /* Locate the first empty (unaligned) cluster */ | |
760 | for (; last_in_cluster <= si->highest_bit; offset++) { | |
1da177e4 | 761 | if (si->swap_map[offset]) |
7dfad418 HD |
762 | last_in_cluster = offset + SWAPFILE_CLUSTER; |
763 | else if (offset == last_in_cluster) { | |
ec8acf20 | 764 | spin_lock(&si->lock); |
ebebbbe9 HD |
765 | offset -= SWAPFILE_CLUSTER - 1; |
766 | si->cluster_next = offset; | |
767 | si->cluster_nr = SWAPFILE_CLUSTER - 1; | |
c60aa176 HD |
768 | goto checks; |
769 | } | |
770 | if (unlikely(--latency_ration < 0)) { | |
771 | cond_resched(); | |
772 | latency_ration = LATENCY_LIMIT; | |
773 | } | |
774 | } | |
775 | ||
776 | offset = scan_base; | |
ec8acf20 | 777 | spin_lock(&si->lock); |
ebebbbe9 | 778 | si->cluster_nr = SWAPFILE_CLUSTER - 1; |
1da177e4 | 779 | } |
7dfad418 | 780 | |
ebebbbe9 | 781 | checks: |
ebc2a1a6 | 782 | if (si->cluster_info) { |
36005bae TC |
783 | while (scan_swap_map_ssd_cluster_conflict(si, offset)) { |
784 | /* take a break if we already got some slots */ | |
785 | if (n_ret) | |
786 | goto done; | |
787 | if (!scan_swap_map_try_ssd_cluster(si, &offset, | |
788 | &scan_base)) | |
789 | goto scan; | |
790 | } | |
ebc2a1a6 | 791 | } |
ebebbbe9 | 792 | if (!(si->flags & SWP_WRITEOK)) |
52b7efdb | 793 | goto no_page; |
7dfad418 HD |
794 | if (!si->highest_bit) |
795 | goto no_page; | |
ebebbbe9 | 796 | if (offset > si->highest_bit) |
c60aa176 | 797 | scan_base = offset = si->lowest_bit; |
c9e44410 | 798 | |
235b6217 | 799 | ci = lock_cluster(si, offset); |
b73d7fce HD |
800 | /* reuse swap entry of cache-only swap if not busy. */ |
801 | if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) { | |
c9e44410 | 802 | int swap_was_freed; |
235b6217 | 803 | unlock_cluster(ci); |
ec8acf20 | 804 | spin_unlock(&si->lock); |
bcd49e86 | 805 | swap_was_freed = __try_to_reclaim_swap(si, offset, TTRS_ANYWAY); |
ec8acf20 | 806 | spin_lock(&si->lock); |
c9e44410 KH |
807 | /* entry was freed successfully, try to use this again */ |
808 | if (swap_was_freed) | |
809 | goto checks; | |
810 | goto scan; /* check next one */ | |
811 | } | |
812 | ||
235b6217 HY |
813 | if (si->swap_map[offset]) { |
814 | unlock_cluster(ci); | |
36005bae TC |
815 | if (!n_ret) |
816 | goto scan; | |
817 | else | |
818 | goto done; | |
235b6217 | 819 | } |
2872bb2d HY |
820 | si->swap_map[offset] = usage; |
821 | inc_cluster_info_page(si, si->cluster_info, offset); | |
822 | unlock_cluster(ci); | |
ebebbbe9 | 823 | |
38d8b4e6 | 824 | swap_range_alloc(si, offset, 1); |
ebebbbe9 | 825 | si->cluster_next = offset + 1; |
36005bae TC |
826 | slots[n_ret++] = swp_entry(si->type, offset); |
827 | ||
828 | /* got enough slots or reach max slots? */ | |
829 | if ((n_ret == nr) || (offset >= si->highest_bit)) | |
830 | goto done; | |
831 | ||
832 | /* search for next available slot */ | |
833 | ||
834 | /* time to take a break? */ | |
835 | if (unlikely(--latency_ration < 0)) { | |
836 | if (n_ret) | |
837 | goto done; | |
838 | spin_unlock(&si->lock); | |
839 | cond_resched(); | |
840 | spin_lock(&si->lock); | |
841 | latency_ration = LATENCY_LIMIT; | |
842 | } | |
843 | ||
844 | /* try to get more slots in cluster */ | |
845 | if (si->cluster_info) { | |
846 | if (scan_swap_map_try_ssd_cluster(si, &offset, &scan_base)) | |
847 | goto checks; | |
848 | else | |
849 | goto done; | |
850 | } | |
851 | /* non-ssd case */ | |
852 | ++offset; | |
853 | ||
854 | /* non-ssd case, still more slots in cluster? */ | |
855 | if (si->cluster_nr && !si->swap_map[offset]) { | |
856 | --si->cluster_nr; | |
857 | goto checks; | |
858 | } | |
7992fde7 | 859 | |
36005bae TC |
860 | done: |
861 | si->flags -= SWP_SCANNING; | |
862 | return n_ret; | |
7dfad418 | 863 | |
ebebbbe9 | 864 | scan: |
ec8acf20 | 865 | spin_unlock(&si->lock); |
7dfad418 | 866 | while (++offset <= si->highest_bit) { |
52b7efdb | 867 | if (!si->swap_map[offset]) { |
ec8acf20 | 868 | spin_lock(&si->lock); |
52b7efdb HD |
869 | goto checks; |
870 | } | |
c9e44410 | 871 | if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) { |
ec8acf20 | 872 | spin_lock(&si->lock); |
c9e44410 KH |
873 | goto checks; |
874 | } | |
048c27fd HD |
875 | if (unlikely(--latency_ration < 0)) { |
876 | cond_resched(); | |
877 | latency_ration = LATENCY_LIMIT; | |
878 | } | |
7dfad418 | 879 | } |
c60aa176 | 880 | offset = si->lowest_bit; |
a5998061 | 881 | while (offset < scan_base) { |
c60aa176 | 882 | if (!si->swap_map[offset]) { |
ec8acf20 | 883 | spin_lock(&si->lock); |
c60aa176 HD |
884 | goto checks; |
885 | } | |
c9e44410 | 886 | if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) { |
ec8acf20 | 887 | spin_lock(&si->lock); |
c9e44410 KH |
888 | goto checks; |
889 | } | |
c60aa176 HD |
890 | if (unlikely(--latency_ration < 0)) { |
891 | cond_resched(); | |
892 | latency_ration = LATENCY_LIMIT; | |
893 | } | |
a5998061 | 894 | offset++; |
c60aa176 | 895 | } |
ec8acf20 | 896 | spin_lock(&si->lock); |
7dfad418 HD |
897 | |
898 | no_page: | |
52b7efdb | 899 | si->flags -= SWP_SCANNING; |
36005bae | 900 | return n_ret; |
1da177e4 LT |
901 | } |
902 | ||
38d8b4e6 HY |
903 | static int swap_alloc_cluster(struct swap_info_struct *si, swp_entry_t *slot) |
904 | { | |
905 | unsigned long idx; | |
906 | struct swap_cluster_info *ci; | |
907 | unsigned long offset, i; | |
908 | unsigned char *map; | |
909 | ||
fe5266d5 HY |
910 | /* |
911 | * Should not even be attempting cluster allocations when huge | |
912 | * page swap is disabled. Warn and fail the allocation. | |
913 | */ | |
914 | if (!IS_ENABLED(CONFIG_THP_SWAP)) { | |
915 | VM_WARN_ON_ONCE(1); | |
916 | return 0; | |
917 | } | |
918 | ||
38d8b4e6 HY |
919 | if (cluster_list_empty(&si->free_clusters)) |
920 | return 0; | |
921 | ||
922 | idx = cluster_list_first(&si->free_clusters); | |
923 | offset = idx * SWAPFILE_CLUSTER; | |
924 | ci = lock_cluster(si, offset); | |
925 | alloc_cluster(si, idx); | |
e0709829 | 926 | cluster_set_count_flag(ci, SWAPFILE_CLUSTER, CLUSTER_FLAG_HUGE); |
38d8b4e6 HY |
927 | |
928 | map = si->swap_map + offset; | |
929 | for (i = 0; i < SWAPFILE_CLUSTER; i++) | |
930 | map[i] = SWAP_HAS_CACHE; | |
931 | unlock_cluster(ci); | |
932 | swap_range_alloc(si, offset, SWAPFILE_CLUSTER); | |
933 | *slot = swp_entry(si->type, offset); | |
934 | ||
935 | return 1; | |
936 | } | |
937 | ||
938 | static void swap_free_cluster(struct swap_info_struct *si, unsigned long idx) | |
939 | { | |
940 | unsigned long offset = idx * SWAPFILE_CLUSTER; | |
941 | struct swap_cluster_info *ci; | |
942 | ||
943 | ci = lock_cluster(si, offset); | |
979aafa5 | 944 | memset(si->swap_map + offset, 0, SWAPFILE_CLUSTER); |
38d8b4e6 HY |
945 | cluster_set_count_flag(ci, 0, 0); |
946 | free_cluster(si, idx); | |
947 | unlock_cluster(ci); | |
948 | swap_range_free(si, offset, SWAPFILE_CLUSTER); | |
949 | } | |
38d8b4e6 | 950 | |
36005bae TC |
951 | static unsigned long scan_swap_map(struct swap_info_struct *si, |
952 | unsigned char usage) | |
953 | { | |
954 | swp_entry_t entry; | |
955 | int n_ret; | |
956 | ||
957 | n_ret = scan_swap_map_slots(si, usage, 1, &entry); | |
958 | ||
959 | if (n_ret) | |
960 | return swp_offset(entry); | |
961 | else | |
962 | return 0; | |
963 | ||
964 | } | |
965 | ||
5d5e8f19 | 966 | int get_swap_pages(int n_goal, swp_entry_t swp_entries[], int entry_size) |
1da177e4 | 967 | { |
5d5e8f19 | 968 | unsigned long size = swap_entry_size(entry_size); |
adfab836 | 969 | struct swap_info_struct *si, *next; |
36005bae TC |
970 | long avail_pgs; |
971 | int n_ret = 0; | |
a2468cc9 | 972 | int node; |
1da177e4 | 973 | |
38d8b4e6 | 974 | /* Only single cluster request supported */ |
5d5e8f19 | 975 | WARN_ON_ONCE(n_goal > 1 && size == SWAPFILE_CLUSTER); |
38d8b4e6 | 976 | |
5d5e8f19 | 977 | avail_pgs = atomic_long_read(&nr_swap_pages) / size; |
36005bae | 978 | if (avail_pgs <= 0) |
fb4f88dc | 979 | goto noswap; |
36005bae TC |
980 | |
981 | if (n_goal > SWAP_BATCH) | |
982 | n_goal = SWAP_BATCH; | |
983 | ||
984 | if (n_goal > avail_pgs) | |
985 | n_goal = avail_pgs; | |
986 | ||
5d5e8f19 | 987 | atomic_long_sub(n_goal * size, &nr_swap_pages); |
fb4f88dc | 988 | |
18ab4d4c DS |
989 | spin_lock(&swap_avail_lock); |
990 | ||
991 | start_over: | |
a2468cc9 AL |
992 | node = numa_node_id(); |
993 | plist_for_each_entry_safe(si, next, &swap_avail_heads[node], avail_lists[node]) { | |
18ab4d4c | 994 | /* requeue si to after same-priority siblings */ |
a2468cc9 | 995 | plist_requeue(&si->avail_lists[node], &swap_avail_heads[node]); |
18ab4d4c | 996 | spin_unlock(&swap_avail_lock); |
ec8acf20 | 997 | spin_lock(&si->lock); |
adfab836 | 998 | if (!si->highest_bit || !(si->flags & SWP_WRITEOK)) { |
18ab4d4c | 999 | spin_lock(&swap_avail_lock); |
a2468cc9 | 1000 | if (plist_node_empty(&si->avail_lists[node])) { |
18ab4d4c DS |
1001 | spin_unlock(&si->lock); |
1002 | goto nextsi; | |
1003 | } | |
1004 | WARN(!si->highest_bit, | |
1005 | "swap_info %d in list but !highest_bit\n", | |
1006 | si->type); | |
1007 | WARN(!(si->flags & SWP_WRITEOK), | |
1008 | "swap_info %d in list but !SWP_WRITEOK\n", | |
1009 | si->type); | |
a2468cc9 | 1010 | __del_from_avail_list(si); |
ec8acf20 | 1011 | spin_unlock(&si->lock); |
18ab4d4c | 1012 | goto nextsi; |
ec8acf20 | 1013 | } |
5d5e8f19 | 1014 | if (size == SWAPFILE_CLUSTER) { |
bc4ae27d | 1015 | if (!(si->flags & SWP_FS)) |
f0eea189 HY |
1016 | n_ret = swap_alloc_cluster(si, swp_entries); |
1017 | } else | |
38d8b4e6 HY |
1018 | n_ret = scan_swap_map_slots(si, SWAP_HAS_CACHE, |
1019 | n_goal, swp_entries); | |
ec8acf20 | 1020 | spin_unlock(&si->lock); |
5d5e8f19 | 1021 | if (n_ret || size == SWAPFILE_CLUSTER) |
36005bae | 1022 | goto check_out; |
18ab4d4c | 1023 | pr_debug("scan_swap_map of si %d failed to find offset\n", |
36005bae TC |
1024 | si->type); |
1025 | ||
18ab4d4c DS |
1026 | spin_lock(&swap_avail_lock); |
1027 | nextsi: | |
adfab836 DS |
1028 | /* |
1029 | * if we got here, it's likely that si was almost full before, | |
1030 | * and since scan_swap_map() can drop the si->lock, multiple | |
1031 | * callers probably all tried to get a page from the same si | |
18ab4d4c DS |
1032 | * and it filled up before we could get one; or, the si filled |
1033 | * up between us dropping swap_avail_lock and taking si->lock. | |
1034 | * Since we dropped the swap_avail_lock, the swap_avail_head | |
1035 | * list may have been modified; so if next is still in the | |
36005bae TC |
1036 | * swap_avail_head list then try it, otherwise start over |
1037 | * if we have not gotten any slots. | |
adfab836 | 1038 | */ |
a2468cc9 | 1039 | if (plist_node_empty(&next->avail_lists[node])) |
18ab4d4c | 1040 | goto start_over; |
1da177e4 | 1041 | } |
fb4f88dc | 1042 | |
18ab4d4c DS |
1043 | spin_unlock(&swap_avail_lock); |
1044 | ||
36005bae TC |
1045 | check_out: |
1046 | if (n_ret < n_goal) | |
5d5e8f19 | 1047 | atomic_long_add((long)(n_goal - n_ret) * size, |
38d8b4e6 | 1048 | &nr_swap_pages); |
fb4f88dc | 1049 | noswap: |
36005bae TC |
1050 | return n_ret; |
1051 | } | |
1052 | ||
2de1a7e4 | 1053 | /* The only caller of this function is now suspend routine */ |
910321ea HD |
1054 | swp_entry_t get_swap_page_of_type(int type) |
1055 | { | |
c10d38cc | 1056 | struct swap_info_struct *si = swap_type_to_swap_info(type); |
910321ea HD |
1057 | pgoff_t offset; |
1058 | ||
c10d38cc DJ |
1059 | if (!si) |
1060 | goto fail; | |
1061 | ||
ec8acf20 | 1062 | spin_lock(&si->lock); |
c10d38cc | 1063 | if (si->flags & SWP_WRITEOK) { |
ec8acf20 | 1064 | atomic_long_dec(&nr_swap_pages); |
910321ea HD |
1065 | /* This is called for allocating swap entry, not cache */ |
1066 | offset = scan_swap_map(si, 1); | |
1067 | if (offset) { | |
ec8acf20 | 1068 | spin_unlock(&si->lock); |
910321ea HD |
1069 | return swp_entry(type, offset); |
1070 | } | |
ec8acf20 | 1071 | atomic_long_inc(&nr_swap_pages); |
910321ea | 1072 | } |
ec8acf20 | 1073 | spin_unlock(&si->lock); |
c10d38cc | 1074 | fail: |
910321ea HD |
1075 | return (swp_entry_t) {0}; |
1076 | } | |
1077 | ||
e8c26ab6 | 1078 | static struct swap_info_struct *__swap_info_get(swp_entry_t entry) |
1da177e4 | 1079 | { |
73c34b6a | 1080 | struct swap_info_struct *p; |
1da177e4 LT |
1081 | unsigned long offset, type; |
1082 | ||
1083 | if (!entry.val) | |
1084 | goto out; | |
1085 | type = swp_type(entry); | |
c10d38cc DJ |
1086 | p = swap_type_to_swap_info(type); |
1087 | if (!p) | |
1da177e4 | 1088 | goto bad_nofile; |
1da177e4 LT |
1089 | if (!(p->flags & SWP_USED)) |
1090 | goto bad_device; | |
1091 | offset = swp_offset(entry); | |
1092 | if (offset >= p->max) | |
1093 | goto bad_offset; | |
1da177e4 LT |
1094 | return p; |
1095 | ||
1da177e4 | 1096 | bad_offset: |
6a991fc7 | 1097 | pr_err("swap_info_get: %s%08lx\n", Bad_offset, entry.val); |
1da177e4 LT |
1098 | goto out; |
1099 | bad_device: | |
6a991fc7 | 1100 | pr_err("swap_info_get: %s%08lx\n", Unused_file, entry.val); |
1da177e4 LT |
1101 | goto out; |
1102 | bad_nofile: | |
6a991fc7 | 1103 | pr_err("swap_info_get: %s%08lx\n", Bad_file, entry.val); |
1da177e4 LT |
1104 | out: |
1105 | return NULL; | |
886bb7e9 | 1106 | } |
1da177e4 | 1107 | |
e8c26ab6 TC |
1108 | static struct swap_info_struct *_swap_info_get(swp_entry_t entry) |
1109 | { | |
1110 | struct swap_info_struct *p; | |
1111 | ||
1112 | p = __swap_info_get(entry); | |
1113 | if (!p) | |
1114 | goto out; | |
1115 | if (!p->swap_map[swp_offset(entry)]) | |
1116 | goto bad_free; | |
1117 | return p; | |
1118 | ||
1119 | bad_free: | |
1120 | pr_err("swap_info_get: %s%08lx\n", Unused_offset, entry.val); | |
1121 | goto out; | |
1122 | out: | |
1123 | return NULL; | |
1124 | } | |
1125 | ||
235b6217 HY |
1126 | static struct swap_info_struct *swap_info_get(swp_entry_t entry) |
1127 | { | |
1128 | struct swap_info_struct *p; | |
1129 | ||
1130 | p = _swap_info_get(entry); | |
1131 | if (p) | |
1132 | spin_lock(&p->lock); | |
1133 | return p; | |
1134 | } | |
1135 | ||
7c00bafe TC |
1136 | static struct swap_info_struct *swap_info_get_cont(swp_entry_t entry, |
1137 | struct swap_info_struct *q) | |
1138 | { | |
1139 | struct swap_info_struct *p; | |
1140 | ||
1141 | p = _swap_info_get(entry); | |
1142 | ||
1143 | if (p != q) { | |
1144 | if (q != NULL) | |
1145 | spin_unlock(&q->lock); | |
1146 | if (p != NULL) | |
1147 | spin_lock(&p->lock); | |
1148 | } | |
1149 | return p; | |
1150 | } | |
1151 | ||
b32d5f32 HY |
1152 | static unsigned char __swap_entry_free_locked(struct swap_info_struct *p, |
1153 | unsigned long offset, | |
1154 | unsigned char usage) | |
1da177e4 | 1155 | { |
8d69aaee HD |
1156 | unsigned char count; |
1157 | unsigned char has_cache; | |
235b6217 | 1158 | |
253d553b | 1159 | count = p->swap_map[offset]; |
235b6217 | 1160 | |
253d553b HD |
1161 | has_cache = count & SWAP_HAS_CACHE; |
1162 | count &= ~SWAP_HAS_CACHE; | |
355cfa73 | 1163 | |
253d553b | 1164 | if (usage == SWAP_HAS_CACHE) { |
355cfa73 | 1165 | VM_BUG_ON(!has_cache); |
253d553b | 1166 | has_cache = 0; |
aaa46865 HD |
1167 | } else if (count == SWAP_MAP_SHMEM) { |
1168 | /* | |
1169 | * Or we could insist on shmem.c using a special | |
1170 | * swap_shmem_free() and free_shmem_swap_and_cache()... | |
1171 | */ | |
1172 | count = 0; | |
570a335b HD |
1173 | } else if ((count & ~COUNT_CONTINUED) <= SWAP_MAP_MAX) { |
1174 | if (count == COUNT_CONTINUED) { | |
1175 | if (swap_count_continued(p, offset, count)) | |
1176 | count = SWAP_MAP_MAX | COUNT_CONTINUED; | |
1177 | else | |
1178 | count = SWAP_MAP_MAX; | |
1179 | } else | |
1180 | count--; | |
1181 | } | |
253d553b | 1182 | |
253d553b | 1183 | usage = count | has_cache; |
7c00bafe TC |
1184 | p->swap_map[offset] = usage ? : SWAP_HAS_CACHE; |
1185 | ||
b32d5f32 HY |
1186 | return usage; |
1187 | } | |
1188 | ||
1189 | static unsigned char __swap_entry_free(struct swap_info_struct *p, | |
1190 | swp_entry_t entry, unsigned char usage) | |
1191 | { | |
1192 | struct swap_cluster_info *ci; | |
1193 | unsigned long offset = swp_offset(entry); | |
1194 | ||
1195 | ci = lock_cluster_or_swap_info(p, offset); | |
1196 | usage = __swap_entry_free_locked(p, offset, usage); | |
7c00bafe | 1197 | unlock_cluster_or_swap_info(p, ci); |
10e364da HY |
1198 | if (!usage) |
1199 | free_swap_slot(entry); | |
7c00bafe TC |
1200 | |
1201 | return usage; | |
1202 | } | |
355cfa73 | 1203 | |
7c00bafe TC |
1204 | static void swap_entry_free(struct swap_info_struct *p, swp_entry_t entry) |
1205 | { | |
1206 | struct swap_cluster_info *ci; | |
1207 | unsigned long offset = swp_offset(entry); | |
1208 | unsigned char count; | |
1209 | ||
1210 | ci = lock_cluster(p, offset); | |
1211 | count = p->swap_map[offset]; | |
1212 | VM_BUG_ON(count != SWAP_HAS_CACHE); | |
1213 | p->swap_map[offset] = 0; | |
1214 | dec_cluster_info_page(p, p->cluster_info, offset); | |
235b6217 HY |
1215 | unlock_cluster(ci); |
1216 | ||
38d8b4e6 HY |
1217 | mem_cgroup_uncharge_swap(entry, 1); |
1218 | swap_range_free(p, offset, 1); | |
1da177e4 LT |
1219 | } |
1220 | ||
1221 | /* | |
2de1a7e4 | 1222 | * Caller has made sure that the swap device corresponding to entry |
1da177e4 LT |
1223 | * is still around or has not been recycled. |
1224 | */ | |
1225 | void swap_free(swp_entry_t entry) | |
1226 | { | |
73c34b6a | 1227 | struct swap_info_struct *p; |
1da177e4 | 1228 | |
235b6217 | 1229 | p = _swap_info_get(entry); |
10e364da HY |
1230 | if (p) |
1231 | __swap_entry_free(p, entry, 1); | |
1da177e4 LT |
1232 | } |
1233 | ||
cb4b86ba KH |
1234 | /* |
1235 | * Called after dropping swapcache to decrease refcnt to swap entries. | |
1236 | */ | |
a448f2d0 | 1237 | void put_swap_page(struct page *page, swp_entry_t entry) |
38d8b4e6 HY |
1238 | { |
1239 | unsigned long offset = swp_offset(entry); | |
1240 | unsigned long idx = offset / SWAPFILE_CLUSTER; | |
1241 | struct swap_cluster_info *ci; | |
1242 | struct swap_info_struct *si; | |
1243 | unsigned char *map; | |
a3aea839 HY |
1244 | unsigned int i, free_entries = 0; |
1245 | unsigned char val; | |
a448f2d0 | 1246 | int size = swap_entry_size(hpage_nr_pages(page)); |
fe5266d5 | 1247 | |
a3aea839 | 1248 | si = _swap_info_get(entry); |
38d8b4e6 HY |
1249 | if (!si) |
1250 | return; | |
1251 | ||
c2343d27 | 1252 | ci = lock_cluster_or_swap_info(si, offset); |
a448f2d0 | 1253 | if (size == SWAPFILE_CLUSTER) { |
a448f2d0 HY |
1254 | VM_BUG_ON(!cluster_is_huge(ci)); |
1255 | map = si->swap_map + offset; | |
1256 | for (i = 0; i < SWAPFILE_CLUSTER; i++) { | |
1257 | val = map[i]; | |
1258 | VM_BUG_ON(!(val & SWAP_HAS_CACHE)); | |
1259 | if (val == SWAP_HAS_CACHE) | |
1260 | free_entries++; | |
1261 | } | |
a448f2d0 | 1262 | cluster_clear_huge(ci); |
a448f2d0 | 1263 | if (free_entries == SWAPFILE_CLUSTER) { |
c2343d27 | 1264 | unlock_cluster_or_swap_info(si, ci); |
a448f2d0 | 1265 | spin_lock(&si->lock); |
a448f2d0 HY |
1266 | mem_cgroup_uncharge_swap(entry, SWAPFILE_CLUSTER); |
1267 | swap_free_cluster(si, idx); | |
1268 | spin_unlock(&si->lock); | |
1269 | return; | |
1270 | } | |
1271 | } | |
c2343d27 HY |
1272 | for (i = 0; i < size; i++, entry.val++) { |
1273 | if (!__swap_entry_free_locked(si, offset + i, SWAP_HAS_CACHE)) { | |
1274 | unlock_cluster_or_swap_info(si, ci); | |
1275 | free_swap_slot(entry); | |
1276 | if (i == size - 1) | |
1277 | return; | |
1278 | lock_cluster_or_swap_info(si, offset); | |
a3aea839 HY |
1279 | } |
1280 | } | |
c2343d27 | 1281 | unlock_cluster_or_swap_info(si, ci); |
38d8b4e6 | 1282 | } |
59807685 | 1283 | |
fe5266d5 | 1284 | #ifdef CONFIG_THP_SWAP |
59807685 HY |
1285 | int split_swap_cluster(swp_entry_t entry) |
1286 | { | |
1287 | struct swap_info_struct *si; | |
1288 | struct swap_cluster_info *ci; | |
1289 | unsigned long offset = swp_offset(entry); | |
1290 | ||
1291 | si = _swap_info_get(entry); | |
1292 | if (!si) | |
1293 | return -EBUSY; | |
1294 | ci = lock_cluster(si, offset); | |
1295 | cluster_clear_huge(ci); | |
1296 | unlock_cluster(ci); | |
1297 | return 0; | |
1298 | } | |
fe5266d5 | 1299 | #endif |
38d8b4e6 | 1300 | |
155b5f88 HY |
1301 | static int swp_entry_cmp(const void *ent1, const void *ent2) |
1302 | { | |
1303 | const swp_entry_t *e1 = ent1, *e2 = ent2; | |
1304 | ||
1305 | return (int)swp_type(*e1) - (int)swp_type(*e2); | |
1306 | } | |
1307 | ||
7c00bafe TC |
1308 | void swapcache_free_entries(swp_entry_t *entries, int n) |
1309 | { | |
1310 | struct swap_info_struct *p, *prev; | |
1311 | int i; | |
1312 | ||
1313 | if (n <= 0) | |
1314 | return; | |
1315 | ||
1316 | prev = NULL; | |
1317 | p = NULL; | |
155b5f88 HY |
1318 | |
1319 | /* | |
1320 | * Sort swap entries by swap device, so each lock is only taken once. | |
1321 | * nr_swapfiles isn't absolutely correct, but the overhead of sort() is | |
1322 | * so low that it isn't necessary to optimize further. | |
1323 | */ | |
1324 | if (nr_swapfiles > 1) | |
1325 | sort(entries, n, sizeof(entries[0]), swp_entry_cmp, NULL); | |
7c00bafe TC |
1326 | for (i = 0; i < n; ++i) { |
1327 | p = swap_info_get_cont(entries[i], prev); | |
1328 | if (p) | |
1329 | swap_entry_free(p, entries[i]); | |
7c00bafe TC |
1330 | prev = p; |
1331 | } | |
235b6217 | 1332 | if (p) |
7c00bafe | 1333 | spin_unlock(&p->lock); |
cb4b86ba KH |
1334 | } |
1335 | ||
1da177e4 | 1336 | /* |
c475a8ab | 1337 | * How many references to page are currently swapped out? |
570a335b HD |
1338 | * This does not give an exact answer when swap count is continued, |
1339 | * but does include the high COUNT_CONTINUED flag to allow for that. | |
1da177e4 | 1340 | */ |
bde05d1c | 1341 | int page_swapcount(struct page *page) |
1da177e4 | 1342 | { |
c475a8ab HD |
1343 | int count = 0; |
1344 | struct swap_info_struct *p; | |
235b6217 | 1345 | struct swap_cluster_info *ci; |
1da177e4 | 1346 | swp_entry_t entry; |
235b6217 | 1347 | unsigned long offset; |
1da177e4 | 1348 | |
4c21e2f2 | 1349 | entry.val = page_private(page); |
235b6217 | 1350 | p = _swap_info_get(entry); |
1da177e4 | 1351 | if (p) { |
235b6217 HY |
1352 | offset = swp_offset(entry); |
1353 | ci = lock_cluster_or_swap_info(p, offset); | |
1354 | count = swap_count(p->swap_map[offset]); | |
1355 | unlock_cluster_or_swap_info(p, ci); | |
1da177e4 | 1356 | } |
c475a8ab | 1357 | return count; |
1da177e4 LT |
1358 | } |
1359 | ||
aa8d22a1 MK |
1360 | int __swap_count(struct swap_info_struct *si, swp_entry_t entry) |
1361 | { | |
1362 | pgoff_t offset = swp_offset(entry); | |
1363 | ||
1364 | return swap_count(si->swap_map[offset]); | |
1365 | } | |
1366 | ||
322b8afe HY |
1367 | static int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry) |
1368 | { | |
1369 | int count = 0; | |
1370 | pgoff_t offset = swp_offset(entry); | |
1371 | struct swap_cluster_info *ci; | |
1372 | ||
1373 | ci = lock_cluster_or_swap_info(si, offset); | |
1374 | count = swap_count(si->swap_map[offset]); | |
1375 | unlock_cluster_or_swap_info(si, ci); | |
1376 | return count; | |
1377 | } | |
1378 | ||
e8c26ab6 TC |
1379 | /* |
1380 | * How many references to @entry are currently swapped out? | |
1381 | * This does not give an exact answer when swap count is continued, | |
1382 | * but does include the high COUNT_CONTINUED flag to allow for that. | |
1383 | */ | |
1384 | int __swp_swapcount(swp_entry_t entry) | |
1385 | { | |
1386 | int count = 0; | |
e8c26ab6 | 1387 | struct swap_info_struct *si; |
e8c26ab6 TC |
1388 | |
1389 | si = __swap_info_get(entry); | |
322b8afe HY |
1390 | if (si) |
1391 | count = swap_swapcount(si, entry); | |
e8c26ab6 TC |
1392 | return count; |
1393 | } | |
1394 | ||
8334b962 MK |
1395 | /* |
1396 | * How many references to @entry are currently swapped out? | |
1397 | * This considers COUNT_CONTINUED so it returns exact answer. | |
1398 | */ | |
1399 | int swp_swapcount(swp_entry_t entry) | |
1400 | { | |
1401 | int count, tmp_count, n; | |
1402 | struct swap_info_struct *p; | |
235b6217 | 1403 | struct swap_cluster_info *ci; |
8334b962 MK |
1404 | struct page *page; |
1405 | pgoff_t offset; | |
1406 | unsigned char *map; | |
1407 | ||
235b6217 | 1408 | p = _swap_info_get(entry); |
8334b962 MK |
1409 | if (!p) |
1410 | return 0; | |
1411 | ||
235b6217 HY |
1412 | offset = swp_offset(entry); |
1413 | ||
1414 | ci = lock_cluster_or_swap_info(p, offset); | |
1415 | ||
1416 | count = swap_count(p->swap_map[offset]); | |
8334b962 MK |
1417 | if (!(count & COUNT_CONTINUED)) |
1418 | goto out; | |
1419 | ||
1420 | count &= ~COUNT_CONTINUED; | |
1421 | n = SWAP_MAP_MAX + 1; | |
1422 | ||
8334b962 MK |
1423 | page = vmalloc_to_page(p->swap_map + offset); |
1424 | offset &= ~PAGE_MASK; | |
1425 | VM_BUG_ON(page_private(page) != SWP_CONTINUED); | |
1426 | ||
1427 | do { | |
a8ae4991 | 1428 | page = list_next_entry(page, lru); |
8334b962 MK |
1429 | map = kmap_atomic(page); |
1430 | tmp_count = map[offset]; | |
1431 | kunmap_atomic(map); | |
1432 | ||
1433 | count += (tmp_count & ~COUNT_CONTINUED) * n; | |
1434 | n *= (SWAP_CONT_MAX + 1); | |
1435 | } while (tmp_count & COUNT_CONTINUED); | |
1436 | out: | |
235b6217 | 1437 | unlock_cluster_or_swap_info(p, ci); |
8334b962 MK |
1438 | return count; |
1439 | } | |
1440 | ||
e0709829 HY |
1441 | static bool swap_page_trans_huge_swapped(struct swap_info_struct *si, |
1442 | swp_entry_t entry) | |
1443 | { | |
1444 | struct swap_cluster_info *ci; | |
1445 | unsigned char *map = si->swap_map; | |
1446 | unsigned long roffset = swp_offset(entry); | |
1447 | unsigned long offset = round_down(roffset, SWAPFILE_CLUSTER); | |
1448 | int i; | |
1449 | bool ret = false; | |
1450 | ||
1451 | ci = lock_cluster_or_swap_info(si, offset); | |
1452 | if (!ci || !cluster_is_huge(ci)) { | |
afa4711e | 1453 | if (swap_count(map[roffset])) |
e0709829 HY |
1454 | ret = true; |
1455 | goto unlock_out; | |
1456 | } | |
1457 | for (i = 0; i < SWAPFILE_CLUSTER; i++) { | |
afa4711e | 1458 | if (swap_count(map[offset + i])) { |
e0709829 HY |
1459 | ret = true; |
1460 | break; | |
1461 | } | |
1462 | } | |
1463 | unlock_out: | |
1464 | unlock_cluster_or_swap_info(si, ci); | |
1465 | return ret; | |
1466 | } | |
1467 | ||
1468 | static bool page_swapped(struct page *page) | |
1469 | { | |
1470 | swp_entry_t entry; | |
1471 | struct swap_info_struct *si; | |
1472 | ||
fe5266d5 | 1473 | if (!IS_ENABLED(CONFIG_THP_SWAP) || likely(!PageTransCompound(page))) |
e0709829 HY |
1474 | return page_swapcount(page) != 0; |
1475 | ||
1476 | page = compound_head(page); | |
1477 | entry.val = page_private(page); | |
1478 | si = _swap_info_get(entry); | |
1479 | if (si) | |
1480 | return swap_page_trans_huge_swapped(si, entry); | |
1481 | return false; | |
1482 | } | |
ba3c4ce6 HY |
1483 | |
1484 | static int page_trans_huge_map_swapcount(struct page *page, int *total_mapcount, | |
1485 | int *total_swapcount) | |
1486 | { | |
1487 | int i, map_swapcount, _total_mapcount, _total_swapcount; | |
1488 | unsigned long offset = 0; | |
1489 | struct swap_info_struct *si; | |
1490 | struct swap_cluster_info *ci = NULL; | |
1491 | unsigned char *map = NULL; | |
1492 | int mapcount, swapcount = 0; | |
1493 | ||
1494 | /* hugetlbfs shouldn't call it */ | |
1495 | VM_BUG_ON_PAGE(PageHuge(page), page); | |
1496 | ||
fe5266d5 HY |
1497 | if (!IS_ENABLED(CONFIG_THP_SWAP) || likely(!PageTransCompound(page))) { |
1498 | mapcount = page_trans_huge_mapcount(page, total_mapcount); | |
ba3c4ce6 HY |
1499 | if (PageSwapCache(page)) |
1500 | swapcount = page_swapcount(page); | |
1501 | if (total_swapcount) | |
1502 | *total_swapcount = swapcount; | |
1503 | return mapcount + swapcount; | |
1504 | } | |
1505 | ||
1506 | page = compound_head(page); | |
1507 | ||
1508 | _total_mapcount = _total_swapcount = map_swapcount = 0; | |
1509 | if (PageSwapCache(page)) { | |
1510 | swp_entry_t entry; | |
1511 | ||
1512 | entry.val = page_private(page); | |
1513 | si = _swap_info_get(entry); | |
1514 | if (si) { | |
1515 | map = si->swap_map; | |
1516 | offset = swp_offset(entry); | |
1517 | } | |
1518 | } | |
1519 | if (map) | |
1520 | ci = lock_cluster(si, offset); | |
1521 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1522 | mapcount = atomic_read(&page[i]._mapcount) + 1; | |
1523 | _total_mapcount += mapcount; | |
1524 | if (map) { | |
1525 | swapcount = swap_count(map[offset + i]); | |
1526 | _total_swapcount += swapcount; | |
1527 | } | |
1528 | map_swapcount = max(map_swapcount, mapcount + swapcount); | |
1529 | } | |
1530 | unlock_cluster(ci); | |
1531 | if (PageDoubleMap(page)) { | |
1532 | map_swapcount -= 1; | |
1533 | _total_mapcount -= HPAGE_PMD_NR; | |
1534 | } | |
1535 | mapcount = compound_mapcount(page); | |
1536 | map_swapcount += mapcount; | |
1537 | _total_mapcount += mapcount; | |
1538 | if (total_mapcount) | |
1539 | *total_mapcount = _total_mapcount; | |
1540 | if (total_swapcount) | |
1541 | *total_swapcount = _total_swapcount; | |
1542 | ||
1543 | return map_swapcount; | |
1544 | } | |
e0709829 | 1545 | |
1da177e4 | 1546 | /* |
7b1fe597 HD |
1547 | * We can write to an anon page without COW if there are no other references |
1548 | * to it. And as a side-effect, free up its swap: because the old content | |
1549 | * on disk will never be read, and seeking back there to write new content | |
1550 | * later would only waste time away from clustering. | |
6d0a07ed | 1551 | * |
ba3c4ce6 | 1552 | * NOTE: total_map_swapcount should not be relied upon by the caller if |
6d0a07ed AA |
1553 | * reuse_swap_page() returns false, but it may be always overwritten |
1554 | * (see the other implementation for CONFIG_SWAP=n). | |
1da177e4 | 1555 | */ |
ba3c4ce6 | 1556 | bool reuse_swap_page(struct page *page, int *total_map_swapcount) |
1da177e4 | 1557 | { |
ba3c4ce6 | 1558 | int count, total_mapcount, total_swapcount; |
c475a8ab | 1559 | |
309381fe | 1560 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
5ad64688 | 1561 | if (unlikely(PageKsm(page))) |
6d0a07ed | 1562 | return false; |
ba3c4ce6 HY |
1563 | count = page_trans_huge_map_swapcount(page, &total_mapcount, |
1564 | &total_swapcount); | |
1565 | if (total_map_swapcount) | |
1566 | *total_map_swapcount = total_mapcount + total_swapcount; | |
1567 | if (count == 1 && PageSwapCache(page) && | |
1568 | (likely(!PageTransCompound(page)) || | |
1569 | /* The remaining swap count will be freed soon */ | |
1570 | total_swapcount == page_swapcount(page))) { | |
f0571429 | 1571 | if (!PageWriteback(page)) { |
ba3c4ce6 | 1572 | page = compound_head(page); |
7b1fe597 HD |
1573 | delete_from_swap_cache(page); |
1574 | SetPageDirty(page); | |
f0571429 MK |
1575 | } else { |
1576 | swp_entry_t entry; | |
1577 | struct swap_info_struct *p; | |
1578 | ||
1579 | entry.val = page_private(page); | |
1580 | p = swap_info_get(entry); | |
1581 | if (p->flags & SWP_STABLE_WRITES) { | |
1582 | spin_unlock(&p->lock); | |
1583 | return false; | |
1584 | } | |
1585 | spin_unlock(&p->lock); | |
7b1fe597 HD |
1586 | } |
1587 | } | |
ba3c4ce6 | 1588 | |
5ad64688 | 1589 | return count <= 1; |
1da177e4 LT |
1590 | } |
1591 | ||
1592 | /* | |
a2c43eed HD |
1593 | * If swap is getting full, or if there are no more mappings of this page, |
1594 | * then try_to_free_swap is called to free its swap space. | |
1da177e4 | 1595 | */ |
a2c43eed | 1596 | int try_to_free_swap(struct page *page) |
1da177e4 | 1597 | { |
309381fe | 1598 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
1da177e4 LT |
1599 | |
1600 | if (!PageSwapCache(page)) | |
1601 | return 0; | |
1602 | if (PageWriteback(page)) | |
1603 | return 0; | |
e0709829 | 1604 | if (page_swapped(page)) |
1da177e4 LT |
1605 | return 0; |
1606 | ||
b73d7fce HD |
1607 | /* |
1608 | * Once hibernation has begun to create its image of memory, | |
1609 | * there's a danger that one of the calls to try_to_free_swap() | |
1610 | * - most probably a call from __try_to_reclaim_swap() while | |
1611 | * hibernation is allocating its own swap pages for the image, | |
1612 | * but conceivably even a call from memory reclaim - will free | |
1613 | * the swap from a page which has already been recorded in the | |
1614 | * image as a clean swapcache page, and then reuse its swap for | |
1615 | * another page of the image. On waking from hibernation, the | |
1616 | * original page might be freed under memory pressure, then | |
1617 | * later read back in from swap, now with the wrong data. | |
1618 | * | |
2de1a7e4 | 1619 | * Hibernation suspends storage while it is writing the image |
f90ac398 | 1620 | * to disk so check that here. |
b73d7fce | 1621 | */ |
f90ac398 | 1622 | if (pm_suspended_storage()) |
b73d7fce HD |
1623 | return 0; |
1624 | ||
e0709829 | 1625 | page = compound_head(page); |
a2c43eed HD |
1626 | delete_from_swap_cache(page); |
1627 | SetPageDirty(page); | |
1628 | return 1; | |
68a22394 RR |
1629 | } |
1630 | ||
1da177e4 LT |
1631 | /* |
1632 | * Free the swap entry like above, but also try to | |
1633 | * free the page cache entry if it is the last user. | |
1634 | */ | |
2509ef26 | 1635 | int free_swap_and_cache(swp_entry_t entry) |
1da177e4 | 1636 | { |
2509ef26 | 1637 | struct swap_info_struct *p; |
7c00bafe | 1638 | unsigned char count; |
1da177e4 | 1639 | |
a7420aa5 | 1640 | if (non_swap_entry(entry)) |
2509ef26 | 1641 | return 1; |
0697212a | 1642 | |
7c00bafe | 1643 | p = _swap_info_get(entry); |
1da177e4 | 1644 | if (p) { |
7c00bafe | 1645 | count = __swap_entry_free(p, entry, 1); |
e0709829 | 1646 | if (count == SWAP_HAS_CACHE && |
bcd49e86 HY |
1647 | !swap_page_trans_huge_swapped(p, entry)) |
1648 | __try_to_reclaim_swap(p, swp_offset(entry), | |
1649 | TTRS_UNMAPPED | TTRS_FULL); | |
1da177e4 | 1650 | } |
2509ef26 | 1651 | return p != NULL; |
1da177e4 LT |
1652 | } |
1653 | ||
b0cb1a19 | 1654 | #ifdef CONFIG_HIBERNATION |
f577eb30 | 1655 | /* |
915bae9e | 1656 | * Find the swap type that corresponds to given device (if any). |
f577eb30 | 1657 | * |
915bae9e RW |
1658 | * @offset - number of the PAGE_SIZE-sized block of the device, starting |
1659 | * from 0, in which the swap header is expected to be located. | |
1660 | * | |
1661 | * This is needed for the suspend to disk (aka swsusp). | |
f577eb30 | 1662 | */ |
7bf23687 | 1663 | int swap_type_of(dev_t device, sector_t offset, struct block_device **bdev_p) |
f577eb30 | 1664 | { |
915bae9e | 1665 | struct block_device *bdev = NULL; |
efa90a98 | 1666 | int type; |
f577eb30 | 1667 | |
915bae9e RW |
1668 | if (device) |
1669 | bdev = bdget(device); | |
1670 | ||
f577eb30 | 1671 | spin_lock(&swap_lock); |
efa90a98 HD |
1672 | for (type = 0; type < nr_swapfiles; type++) { |
1673 | struct swap_info_struct *sis = swap_info[type]; | |
f577eb30 | 1674 | |
915bae9e | 1675 | if (!(sis->flags & SWP_WRITEOK)) |
f577eb30 | 1676 | continue; |
b6b5bce3 | 1677 | |
915bae9e | 1678 | if (!bdev) { |
7bf23687 | 1679 | if (bdev_p) |
dddac6a7 | 1680 | *bdev_p = bdgrab(sis->bdev); |
7bf23687 | 1681 | |
6e1819d6 | 1682 | spin_unlock(&swap_lock); |
efa90a98 | 1683 | return type; |
6e1819d6 | 1684 | } |
915bae9e | 1685 | if (bdev == sis->bdev) { |
9625a5f2 | 1686 | struct swap_extent *se = &sis->first_swap_extent; |
915bae9e | 1687 | |
915bae9e | 1688 | if (se->start_block == offset) { |
7bf23687 | 1689 | if (bdev_p) |
dddac6a7 | 1690 | *bdev_p = bdgrab(sis->bdev); |
7bf23687 | 1691 | |
915bae9e RW |
1692 | spin_unlock(&swap_lock); |
1693 | bdput(bdev); | |
efa90a98 | 1694 | return type; |
915bae9e | 1695 | } |
f577eb30 RW |
1696 | } |
1697 | } | |
1698 | spin_unlock(&swap_lock); | |
915bae9e RW |
1699 | if (bdev) |
1700 | bdput(bdev); | |
1701 | ||
f577eb30 RW |
1702 | return -ENODEV; |
1703 | } | |
1704 | ||
73c34b6a HD |
1705 | /* |
1706 | * Get the (PAGE_SIZE) block corresponding to given offset on the swapdev | |
1707 | * corresponding to given index in swap_info (swap type). | |
1708 | */ | |
1709 | sector_t swapdev_block(int type, pgoff_t offset) | |
1710 | { | |
1711 | struct block_device *bdev; | |
c10d38cc | 1712 | struct swap_info_struct *si = swap_type_to_swap_info(type); |
73c34b6a | 1713 | |
c10d38cc | 1714 | if (!si || !(si->flags & SWP_WRITEOK)) |
73c34b6a | 1715 | return 0; |
d4906e1a | 1716 | return map_swap_entry(swp_entry(type, offset), &bdev); |
73c34b6a HD |
1717 | } |
1718 | ||
f577eb30 RW |
1719 | /* |
1720 | * Return either the total number of swap pages of given type, or the number | |
1721 | * of free pages of that type (depending on @free) | |
1722 | * | |
1723 | * This is needed for software suspend | |
1724 | */ | |
1725 | unsigned int count_swap_pages(int type, int free) | |
1726 | { | |
1727 | unsigned int n = 0; | |
1728 | ||
efa90a98 HD |
1729 | spin_lock(&swap_lock); |
1730 | if ((unsigned int)type < nr_swapfiles) { | |
1731 | struct swap_info_struct *sis = swap_info[type]; | |
1732 | ||
ec8acf20 | 1733 | spin_lock(&sis->lock); |
efa90a98 HD |
1734 | if (sis->flags & SWP_WRITEOK) { |
1735 | n = sis->pages; | |
f577eb30 | 1736 | if (free) |
efa90a98 | 1737 | n -= sis->inuse_pages; |
f577eb30 | 1738 | } |
ec8acf20 | 1739 | spin_unlock(&sis->lock); |
f577eb30 | 1740 | } |
efa90a98 | 1741 | spin_unlock(&swap_lock); |
f577eb30 RW |
1742 | return n; |
1743 | } | |
73c34b6a | 1744 | #endif /* CONFIG_HIBERNATION */ |
f577eb30 | 1745 | |
9f8bdb3f | 1746 | static inline int pte_same_as_swp(pte_t pte, pte_t swp_pte) |
179ef71c | 1747 | { |
9f8bdb3f | 1748 | return pte_same(pte_swp_clear_soft_dirty(pte), swp_pte); |
179ef71c CG |
1749 | } |
1750 | ||
1da177e4 | 1751 | /* |
72866f6f HD |
1752 | * No need to decide whether this PTE shares the swap entry with others, |
1753 | * just let do_wp_page work it out if a write is requested later - to | |
1754 | * force COW, vm_page_prot omits write permission from any private vma. | |
1da177e4 | 1755 | */ |
044d66c1 | 1756 | static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, |
1da177e4 LT |
1757 | unsigned long addr, swp_entry_t entry, struct page *page) |
1758 | { | |
9e16b7fb | 1759 | struct page *swapcache; |
72835c86 | 1760 | struct mem_cgroup *memcg; |
044d66c1 HD |
1761 | spinlock_t *ptl; |
1762 | pte_t *pte; | |
1763 | int ret = 1; | |
1764 | ||
9e16b7fb HD |
1765 | swapcache = page; |
1766 | page = ksm_might_need_to_copy(page, vma, addr); | |
1767 | if (unlikely(!page)) | |
1768 | return -ENOMEM; | |
1769 | ||
f627c2f5 KS |
1770 | if (mem_cgroup_try_charge(page, vma->vm_mm, GFP_KERNEL, |
1771 | &memcg, false)) { | |
044d66c1 | 1772 | ret = -ENOMEM; |
85d9fc89 KH |
1773 | goto out_nolock; |
1774 | } | |
044d66c1 HD |
1775 | |
1776 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); | |
9f8bdb3f | 1777 | if (unlikely(!pte_same_as_swp(*pte, swp_entry_to_pte(entry)))) { |
f627c2f5 | 1778 | mem_cgroup_cancel_charge(page, memcg, false); |
044d66c1 HD |
1779 | ret = 0; |
1780 | goto out; | |
1781 | } | |
8a9f3ccd | 1782 | |
b084d435 | 1783 | dec_mm_counter(vma->vm_mm, MM_SWAPENTS); |
d559db08 | 1784 | inc_mm_counter(vma->vm_mm, MM_ANONPAGES); |
1da177e4 LT |
1785 | get_page(page); |
1786 | set_pte_at(vma->vm_mm, addr, pte, | |
1787 | pte_mkold(mk_pte(page, vma->vm_page_prot))); | |
00501b53 | 1788 | if (page == swapcache) { |
d281ee61 | 1789 | page_add_anon_rmap(page, vma, addr, false); |
f627c2f5 | 1790 | mem_cgroup_commit_charge(page, memcg, true, false); |
00501b53 | 1791 | } else { /* ksm created a completely new copy */ |
d281ee61 | 1792 | page_add_new_anon_rmap(page, vma, addr, false); |
f627c2f5 | 1793 | mem_cgroup_commit_charge(page, memcg, false, false); |
00501b53 JW |
1794 | lru_cache_add_active_or_unevictable(page, vma); |
1795 | } | |
1da177e4 LT |
1796 | swap_free(entry); |
1797 | /* | |
1798 | * Move the page to the active list so it is not | |
1799 | * immediately swapped out again after swapon. | |
1800 | */ | |
1801 | activate_page(page); | |
044d66c1 HD |
1802 | out: |
1803 | pte_unmap_unlock(pte, ptl); | |
85d9fc89 | 1804 | out_nolock: |
9e16b7fb HD |
1805 | if (page != swapcache) { |
1806 | unlock_page(page); | |
1807 | put_page(page); | |
1808 | } | |
044d66c1 | 1809 | return ret; |
1da177e4 LT |
1810 | } |
1811 | ||
1812 | static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, | |
b56a2d8a VRP |
1813 | unsigned long addr, unsigned long end, |
1814 | unsigned int type, bool frontswap, | |
1815 | unsigned long *fs_pages_to_unuse) | |
1da177e4 | 1816 | { |
b56a2d8a VRP |
1817 | struct page *page; |
1818 | swp_entry_t entry; | |
705e87c0 | 1819 | pte_t *pte; |
b56a2d8a VRP |
1820 | struct swap_info_struct *si; |
1821 | unsigned long offset; | |
8a9f3ccd | 1822 | int ret = 0; |
b56a2d8a | 1823 | volatile unsigned char *swap_map; |
1da177e4 | 1824 | |
b56a2d8a | 1825 | si = swap_info[type]; |
044d66c1 | 1826 | pte = pte_offset_map(pmd, addr); |
1da177e4 | 1827 | do { |
b56a2d8a VRP |
1828 | struct vm_fault vmf; |
1829 | ||
1830 | if (!is_swap_pte(*pte)) | |
1831 | continue; | |
1832 | ||
1833 | entry = pte_to_swp_entry(*pte); | |
1834 | if (swp_type(entry) != type) | |
1835 | continue; | |
1836 | ||
1837 | offset = swp_offset(entry); | |
1838 | if (frontswap && !frontswap_test(si, offset)) | |
1839 | continue; | |
1840 | ||
1841 | pte_unmap(pte); | |
1842 | swap_map = &si->swap_map[offset]; | |
1843 | vmf.vma = vma; | |
1844 | vmf.address = addr; | |
1845 | vmf.pmd = pmd; | |
1846 | page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, &vmf); | |
1847 | if (!page) { | |
1848 | if (*swap_map == 0 || *swap_map == SWAP_MAP_BAD) | |
1849 | goto try_next; | |
1850 | return -ENOMEM; | |
1851 | } | |
1852 | ||
1853 | lock_page(page); | |
1854 | wait_on_page_writeback(page); | |
1855 | ret = unuse_pte(vma, pmd, addr, entry, page); | |
1856 | if (ret < 0) { | |
1857 | unlock_page(page); | |
1858 | put_page(page); | |
1859 | goto out; | |
1860 | } | |
1861 | ||
1862 | try_to_free_swap(page); | |
1863 | unlock_page(page); | |
1864 | put_page(page); | |
1865 | ||
1866 | if (*fs_pages_to_unuse && !--(*fs_pages_to_unuse)) { | |
1867 | ret = FRONTSWAP_PAGES_UNUSED; | |
1868 | goto out; | |
1da177e4 | 1869 | } |
b56a2d8a VRP |
1870 | try_next: |
1871 | pte = pte_offset_map(pmd, addr); | |
1da177e4 | 1872 | } while (pte++, addr += PAGE_SIZE, addr != end); |
044d66c1 | 1873 | pte_unmap(pte - 1); |
b56a2d8a VRP |
1874 | |
1875 | ret = 0; | |
044d66c1 | 1876 | out: |
8a9f3ccd | 1877 | return ret; |
1da177e4 LT |
1878 | } |
1879 | ||
1880 | static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, | |
1881 | unsigned long addr, unsigned long end, | |
b56a2d8a VRP |
1882 | unsigned int type, bool frontswap, |
1883 | unsigned long *fs_pages_to_unuse) | |
1da177e4 LT |
1884 | { |
1885 | pmd_t *pmd; | |
1886 | unsigned long next; | |
8a9f3ccd | 1887 | int ret; |
1da177e4 LT |
1888 | |
1889 | pmd = pmd_offset(pud, addr); | |
1890 | do { | |
dc644a07 | 1891 | cond_resched(); |
1da177e4 | 1892 | next = pmd_addr_end(addr, end); |
1a5a9906 | 1893 | if (pmd_none_or_trans_huge_or_clear_bad(pmd)) |
1da177e4 | 1894 | continue; |
b56a2d8a VRP |
1895 | ret = unuse_pte_range(vma, pmd, addr, next, type, |
1896 | frontswap, fs_pages_to_unuse); | |
8a9f3ccd BS |
1897 | if (ret) |
1898 | return ret; | |
1da177e4 LT |
1899 | } while (pmd++, addr = next, addr != end); |
1900 | return 0; | |
1901 | } | |
1902 | ||
c2febafc | 1903 | static inline int unuse_pud_range(struct vm_area_struct *vma, p4d_t *p4d, |
1da177e4 | 1904 | unsigned long addr, unsigned long end, |
b56a2d8a VRP |
1905 | unsigned int type, bool frontswap, |
1906 | unsigned long *fs_pages_to_unuse) | |
1da177e4 LT |
1907 | { |
1908 | pud_t *pud; | |
1909 | unsigned long next; | |
8a9f3ccd | 1910 | int ret; |
1da177e4 | 1911 | |
c2febafc | 1912 | pud = pud_offset(p4d, addr); |
1da177e4 LT |
1913 | do { |
1914 | next = pud_addr_end(addr, end); | |
1915 | if (pud_none_or_clear_bad(pud)) | |
1916 | continue; | |
b56a2d8a VRP |
1917 | ret = unuse_pmd_range(vma, pud, addr, next, type, |
1918 | frontswap, fs_pages_to_unuse); | |
8a9f3ccd BS |
1919 | if (ret) |
1920 | return ret; | |
1da177e4 LT |
1921 | } while (pud++, addr = next, addr != end); |
1922 | return 0; | |
1923 | } | |
1924 | ||
c2febafc KS |
1925 | static inline int unuse_p4d_range(struct vm_area_struct *vma, pgd_t *pgd, |
1926 | unsigned long addr, unsigned long end, | |
b56a2d8a VRP |
1927 | unsigned int type, bool frontswap, |
1928 | unsigned long *fs_pages_to_unuse) | |
c2febafc KS |
1929 | { |
1930 | p4d_t *p4d; | |
1931 | unsigned long next; | |
1932 | int ret; | |
1933 | ||
1934 | p4d = p4d_offset(pgd, addr); | |
1935 | do { | |
1936 | next = p4d_addr_end(addr, end); | |
1937 | if (p4d_none_or_clear_bad(p4d)) | |
1938 | continue; | |
b56a2d8a VRP |
1939 | ret = unuse_pud_range(vma, p4d, addr, next, type, |
1940 | frontswap, fs_pages_to_unuse); | |
c2febafc KS |
1941 | if (ret) |
1942 | return ret; | |
1943 | } while (p4d++, addr = next, addr != end); | |
1944 | return 0; | |
1945 | } | |
1946 | ||
b56a2d8a VRP |
1947 | static int unuse_vma(struct vm_area_struct *vma, unsigned int type, |
1948 | bool frontswap, unsigned long *fs_pages_to_unuse) | |
1da177e4 LT |
1949 | { |
1950 | pgd_t *pgd; | |
1951 | unsigned long addr, end, next; | |
8a9f3ccd | 1952 | int ret; |
1da177e4 | 1953 | |
b56a2d8a VRP |
1954 | addr = vma->vm_start; |
1955 | end = vma->vm_end; | |
1da177e4 LT |
1956 | |
1957 | pgd = pgd_offset(vma->vm_mm, addr); | |
1958 | do { | |
1959 | next = pgd_addr_end(addr, end); | |
1960 | if (pgd_none_or_clear_bad(pgd)) | |
1961 | continue; | |
b56a2d8a VRP |
1962 | ret = unuse_p4d_range(vma, pgd, addr, next, type, |
1963 | frontswap, fs_pages_to_unuse); | |
8a9f3ccd BS |
1964 | if (ret) |
1965 | return ret; | |
1da177e4 LT |
1966 | } while (pgd++, addr = next, addr != end); |
1967 | return 0; | |
1968 | } | |
1969 | ||
b56a2d8a VRP |
1970 | static int unuse_mm(struct mm_struct *mm, unsigned int type, |
1971 | bool frontswap, unsigned long *fs_pages_to_unuse) | |
1da177e4 LT |
1972 | { |
1973 | struct vm_area_struct *vma; | |
8a9f3ccd | 1974 | int ret = 0; |
1da177e4 | 1975 | |
b56a2d8a | 1976 | down_read(&mm->mmap_sem); |
1da177e4 | 1977 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
b56a2d8a VRP |
1978 | if (vma->anon_vma) { |
1979 | ret = unuse_vma(vma, type, frontswap, | |
1980 | fs_pages_to_unuse); | |
1981 | if (ret) | |
1982 | break; | |
1983 | } | |
dc644a07 | 1984 | cond_resched(); |
1da177e4 | 1985 | } |
1da177e4 | 1986 | up_read(&mm->mmap_sem); |
b56a2d8a | 1987 | return ret; |
1da177e4 LT |
1988 | } |
1989 | ||
1990 | /* | |
38b5faf4 | 1991 | * Scan swap_map (or frontswap_map if frontswap parameter is true) |
b56a2d8a VRP |
1992 | * from current position to next entry still in use. Return 0 |
1993 | * if there are no inuse entries after prev till end of the map. | |
1da177e4 | 1994 | */ |
6eb396dc | 1995 | static unsigned int find_next_to_unuse(struct swap_info_struct *si, |
38b5faf4 | 1996 | unsigned int prev, bool frontswap) |
1da177e4 | 1997 | { |
b56a2d8a | 1998 | unsigned int i; |
8d69aaee | 1999 | unsigned char count; |
1da177e4 LT |
2000 | |
2001 | /* | |
5d337b91 | 2002 | * No need for swap_lock here: we're just looking |
1da177e4 LT |
2003 | * for whether an entry is in use, not modifying it; false |
2004 | * hits are okay, and sys_swapoff() has already prevented new | |
5d337b91 | 2005 | * allocations from this area (while holding swap_lock). |
1da177e4 | 2006 | */ |
b56a2d8a | 2007 | for (i = prev + 1; i < si->max; i++) { |
4db0c3c2 | 2008 | count = READ_ONCE(si->swap_map[i]); |
355cfa73 | 2009 | if (count && swap_count(count) != SWAP_MAP_BAD) |
dc644a07 HD |
2010 | if (!frontswap || frontswap_test(si, i)) |
2011 | break; | |
2012 | if ((i % LATENCY_LIMIT) == 0) | |
2013 | cond_resched(); | |
1da177e4 | 2014 | } |
b56a2d8a VRP |
2015 | |
2016 | if (i == si->max) | |
2017 | i = 0; | |
2018 | ||
1da177e4 LT |
2019 | return i; |
2020 | } | |
2021 | ||
2022 | /* | |
b56a2d8a | 2023 | * If the boolean frontswap is true, only unuse pages_to_unuse pages; |
38b5faf4 | 2024 | * pages_to_unuse==0 means all pages; ignored if frontswap is false |
1da177e4 | 2025 | */ |
b56a2d8a | 2026 | #define SWAP_UNUSE_MAX_TRIES 3 |
38b5faf4 DM |
2027 | int try_to_unuse(unsigned int type, bool frontswap, |
2028 | unsigned long pages_to_unuse) | |
1da177e4 | 2029 | { |
b56a2d8a VRP |
2030 | struct mm_struct *prev_mm; |
2031 | struct mm_struct *mm; | |
2032 | struct list_head *p; | |
2033 | int retval = 0; | |
efa90a98 | 2034 | struct swap_info_struct *si = swap_info[type]; |
1da177e4 LT |
2035 | struct page *page; |
2036 | swp_entry_t entry; | |
b56a2d8a VRP |
2037 | unsigned int i; |
2038 | int retries = 0; | |
1da177e4 | 2039 | |
b56a2d8a VRP |
2040 | if (!si->inuse_pages) |
2041 | return 0; | |
1da177e4 | 2042 | |
b56a2d8a VRP |
2043 | if (!frontswap) |
2044 | pages_to_unuse = 0; | |
2045 | ||
2046 | retry: | |
2047 | retval = shmem_unuse(type, frontswap, &pages_to_unuse); | |
2048 | if (retval) | |
2049 | goto out; | |
2050 | ||
2051 | prev_mm = &init_mm; | |
2052 | mmget(prev_mm); | |
2053 | ||
2054 | spin_lock(&mmlist_lock); | |
2055 | p = &init_mm.mmlist; | |
2056 | while ((p = p->next) != &init_mm.mmlist) { | |
1da177e4 LT |
2057 | if (signal_pending(current)) { |
2058 | retval = -EINTR; | |
2059 | break; | |
2060 | } | |
2061 | ||
b56a2d8a VRP |
2062 | mm = list_entry(p, struct mm_struct, mmlist); |
2063 | if (!mmget_not_zero(mm)) | |
2064 | continue; | |
2065 | spin_unlock(&mmlist_lock); | |
2066 | mmput(prev_mm); | |
2067 | prev_mm = mm; | |
2068 | retval = unuse_mm(mm, type, frontswap, &pages_to_unuse); | |
1da177e4 | 2069 | |
b56a2d8a VRP |
2070 | if (retval) { |
2071 | mmput(prev_mm); | |
2072 | goto out; | |
1da177e4 LT |
2073 | } |
2074 | ||
2075 | /* | |
b56a2d8a VRP |
2076 | * Make sure that we aren't completely killing |
2077 | * interactive performance. | |
1da177e4 | 2078 | */ |
b56a2d8a VRP |
2079 | cond_resched(); |
2080 | spin_lock(&mmlist_lock); | |
2081 | } | |
2082 | spin_unlock(&mmlist_lock); | |
1da177e4 | 2083 | |
b56a2d8a | 2084 | mmput(prev_mm); |
1da177e4 | 2085 | |
b56a2d8a VRP |
2086 | i = 0; |
2087 | while ((i = find_next_to_unuse(si, i, frontswap)) != 0) { | |
1da177e4 | 2088 | |
b56a2d8a VRP |
2089 | entry = swp_entry(type, i); |
2090 | page = find_get_page(swap_address_space(entry), i); | |
2091 | if (!page) | |
2092 | continue; | |
68bdc8d6 HD |
2093 | |
2094 | /* | |
2095 | * It is conceivable that a racing task removed this page from | |
b56a2d8a VRP |
2096 | * swap cache just before we acquired the page lock. The page |
2097 | * might even be back in swap cache on another swap area. But | |
2098 | * that is okay, try_to_free_swap() only removes stale pages. | |
1da177e4 | 2099 | */ |
b56a2d8a VRP |
2100 | lock_page(page); |
2101 | wait_on_page_writeback(page); | |
2102 | try_to_free_swap(page); | |
1da177e4 | 2103 | unlock_page(page); |
09cbfeaf | 2104 | put_page(page); |
1da177e4 LT |
2105 | |
2106 | /* | |
b56a2d8a VRP |
2107 | * For frontswap, we just need to unuse pages_to_unuse, if |
2108 | * it was specified. Need not check frontswap again here as | |
2109 | * we already zeroed out pages_to_unuse if not frontswap. | |
1da177e4 | 2110 | */ |
b56a2d8a VRP |
2111 | if (pages_to_unuse && --pages_to_unuse == 0) |
2112 | goto out; | |
1da177e4 LT |
2113 | } |
2114 | ||
b56a2d8a VRP |
2115 | /* |
2116 | * Lets check again to see if there are still swap entries in the map. | |
2117 | * If yes, we would need to do retry the unuse logic again. | |
2118 | * Under global memory pressure, swap entries can be reinserted back | |
2119 | * into process space after the mmlist loop above passes over them. | |
2120 | * Its not worth continuosuly retrying to unuse the swap in this case. | |
2121 | * So we try SWAP_UNUSE_MAX_TRIES times. | |
2122 | */ | |
2123 | if (++retries >= SWAP_UNUSE_MAX_TRIES) | |
2124 | retval = -EBUSY; | |
2125 | else if (si->inuse_pages) | |
2126 | goto retry; | |
2127 | ||
2128 | out: | |
2129 | return (retval == FRONTSWAP_PAGES_UNUSED) ? 0 : retval; | |
1da177e4 LT |
2130 | } |
2131 | ||
2132 | /* | |
5d337b91 HD |
2133 | * After a successful try_to_unuse, if no swap is now in use, we know |
2134 | * we can empty the mmlist. swap_lock must be held on entry and exit. | |
2135 | * Note that mmlist_lock nests inside swap_lock, and an mm must be | |
1da177e4 LT |
2136 | * added to the mmlist just after page_duplicate - before would be racy. |
2137 | */ | |
2138 | static void drain_mmlist(void) | |
2139 | { | |
2140 | struct list_head *p, *next; | |
efa90a98 | 2141 | unsigned int type; |
1da177e4 | 2142 | |
efa90a98 HD |
2143 | for (type = 0; type < nr_swapfiles; type++) |
2144 | if (swap_info[type]->inuse_pages) | |
1da177e4 LT |
2145 | return; |
2146 | spin_lock(&mmlist_lock); | |
2147 | list_for_each_safe(p, next, &init_mm.mmlist) | |
2148 | list_del_init(p); | |
2149 | spin_unlock(&mmlist_lock); | |
2150 | } | |
2151 | ||
2152 | /* | |
2153 | * Use this swapdev's extent info to locate the (PAGE_SIZE) block which | |
d4906e1a LS |
2154 | * corresponds to page offset for the specified swap entry. |
2155 | * Note that the type of this function is sector_t, but it returns page offset | |
2156 | * into the bdev, not sector offset. | |
1da177e4 | 2157 | */ |
d4906e1a | 2158 | static sector_t map_swap_entry(swp_entry_t entry, struct block_device **bdev) |
1da177e4 | 2159 | { |
f29ad6a9 HD |
2160 | struct swap_info_struct *sis; |
2161 | struct swap_extent *start_se; | |
2162 | struct swap_extent *se; | |
2163 | pgoff_t offset; | |
2164 | ||
c10d38cc | 2165 | sis = swp_swap_info(entry); |
f29ad6a9 HD |
2166 | *bdev = sis->bdev; |
2167 | ||
2168 | offset = swp_offset(entry); | |
2169 | start_se = sis->curr_swap_extent; | |
2170 | se = start_se; | |
1da177e4 LT |
2171 | |
2172 | for ( ; ; ) { | |
1da177e4 LT |
2173 | if (se->start_page <= offset && |
2174 | offset < (se->start_page + se->nr_pages)) { | |
2175 | return se->start_block + (offset - se->start_page); | |
2176 | } | |
a8ae4991 | 2177 | se = list_next_entry(se, list); |
1da177e4 LT |
2178 | sis->curr_swap_extent = se; |
2179 | BUG_ON(se == start_se); /* It *must* be present */ | |
2180 | } | |
2181 | } | |
2182 | ||
d4906e1a LS |
2183 | /* |
2184 | * Returns the page offset into bdev for the specified page's swap entry. | |
2185 | */ | |
2186 | sector_t map_swap_page(struct page *page, struct block_device **bdev) | |
2187 | { | |
2188 | swp_entry_t entry; | |
2189 | entry.val = page_private(page); | |
2190 | return map_swap_entry(entry, bdev); | |
2191 | } | |
2192 | ||
1da177e4 LT |
2193 | /* |
2194 | * Free all of a swapdev's extent information | |
2195 | */ | |
2196 | static void destroy_swap_extents(struct swap_info_struct *sis) | |
2197 | { | |
9625a5f2 | 2198 | while (!list_empty(&sis->first_swap_extent.list)) { |
1da177e4 LT |
2199 | struct swap_extent *se; |
2200 | ||
a8ae4991 | 2201 | se = list_first_entry(&sis->first_swap_extent.list, |
1da177e4 LT |
2202 | struct swap_extent, list); |
2203 | list_del(&se->list); | |
2204 | kfree(se); | |
2205 | } | |
62c230bc | 2206 | |
bc4ae27d | 2207 | if (sis->flags & SWP_ACTIVATED) { |
62c230bc MG |
2208 | struct file *swap_file = sis->swap_file; |
2209 | struct address_space *mapping = swap_file->f_mapping; | |
2210 | ||
bc4ae27d OS |
2211 | sis->flags &= ~SWP_ACTIVATED; |
2212 | if (mapping->a_ops->swap_deactivate) | |
2213 | mapping->a_ops->swap_deactivate(swap_file); | |
62c230bc | 2214 | } |
1da177e4 LT |
2215 | } |
2216 | ||
2217 | /* | |
2218 | * Add a block range (and the corresponding page range) into this swapdev's | |
11d31886 | 2219 | * extent list. The extent list is kept sorted in page order. |
1da177e4 | 2220 | * |
11d31886 | 2221 | * This function rather assumes that it is called in ascending page order. |
1da177e4 | 2222 | */ |
a509bc1a | 2223 | int |
1da177e4 LT |
2224 | add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, |
2225 | unsigned long nr_pages, sector_t start_block) | |
2226 | { | |
2227 | struct swap_extent *se; | |
2228 | struct swap_extent *new_se; | |
2229 | struct list_head *lh; | |
2230 | ||
9625a5f2 HD |
2231 | if (start_page == 0) { |
2232 | se = &sis->first_swap_extent; | |
2233 | sis->curr_swap_extent = se; | |
2234 | se->start_page = 0; | |
2235 | se->nr_pages = nr_pages; | |
2236 | se->start_block = start_block; | |
2237 | return 1; | |
2238 | } else { | |
2239 | lh = sis->first_swap_extent.list.prev; /* Highest extent */ | |
1da177e4 | 2240 | se = list_entry(lh, struct swap_extent, list); |
11d31886 HD |
2241 | BUG_ON(se->start_page + se->nr_pages != start_page); |
2242 | if (se->start_block + se->nr_pages == start_block) { | |
1da177e4 LT |
2243 | /* Merge it */ |
2244 | se->nr_pages += nr_pages; | |
2245 | return 0; | |
2246 | } | |
1da177e4 LT |
2247 | } |
2248 | ||
2249 | /* | |
2250 | * No merge. Insert a new extent, preserving ordering. | |
2251 | */ | |
2252 | new_se = kmalloc(sizeof(*se), GFP_KERNEL); | |
2253 | if (new_se == NULL) | |
2254 | return -ENOMEM; | |
2255 | new_se->start_page = start_page; | |
2256 | new_se->nr_pages = nr_pages; | |
2257 | new_se->start_block = start_block; | |
2258 | ||
9625a5f2 | 2259 | list_add_tail(&new_se->list, &sis->first_swap_extent.list); |
53092a74 | 2260 | return 1; |
1da177e4 | 2261 | } |
aa8aa8a3 | 2262 | EXPORT_SYMBOL_GPL(add_swap_extent); |
1da177e4 LT |
2263 | |
2264 | /* | |
2265 | * A `swap extent' is a simple thing which maps a contiguous range of pages | |
2266 | * onto a contiguous range of disk blocks. An ordered list of swap extents | |
2267 | * is built at swapon time and is then used at swap_writepage/swap_readpage | |
2268 | * time for locating where on disk a page belongs. | |
2269 | * | |
2270 | * If the swapfile is an S_ISBLK block device, a single extent is installed. | |
2271 | * This is done so that the main operating code can treat S_ISBLK and S_ISREG | |
2272 | * swap files identically. | |
2273 | * | |
2274 | * Whether the swapdev is an S_ISREG file or an S_ISBLK blockdev, the swap | |
2275 | * extent list operates in PAGE_SIZE disk blocks. Both S_ISREG and S_ISBLK | |
2276 | * swapfiles are handled *identically* after swapon time. | |
2277 | * | |
2278 | * For S_ISREG swapfiles, setup_swap_extents() will walk all the file's blocks | |
2279 | * and will parse them into an ordered extent list, in PAGE_SIZE chunks. If | |
2280 | * some stray blocks are found which do not fall within the PAGE_SIZE alignment | |
2281 | * requirements, they are simply tossed out - we will never use those blocks | |
2282 | * for swapping. | |
2283 | * | |
b0d9bcd4 | 2284 | * For S_ISREG swapfiles we set S_SWAPFILE across the life of the swapon. This |
1da177e4 LT |
2285 | * prevents root from shooting her foot off by ftruncating an in-use swapfile, |
2286 | * which will scribble on the fs. | |
2287 | * | |
2288 | * The amount of disk space which a single swap extent represents varies. | |
2289 | * Typically it is in the 1-4 megabyte range. So we can have hundreds of | |
2290 | * extents in the list. To avoid much list walking, we cache the previous | |
2291 | * search location in `curr_swap_extent', and start new searches from there. | |
2292 | * This is extremely effective. The average number of iterations in | |
2293 | * map_swap_page() has been measured at about 0.3 per page. - akpm. | |
2294 | */ | |
53092a74 | 2295 | static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) |
1da177e4 | 2296 | { |
62c230bc MG |
2297 | struct file *swap_file = sis->swap_file; |
2298 | struct address_space *mapping = swap_file->f_mapping; | |
2299 | struct inode *inode = mapping->host; | |
1da177e4 LT |
2300 | int ret; |
2301 | ||
1da177e4 LT |
2302 | if (S_ISBLK(inode->i_mode)) { |
2303 | ret = add_swap_extent(sis, 0, sis->max, 0); | |
53092a74 | 2304 | *span = sis->pages; |
a509bc1a | 2305 | return ret; |
1da177e4 LT |
2306 | } |
2307 | ||
62c230bc | 2308 | if (mapping->a_ops->swap_activate) { |
a509bc1a | 2309 | ret = mapping->a_ops->swap_activate(sis, swap_file, span); |
bc4ae27d OS |
2310 | if (ret >= 0) |
2311 | sis->flags |= SWP_ACTIVATED; | |
62c230bc | 2312 | if (!ret) { |
bc4ae27d | 2313 | sis->flags |= SWP_FS; |
62c230bc MG |
2314 | ret = add_swap_extent(sis, 0, sis->max, 0); |
2315 | *span = sis->pages; | |
2316 | } | |
a509bc1a | 2317 | return ret; |
62c230bc MG |
2318 | } |
2319 | ||
a509bc1a | 2320 | return generic_swapfile_activate(sis, swap_file, span); |
1da177e4 LT |
2321 | } |
2322 | ||
a2468cc9 AL |
2323 | static int swap_node(struct swap_info_struct *p) |
2324 | { | |
2325 | struct block_device *bdev; | |
2326 | ||
2327 | if (p->bdev) | |
2328 | bdev = p->bdev; | |
2329 | else | |
2330 | bdev = p->swap_file->f_inode->i_sb->s_bdev; | |
2331 | ||
2332 | return bdev ? bdev->bd_disk->node_id : NUMA_NO_NODE; | |
2333 | } | |
2334 | ||
cf0cac0a | 2335 | static void _enable_swap_info(struct swap_info_struct *p, int prio, |
2a8f9449 SL |
2336 | unsigned char *swap_map, |
2337 | struct swap_cluster_info *cluster_info) | |
40531542 | 2338 | { |
a2468cc9 AL |
2339 | int i; |
2340 | ||
40531542 CEB |
2341 | if (prio >= 0) |
2342 | p->prio = prio; | |
2343 | else | |
2344 | p->prio = --least_priority; | |
18ab4d4c DS |
2345 | /* |
2346 | * the plist prio is negated because plist ordering is | |
2347 | * low-to-high, while swap ordering is high-to-low | |
2348 | */ | |
2349 | p->list.prio = -p->prio; | |
a2468cc9 AL |
2350 | for_each_node(i) { |
2351 | if (p->prio >= 0) | |
2352 | p->avail_lists[i].prio = -p->prio; | |
2353 | else { | |
2354 | if (swap_node(p) == i) | |
2355 | p->avail_lists[i].prio = 1; | |
2356 | else | |
2357 | p->avail_lists[i].prio = -p->prio; | |
2358 | } | |
2359 | } | |
40531542 | 2360 | p->swap_map = swap_map; |
2a8f9449 | 2361 | p->cluster_info = cluster_info; |
40531542 | 2362 | p->flags |= SWP_WRITEOK; |
ec8acf20 | 2363 | atomic_long_add(p->pages, &nr_swap_pages); |
40531542 CEB |
2364 | total_swap_pages += p->pages; |
2365 | ||
adfab836 | 2366 | assert_spin_locked(&swap_lock); |
adfab836 | 2367 | /* |
18ab4d4c DS |
2368 | * both lists are plists, and thus priority ordered. |
2369 | * swap_active_head needs to be priority ordered for swapoff(), | |
2370 | * which on removal of any swap_info_struct with an auto-assigned | |
2371 | * (i.e. negative) priority increments the auto-assigned priority | |
2372 | * of any lower-priority swap_info_structs. | |
2373 | * swap_avail_head needs to be priority ordered for get_swap_page(), | |
2374 | * which allocates swap pages from the highest available priority | |
2375 | * swap_info_struct. | |
adfab836 | 2376 | */ |
18ab4d4c | 2377 | plist_add(&p->list, &swap_active_head); |
a2468cc9 | 2378 | add_to_avail_list(p); |
cf0cac0a CEB |
2379 | } |
2380 | ||
2381 | static void enable_swap_info(struct swap_info_struct *p, int prio, | |
2382 | unsigned char *swap_map, | |
2a8f9449 | 2383 | struct swap_cluster_info *cluster_info, |
cf0cac0a CEB |
2384 | unsigned long *frontswap_map) |
2385 | { | |
4f89849d | 2386 | frontswap_init(p->type, frontswap_map); |
cf0cac0a | 2387 | spin_lock(&swap_lock); |
ec8acf20 | 2388 | spin_lock(&p->lock); |
2a8f9449 | 2389 | _enable_swap_info(p, prio, swap_map, cluster_info); |
ec8acf20 | 2390 | spin_unlock(&p->lock); |
cf0cac0a CEB |
2391 | spin_unlock(&swap_lock); |
2392 | } | |
2393 | ||
2394 | static void reinsert_swap_info(struct swap_info_struct *p) | |
2395 | { | |
2396 | spin_lock(&swap_lock); | |
ec8acf20 | 2397 | spin_lock(&p->lock); |
2a8f9449 | 2398 | _enable_swap_info(p, p->prio, p->swap_map, p->cluster_info); |
ec8acf20 | 2399 | spin_unlock(&p->lock); |
40531542 CEB |
2400 | spin_unlock(&swap_lock); |
2401 | } | |
2402 | ||
67afa38e TC |
2403 | bool has_usable_swap(void) |
2404 | { | |
2405 | bool ret = true; | |
2406 | ||
2407 | spin_lock(&swap_lock); | |
2408 | if (plist_head_empty(&swap_active_head)) | |
2409 | ret = false; | |
2410 | spin_unlock(&swap_lock); | |
2411 | return ret; | |
2412 | } | |
2413 | ||
c4ea37c2 | 2414 | SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) |
1da177e4 | 2415 | { |
73c34b6a | 2416 | struct swap_info_struct *p = NULL; |
8d69aaee | 2417 | unsigned char *swap_map; |
2a8f9449 | 2418 | struct swap_cluster_info *cluster_info; |
4f89849d | 2419 | unsigned long *frontswap_map; |
1da177e4 LT |
2420 | struct file *swap_file, *victim; |
2421 | struct address_space *mapping; | |
2422 | struct inode *inode; | |
91a27b2a | 2423 | struct filename *pathname; |
adfab836 | 2424 | int err, found = 0; |
5b808a23 | 2425 | unsigned int old_block_size; |
886bb7e9 | 2426 | |
1da177e4 LT |
2427 | if (!capable(CAP_SYS_ADMIN)) |
2428 | return -EPERM; | |
2429 | ||
191c5424 AV |
2430 | BUG_ON(!current->mm); |
2431 | ||
1da177e4 | 2432 | pathname = getname(specialfile); |
1da177e4 | 2433 | if (IS_ERR(pathname)) |
f58b59c1 | 2434 | return PTR_ERR(pathname); |
1da177e4 | 2435 | |
669abf4e | 2436 | victim = file_open_name(pathname, O_RDWR|O_LARGEFILE, 0); |
1da177e4 LT |
2437 | err = PTR_ERR(victim); |
2438 | if (IS_ERR(victim)) | |
2439 | goto out; | |
2440 | ||
2441 | mapping = victim->f_mapping; | |
5d337b91 | 2442 | spin_lock(&swap_lock); |
18ab4d4c | 2443 | plist_for_each_entry(p, &swap_active_head, list) { |
22c6f8fd | 2444 | if (p->flags & SWP_WRITEOK) { |
adfab836 DS |
2445 | if (p->swap_file->f_mapping == mapping) { |
2446 | found = 1; | |
1da177e4 | 2447 | break; |
adfab836 | 2448 | } |
1da177e4 | 2449 | } |
1da177e4 | 2450 | } |
adfab836 | 2451 | if (!found) { |
1da177e4 | 2452 | err = -EINVAL; |
5d337b91 | 2453 | spin_unlock(&swap_lock); |
1da177e4 LT |
2454 | goto out_dput; |
2455 | } | |
191c5424 | 2456 | if (!security_vm_enough_memory_mm(current->mm, p->pages)) |
1da177e4 LT |
2457 | vm_unacct_memory(p->pages); |
2458 | else { | |
2459 | err = -ENOMEM; | |
5d337b91 | 2460 | spin_unlock(&swap_lock); |
1da177e4 LT |
2461 | goto out_dput; |
2462 | } | |
a2468cc9 | 2463 | del_from_avail_list(p); |
ec8acf20 | 2464 | spin_lock(&p->lock); |
78ecba08 | 2465 | if (p->prio < 0) { |
adfab836 | 2466 | struct swap_info_struct *si = p; |
a2468cc9 | 2467 | int nid; |
adfab836 | 2468 | |
18ab4d4c | 2469 | plist_for_each_entry_continue(si, &swap_active_head, list) { |
adfab836 | 2470 | si->prio++; |
18ab4d4c | 2471 | si->list.prio--; |
a2468cc9 AL |
2472 | for_each_node(nid) { |
2473 | if (si->avail_lists[nid].prio != 1) | |
2474 | si->avail_lists[nid].prio--; | |
2475 | } | |
adfab836 | 2476 | } |
78ecba08 HD |
2477 | least_priority++; |
2478 | } | |
18ab4d4c | 2479 | plist_del(&p->list, &swap_active_head); |
ec8acf20 | 2480 | atomic_long_sub(p->pages, &nr_swap_pages); |
1da177e4 LT |
2481 | total_swap_pages -= p->pages; |
2482 | p->flags &= ~SWP_WRITEOK; | |
ec8acf20 | 2483 | spin_unlock(&p->lock); |
5d337b91 | 2484 | spin_unlock(&swap_lock); |
fb4f88dc | 2485 | |
039939a6 TC |
2486 | disable_swap_slots_cache_lock(); |
2487 | ||
e1e12d2f | 2488 | set_current_oom_origin(); |
adfab836 | 2489 | err = try_to_unuse(p->type, false, 0); /* force unuse all pages */ |
e1e12d2f | 2490 | clear_current_oom_origin(); |
1da177e4 | 2491 | |
1da177e4 LT |
2492 | if (err) { |
2493 | /* re-insert swap space back into swap_list */ | |
cf0cac0a | 2494 | reinsert_swap_info(p); |
039939a6 | 2495 | reenable_swap_slots_cache_unlock(); |
1da177e4 LT |
2496 | goto out_dput; |
2497 | } | |
52b7efdb | 2498 | |
039939a6 TC |
2499 | reenable_swap_slots_cache_unlock(); |
2500 | ||
815c2c54 SL |
2501 | flush_work(&p->discard_work); |
2502 | ||
5d337b91 | 2503 | destroy_swap_extents(p); |
570a335b HD |
2504 | if (p->flags & SWP_CONTINUED) |
2505 | free_swap_count_continuations(p); | |
2506 | ||
81a0298b HY |
2507 | if (!p->bdev || !blk_queue_nonrot(bdev_get_queue(p->bdev))) |
2508 | atomic_dec(&nr_rotate_swap); | |
2509 | ||
fc0abb14 | 2510 | mutex_lock(&swapon_mutex); |
5d337b91 | 2511 | spin_lock(&swap_lock); |
ec8acf20 | 2512 | spin_lock(&p->lock); |
5d337b91 HD |
2513 | drain_mmlist(); |
2514 | ||
52b7efdb | 2515 | /* wait for anyone still in scan_swap_map */ |
52b7efdb HD |
2516 | p->highest_bit = 0; /* cuts scans short */ |
2517 | while (p->flags >= SWP_SCANNING) { | |
ec8acf20 | 2518 | spin_unlock(&p->lock); |
5d337b91 | 2519 | spin_unlock(&swap_lock); |
13e4b57f | 2520 | schedule_timeout_uninterruptible(1); |
5d337b91 | 2521 | spin_lock(&swap_lock); |
ec8acf20 | 2522 | spin_lock(&p->lock); |
52b7efdb | 2523 | } |
52b7efdb | 2524 | |
1da177e4 | 2525 | swap_file = p->swap_file; |
5b808a23 | 2526 | old_block_size = p->old_block_size; |
1da177e4 LT |
2527 | p->swap_file = NULL; |
2528 | p->max = 0; | |
2529 | swap_map = p->swap_map; | |
2530 | p->swap_map = NULL; | |
2a8f9449 SL |
2531 | cluster_info = p->cluster_info; |
2532 | p->cluster_info = NULL; | |
4f89849d | 2533 | frontswap_map = frontswap_map_get(p); |
ec8acf20 | 2534 | spin_unlock(&p->lock); |
5d337b91 | 2535 | spin_unlock(&swap_lock); |
adfab836 | 2536 | frontswap_invalidate_area(p->type); |
58e97ba6 | 2537 | frontswap_map_set(p, NULL); |
fc0abb14 | 2538 | mutex_unlock(&swapon_mutex); |
ebc2a1a6 SL |
2539 | free_percpu(p->percpu_cluster); |
2540 | p->percpu_cluster = NULL; | |
1da177e4 | 2541 | vfree(swap_map); |
54f180d3 HY |
2542 | kvfree(cluster_info); |
2543 | kvfree(frontswap_map); | |
2de1a7e4 | 2544 | /* Destroy swap account information */ |
adfab836 | 2545 | swap_cgroup_swapoff(p->type); |
4b3ef9da | 2546 | exit_swap_address_space(p->type); |
27a7faa0 | 2547 | |
1da177e4 LT |
2548 | inode = mapping->host; |
2549 | if (S_ISBLK(inode->i_mode)) { | |
2550 | struct block_device *bdev = I_BDEV(inode); | |
5b808a23 | 2551 | set_blocksize(bdev, old_block_size); |
e525fd89 | 2552 | blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); |
1da177e4 | 2553 | } else { |
5955102c | 2554 | inode_lock(inode); |
1da177e4 | 2555 | inode->i_flags &= ~S_SWAPFILE; |
5955102c | 2556 | inode_unlock(inode); |
1da177e4 LT |
2557 | } |
2558 | filp_close(swap_file, NULL); | |
f893ab41 WY |
2559 | |
2560 | /* | |
2561 | * Clear the SWP_USED flag after all resources are freed so that swapon | |
2562 | * can reuse this swap_info in alloc_swap_info() safely. It is ok to | |
2563 | * not hold p->lock after we cleared its SWP_WRITEOK. | |
2564 | */ | |
2565 | spin_lock(&swap_lock); | |
2566 | p->flags = 0; | |
2567 | spin_unlock(&swap_lock); | |
2568 | ||
1da177e4 | 2569 | err = 0; |
66d7dd51 KS |
2570 | atomic_inc(&proc_poll_event); |
2571 | wake_up_interruptible(&proc_poll_wait); | |
1da177e4 LT |
2572 | |
2573 | out_dput: | |
2574 | filp_close(victim, NULL); | |
2575 | out: | |
f58b59c1 | 2576 | putname(pathname); |
1da177e4 LT |
2577 | return err; |
2578 | } | |
2579 | ||
2580 | #ifdef CONFIG_PROC_FS | |
9dd95748 | 2581 | static __poll_t swaps_poll(struct file *file, poll_table *wait) |
66d7dd51 | 2582 | { |
f1514638 | 2583 | struct seq_file *seq = file->private_data; |
66d7dd51 KS |
2584 | |
2585 | poll_wait(file, &proc_poll_wait, wait); | |
2586 | ||
f1514638 KS |
2587 | if (seq->poll_event != atomic_read(&proc_poll_event)) { |
2588 | seq->poll_event = atomic_read(&proc_poll_event); | |
a9a08845 | 2589 | return EPOLLIN | EPOLLRDNORM | EPOLLERR | EPOLLPRI; |
66d7dd51 KS |
2590 | } |
2591 | ||
a9a08845 | 2592 | return EPOLLIN | EPOLLRDNORM; |
66d7dd51 KS |
2593 | } |
2594 | ||
1da177e4 LT |
2595 | /* iterator */ |
2596 | static void *swap_start(struct seq_file *swap, loff_t *pos) | |
2597 | { | |
efa90a98 HD |
2598 | struct swap_info_struct *si; |
2599 | int type; | |
1da177e4 LT |
2600 | loff_t l = *pos; |
2601 | ||
fc0abb14 | 2602 | mutex_lock(&swapon_mutex); |
1da177e4 | 2603 | |
881e4aab SS |
2604 | if (!l) |
2605 | return SEQ_START_TOKEN; | |
2606 | ||
c10d38cc | 2607 | for (type = 0; (si = swap_type_to_swap_info(type)); type++) { |
efa90a98 | 2608 | if (!(si->flags & SWP_USED) || !si->swap_map) |
1da177e4 | 2609 | continue; |
881e4aab | 2610 | if (!--l) |
efa90a98 | 2611 | return si; |
1da177e4 LT |
2612 | } |
2613 | ||
2614 | return NULL; | |
2615 | } | |
2616 | ||
2617 | static void *swap_next(struct seq_file *swap, void *v, loff_t *pos) | |
2618 | { | |
efa90a98 HD |
2619 | struct swap_info_struct *si = v; |
2620 | int type; | |
1da177e4 | 2621 | |
881e4aab | 2622 | if (v == SEQ_START_TOKEN) |
efa90a98 HD |
2623 | type = 0; |
2624 | else | |
2625 | type = si->type + 1; | |
881e4aab | 2626 | |
c10d38cc | 2627 | for (; (si = swap_type_to_swap_info(type)); type++) { |
efa90a98 | 2628 | if (!(si->flags & SWP_USED) || !si->swap_map) |
1da177e4 LT |
2629 | continue; |
2630 | ++*pos; | |
efa90a98 | 2631 | return si; |
1da177e4 LT |
2632 | } |
2633 | ||
2634 | return NULL; | |
2635 | } | |
2636 | ||
2637 | static void swap_stop(struct seq_file *swap, void *v) | |
2638 | { | |
fc0abb14 | 2639 | mutex_unlock(&swapon_mutex); |
1da177e4 LT |
2640 | } |
2641 | ||
2642 | static int swap_show(struct seq_file *swap, void *v) | |
2643 | { | |
efa90a98 | 2644 | struct swap_info_struct *si = v; |
1da177e4 LT |
2645 | struct file *file; |
2646 | int len; | |
2647 | ||
efa90a98 | 2648 | if (si == SEQ_START_TOKEN) { |
881e4aab SS |
2649 | seq_puts(swap,"Filename\t\t\t\tType\t\tSize\tUsed\tPriority\n"); |
2650 | return 0; | |
2651 | } | |
1da177e4 | 2652 | |
efa90a98 | 2653 | file = si->swap_file; |
2726d566 | 2654 | len = seq_file_path(swap, file, " \t\n\\"); |
6eb396dc | 2655 | seq_printf(swap, "%*s%s\t%u\t%u\t%d\n", |
886bb7e9 | 2656 | len < 40 ? 40 - len : 1, " ", |
496ad9aa | 2657 | S_ISBLK(file_inode(file)->i_mode) ? |
1da177e4 | 2658 | "partition" : "file\t", |
efa90a98 HD |
2659 | si->pages << (PAGE_SHIFT - 10), |
2660 | si->inuse_pages << (PAGE_SHIFT - 10), | |
2661 | si->prio); | |
1da177e4 LT |
2662 | return 0; |
2663 | } | |
2664 | ||
15ad7cdc | 2665 | static const struct seq_operations swaps_op = { |
1da177e4 LT |
2666 | .start = swap_start, |
2667 | .next = swap_next, | |
2668 | .stop = swap_stop, | |
2669 | .show = swap_show | |
2670 | }; | |
2671 | ||
2672 | static int swaps_open(struct inode *inode, struct file *file) | |
2673 | { | |
f1514638 | 2674 | struct seq_file *seq; |
66d7dd51 KS |
2675 | int ret; |
2676 | ||
66d7dd51 | 2677 | ret = seq_open(file, &swaps_op); |
f1514638 | 2678 | if (ret) |
66d7dd51 | 2679 | return ret; |
66d7dd51 | 2680 | |
f1514638 KS |
2681 | seq = file->private_data; |
2682 | seq->poll_event = atomic_read(&proc_poll_event); | |
2683 | return 0; | |
1da177e4 LT |
2684 | } |
2685 | ||
15ad7cdc | 2686 | static const struct file_operations proc_swaps_operations = { |
1da177e4 LT |
2687 | .open = swaps_open, |
2688 | .read = seq_read, | |
2689 | .llseek = seq_lseek, | |
2690 | .release = seq_release, | |
66d7dd51 | 2691 | .poll = swaps_poll, |
1da177e4 LT |
2692 | }; |
2693 | ||
2694 | static int __init procswaps_init(void) | |
2695 | { | |
3d71f86f | 2696 | proc_create("swaps", 0, NULL, &proc_swaps_operations); |
1da177e4 LT |
2697 | return 0; |
2698 | } | |
2699 | __initcall(procswaps_init); | |
2700 | #endif /* CONFIG_PROC_FS */ | |
2701 | ||
1796316a JB |
2702 | #ifdef MAX_SWAPFILES_CHECK |
2703 | static int __init max_swapfiles_check(void) | |
2704 | { | |
2705 | MAX_SWAPFILES_CHECK(); | |
2706 | return 0; | |
2707 | } | |
2708 | late_initcall(max_swapfiles_check); | |
2709 | #endif | |
2710 | ||
53cbb243 | 2711 | static struct swap_info_struct *alloc_swap_info(void) |
1da177e4 | 2712 | { |
73c34b6a | 2713 | struct swap_info_struct *p; |
1da177e4 | 2714 | unsigned int type; |
a2468cc9 | 2715 | int i; |
b9726c26 | 2716 | unsigned int size = sizeof(*p) + nr_node_ids * sizeof(struct plist_node); |
efa90a98 | 2717 | |
66f71da9 | 2718 | p = kvzalloc(size, GFP_KERNEL); |
efa90a98 | 2719 | if (!p) |
53cbb243 | 2720 | return ERR_PTR(-ENOMEM); |
efa90a98 | 2721 | |
5d337b91 | 2722 | spin_lock(&swap_lock); |
efa90a98 HD |
2723 | for (type = 0; type < nr_swapfiles; type++) { |
2724 | if (!(swap_info[type]->flags & SWP_USED)) | |
1da177e4 | 2725 | break; |
efa90a98 | 2726 | } |
0697212a | 2727 | if (type >= MAX_SWAPFILES) { |
5d337b91 | 2728 | spin_unlock(&swap_lock); |
873d7bcf | 2729 | kvfree(p); |
730c0581 | 2730 | return ERR_PTR(-EPERM); |
1da177e4 | 2731 | } |
efa90a98 HD |
2732 | if (type >= nr_swapfiles) { |
2733 | p->type = type; | |
c10d38cc | 2734 | WRITE_ONCE(swap_info[type], p); |
efa90a98 HD |
2735 | /* |
2736 | * Write swap_info[type] before nr_swapfiles, in case a | |
2737 | * racing procfs swap_start() or swap_next() is reading them. | |
2738 | * (We never shrink nr_swapfiles, we never free this entry.) | |
2739 | */ | |
2740 | smp_wmb(); | |
c10d38cc | 2741 | WRITE_ONCE(nr_swapfiles, nr_swapfiles + 1); |
efa90a98 | 2742 | } else { |
873d7bcf | 2743 | kvfree(p); |
efa90a98 HD |
2744 | p = swap_info[type]; |
2745 | /* | |
2746 | * Do not memset this entry: a racing procfs swap_next() | |
2747 | * would be relying on p->type to remain valid. | |
2748 | */ | |
2749 | } | |
9625a5f2 | 2750 | INIT_LIST_HEAD(&p->first_swap_extent.list); |
18ab4d4c | 2751 | plist_node_init(&p->list, 0); |
a2468cc9 AL |
2752 | for_each_node(i) |
2753 | plist_node_init(&p->avail_lists[i], 0); | |
1da177e4 | 2754 | p->flags = SWP_USED; |
5d337b91 | 2755 | spin_unlock(&swap_lock); |
ec8acf20 | 2756 | spin_lock_init(&p->lock); |
2628bd6f | 2757 | spin_lock_init(&p->cont_lock); |
efa90a98 | 2758 | |
53cbb243 | 2759 | return p; |
53cbb243 CEB |
2760 | } |
2761 | ||
4d0e1e10 CEB |
2762 | static int claim_swapfile(struct swap_info_struct *p, struct inode *inode) |
2763 | { | |
2764 | int error; | |
2765 | ||
2766 | if (S_ISBLK(inode->i_mode)) { | |
2767 | p->bdev = bdgrab(I_BDEV(inode)); | |
2768 | error = blkdev_get(p->bdev, | |
6f179af8 | 2769 | FMODE_READ | FMODE_WRITE | FMODE_EXCL, p); |
4d0e1e10 CEB |
2770 | if (error < 0) { |
2771 | p->bdev = NULL; | |
6f179af8 | 2772 | return error; |
4d0e1e10 CEB |
2773 | } |
2774 | p->old_block_size = block_size(p->bdev); | |
2775 | error = set_blocksize(p->bdev, PAGE_SIZE); | |
2776 | if (error < 0) | |
87ade72a | 2777 | return error; |
4d0e1e10 CEB |
2778 | p->flags |= SWP_BLKDEV; |
2779 | } else if (S_ISREG(inode->i_mode)) { | |
2780 | p->bdev = inode->i_sb->s_bdev; | |
5955102c | 2781 | inode_lock(inode); |
87ade72a CEB |
2782 | if (IS_SWAPFILE(inode)) |
2783 | return -EBUSY; | |
2784 | } else | |
2785 | return -EINVAL; | |
4d0e1e10 CEB |
2786 | |
2787 | return 0; | |
4d0e1e10 CEB |
2788 | } |
2789 | ||
377eeaa8 AK |
2790 | |
2791 | /* | |
2792 | * Find out how many pages are allowed for a single swap device. There | |
2793 | * are two limiting factors: | |
2794 | * 1) the number of bits for the swap offset in the swp_entry_t type, and | |
2795 | * 2) the number of bits in the swap pte, as defined by the different | |
2796 | * architectures. | |
2797 | * | |
2798 | * In order to find the largest possible bit mask, a swap entry with | |
2799 | * swap type 0 and swap offset ~0UL is created, encoded to a swap pte, | |
2800 | * decoded to a swp_entry_t again, and finally the swap offset is | |
2801 | * extracted. | |
2802 | * | |
2803 | * This will mask all the bits from the initial ~0UL mask that can't | |
2804 | * be encoded in either the swp_entry_t or the architecture definition | |
2805 | * of a swap pte. | |
2806 | */ | |
2807 | unsigned long generic_max_swapfile_size(void) | |
2808 | { | |
2809 | return swp_offset(pte_to_swp_entry( | |
2810 | swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1; | |
2811 | } | |
2812 | ||
2813 | /* Can be overridden by an architecture for additional checks. */ | |
2814 | __weak unsigned long max_swapfile_size(void) | |
2815 | { | |
2816 | return generic_max_swapfile_size(); | |
2817 | } | |
2818 | ||
ca8bd38b CEB |
2819 | static unsigned long read_swap_header(struct swap_info_struct *p, |
2820 | union swap_header *swap_header, | |
2821 | struct inode *inode) | |
2822 | { | |
2823 | int i; | |
2824 | unsigned long maxpages; | |
2825 | unsigned long swapfilepages; | |
d6bbbd29 | 2826 | unsigned long last_page; |
ca8bd38b CEB |
2827 | |
2828 | if (memcmp("SWAPSPACE2", swap_header->magic.magic, 10)) { | |
465c47fd | 2829 | pr_err("Unable to find swap-space signature\n"); |
38719025 | 2830 | return 0; |
ca8bd38b CEB |
2831 | } |
2832 | ||
2833 | /* swap partition endianess hack... */ | |
2834 | if (swab32(swap_header->info.version) == 1) { | |
2835 | swab32s(&swap_header->info.version); | |
2836 | swab32s(&swap_header->info.last_page); | |
2837 | swab32s(&swap_header->info.nr_badpages); | |
dd111be6 JH |
2838 | if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES) |
2839 | return 0; | |
ca8bd38b CEB |
2840 | for (i = 0; i < swap_header->info.nr_badpages; i++) |
2841 | swab32s(&swap_header->info.badpages[i]); | |
2842 | } | |
2843 | /* Check the swap header's sub-version */ | |
2844 | if (swap_header->info.version != 1) { | |
465c47fd AM |
2845 | pr_warn("Unable to handle swap header version %d\n", |
2846 | swap_header->info.version); | |
38719025 | 2847 | return 0; |
ca8bd38b CEB |
2848 | } |
2849 | ||
2850 | p->lowest_bit = 1; | |
2851 | p->cluster_next = 1; | |
2852 | p->cluster_nr = 0; | |
2853 | ||
377eeaa8 | 2854 | maxpages = max_swapfile_size(); |
d6bbbd29 | 2855 | last_page = swap_header->info.last_page; |
a06ad633 TA |
2856 | if (!last_page) { |
2857 | pr_warn("Empty swap-file\n"); | |
2858 | return 0; | |
2859 | } | |
d6bbbd29 | 2860 | if (last_page > maxpages) { |
465c47fd | 2861 | pr_warn("Truncating oversized swap area, only using %luk out of %luk\n", |
d6bbbd29 RJ |
2862 | maxpages << (PAGE_SHIFT - 10), |
2863 | last_page << (PAGE_SHIFT - 10)); | |
2864 | } | |
2865 | if (maxpages > last_page) { | |
2866 | maxpages = last_page + 1; | |
ca8bd38b CEB |
2867 | /* p->max is an unsigned int: don't overflow it */ |
2868 | if ((unsigned int)maxpages == 0) | |
2869 | maxpages = UINT_MAX; | |
2870 | } | |
2871 | p->highest_bit = maxpages - 1; | |
2872 | ||
2873 | if (!maxpages) | |
38719025 | 2874 | return 0; |
ca8bd38b CEB |
2875 | swapfilepages = i_size_read(inode) >> PAGE_SHIFT; |
2876 | if (swapfilepages && maxpages > swapfilepages) { | |
465c47fd | 2877 | pr_warn("Swap area shorter than signature indicates\n"); |
38719025 | 2878 | return 0; |
ca8bd38b CEB |
2879 | } |
2880 | if (swap_header->info.nr_badpages && S_ISREG(inode->i_mode)) | |
38719025 | 2881 | return 0; |
ca8bd38b | 2882 | if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES) |
38719025 | 2883 | return 0; |
ca8bd38b CEB |
2884 | |
2885 | return maxpages; | |
ca8bd38b CEB |
2886 | } |
2887 | ||
4b3ef9da | 2888 | #define SWAP_CLUSTER_INFO_COLS \ |
235b6217 | 2889 | DIV_ROUND_UP(L1_CACHE_BYTES, sizeof(struct swap_cluster_info)) |
4b3ef9da HY |
2890 | #define SWAP_CLUSTER_SPACE_COLS \ |
2891 | DIV_ROUND_UP(SWAP_ADDRESS_SPACE_PAGES, SWAPFILE_CLUSTER) | |
2892 | #define SWAP_CLUSTER_COLS \ | |
2893 | max_t(unsigned int, SWAP_CLUSTER_INFO_COLS, SWAP_CLUSTER_SPACE_COLS) | |
235b6217 | 2894 | |
915d4d7b CEB |
2895 | static int setup_swap_map_and_extents(struct swap_info_struct *p, |
2896 | union swap_header *swap_header, | |
2897 | unsigned char *swap_map, | |
2a8f9449 | 2898 | struct swap_cluster_info *cluster_info, |
915d4d7b CEB |
2899 | unsigned long maxpages, |
2900 | sector_t *span) | |
2901 | { | |
235b6217 | 2902 | unsigned int j, k; |
915d4d7b CEB |
2903 | unsigned int nr_good_pages; |
2904 | int nr_extents; | |
2a8f9449 | 2905 | unsigned long nr_clusters = DIV_ROUND_UP(maxpages, SWAPFILE_CLUSTER); |
235b6217 HY |
2906 | unsigned long col = p->cluster_next / SWAPFILE_CLUSTER % SWAP_CLUSTER_COLS; |
2907 | unsigned long i, idx; | |
915d4d7b CEB |
2908 | |
2909 | nr_good_pages = maxpages - 1; /* omit header page */ | |
2910 | ||
6b534915 HY |
2911 | cluster_list_init(&p->free_clusters); |
2912 | cluster_list_init(&p->discard_clusters); | |
2a8f9449 | 2913 | |
915d4d7b CEB |
2914 | for (i = 0; i < swap_header->info.nr_badpages; i++) { |
2915 | unsigned int page_nr = swap_header->info.badpages[i]; | |
bdb8e3f6 CEB |
2916 | if (page_nr == 0 || page_nr > swap_header->info.last_page) |
2917 | return -EINVAL; | |
915d4d7b CEB |
2918 | if (page_nr < maxpages) { |
2919 | swap_map[page_nr] = SWAP_MAP_BAD; | |
2920 | nr_good_pages--; | |
2a8f9449 SL |
2921 | /* |
2922 | * Haven't marked the cluster free yet, no list | |
2923 | * operation involved | |
2924 | */ | |
2925 | inc_cluster_info_page(p, cluster_info, page_nr); | |
915d4d7b CEB |
2926 | } |
2927 | } | |
2928 | ||
2a8f9449 SL |
2929 | /* Haven't marked the cluster free yet, no list operation involved */ |
2930 | for (i = maxpages; i < round_up(maxpages, SWAPFILE_CLUSTER); i++) | |
2931 | inc_cluster_info_page(p, cluster_info, i); | |
2932 | ||
915d4d7b CEB |
2933 | if (nr_good_pages) { |
2934 | swap_map[0] = SWAP_MAP_BAD; | |
2a8f9449 SL |
2935 | /* |
2936 | * Not mark the cluster free yet, no list | |
2937 | * operation involved | |
2938 | */ | |
2939 | inc_cluster_info_page(p, cluster_info, 0); | |
915d4d7b CEB |
2940 | p->max = maxpages; |
2941 | p->pages = nr_good_pages; | |
2942 | nr_extents = setup_swap_extents(p, span); | |
bdb8e3f6 CEB |
2943 | if (nr_extents < 0) |
2944 | return nr_extents; | |
915d4d7b CEB |
2945 | nr_good_pages = p->pages; |
2946 | } | |
2947 | if (!nr_good_pages) { | |
465c47fd | 2948 | pr_warn("Empty swap-file\n"); |
bdb8e3f6 | 2949 | return -EINVAL; |
915d4d7b CEB |
2950 | } |
2951 | ||
2a8f9449 SL |
2952 | if (!cluster_info) |
2953 | return nr_extents; | |
2954 | ||
235b6217 | 2955 | |
4b3ef9da HY |
2956 | /* |
2957 | * Reduce false cache line sharing between cluster_info and | |
2958 | * sharing same address space. | |
2959 | */ | |
235b6217 HY |
2960 | for (k = 0; k < SWAP_CLUSTER_COLS; k++) { |
2961 | j = (k + col) % SWAP_CLUSTER_COLS; | |
2962 | for (i = 0; i < DIV_ROUND_UP(nr_clusters, SWAP_CLUSTER_COLS); i++) { | |
2963 | idx = i * SWAP_CLUSTER_COLS + j; | |
2964 | if (idx >= nr_clusters) | |
2965 | continue; | |
2966 | if (cluster_count(&cluster_info[idx])) | |
2967 | continue; | |
2a8f9449 | 2968 | cluster_set_flag(&cluster_info[idx], CLUSTER_FLAG_FREE); |
6b534915 HY |
2969 | cluster_list_add_tail(&p->free_clusters, cluster_info, |
2970 | idx); | |
2a8f9449 | 2971 | } |
2a8f9449 | 2972 | } |
915d4d7b | 2973 | return nr_extents; |
915d4d7b CEB |
2974 | } |
2975 | ||
dcf6b7dd RA |
2976 | /* |
2977 | * Helper to sys_swapon determining if a given swap | |
2978 | * backing device queue supports DISCARD operations. | |
2979 | */ | |
2980 | static bool swap_discardable(struct swap_info_struct *si) | |
2981 | { | |
2982 | struct request_queue *q = bdev_get_queue(si->bdev); | |
2983 | ||
2984 | if (!q || !blk_queue_discard(q)) | |
2985 | return false; | |
2986 | ||
2987 | return true; | |
2988 | } | |
2989 | ||
53cbb243 CEB |
2990 | SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) |
2991 | { | |
2992 | struct swap_info_struct *p; | |
91a27b2a | 2993 | struct filename *name; |
53cbb243 CEB |
2994 | struct file *swap_file = NULL; |
2995 | struct address_space *mapping; | |
40531542 | 2996 | int prio; |
53cbb243 CEB |
2997 | int error; |
2998 | union swap_header *swap_header; | |
915d4d7b | 2999 | int nr_extents; |
53cbb243 CEB |
3000 | sector_t span; |
3001 | unsigned long maxpages; | |
53cbb243 | 3002 | unsigned char *swap_map = NULL; |
2a8f9449 | 3003 | struct swap_cluster_info *cluster_info = NULL; |
38b5faf4 | 3004 | unsigned long *frontswap_map = NULL; |
53cbb243 CEB |
3005 | struct page *page = NULL; |
3006 | struct inode *inode = NULL; | |
7cbf3192 | 3007 | bool inced_nr_rotate_swap = false; |
53cbb243 | 3008 | |
d15cab97 HD |
3009 | if (swap_flags & ~SWAP_FLAGS_VALID) |
3010 | return -EINVAL; | |
3011 | ||
53cbb243 CEB |
3012 | if (!capable(CAP_SYS_ADMIN)) |
3013 | return -EPERM; | |
3014 | ||
a2468cc9 AL |
3015 | if (!swap_avail_heads) |
3016 | return -ENOMEM; | |
3017 | ||
53cbb243 | 3018 | p = alloc_swap_info(); |
2542e513 CEB |
3019 | if (IS_ERR(p)) |
3020 | return PTR_ERR(p); | |
53cbb243 | 3021 | |
815c2c54 SL |
3022 | INIT_WORK(&p->discard_work, swap_discard_work); |
3023 | ||
1da177e4 | 3024 | name = getname(specialfile); |
1da177e4 | 3025 | if (IS_ERR(name)) { |
7de7fb6b | 3026 | error = PTR_ERR(name); |
1da177e4 | 3027 | name = NULL; |
bd69010b | 3028 | goto bad_swap; |
1da177e4 | 3029 | } |
669abf4e | 3030 | swap_file = file_open_name(name, O_RDWR|O_LARGEFILE, 0); |
1da177e4 | 3031 | if (IS_ERR(swap_file)) { |
7de7fb6b | 3032 | error = PTR_ERR(swap_file); |
1da177e4 | 3033 | swap_file = NULL; |
bd69010b | 3034 | goto bad_swap; |
1da177e4 LT |
3035 | } |
3036 | ||
3037 | p->swap_file = swap_file; | |
3038 | mapping = swap_file->f_mapping; | |
2130781e | 3039 | inode = mapping->host; |
6f179af8 | 3040 | |
5955102c | 3041 | /* If S_ISREG(inode->i_mode) will do inode_lock(inode); */ |
4d0e1e10 CEB |
3042 | error = claim_swapfile(p, inode); |
3043 | if (unlikely(error)) | |
1da177e4 | 3044 | goto bad_swap; |
1da177e4 | 3045 | |
1da177e4 LT |
3046 | /* |
3047 | * Read the swap header. | |
3048 | */ | |
3049 | if (!mapping->a_ops->readpage) { | |
3050 | error = -EINVAL; | |
3051 | goto bad_swap; | |
3052 | } | |
090d2b18 | 3053 | page = read_mapping_page(mapping, 0, swap_file); |
1da177e4 LT |
3054 | if (IS_ERR(page)) { |
3055 | error = PTR_ERR(page); | |
3056 | goto bad_swap; | |
3057 | } | |
81e33971 | 3058 | swap_header = kmap(page); |
1da177e4 | 3059 | |
ca8bd38b CEB |
3060 | maxpages = read_swap_header(p, swap_header, inode); |
3061 | if (unlikely(!maxpages)) { | |
1da177e4 LT |
3062 | error = -EINVAL; |
3063 | goto bad_swap; | |
3064 | } | |
886bb7e9 | 3065 | |
81e33971 | 3066 | /* OK, set up the swap map and apply the bad block list */ |
803d0c83 | 3067 | swap_map = vzalloc(maxpages); |
81e33971 HD |
3068 | if (!swap_map) { |
3069 | error = -ENOMEM; | |
3070 | goto bad_swap; | |
3071 | } | |
f0571429 MK |
3072 | |
3073 | if (bdi_cap_stable_pages_required(inode_to_bdi(inode))) | |
3074 | p->flags |= SWP_STABLE_WRITES; | |
3075 | ||
539a6fea MK |
3076 | if (bdi_cap_synchronous_io(inode_to_bdi(inode))) |
3077 | p->flags |= SWP_SYNCHRONOUS_IO; | |
3078 | ||
2a8f9449 | 3079 | if (p->bdev && blk_queue_nonrot(bdev_get_queue(p->bdev))) { |
6f179af8 | 3080 | int cpu; |
235b6217 | 3081 | unsigned long ci, nr_cluster; |
6f179af8 | 3082 | |
2a8f9449 SL |
3083 | p->flags |= SWP_SOLIDSTATE; |
3084 | /* | |
3085 | * select a random position to start with to help wear leveling | |
3086 | * SSD | |
3087 | */ | |
3088 | p->cluster_next = 1 + (prandom_u32() % p->highest_bit); | |
235b6217 | 3089 | nr_cluster = DIV_ROUND_UP(maxpages, SWAPFILE_CLUSTER); |
2a8f9449 | 3090 | |
778e1cdd | 3091 | cluster_info = kvcalloc(nr_cluster, sizeof(*cluster_info), |
54f180d3 | 3092 | GFP_KERNEL); |
2a8f9449 SL |
3093 | if (!cluster_info) { |
3094 | error = -ENOMEM; | |
3095 | goto bad_swap; | |
3096 | } | |
235b6217 HY |
3097 | |
3098 | for (ci = 0; ci < nr_cluster; ci++) | |
3099 | spin_lock_init(&((cluster_info + ci)->lock)); | |
3100 | ||
ebc2a1a6 SL |
3101 | p->percpu_cluster = alloc_percpu(struct percpu_cluster); |
3102 | if (!p->percpu_cluster) { | |
3103 | error = -ENOMEM; | |
3104 | goto bad_swap; | |
3105 | } | |
6f179af8 | 3106 | for_each_possible_cpu(cpu) { |
ebc2a1a6 | 3107 | struct percpu_cluster *cluster; |
6f179af8 | 3108 | cluster = per_cpu_ptr(p->percpu_cluster, cpu); |
ebc2a1a6 SL |
3109 | cluster_set_null(&cluster->index); |
3110 | } | |
7cbf3192 | 3111 | } else { |
81a0298b | 3112 | atomic_inc(&nr_rotate_swap); |
7cbf3192 OS |
3113 | inced_nr_rotate_swap = true; |
3114 | } | |
1da177e4 | 3115 | |
1421ef3c CEB |
3116 | error = swap_cgroup_swapon(p->type, maxpages); |
3117 | if (error) | |
3118 | goto bad_swap; | |
3119 | ||
915d4d7b | 3120 | nr_extents = setup_swap_map_and_extents(p, swap_header, swap_map, |
2a8f9449 | 3121 | cluster_info, maxpages, &span); |
915d4d7b CEB |
3122 | if (unlikely(nr_extents < 0)) { |
3123 | error = nr_extents; | |
1da177e4 LT |
3124 | goto bad_swap; |
3125 | } | |
38b5faf4 | 3126 | /* frontswap enabled? set up bit-per-page map for frontswap */ |
8ea1d2a1 | 3127 | if (IS_ENABLED(CONFIG_FRONTSWAP)) |
778e1cdd KC |
3128 | frontswap_map = kvcalloc(BITS_TO_LONGS(maxpages), |
3129 | sizeof(long), | |
54f180d3 | 3130 | GFP_KERNEL); |
1da177e4 | 3131 | |
2a8f9449 SL |
3132 | if (p->bdev &&(swap_flags & SWAP_FLAG_DISCARD) && swap_discardable(p)) { |
3133 | /* | |
3134 | * When discard is enabled for swap with no particular | |
3135 | * policy flagged, we set all swap discard flags here in | |
3136 | * order to sustain backward compatibility with older | |
3137 | * swapon(8) releases. | |
3138 | */ | |
3139 | p->flags |= (SWP_DISCARDABLE | SWP_AREA_DISCARD | | |
3140 | SWP_PAGE_DISCARD); | |
dcf6b7dd | 3141 | |
2a8f9449 SL |
3142 | /* |
3143 | * By flagging sys_swapon, a sysadmin can tell us to | |
3144 | * either do single-time area discards only, or to just | |
3145 | * perform discards for released swap page-clusters. | |
3146 | * Now it's time to adjust the p->flags accordingly. | |
3147 | */ | |
3148 | if (swap_flags & SWAP_FLAG_DISCARD_ONCE) | |
3149 | p->flags &= ~SWP_PAGE_DISCARD; | |
3150 | else if (swap_flags & SWAP_FLAG_DISCARD_PAGES) | |
3151 | p->flags &= ~SWP_AREA_DISCARD; | |
3152 | ||
3153 | /* issue a swapon-time discard if it's still required */ | |
3154 | if (p->flags & SWP_AREA_DISCARD) { | |
3155 | int err = discard_swap(p); | |
3156 | if (unlikely(err)) | |
3157 | pr_err("swapon: discard_swap(%p): %d\n", | |
3158 | p, err); | |
dcf6b7dd | 3159 | } |
20137a49 | 3160 | } |
6a6ba831 | 3161 | |
4b3ef9da HY |
3162 | error = init_swap_address_space(p->type, maxpages); |
3163 | if (error) | |
3164 | goto bad_swap; | |
3165 | ||
fc0abb14 | 3166 | mutex_lock(&swapon_mutex); |
40531542 | 3167 | prio = -1; |
78ecba08 | 3168 | if (swap_flags & SWAP_FLAG_PREFER) |
40531542 | 3169 | prio = |
78ecba08 | 3170 | (swap_flags & SWAP_FLAG_PRIO_MASK) >> SWAP_FLAG_PRIO_SHIFT; |
2a8f9449 | 3171 | enable_swap_info(p, prio, swap_map, cluster_info, frontswap_map); |
c69dbfb8 | 3172 | |
756a025f | 3173 | pr_info("Adding %uk swap on %s. Priority:%d extents:%d across:%lluk %s%s%s%s%s\n", |
91a27b2a | 3174 | p->pages<<(PAGE_SHIFT-10), name->name, p->prio, |
c69dbfb8 CEB |
3175 | nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10), |
3176 | (p->flags & SWP_SOLIDSTATE) ? "SS" : "", | |
38b5faf4 | 3177 | (p->flags & SWP_DISCARDABLE) ? "D" : "", |
dcf6b7dd RA |
3178 | (p->flags & SWP_AREA_DISCARD) ? "s" : "", |
3179 | (p->flags & SWP_PAGE_DISCARD) ? "c" : "", | |
38b5faf4 | 3180 | (frontswap_map) ? "FS" : ""); |
c69dbfb8 | 3181 | |
fc0abb14 | 3182 | mutex_unlock(&swapon_mutex); |
66d7dd51 KS |
3183 | atomic_inc(&proc_poll_event); |
3184 | wake_up_interruptible(&proc_poll_wait); | |
3185 | ||
9b01c350 CEB |
3186 | if (S_ISREG(inode->i_mode)) |
3187 | inode->i_flags |= S_SWAPFILE; | |
1da177e4 LT |
3188 | error = 0; |
3189 | goto out; | |
3190 | bad_swap: | |
ebc2a1a6 SL |
3191 | free_percpu(p->percpu_cluster); |
3192 | p->percpu_cluster = NULL; | |
bd69010b | 3193 | if (inode && S_ISBLK(inode->i_mode) && p->bdev) { |
f2090d2d CEB |
3194 | set_blocksize(p->bdev, p->old_block_size); |
3195 | blkdev_put(p->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); | |
1da177e4 | 3196 | } |
4cd3bb10 | 3197 | destroy_swap_extents(p); |
e8e6c2ec | 3198 | swap_cgroup_swapoff(p->type); |
5d337b91 | 3199 | spin_lock(&swap_lock); |
1da177e4 | 3200 | p->swap_file = NULL; |
1da177e4 | 3201 | p->flags = 0; |
5d337b91 | 3202 | spin_unlock(&swap_lock); |
1da177e4 | 3203 | vfree(swap_map); |
8606a1a9 | 3204 | kvfree(cluster_info); |
b6b1fd2a | 3205 | kvfree(frontswap_map); |
7cbf3192 OS |
3206 | if (inced_nr_rotate_swap) |
3207 | atomic_dec(&nr_rotate_swap); | |
52c50567 | 3208 | if (swap_file) { |
2130781e | 3209 | if (inode && S_ISREG(inode->i_mode)) { |
5955102c | 3210 | inode_unlock(inode); |
2130781e CEB |
3211 | inode = NULL; |
3212 | } | |
1da177e4 | 3213 | filp_close(swap_file, NULL); |
52c50567 | 3214 | } |
1da177e4 LT |
3215 | out: |
3216 | if (page && !IS_ERR(page)) { | |
3217 | kunmap(page); | |
09cbfeaf | 3218 | put_page(page); |
1da177e4 LT |
3219 | } |
3220 | if (name) | |
3221 | putname(name); | |
9b01c350 | 3222 | if (inode && S_ISREG(inode->i_mode)) |
5955102c | 3223 | inode_unlock(inode); |
039939a6 TC |
3224 | if (!error) |
3225 | enable_swap_slots_cache(); | |
1da177e4 LT |
3226 | return error; |
3227 | } | |
3228 | ||
3229 | void si_swapinfo(struct sysinfo *val) | |
3230 | { | |
efa90a98 | 3231 | unsigned int type; |
1da177e4 LT |
3232 | unsigned long nr_to_be_unused = 0; |
3233 | ||
5d337b91 | 3234 | spin_lock(&swap_lock); |
efa90a98 HD |
3235 | for (type = 0; type < nr_swapfiles; type++) { |
3236 | struct swap_info_struct *si = swap_info[type]; | |
3237 | ||
3238 | if ((si->flags & SWP_USED) && !(si->flags & SWP_WRITEOK)) | |
3239 | nr_to_be_unused += si->inuse_pages; | |
1da177e4 | 3240 | } |
ec8acf20 | 3241 | val->freeswap = atomic_long_read(&nr_swap_pages) + nr_to_be_unused; |
1da177e4 | 3242 | val->totalswap = total_swap_pages + nr_to_be_unused; |
5d337b91 | 3243 | spin_unlock(&swap_lock); |
1da177e4 LT |
3244 | } |
3245 | ||
3246 | /* | |
3247 | * Verify that a swap entry is valid and increment its swap map count. | |
3248 | * | |
355cfa73 KH |
3249 | * Returns error code in following case. |
3250 | * - success -> 0 | |
3251 | * - swp_entry is invalid -> EINVAL | |
3252 | * - swp_entry is migration entry -> EINVAL | |
3253 | * - swap-cache reference is requested but there is already one. -> EEXIST | |
3254 | * - swap-cache reference is requested but the entry is not used. -> ENOENT | |
570a335b | 3255 | * - swap-mapped reference requested but needs continued swap count. -> ENOMEM |
1da177e4 | 3256 | */ |
8d69aaee | 3257 | static int __swap_duplicate(swp_entry_t entry, unsigned char usage) |
1da177e4 | 3258 | { |
73c34b6a | 3259 | struct swap_info_struct *p; |
235b6217 | 3260 | struct swap_cluster_info *ci; |
c10d38cc | 3261 | unsigned long offset; |
8d69aaee HD |
3262 | unsigned char count; |
3263 | unsigned char has_cache; | |
253d553b | 3264 | int err = -EINVAL; |
1da177e4 | 3265 | |
a7420aa5 | 3266 | if (non_swap_entry(entry)) |
253d553b | 3267 | goto out; |
0697212a | 3268 | |
c10d38cc DJ |
3269 | p = swp_swap_info(entry); |
3270 | if (!p) | |
1da177e4 | 3271 | goto bad_file; |
c10d38cc | 3272 | |
1da177e4 | 3273 | offset = swp_offset(entry); |
355cfa73 | 3274 | if (unlikely(offset >= p->max)) |
235b6217 HY |
3275 | goto out; |
3276 | ||
3277 | ci = lock_cluster_or_swap_info(p, offset); | |
355cfa73 | 3278 | |
253d553b | 3279 | count = p->swap_map[offset]; |
edfe23da SL |
3280 | |
3281 | /* | |
3282 | * swapin_readahead() doesn't check if a swap entry is valid, so the | |
3283 | * swap entry could be SWAP_MAP_BAD. Check here with lock held. | |
3284 | */ | |
3285 | if (unlikely(swap_count(count) == SWAP_MAP_BAD)) { | |
3286 | err = -ENOENT; | |
3287 | goto unlock_out; | |
3288 | } | |
3289 | ||
253d553b HD |
3290 | has_cache = count & SWAP_HAS_CACHE; |
3291 | count &= ~SWAP_HAS_CACHE; | |
3292 | err = 0; | |
355cfa73 | 3293 | |
253d553b | 3294 | if (usage == SWAP_HAS_CACHE) { |
355cfa73 KH |
3295 | |
3296 | /* set SWAP_HAS_CACHE if there is no cache and entry is used */ | |
253d553b HD |
3297 | if (!has_cache && count) |
3298 | has_cache = SWAP_HAS_CACHE; | |
3299 | else if (has_cache) /* someone else added cache */ | |
3300 | err = -EEXIST; | |
3301 | else /* no users remaining */ | |
3302 | err = -ENOENT; | |
355cfa73 KH |
3303 | |
3304 | } else if (count || has_cache) { | |
253d553b | 3305 | |
570a335b HD |
3306 | if ((count & ~COUNT_CONTINUED) < SWAP_MAP_MAX) |
3307 | count += usage; | |
3308 | else if ((count & ~COUNT_CONTINUED) > SWAP_MAP_MAX) | |
253d553b | 3309 | err = -EINVAL; |
570a335b HD |
3310 | else if (swap_count_continued(p, offset, count)) |
3311 | count = COUNT_CONTINUED; | |
3312 | else | |
3313 | err = -ENOMEM; | |
355cfa73 | 3314 | } else |
253d553b HD |
3315 | err = -ENOENT; /* unused swap entry */ |
3316 | ||
3317 | p->swap_map[offset] = count | has_cache; | |
3318 | ||
355cfa73 | 3319 | unlock_out: |
235b6217 | 3320 | unlock_cluster_or_swap_info(p, ci); |
1da177e4 | 3321 | out: |
253d553b | 3322 | return err; |
1da177e4 LT |
3323 | |
3324 | bad_file: | |
465c47fd | 3325 | pr_err("swap_dup: %s%08lx\n", Bad_file, entry.val); |
1da177e4 LT |
3326 | goto out; |
3327 | } | |
253d553b | 3328 | |
aaa46865 HD |
3329 | /* |
3330 | * Help swapoff by noting that swap entry belongs to shmem/tmpfs | |
3331 | * (in which case its reference count is never incremented). | |
3332 | */ | |
3333 | void swap_shmem_alloc(swp_entry_t entry) | |
3334 | { | |
3335 | __swap_duplicate(entry, SWAP_MAP_SHMEM); | |
3336 | } | |
3337 | ||
355cfa73 | 3338 | /* |
08259d58 HD |
3339 | * Increase reference count of swap entry by 1. |
3340 | * Returns 0 for success, or -ENOMEM if a swap_count_continuation is required | |
3341 | * but could not be atomically allocated. Returns 0, just as if it succeeded, | |
3342 | * if __swap_duplicate() fails for another reason (-EINVAL or -ENOENT), which | |
3343 | * might occur if a page table entry has got corrupted. | |
355cfa73 | 3344 | */ |
570a335b | 3345 | int swap_duplicate(swp_entry_t entry) |
355cfa73 | 3346 | { |
570a335b HD |
3347 | int err = 0; |
3348 | ||
3349 | while (!err && __swap_duplicate(entry, 1) == -ENOMEM) | |
3350 | err = add_swap_count_continuation(entry, GFP_ATOMIC); | |
3351 | return err; | |
355cfa73 | 3352 | } |
1da177e4 | 3353 | |
cb4b86ba | 3354 | /* |
355cfa73 KH |
3355 | * @entry: swap entry for which we allocate swap cache. |
3356 | * | |
73c34b6a | 3357 | * Called when allocating swap cache for existing swap entry, |
355cfa73 KH |
3358 | * This can return error codes. Returns 0 at success. |
3359 | * -EBUSY means there is a swap cache. | |
3360 | * Note: return code is different from swap_duplicate(). | |
cb4b86ba KH |
3361 | */ |
3362 | int swapcache_prepare(swp_entry_t entry) | |
3363 | { | |
253d553b | 3364 | return __swap_duplicate(entry, SWAP_HAS_CACHE); |
cb4b86ba KH |
3365 | } |
3366 | ||
0bcac06f MK |
3367 | struct swap_info_struct *swp_swap_info(swp_entry_t entry) |
3368 | { | |
c10d38cc | 3369 | return swap_type_to_swap_info(swp_type(entry)); |
0bcac06f MK |
3370 | } |
3371 | ||
f981c595 MG |
3372 | struct swap_info_struct *page_swap_info(struct page *page) |
3373 | { | |
0bcac06f MK |
3374 | swp_entry_t entry = { .val = page_private(page) }; |
3375 | return swp_swap_info(entry); | |
f981c595 MG |
3376 | } |
3377 | ||
3378 | /* | |
3379 | * out-of-line __page_file_ methods to avoid include hell. | |
3380 | */ | |
3381 | struct address_space *__page_file_mapping(struct page *page) | |
3382 | { | |
f981c595 MG |
3383 | return page_swap_info(page)->swap_file->f_mapping; |
3384 | } | |
3385 | EXPORT_SYMBOL_GPL(__page_file_mapping); | |
3386 | ||
3387 | pgoff_t __page_file_index(struct page *page) | |
3388 | { | |
3389 | swp_entry_t swap = { .val = page_private(page) }; | |
f981c595 MG |
3390 | return swp_offset(swap); |
3391 | } | |
3392 | EXPORT_SYMBOL_GPL(__page_file_index); | |
3393 | ||
570a335b HD |
3394 | /* |
3395 | * add_swap_count_continuation - called when a swap count is duplicated | |
3396 | * beyond SWAP_MAP_MAX, it allocates a new page and links that to the entry's | |
3397 | * page of the original vmalloc'ed swap_map, to hold the continuation count | |
3398 | * (for that entry and for its neighbouring PAGE_SIZE swap entries). Called | |
3399 | * again when count is duplicated beyond SWAP_MAP_MAX * SWAP_CONT_MAX, etc. | |
3400 | * | |
3401 | * These continuation pages are seldom referenced: the common paths all work | |
3402 | * on the original swap_map, only referring to a continuation page when the | |
3403 | * low "digit" of a count is incremented or decremented through SWAP_MAP_MAX. | |
3404 | * | |
3405 | * add_swap_count_continuation(, GFP_ATOMIC) can be called while holding | |
3406 | * page table locks; if it fails, add_swap_count_continuation(, GFP_KERNEL) | |
3407 | * can be called after dropping locks. | |
3408 | */ | |
3409 | int add_swap_count_continuation(swp_entry_t entry, gfp_t gfp_mask) | |
3410 | { | |
3411 | struct swap_info_struct *si; | |
235b6217 | 3412 | struct swap_cluster_info *ci; |
570a335b HD |
3413 | struct page *head; |
3414 | struct page *page; | |
3415 | struct page *list_page; | |
3416 | pgoff_t offset; | |
3417 | unsigned char count; | |
3418 | ||
3419 | /* | |
3420 | * When debugging, it's easier to use __GFP_ZERO here; but it's better | |
3421 | * for latency not to zero a page while GFP_ATOMIC and holding locks. | |
3422 | */ | |
3423 | page = alloc_page(gfp_mask | __GFP_HIGHMEM); | |
3424 | ||
3425 | si = swap_info_get(entry); | |
3426 | if (!si) { | |
3427 | /* | |
3428 | * An acceptable race has occurred since the failing | |
3429 | * __swap_duplicate(): the swap entry has been freed, | |
3430 | * perhaps even the whole swap_map cleared for swapoff. | |
3431 | */ | |
3432 | goto outer; | |
3433 | } | |
3434 | ||
3435 | offset = swp_offset(entry); | |
235b6217 HY |
3436 | |
3437 | ci = lock_cluster(si, offset); | |
3438 | ||
570a335b HD |
3439 | count = si->swap_map[offset] & ~SWAP_HAS_CACHE; |
3440 | ||
3441 | if ((count & ~COUNT_CONTINUED) != SWAP_MAP_MAX) { | |
3442 | /* | |
3443 | * The higher the swap count, the more likely it is that tasks | |
3444 | * will race to add swap count continuation: we need to avoid | |
3445 | * over-provisioning. | |
3446 | */ | |
3447 | goto out; | |
3448 | } | |
3449 | ||
3450 | if (!page) { | |
235b6217 | 3451 | unlock_cluster(ci); |
ec8acf20 | 3452 | spin_unlock(&si->lock); |
570a335b HD |
3453 | return -ENOMEM; |
3454 | } | |
3455 | ||
3456 | /* | |
3457 | * We are fortunate that although vmalloc_to_page uses pte_offset_map, | |
2de1a7e4 SJ |
3458 | * no architecture is using highmem pages for kernel page tables: so it |
3459 | * will not corrupt the GFP_ATOMIC caller's atomic page table kmaps. | |
570a335b HD |
3460 | */ |
3461 | head = vmalloc_to_page(si->swap_map + offset); | |
3462 | offset &= ~PAGE_MASK; | |
3463 | ||
2628bd6f | 3464 | spin_lock(&si->cont_lock); |
570a335b HD |
3465 | /* |
3466 | * Page allocation does not initialize the page's lru field, | |
3467 | * but it does always reset its private field. | |
3468 | */ | |
3469 | if (!page_private(head)) { | |
3470 | BUG_ON(count & COUNT_CONTINUED); | |
3471 | INIT_LIST_HEAD(&head->lru); | |
3472 | set_page_private(head, SWP_CONTINUED); | |
3473 | si->flags |= SWP_CONTINUED; | |
3474 | } | |
3475 | ||
3476 | list_for_each_entry(list_page, &head->lru, lru) { | |
3477 | unsigned char *map; | |
3478 | ||
3479 | /* | |
3480 | * If the previous map said no continuation, but we've found | |
3481 | * a continuation page, free our allocation and use this one. | |
3482 | */ | |
3483 | if (!(count & COUNT_CONTINUED)) | |
2628bd6f | 3484 | goto out_unlock_cont; |
570a335b | 3485 | |
9b04c5fe | 3486 | map = kmap_atomic(list_page) + offset; |
570a335b | 3487 | count = *map; |
9b04c5fe | 3488 | kunmap_atomic(map); |
570a335b HD |
3489 | |
3490 | /* | |
3491 | * If this continuation count now has some space in it, | |
3492 | * free our allocation and use this one. | |
3493 | */ | |
3494 | if ((count & ~COUNT_CONTINUED) != SWAP_CONT_MAX) | |
2628bd6f | 3495 | goto out_unlock_cont; |
570a335b HD |
3496 | } |
3497 | ||
3498 | list_add_tail(&page->lru, &head->lru); | |
3499 | page = NULL; /* now it's attached, don't free it */ | |
2628bd6f HY |
3500 | out_unlock_cont: |
3501 | spin_unlock(&si->cont_lock); | |
570a335b | 3502 | out: |
235b6217 | 3503 | unlock_cluster(ci); |
ec8acf20 | 3504 | spin_unlock(&si->lock); |
570a335b HD |
3505 | outer: |
3506 | if (page) | |
3507 | __free_page(page); | |
3508 | return 0; | |
3509 | } | |
3510 | ||
3511 | /* | |
3512 | * swap_count_continued - when the original swap_map count is incremented | |
3513 | * from SWAP_MAP_MAX, check if there is already a continuation page to carry | |
3514 | * into, carry if so, or else fail until a new continuation page is allocated; | |
3515 | * when the original swap_map count is decremented from 0 with continuation, | |
3516 | * borrow from the continuation and report whether it still holds more. | |
235b6217 HY |
3517 | * Called while __swap_duplicate() or swap_entry_free() holds swap or cluster |
3518 | * lock. | |
570a335b HD |
3519 | */ |
3520 | static bool swap_count_continued(struct swap_info_struct *si, | |
3521 | pgoff_t offset, unsigned char count) | |
3522 | { | |
3523 | struct page *head; | |
3524 | struct page *page; | |
3525 | unsigned char *map; | |
2628bd6f | 3526 | bool ret; |
570a335b HD |
3527 | |
3528 | head = vmalloc_to_page(si->swap_map + offset); | |
3529 | if (page_private(head) != SWP_CONTINUED) { | |
3530 | BUG_ON(count & COUNT_CONTINUED); | |
3531 | return false; /* need to add count continuation */ | |
3532 | } | |
3533 | ||
2628bd6f | 3534 | spin_lock(&si->cont_lock); |
570a335b HD |
3535 | offset &= ~PAGE_MASK; |
3536 | page = list_entry(head->lru.next, struct page, lru); | |
9b04c5fe | 3537 | map = kmap_atomic(page) + offset; |
570a335b HD |
3538 | |
3539 | if (count == SWAP_MAP_MAX) /* initial increment from swap_map */ | |
3540 | goto init_map; /* jump over SWAP_CONT_MAX checks */ | |
3541 | ||
3542 | if (count == (SWAP_MAP_MAX | COUNT_CONTINUED)) { /* incrementing */ | |
3543 | /* | |
3544 | * Think of how you add 1 to 999 | |
3545 | */ | |
3546 | while (*map == (SWAP_CONT_MAX | COUNT_CONTINUED)) { | |
9b04c5fe | 3547 | kunmap_atomic(map); |
570a335b HD |
3548 | page = list_entry(page->lru.next, struct page, lru); |
3549 | BUG_ON(page == head); | |
9b04c5fe | 3550 | map = kmap_atomic(page) + offset; |
570a335b HD |
3551 | } |
3552 | if (*map == SWAP_CONT_MAX) { | |
9b04c5fe | 3553 | kunmap_atomic(map); |
570a335b | 3554 | page = list_entry(page->lru.next, struct page, lru); |
2628bd6f HY |
3555 | if (page == head) { |
3556 | ret = false; /* add count continuation */ | |
3557 | goto out; | |
3558 | } | |
9b04c5fe | 3559 | map = kmap_atomic(page) + offset; |
570a335b HD |
3560 | init_map: *map = 0; /* we didn't zero the page */ |
3561 | } | |
3562 | *map += 1; | |
9b04c5fe | 3563 | kunmap_atomic(map); |
570a335b HD |
3564 | page = list_entry(page->lru.prev, struct page, lru); |
3565 | while (page != head) { | |
9b04c5fe | 3566 | map = kmap_atomic(page) + offset; |
570a335b | 3567 | *map = COUNT_CONTINUED; |
9b04c5fe | 3568 | kunmap_atomic(map); |
570a335b HD |
3569 | page = list_entry(page->lru.prev, struct page, lru); |
3570 | } | |
2628bd6f | 3571 | ret = true; /* incremented */ |
570a335b HD |
3572 | |
3573 | } else { /* decrementing */ | |
3574 | /* | |
3575 | * Think of how you subtract 1 from 1000 | |
3576 | */ | |
3577 | BUG_ON(count != COUNT_CONTINUED); | |
3578 | while (*map == COUNT_CONTINUED) { | |
9b04c5fe | 3579 | kunmap_atomic(map); |
570a335b HD |
3580 | page = list_entry(page->lru.next, struct page, lru); |
3581 | BUG_ON(page == head); | |
9b04c5fe | 3582 | map = kmap_atomic(page) + offset; |
570a335b HD |
3583 | } |
3584 | BUG_ON(*map == 0); | |
3585 | *map -= 1; | |
3586 | if (*map == 0) | |
3587 | count = 0; | |
9b04c5fe | 3588 | kunmap_atomic(map); |
570a335b HD |
3589 | page = list_entry(page->lru.prev, struct page, lru); |
3590 | while (page != head) { | |
9b04c5fe | 3591 | map = kmap_atomic(page) + offset; |
570a335b HD |
3592 | *map = SWAP_CONT_MAX | count; |
3593 | count = COUNT_CONTINUED; | |
9b04c5fe | 3594 | kunmap_atomic(map); |
570a335b HD |
3595 | page = list_entry(page->lru.prev, struct page, lru); |
3596 | } | |
2628bd6f | 3597 | ret = count == COUNT_CONTINUED; |
570a335b | 3598 | } |
2628bd6f HY |
3599 | out: |
3600 | spin_unlock(&si->cont_lock); | |
3601 | return ret; | |
570a335b HD |
3602 | } |
3603 | ||
3604 | /* | |
3605 | * free_swap_count_continuations - swapoff free all the continuation pages | |
3606 | * appended to the swap_map, after swap_map is quiesced, before vfree'ing it. | |
3607 | */ | |
3608 | static void free_swap_count_continuations(struct swap_info_struct *si) | |
3609 | { | |
3610 | pgoff_t offset; | |
3611 | ||
3612 | for (offset = 0; offset < si->max; offset += PAGE_SIZE) { | |
3613 | struct page *head; | |
3614 | head = vmalloc_to_page(si->swap_map + offset); | |
3615 | if (page_private(head)) { | |
0d576d20 GT |
3616 | struct page *page, *next; |
3617 | ||
3618 | list_for_each_entry_safe(page, next, &head->lru, lru) { | |
3619 | list_del(&page->lru); | |
570a335b HD |
3620 | __free_page(page); |
3621 | } | |
3622 | } | |
3623 | } | |
3624 | } | |
a2468cc9 | 3625 | |
2cf85583 TH |
3626 | #if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP) |
3627 | void mem_cgroup_throttle_swaprate(struct mem_cgroup *memcg, int node, | |
3628 | gfp_t gfp_mask) | |
3629 | { | |
3630 | struct swap_info_struct *si, *next; | |
3631 | if (!(gfp_mask & __GFP_IO) || !memcg) | |
3632 | return; | |
3633 | ||
3634 | if (!blk_cgroup_congested()) | |
3635 | return; | |
3636 | ||
3637 | /* | |
3638 | * We've already scheduled a throttle, avoid taking the global swap | |
3639 | * lock. | |
3640 | */ | |
3641 | if (current->throttle_queue) | |
3642 | return; | |
3643 | ||
3644 | spin_lock(&swap_avail_lock); | |
3645 | plist_for_each_entry_safe(si, next, &swap_avail_heads[node], | |
3646 | avail_lists[node]) { | |
3647 | if (si->bdev) { | |
3648 | blkcg_schedule_throttle(bdev_get_queue(si->bdev), | |
3649 | true); | |
3650 | break; | |
3651 | } | |
3652 | } | |
3653 | spin_unlock(&swap_avail_lock); | |
3654 | } | |
3655 | #endif | |
3656 | ||
a2468cc9 AL |
3657 | static int __init swapfile_init(void) |
3658 | { | |
3659 | int nid; | |
3660 | ||
3661 | swap_avail_heads = kmalloc_array(nr_node_ids, sizeof(struct plist_head), | |
3662 | GFP_KERNEL); | |
3663 | if (!swap_avail_heads) { | |
3664 | pr_emerg("Not enough memory for swap heads, swap is disabled\n"); | |
3665 | return -ENOMEM; | |
3666 | } | |
3667 | ||
3668 | for_each_node(nid) | |
3669 | plist_head_init(&swap_avail_heads[nid]); | |
3670 | ||
3671 | return 0; | |
3672 | } | |
3673 | subsys_initcall(swapfile_init); |