Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/mm/page_io.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds | |
5 | * | |
6 | * Swap reorganised 29.12.95, | |
7 | * Asynchronous swapping added 30.12.95. Stephen Tweedie | |
8 | * Removed race in async swapping. 14.4.1996. Bruno Haible | |
9 | * Add swap of shared pages through the page cache. 20.2.1998. Stephen Tweedie | |
10 | * Always use brw_page, life becomes simpler. 12 May 1998 Eric Biederman | |
11 | */ | |
12 | ||
13 | #include <linux/mm.h> | |
14 | #include <linux/kernel_stat.h> | |
5a0e3ad6 | 15 | #include <linux/gfp.h> |
1da177e4 LT |
16 | #include <linux/pagemap.h> |
17 | #include <linux/swap.h> | |
18 | #include <linux/bio.h> | |
19 | #include <linux/swapops.h> | |
62c230bc | 20 | #include <linux/buffer_head.h> |
1da177e4 | 21 | #include <linux/writeback.h> |
38b5faf4 | 22 | #include <linux/frontswap.h> |
a27bb332 | 23 | #include <linux/aio.h> |
6fa3eb70 | 24 | #include <linux/blkdev.h> |
1da177e4 LT |
25 | #include <asm/pgtable.h> |
26 | ||
f29ad6a9 | 27 | static struct bio *get_swap_bio(gfp_t gfp_flags, |
1da177e4 LT |
28 | struct page *page, bio_end_io_t end_io) |
29 | { | |
30 | struct bio *bio; | |
31 | ||
32 | bio = bio_alloc(gfp_flags, 1); | |
33 | if (bio) { | |
d4906e1a | 34 | bio->bi_sector = map_swap_page(page, &bio->bi_bdev); |
f29ad6a9 | 35 | bio->bi_sector <<= PAGE_SHIFT - 9; |
1da177e4 LT |
36 | bio->bi_io_vec[0].bv_page = page; |
37 | bio->bi_io_vec[0].bv_len = PAGE_SIZE; | |
38 | bio->bi_io_vec[0].bv_offset = 0; | |
39 | bio->bi_vcnt = 1; | |
1da177e4 LT |
40 | bio->bi_size = PAGE_SIZE; |
41 | bio->bi_end_io = end_io; | |
42 | } | |
43 | return bio; | |
44 | } | |
45 | ||
1eec6702 | 46 | void end_swap_bio_write(struct bio *bio, int err) |
1da177e4 LT |
47 | { |
48 | const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); | |
49 | struct page *page = bio->bi_io_vec[0].bv_page; | |
50 | ||
6ddab3b9 | 51 | if (!uptodate) { |
6fa3eb70 S |
52 | if (!task_in_mtkpasr(current)) { |
53 | SetPageError(page); | |
54 | } | |
6ddab3b9 PZ |
55 | /* |
56 | * We failed to write the page out to swap-space. | |
57 | * Re-dirty the page in order to avoid it being reclaimed. | |
58 | * Also print a dire warning that things will go BAD (tm) | |
59 | * very quickly. | |
60 | * | |
61 | * Also clear PG_reclaim to avoid rotate_reclaimable_page() | |
62 | */ | |
63 | set_page_dirty(page); | |
6fa3eb70 S |
64 | if (!task_in_mtkpasr(current)) { |
65 | printk(KERN_ALERT "Write-error on swap-device (%u:%u:%Lu)\n", | |
66 | imajor(bio->bi_bdev->bd_inode), | |
67 | iminor(bio->bi_bdev->bd_inode), | |
68 | (unsigned long long)bio->bi_sector); | |
69 | } | |
6ddab3b9 PZ |
70 | ClearPageReclaim(page); |
71 | } | |
1da177e4 LT |
72 | end_page_writeback(page); |
73 | bio_put(bio); | |
1da177e4 LT |
74 | } |
75 | ||
6712ecf8 | 76 | void end_swap_bio_read(struct bio *bio, int err) |
1da177e4 LT |
77 | { |
78 | const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); | |
79 | struct page *page = bio->bi_io_vec[0].bv_page; | |
80 | ||
1da177e4 LT |
81 | if (!uptodate) { |
82 | SetPageError(page); | |
83 | ClearPageUptodate(page); | |
6ddab3b9 PZ |
84 | printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n", |
85 | imajor(bio->bi_bdev->bd_inode), | |
86 | iminor(bio->bi_bdev->bd_inode), | |
87 | (unsigned long long)bio->bi_sector); | |
6fa3eb70 S |
88 | goto out; |
89 | } | |
90 | ||
91 | SetPageUptodate(page); | |
92 | ||
93 | /* | |
94 | * There is no guarantee that the page is in swap cache - the software | |
95 | * suspend code (at least) uses end_swap_bio_read() against a non- | |
96 | * swapcache page. So we must check PG_swapcache before proceeding with | |
97 | * this optimization. | |
98 | */ | |
99 | if (likely(PageSwapCache(page))) { | |
100 | struct swap_info_struct *sis; | |
101 | ||
102 | sis = page_swap_info(page); | |
103 | if (sis->flags & SWP_BLKDEV) { | |
104 | /* | |
105 | * The swap subsystem performs lazy swap slot freeing, | |
106 | * expecting that the page will be swapped out again. | |
107 | * So we can avoid an unnecessary write if the page | |
108 | * isn't redirtied. | |
109 | * This is good for real swap storage because we can | |
110 | * reduce unnecessary I/O and enhance wear-leveling | |
111 | * if an SSD is used as the as swap device. | |
112 | * But if in-memory swap device (eg zram) is used, | |
113 | * this causes a duplicated copy between uncompressed | |
114 | * data in VM-owned memory and compressed data in | |
115 | * zram-owned memory. So let's free zram-owned memory | |
116 | * and make the VM-owned decompressed page *dirty*, | |
117 | * so the page should be swapped out somewhere again if | |
118 | * we again wish to reclaim it. | |
119 | */ | |
120 | struct gendisk *disk = sis->bdev->bd_disk; | |
121 | if (disk->fops->swap_slot_free_notify) { | |
122 | swp_entry_t entry; | |
123 | unsigned long offset; | |
124 | ||
125 | entry.val = page_private(page); | |
126 | offset = swp_offset(entry); | |
127 | ||
128 | SetPageDirty(page); | |
129 | disk->fops->swap_slot_free_notify(sis->bdev, | |
130 | offset); | |
131 | } | |
132 | } | |
1da177e4 | 133 | } |
6fa3eb70 S |
134 | |
135 | out: | |
1da177e4 LT |
136 | unlock_page(page); |
137 | bio_put(bio); | |
1da177e4 LT |
138 | } |
139 | ||
a509bc1a MG |
140 | int generic_swapfile_activate(struct swap_info_struct *sis, |
141 | struct file *swap_file, | |
142 | sector_t *span) | |
143 | { | |
144 | struct address_space *mapping = swap_file->f_mapping; | |
145 | struct inode *inode = mapping->host; | |
146 | unsigned blocks_per_page; | |
147 | unsigned long page_no; | |
148 | unsigned blkbits; | |
149 | sector_t probe_block; | |
150 | sector_t last_block; | |
151 | sector_t lowest_block = -1; | |
152 | sector_t highest_block = 0; | |
153 | int nr_extents = 0; | |
154 | int ret; | |
155 | ||
156 | blkbits = inode->i_blkbits; | |
157 | blocks_per_page = PAGE_SIZE >> blkbits; | |
158 | ||
159 | /* | |
160 | * Map all the blocks into the extent list. This code doesn't try | |
161 | * to be very smart. | |
162 | */ | |
163 | probe_block = 0; | |
164 | page_no = 0; | |
165 | last_block = i_size_read(inode) >> blkbits; | |
166 | while ((probe_block + blocks_per_page) <= last_block && | |
167 | page_no < sis->max) { | |
168 | unsigned block_in_page; | |
169 | sector_t first_block; | |
170 | ||
171 | first_block = bmap(inode, probe_block); | |
172 | if (first_block == 0) | |
173 | goto bad_bmap; | |
174 | ||
175 | /* | |
176 | * It must be PAGE_SIZE aligned on-disk | |
177 | */ | |
178 | if (first_block & (blocks_per_page - 1)) { | |
179 | probe_block++; | |
180 | goto reprobe; | |
181 | } | |
182 | ||
183 | for (block_in_page = 1; block_in_page < blocks_per_page; | |
184 | block_in_page++) { | |
185 | sector_t block; | |
186 | ||
187 | block = bmap(inode, probe_block + block_in_page); | |
188 | if (block == 0) | |
189 | goto bad_bmap; | |
190 | if (block != first_block + block_in_page) { | |
191 | /* Discontiguity */ | |
192 | probe_block++; | |
193 | goto reprobe; | |
194 | } | |
195 | } | |
196 | ||
197 | first_block >>= (PAGE_SHIFT - blkbits); | |
198 | if (page_no) { /* exclude the header page */ | |
199 | if (first_block < lowest_block) | |
200 | lowest_block = first_block; | |
201 | if (first_block > highest_block) | |
202 | highest_block = first_block; | |
203 | } | |
204 | ||
205 | /* | |
206 | * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks | |
207 | */ | |
208 | ret = add_swap_extent(sis, page_no, 1, first_block); | |
209 | if (ret < 0) | |
210 | goto out; | |
211 | nr_extents += ret; | |
212 | page_no++; | |
213 | probe_block += blocks_per_page; | |
214 | reprobe: | |
215 | continue; | |
216 | } | |
217 | ret = nr_extents; | |
218 | *span = 1 + highest_block - lowest_block; | |
219 | if (page_no == 0) | |
220 | page_no = 1; /* force Empty message */ | |
221 | sis->max = page_no; | |
222 | sis->pages = page_no - 1; | |
223 | sis->highest_bit = page_no - 1; | |
224 | out: | |
225 | return ret; | |
226 | bad_bmap: | |
227 | printk(KERN_ERR "swapon: swapfile has holes\n"); | |
228 | ret = -EINVAL; | |
229 | goto out; | |
230 | } | |
231 | ||
1da177e4 LT |
232 | /* |
233 | * We may have stale swap cache pages in memory: notice | |
234 | * them here and get rid of the unnecessary final write. | |
235 | */ | |
236 | int swap_writepage(struct page *page, struct writeback_control *wbc) | |
237 | { | |
2f772e6c | 238 | int ret = 0; |
1da177e4 | 239 | |
a2c43eed | 240 | if (try_to_free_swap(page)) { |
1da177e4 LT |
241 | unlock_page(page); |
242 | goto out; | |
243 | } | |
165c8aed | 244 | if (frontswap_store(page) == 0) { |
38b5faf4 DM |
245 | set_page_writeback(page); |
246 | unlock_page(page); | |
247 | end_page_writeback(page); | |
248 | goto out; | |
249 | } | |
1eec6702 | 250 | ret = __swap_writepage(page, wbc, end_swap_bio_write); |
2f772e6c SJ |
251 | out: |
252 | return ret; | |
253 | } | |
254 | ||
1eec6702 SJ |
255 | int __swap_writepage(struct page *page, struct writeback_control *wbc, |
256 | void (*end_write_func)(struct bio *, int)) | |
2f772e6c SJ |
257 | { |
258 | struct bio *bio; | |
259 | int ret = 0, rw = WRITE; | |
260 | struct swap_info_struct *sis = page_swap_info(page); | |
62c230bc MG |
261 | |
262 | if (sis->flags & SWP_FILE) { | |
263 | struct kiocb kiocb; | |
264 | struct file *swap_file = sis->swap_file; | |
265 | struct address_space *mapping = swap_file->f_mapping; | |
266 | struct iovec iov = { | |
5a178119 | 267 | .iov_base = kmap(page), |
62c230bc MG |
268 | .iov_len = PAGE_SIZE, |
269 | }; | |
270 | ||
271 | init_sync_kiocb(&kiocb, swap_file); | |
272 | kiocb.ki_pos = page_file_offset(page); | |
273 | kiocb.ki_left = PAGE_SIZE; | |
274 | kiocb.ki_nbytes = PAGE_SIZE; | |
275 | ||
0cdc444a | 276 | set_page_writeback(page); |
62c230bc MG |
277 | unlock_page(page); |
278 | ret = mapping->a_ops->direct_IO(KERNEL_WRITE, | |
279 | &kiocb, &iov, | |
280 | kiocb.ki_pos, 1); | |
5a178119 | 281 | kunmap(page); |
62c230bc MG |
282 | if (ret == PAGE_SIZE) { |
283 | count_vm_event(PSWPOUT); | |
284 | ret = 0; | |
2d30d31e | 285 | } else { |
0cdc444a MG |
286 | /* |
287 | * In the case of swap-over-nfs, this can be a | |
288 | * temporary failure if the system has limited | |
289 | * memory for allocating transmit buffers. | |
290 | * Mark the page dirty and avoid | |
291 | * rotate_reclaimable_page but rate-limit the | |
292 | * messages but do not flag PageError like | |
293 | * the normal direct-to-bio case as it could | |
294 | * be temporary. | |
295 | */ | |
2d30d31e | 296 | set_page_dirty(page); |
0cdc444a MG |
297 | ClearPageReclaim(page); |
298 | pr_err_ratelimited("Write error on dio swapfile (%Lu)\n", | |
299 | page_file_offset(page)); | |
62c230bc | 300 | } |
0cdc444a | 301 | end_page_writeback(page); |
62c230bc MG |
302 | return ret; |
303 | } | |
304 | ||
1eec6702 | 305 | bio = get_swap_bio(GFP_NOIO, page, end_write_func); |
1da177e4 LT |
306 | if (bio == NULL) { |
307 | set_page_dirty(page); | |
308 | unlock_page(page); | |
309 | ret = -ENOMEM; | |
310 | goto out; | |
311 | } | |
312 | if (wbc->sync_mode == WB_SYNC_ALL) | |
721a9602 | 313 | rw |= REQ_SYNC; |
6fa3eb70 S |
314 | |
315 | #ifdef CONFIG_ZRAM | |
316 | current->swap_out++; | |
317 | #endif | |
f8891e5e | 318 | count_vm_event(PSWPOUT); |
1da177e4 LT |
319 | set_page_writeback(page); |
320 | unlock_page(page); | |
321 | submit_bio(rw, bio); | |
322 | out: | |
323 | return ret; | |
324 | } | |
325 | ||
aca8bf32 | 326 | int swap_readpage(struct page *page) |
1da177e4 LT |
327 | { |
328 | struct bio *bio; | |
329 | int ret = 0; | |
62c230bc | 330 | struct swap_info_struct *sis = page_swap_info(page); |
1da177e4 | 331 | |
51726b12 HD |
332 | VM_BUG_ON(!PageLocked(page)); |
333 | VM_BUG_ON(PageUptodate(page)); | |
165c8aed | 334 | if (frontswap_load(page) == 0) { |
38b5faf4 DM |
335 | SetPageUptodate(page); |
336 | unlock_page(page); | |
337 | goto out; | |
338 | } | |
62c230bc MG |
339 | |
340 | if (sis->flags & SWP_FILE) { | |
341 | struct file *swap_file = sis->swap_file; | |
342 | struct address_space *mapping = swap_file->f_mapping; | |
343 | ||
344 | ret = mapping->a_ops->readpage(swap_file, page); | |
6fa3eb70 S |
345 | if (!ret) { |
346 | #ifdef CONFIG_ZRAM | |
347 | current->swap_in++; | |
348 | #endif | |
62c230bc | 349 | count_vm_event(PSWPIN); |
6fa3eb70 | 350 | } |
62c230bc MG |
351 | return ret; |
352 | } | |
353 | ||
f29ad6a9 | 354 | bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read); |
1da177e4 LT |
355 | if (bio == NULL) { |
356 | unlock_page(page); | |
357 | ret = -ENOMEM; | |
358 | goto out; | |
359 | } | |
6fa3eb70 S |
360 | |
361 | #ifdef CONFIG_ZRAM | |
362 | current->swap_in++; | |
363 | #endif | |
f8891e5e | 364 | count_vm_event(PSWPIN); |
1da177e4 LT |
365 | submit_bio(READ, bio); |
366 | out: | |
367 | return ret; | |
368 | } | |
62c230bc MG |
369 | |
370 | int swap_set_page_dirty(struct page *page) | |
371 | { | |
372 | struct swap_info_struct *sis = page_swap_info(page); | |
373 | ||
374 | if (sis->flags & SWP_FILE) { | |
375 | struct address_space *mapping = sis->swap_file->f_mapping; | |
376 | return mapping->a_ops->set_page_dirty(page); | |
377 | } else { | |
378 | return __set_page_dirty_no_writeback(page); | |
379 | } | |
380 | } |