]>
Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * linux/mm/page_io.c | |
4 | * | |
5 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds | |
6 | * | |
7 | * Swap reorganised 29.12.95, | |
8 | * Asynchronous swapping added 30.12.95. Stephen Tweedie | |
9 | * Removed race in async swapping. 14.4.1996. Bruno Haible | |
10 | * Add swap of shared pages through the page cache. 20.2.1998. Stephen Tweedie | |
11 | * Always use brw_page, life becomes simpler. 12 May 1998 Eric Biederman | |
12 | */ | |
13 | ||
14 | #include <linux/mm.h> | |
15 | #include <linux/kernel_stat.h> | |
5a0e3ad6 | 16 | #include <linux/gfp.h> |
1da177e4 LT |
17 | #include <linux/pagemap.h> |
18 | #include <linux/swap.h> | |
19 | #include <linux/bio.h> | |
20 | #include <linux/swapops.h> | |
62c230bc | 21 | #include <linux/buffer_head.h> |
1da177e4 | 22 | #include <linux/writeback.h> |
38b5faf4 | 23 | #include <linux/frontswap.h> |
b430e9d1 | 24 | #include <linux/blkdev.h> |
93779069 | 25 | #include <linux/psi.h> |
e2e40f2c | 26 | #include <linux/uio.h> |
b0ba2d0f | 27 | #include <linux/sched/task.h> |
1da177e4 | 28 | |
4246a0b6 | 29 | void end_swap_bio_write(struct bio *bio) |
1da177e4 | 30 | { |
263663cd | 31 | struct page *page = bio_first_page_all(bio); |
1da177e4 | 32 | |
4e4cbee9 | 33 | if (bio->bi_status) { |
1da177e4 | 34 | SetPageError(page); |
6ddab3b9 PZ |
35 | /* |
36 | * We failed to write the page out to swap-space. | |
37 | * Re-dirty the page in order to avoid it being reclaimed. | |
38 | * Also print a dire warning that things will go BAD (tm) | |
39 | * very quickly. | |
40 | * | |
41 | * Also clear PG_reclaim to avoid rotate_reclaimable_page() | |
42 | */ | |
43 | set_page_dirty(page); | |
25eaab43 GD |
44 | pr_alert_ratelimited("Write-error on swap-device (%u:%u:%llu)\n", |
45 | MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)), | |
46 | (unsigned long long)bio->bi_iter.bi_sector); | |
6ddab3b9 PZ |
47 | ClearPageReclaim(page); |
48 | } | |
1da177e4 LT |
49 | end_page_writeback(page); |
50 | bio_put(bio); | |
1da177e4 LT |
51 | } |
52 | ||
4246a0b6 | 53 | static void end_swap_bio_read(struct bio *bio) |
1da177e4 | 54 | { |
263663cd | 55 | struct page *page = bio_first_page_all(bio); |
23955622 | 56 | struct task_struct *waiter = bio->bi_private; |
1da177e4 | 57 | |
4e4cbee9 | 58 | if (bio->bi_status) { |
1da177e4 LT |
59 | SetPageError(page); |
60 | ClearPageUptodate(page); | |
25eaab43 GD |
61 | pr_alert_ratelimited("Read-error on swap-device (%u:%u:%llu)\n", |
62 | MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)), | |
63 | (unsigned long long)bio->bi_iter.bi_sector); | |
b430e9d1 | 64 | goto out; |
1da177e4 | 65 | } |
b430e9d1 MK |
66 | |
67 | SetPageUptodate(page); | |
b430e9d1 | 68 | out: |
1da177e4 | 69 | unlock_page(page); |
23955622 | 70 | WRITE_ONCE(bio->bi_private, NULL); |
1da177e4 | 71 | bio_put(bio); |
87518530 ON |
72 | if (waiter) { |
73 | blk_wake_io_task(waiter); | |
74 | put_task_struct(waiter); | |
75 | } | |
1da177e4 LT |
76 | } |
77 | ||
a509bc1a MG |
78 | int generic_swapfile_activate(struct swap_info_struct *sis, |
79 | struct file *swap_file, | |
80 | sector_t *span) | |
81 | { | |
82 | struct address_space *mapping = swap_file->f_mapping; | |
83 | struct inode *inode = mapping->host; | |
84 | unsigned blocks_per_page; | |
85 | unsigned long page_no; | |
86 | unsigned blkbits; | |
87 | sector_t probe_block; | |
88 | sector_t last_block; | |
89 | sector_t lowest_block = -1; | |
90 | sector_t highest_block = 0; | |
91 | int nr_extents = 0; | |
92 | int ret; | |
93 | ||
94 | blkbits = inode->i_blkbits; | |
95 | blocks_per_page = PAGE_SIZE >> blkbits; | |
96 | ||
97 | /* | |
4efaceb1 | 98 | * Map all the blocks into the extent tree. This code doesn't try |
a509bc1a MG |
99 | * to be very smart. |
100 | */ | |
101 | probe_block = 0; | |
102 | page_no = 0; | |
103 | last_block = i_size_read(inode) >> blkbits; | |
104 | while ((probe_block + blocks_per_page) <= last_block && | |
105 | page_no < sis->max) { | |
106 | unsigned block_in_page; | |
107 | sector_t first_block; | |
108 | ||
7e4411bf MP |
109 | cond_resched(); |
110 | ||
30460e1e CM |
111 | first_block = probe_block; |
112 | ret = bmap(inode, &first_block); | |
113 | if (ret || !first_block) | |
a509bc1a MG |
114 | goto bad_bmap; |
115 | ||
116 | /* | |
117 | * It must be PAGE_SIZE aligned on-disk | |
118 | */ | |
119 | if (first_block & (blocks_per_page - 1)) { | |
120 | probe_block++; | |
121 | goto reprobe; | |
122 | } | |
123 | ||
124 | for (block_in_page = 1; block_in_page < blocks_per_page; | |
125 | block_in_page++) { | |
126 | sector_t block; | |
127 | ||
30460e1e CM |
128 | block = probe_block + block_in_page; |
129 | ret = bmap(inode, &block); | |
130 | if (ret || !block) | |
a509bc1a | 131 | goto bad_bmap; |
30460e1e | 132 | |
a509bc1a MG |
133 | if (block != first_block + block_in_page) { |
134 | /* Discontiguity */ | |
135 | probe_block++; | |
136 | goto reprobe; | |
137 | } | |
138 | } | |
139 | ||
140 | first_block >>= (PAGE_SHIFT - blkbits); | |
141 | if (page_no) { /* exclude the header page */ | |
142 | if (first_block < lowest_block) | |
143 | lowest_block = first_block; | |
144 | if (first_block > highest_block) | |
145 | highest_block = first_block; | |
146 | } | |
147 | ||
148 | /* | |
149 | * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks | |
150 | */ | |
151 | ret = add_swap_extent(sis, page_no, 1, first_block); | |
152 | if (ret < 0) | |
153 | goto out; | |
154 | nr_extents += ret; | |
155 | page_no++; | |
156 | probe_block += blocks_per_page; | |
157 | reprobe: | |
158 | continue; | |
159 | } | |
160 | ret = nr_extents; | |
161 | *span = 1 + highest_block - lowest_block; | |
162 | if (page_no == 0) | |
163 | page_no = 1; /* force Empty message */ | |
164 | sis->max = page_no; | |
165 | sis->pages = page_no - 1; | |
166 | sis->highest_bit = page_no - 1; | |
167 | out: | |
168 | return ret; | |
169 | bad_bmap: | |
1170532b | 170 | pr_err("swapon: swapfile has holes\n"); |
a509bc1a MG |
171 | ret = -EINVAL; |
172 | goto out; | |
173 | } | |
174 | ||
1da177e4 LT |
175 | /* |
176 | * We may have stale swap cache pages in memory: notice | |
177 | * them here and get rid of the unnecessary final write. | |
178 | */ | |
179 | int swap_writepage(struct page *page, struct writeback_control *wbc) | |
180 | { | |
2f772e6c | 181 | int ret = 0; |
1da177e4 | 182 | |
a2c43eed | 183 | if (try_to_free_swap(page)) { |
1da177e4 LT |
184 | unlock_page(page); |
185 | goto out; | |
186 | } | |
8a84802e SP |
187 | /* |
188 | * Arch code may have to preserve more data than just the page | |
189 | * contents, e.g. memory tags. | |
190 | */ | |
191 | ret = arch_prepare_to_swap(page); | |
192 | if (ret) { | |
193 | set_page_dirty(page); | |
194 | unlock_page(page); | |
195 | goto out; | |
196 | } | |
165c8aed | 197 | if (frontswap_store(page) == 0) { |
38b5faf4 DM |
198 | set_page_writeback(page); |
199 | unlock_page(page); | |
200 | end_page_writeback(page); | |
201 | goto out; | |
202 | } | |
1eec6702 | 203 | ret = __swap_writepage(page, wbc, end_swap_bio_write); |
2f772e6c SJ |
204 | out: |
205 | return ret; | |
206 | } | |
207 | ||
225311a4 HY |
208 | static inline void count_swpout_vm_event(struct page *page) |
209 | { | |
210 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
211 | if (unlikely(PageTransHuge(page))) | |
212 | count_vm_event(THP_SWPOUT); | |
213 | #endif | |
6c357848 | 214 | count_vm_events(PSWPOUT, thp_nr_pages(page)); |
225311a4 HY |
215 | } |
216 | ||
a18b9b15 CH |
217 | #if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP) |
218 | static void bio_associate_blkg_from_page(struct bio *bio, struct page *page) | |
219 | { | |
220 | struct cgroup_subsys_state *css; | |
bcfe06bf | 221 | struct mem_cgroup *memcg; |
a18b9b15 | 222 | |
bcfe06bf RG |
223 | memcg = page_memcg(page); |
224 | if (!memcg) | |
a18b9b15 CH |
225 | return; |
226 | ||
227 | rcu_read_lock(); | |
bcfe06bf | 228 | css = cgroup_e_css(memcg->css.cgroup, &io_cgrp_subsys); |
a18b9b15 CH |
229 | bio_associate_blkg_from_css(bio, css); |
230 | rcu_read_unlock(); | |
231 | } | |
232 | #else | |
233 | #define bio_associate_blkg_from_page(bio, page) do { } while (0) | |
234 | #endif /* CONFIG_MEMCG && CONFIG_BLK_CGROUP */ | |
235 | ||
1eec6702 | 236 | int __swap_writepage(struct page *page, struct writeback_control *wbc, |
4246a0b6 | 237 | bio_end_io_t end_write_func) |
2f772e6c SJ |
238 | { |
239 | struct bio *bio; | |
4e49ea4a | 240 | int ret; |
2f772e6c | 241 | struct swap_info_struct *sis = page_swap_info(page); |
62c230bc | 242 | |
cc30c5d6 | 243 | VM_BUG_ON_PAGE(!PageSwapCache(page), page); |
32646315 | 244 | if (data_race(sis->flags & SWP_FS_OPS)) { |
62c230bc MG |
245 | struct kiocb kiocb; |
246 | struct file *swap_file = sis->swap_file; | |
247 | struct address_space *mapping = swap_file->f_mapping; | |
62a8067a AV |
248 | struct bio_vec bv = { |
249 | .bv_page = page, | |
250 | .bv_len = PAGE_SIZE, | |
251 | .bv_offset = 0 | |
252 | }; | |
05afcb77 | 253 | struct iov_iter from; |
62c230bc | 254 | |
aa563d7b | 255 | iov_iter_bvec(&from, WRITE, &bv, 1, PAGE_SIZE); |
62c230bc MG |
256 | init_sync_kiocb(&kiocb, swap_file); |
257 | kiocb.ki_pos = page_file_offset(page); | |
62c230bc | 258 | |
0cdc444a | 259 | set_page_writeback(page); |
62c230bc | 260 | unlock_page(page); |
c8b8e32d | 261 | ret = mapping->a_ops->direct_IO(&kiocb, &from); |
62c230bc MG |
262 | if (ret == PAGE_SIZE) { |
263 | count_vm_event(PSWPOUT); | |
264 | ret = 0; | |
2d30d31e | 265 | } else { |
0cdc444a MG |
266 | /* |
267 | * In the case of swap-over-nfs, this can be a | |
268 | * temporary failure if the system has limited | |
269 | * memory for allocating transmit buffers. | |
270 | * Mark the page dirty and avoid | |
271 | * rotate_reclaimable_page but rate-limit the | |
272 | * messages but do not flag PageError like | |
273 | * the normal direct-to-bio case as it could | |
274 | * be temporary. | |
275 | */ | |
2d30d31e | 276 | set_page_dirty(page); |
0cdc444a | 277 | ClearPageReclaim(page); |
1170532b JP |
278 | pr_err_ratelimited("Write error on dio swapfile (%llu)\n", |
279 | page_file_offset(page)); | |
62c230bc | 280 | } |
0cdc444a | 281 | end_page_writeback(page); |
62c230bc MG |
282 | return ret; |
283 | } | |
284 | ||
dd6bd0d9 MW |
285 | ret = bdev_write_page(sis->bdev, swap_page_sector(page), page, wbc); |
286 | if (!ret) { | |
225311a4 | 287 | count_swpout_vm_event(page); |
dd6bd0d9 MW |
288 | return 0; |
289 | } | |
290 | ||
48d15436 CH |
291 | bio = bio_alloc(GFP_NOIO, 1); |
292 | bio_set_dev(bio, sis->bdev); | |
293 | bio->bi_iter.bi_sector = swap_page_sector(page); | |
0d1e0c7c | 294 | bio->bi_opf = REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc); |
48d15436 CH |
295 | bio->bi_end_io = end_write_func; |
296 | bio_add_page(bio, page, thp_size(page), 0); | |
297 | ||
6a7f6d86 | 298 | bio_associate_blkg_from_page(bio, page); |
225311a4 | 299 | count_swpout_vm_event(page); |
1da177e4 LT |
300 | set_page_writeback(page); |
301 | unlock_page(page); | |
4e49ea4a | 302 | submit_bio(bio); |
548d9782 ML |
303 | |
304 | return 0; | |
1da177e4 LT |
305 | } |
306 | ||
0bcac06f | 307 | int swap_readpage(struct page *page, bool synchronous) |
1da177e4 LT |
308 | { |
309 | struct bio *bio; | |
310 | int ret = 0; | |
62c230bc | 311 | struct swap_info_struct *sis = page_swap_info(page); |
23955622 | 312 | blk_qc_t qc; |
74d46992 | 313 | struct gendisk *disk; |
93779069 | 314 | unsigned long pflags; |
1da177e4 | 315 | |
0bcac06f | 316 | VM_BUG_ON_PAGE(!PageSwapCache(page) && !synchronous, page); |
309381fe SL |
317 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
318 | VM_BUG_ON_PAGE(PageUptodate(page), page); | |
93779069 MK |
319 | |
320 | /* | |
321 | * Count submission time as memory stall. When the device is congested, | |
322 | * or the submitting cgroup IO-throttled, submission can be a | |
323 | * significant part of overall IO time. | |
324 | */ | |
325 | psi_memstall_enter(&pflags); | |
326 | ||
165c8aed | 327 | if (frontswap_load(page) == 0) { |
38b5faf4 DM |
328 | SetPageUptodate(page); |
329 | unlock_page(page); | |
330 | goto out; | |
331 | } | |
62c230bc | 332 | |
32646315 | 333 | if (data_race(sis->flags & SWP_FS_OPS)) { |
62c230bc MG |
334 | struct file *swap_file = sis->swap_file; |
335 | struct address_space *mapping = swap_file->f_mapping; | |
336 | ||
337 | ret = mapping->a_ops->readpage(swap_file, page); | |
338 | if (!ret) | |
339 | count_vm_event(PSWPIN); | |
93779069 | 340 | goto out; |
62c230bc MG |
341 | } |
342 | ||
5115db10 CH |
343 | if (sis->flags & SWP_SYNCHRONOUS_IO) { |
344 | ret = bdev_read_page(sis->bdev, swap_page_sector(page), page); | |
345 | if (!ret) { | |
5115db10 CH |
346 | count_vm_event(PSWPIN); |
347 | goto out; | |
348 | } | |
dd6bd0d9 MW |
349 | } |
350 | ||
351 | ret = 0; | |
48d15436 CH |
352 | bio = bio_alloc(GFP_KERNEL, 1); |
353 | bio_set_dev(bio, sis->bdev); | |
354 | bio->bi_opf = REQ_OP_READ; | |
355 | bio->bi_iter.bi_sector = swap_page_sector(page); | |
356 | bio->bi_end_io = end_swap_bio_read; | |
357 | bio_add_page(bio, page, thp_size(page), 0); | |
358 | ||
309dca30 | 359 | disk = bio->bi_bdev->bd_disk; |
b0ba2d0f TH |
360 | /* |
361 | * Keep this task valid during swap readpage because the oom killer may | |
362 | * attempt to access it in the page fault retry time check. | |
363 | */ | |
87518530 | 364 | if (synchronous) { |
b685a735 | 365 | bio->bi_opf |= REQ_HIPRI; |
87518530 ON |
366 | get_task_struct(current); |
367 | bio->bi_private = current; | |
368 | } | |
f8891e5e | 369 | count_vm_event(PSWPIN); |
23955622 SL |
370 | bio_get(bio); |
371 | qc = submit_bio(bio); | |
0bcac06f | 372 | while (synchronous) { |
1ac5cd49 | 373 | set_current_state(TASK_UNINTERRUPTIBLE); |
23955622 SL |
374 | if (!READ_ONCE(bio->bi_private)) |
375 | break; | |
376 | ||
0a1b8b87 | 377 | if (!blk_poll(disk->queue, qc, true)) |
0f190a7a | 378 | blk_io_schedule(); |
23955622 SL |
379 | } |
380 | __set_current_state(TASK_RUNNING); | |
381 | bio_put(bio); | |
382 | ||
1da177e4 | 383 | out: |
93779069 | 384 | psi_memstall_leave(&pflags); |
1da177e4 LT |
385 | return ret; |
386 | } | |
62c230bc MG |
387 | |
388 | int swap_set_page_dirty(struct page *page) | |
389 | { | |
390 | struct swap_info_struct *sis = page_swap_info(page); | |
391 | ||
32646315 | 392 | if (data_race(sis->flags & SWP_FS_OPS)) { |
62c230bc | 393 | struct address_space *mapping = sis->swap_file->f_mapping; |
cc30c5d6 AM |
394 | |
395 | VM_BUG_ON_PAGE(!PageSwapCache(page), page); | |
62c230bc MG |
396 | return mapping->a_ops->set_page_dirty(page); |
397 | } else { | |
398 | return __set_page_dirty_no_writeback(page); | |
399 | } | |
400 | } |