]>
Commit | Line | Data |
---|---|---|
b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 | 2 | /* |
f30c2269 | 3 | * include/linux/writeback.h |
1da177e4 LT |
4 | */ |
5 | #ifndef WRITEBACK_H | |
6 | #define WRITEBACK_H | |
7 | ||
e8edc6e0 | 8 | #include <linux/sched.h> |
a27bb332 | 9 | #include <linux/workqueue.h> |
f5ff8422 | 10 | #include <linux/fs.h> |
380c27ca | 11 | #include <linux/flex_proportions.h> |
21c6321f | 12 | #include <linux/backing-dev-defs.h> |
7637241e | 13 | #include <linux/blk_types.h> |
653c45c6 | 14 | #include <linux/blk-cgroup.h> |
e8edc6e0 | 15 | |
2f8b5444 CH |
16 | struct bio; |
17 | ||
54848d73 WF |
18 | DECLARE_PER_CPU(int, dirty_throttle_leaks); |
19 | ||
ffd1f609 | 20 | /* |
1a12d8bd WF |
21 | * The 1/4 region under the global dirty thresh is for smooth dirty throttling: |
22 | * | |
23 | * (thresh - thresh/DIRTY_FULL_SCOPE, thresh) | |
24 | * | |
ffd1f609 WF |
25 | * Further beyond, all dirtier tasks will enter a loop waiting (possibly long |
26 | * time) for the dirty pages to drop, unless written enough pages. | |
27 | * | |
28 | * The global dirty threshold is normally equal to the global dirty limit, | |
29 | * except when the system suddenly allocates a lot of anonymous memory and | |
30 | * knocks down the global dirty threshold quickly, in which case the global | |
31 | * dirty limit will follow down slowly to prevent livelocking all dirtier tasks. | |
32 | */ | |
1a12d8bd WF |
33 | #define DIRTY_SCOPE 8 |
34 | #define DIRTY_FULL_SCOPE (DIRTY_SCOPE / 2) | |
ffd1f609 | 35 | |
1da177e4 LT |
36 | struct backing_dev_info; |
37 | ||
1da177e4 LT |
38 | /* |
39 | * fs/fs-writeback.c | |
40 | */ | |
41 | enum writeback_sync_modes { | |
42 | WB_SYNC_NONE, /* Don't wait on anything */ | |
43 | WB_SYNC_ALL, /* Wait on every mapping */ | |
1da177e4 LT |
44 | }; |
45 | ||
46 | /* | |
47 | * A control structure which tells the writeback code what to do. These are | |
48 | * always on the stack, and hence need no locking. They are always initialised | |
49 | * in a manner such that unspecified fields are set to zero. | |
50 | */ | |
51 | struct writeback_control { | |
1da177e4 LT |
52 | long nr_to_write; /* Write this many pages, and decrement |
53 | this for each page written */ | |
54 | long pages_skipped; /* Pages which were not written */ | |
55 | ||
56 | /* | |
95468fd4 | 57 | * For a_ops->writepages(): if start or end are non-zero then this is |
1da177e4 LT |
58 | * a hint that the filesystem need only write out the pages inside that |
59 | * byterange. The byte at `end' is included in the writeout request. | |
60 | */ | |
111ebb6e OH |
61 | loff_t range_start; |
62 | loff_t range_end; | |
1da177e4 | 63 | |
4cd9069a RK |
64 | enum writeback_sync_modes sync_mode; |
65 | ||
22905f77 | 66 | unsigned for_kupdate:1; /* A kupdate writeback */ |
b17621fe | 67 | unsigned for_background:1; /* A background writeback */ |
6e6938b6 | 68 | unsigned tagged_writepages:1; /* tag-and-write to avoid livelock */ |
22905f77 | 69 | unsigned for_reclaim:1; /* Invoked from the page allocator */ |
111ebb6e | 70 | unsigned range_cyclic:1; /* range_start is cyclic */ |
7747bd4b | 71 | unsigned for_sync:1; /* sync(2) WB_SYNC_ALL writeback */ |
27b36d8f TH |
72 | |
73 | /* | |
74 | * When writeback IOs are bounced through async layers, only the | |
75 | * initial synchronous phase should be accounted towards inode | |
76 | * cgroup ownership arbitration to avoid confusion. Later stages | |
77 | * can set the following flag to disable the accounting. | |
78 | */ | |
79 | unsigned no_cgroup_owner:1; | |
80 | ||
d3f77dfd TH |
81 | unsigned punt_to_cgroup:1; /* cgrp punting, see __REQ_CGROUP_PUNT */ |
82 | ||
b16b1deb TH |
83 | #ifdef CONFIG_CGROUP_WRITEBACK |
84 | struct bdi_writeback *wb; /* wb this writeback is issued under */ | |
2a814908 TH |
85 | struct inode *inode; /* inode being written out */ |
86 | ||
87 | /* foreign inode detection, see wbc_detach_inode() */ | |
88 | int wb_id; /* current wb id */ | |
89 | int wb_lcand_id; /* last foreign candidate wb id */ | |
90 | int wb_tcand_id; /* this foreign candidate wb id */ | |
91 | size_t wb_bytes; /* bytes written by current wb */ | |
92 | size_t wb_lcand_bytes; /* bytes written by last candidate */ | |
93 | size_t wb_tcand_bytes; /* bytes written by this candidate */ | |
b16b1deb | 94 | #endif |
1da177e4 LT |
95 | }; |
96 | ||
7637241e JA |
97 | static inline int wbc_to_write_flags(struct writeback_control *wbc) |
98 | { | |
d3f77dfd TH |
99 | int flags = 0; |
100 | ||
101 | if (wbc->punt_to_cgroup) | |
102 | flags = REQ_CGROUP_PUNT; | |
103 | ||
7637241e | 104 | if (wbc->sync_mode == WB_SYNC_ALL) |
d3f77dfd | 105 | flags |= REQ_SYNC; |
13edd5e7 | 106 | else if (wbc->for_kupdate || wbc->for_background) |
d3f77dfd | 107 | flags |= REQ_BACKGROUND; |
7637241e | 108 | |
d3f77dfd | 109 | return flags; |
7637241e JA |
110 | } |
111 | ||
653c45c6 TH |
112 | static inline struct cgroup_subsys_state * |
113 | wbc_blkcg_css(struct writeback_control *wbc) | |
114 | { | |
115 | #ifdef CONFIG_CGROUP_WRITEBACK | |
116 | if (wbc->wb) | |
117 | return wbc->wb->blkcg_css; | |
118 | #endif | |
119 | return blkcg_root_css; | |
120 | } | |
121 | ||
380c27ca TH |
122 | /* |
123 | * A wb_domain represents a domain that wb's (bdi_writeback's) belong to | |
124 | * and are measured against each other in. There always is one global | |
125 | * domain, global_wb_domain, that every wb in the system is a member of. | |
126 | * This allows measuring the relative bandwidth of each wb to distribute | |
127 | * dirtyable memory accordingly. | |
128 | */ | |
129 | struct wb_domain { | |
dcc25ae7 TH |
130 | spinlock_t lock; |
131 | ||
380c27ca TH |
132 | /* |
133 | * Scale the writeback cache size proportional to the relative | |
134 | * writeout speed. | |
135 | * | |
136 | * We do this by keeping a floating proportion between BDIs, based | |
137 | * on page writeback completions [end_page_writeback()]. Those | |
138 | * devices that write out pages fastest will get the larger share, | |
139 | * while the slower will get a smaller share. | |
140 | * | |
141 | * We use page writeout completions because we are interested in | |
142 | * getting rid of dirty pages. Having them written out is the | |
143 | * primary goal. | |
144 | * | |
145 | * We introduce a concept of time, a period over which we measure | |
146 | * these events, because demand can/will vary over time. The length | |
147 | * of this period itself is measured in page writeback completions. | |
148 | */ | |
149 | struct fprop_global completions; | |
150 | struct timer_list period_timer; /* timer for aging of completions */ | |
151 | unsigned long period_time; | |
dcc25ae7 TH |
152 | |
153 | /* | |
154 | * The dirtyable memory and dirty threshold could be suddenly | |
155 | * knocked down by a large amount (eg. on the startup of KVM in a | |
156 | * swapless system). This may throw the system into deep dirty | |
157 | * exceeded state and throttle heavy/light dirtiers alike. To | |
158 | * retain good responsiveness, maintain global_dirty_limit for | |
159 | * tracking slowly down to the knocked down dirty threshold. | |
160 | * | |
161 | * Both fields are protected by ->lock. | |
162 | */ | |
163 | unsigned long dirty_limit_tstamp; | |
164 | unsigned long dirty_limit; | |
380c27ca TH |
165 | }; |
166 | ||
2529bb3a TH |
167 | /** |
168 | * wb_domain_size_changed - memory available to a wb_domain has changed | |
169 | * @dom: wb_domain of interest | |
170 | * | |
171 | * This function should be called when the amount of memory available to | |
172 | * @dom has changed. It resets @dom's dirty limit parameters to prevent | |
173 | * the past values which don't match the current configuration from skewing | |
174 | * dirty throttling. Without this, when memory size of a wb_domain is | |
175 | * greatly reduced, the dirty throttling logic may allow too many pages to | |
176 | * be dirtied leading to consecutive unnecessary OOMs and may get stuck in | |
177 | * that situation. | |
178 | */ | |
179 | static inline void wb_domain_size_changed(struct wb_domain *dom) | |
180 | { | |
181 | spin_lock(&dom->lock); | |
182 | dom->dirty_limit_tstamp = jiffies; | |
183 | dom->dirty_limit = 0; | |
184 | spin_unlock(&dom->lock); | |
185 | } | |
186 | ||
1da177e4 LT |
187 | /* |
188 | * fs/fs-writeback.c | |
189 | */ | |
03ba3782 | 190 | struct bdi_writeback; |
0e175a18 CW |
191 | void writeback_inodes_sb(struct super_block *, enum wb_reason reason); |
192 | void writeback_inodes_sb_nr(struct super_block *, unsigned long nr, | |
193 | enum wb_reason reason); | |
8264c321 | 194 | void try_to_writeback_inodes_sb(struct super_block *sb, enum wb_reason reason); |
0dc83bd3 | 195 | void sync_inodes_sb(struct super_block *); |
9ba4b2df | 196 | void wakeup_flusher_threads(enum wb_reason reason); |
595043e5 JA |
197 | void wakeup_flusher_threads_bdi(struct backing_dev_info *bdi, |
198 | enum wb_reason reason); | |
169ebd90 | 199 | void inode_wait_for_writeback(struct inode *inode); |
4301efa4 | 200 | void inode_io_list_del(struct inode *inode); |
1da177e4 LT |
201 | |
202 | /* writeback.h requires fs.h; it, too, is not included from here. */ | |
203 | static inline void wait_on_inode(struct inode *inode) | |
204 | { | |
205 | might_sleep(); | |
74316201 | 206 | wait_on_bit(&inode->i_state, __I_NEW, TASK_UNINTERRUPTIBLE); |
1da177e4 | 207 | } |
1c0eeaf5 | 208 | |
21c6321f TH |
209 | #ifdef CONFIG_CGROUP_WRITEBACK |
210 | ||
b16b1deb TH |
211 | #include <linux/cgroup.h> |
212 | #include <linux/bio.h> | |
213 | ||
21c6321f | 214 | void __inode_attach_wb(struct inode *inode, struct page *page); |
b16b1deb TH |
215 | void wbc_attach_and_unlock_inode(struct writeback_control *wbc, |
216 | struct inode *inode) | |
217 | __releases(&inode->i_lock); | |
218 | void wbc_detach_inode(struct writeback_control *wbc); | |
34e51a5e TH |
219 | void wbc_account_cgroup_owner(struct writeback_control *wbc, struct page *page, |
220 | size_t bytes); | |
d62241c7 TH |
221 | int cgroup_writeback_by_id(u64 bdi_id, int memcg_id, unsigned long nr_pages, |
222 | enum wb_reason reason, struct wb_completion *done); | |
a1a0e23e | 223 | void cgroup_writeback_umount(void); |
21c6321f TH |
224 | |
225 | /** | |
226 | * inode_attach_wb - associate an inode with its wb | |
227 | * @inode: inode of interest | |
228 | * @page: page being dirtied (may be NULL) | |
229 | * | |
230 | * If @inode doesn't have its wb, associate it with the wb matching the | |
231 | * memcg of @page or, if @page is NULL, %current. May be called w/ or w/o | |
232 | * @inode->i_lock. | |
233 | */ | |
234 | static inline void inode_attach_wb(struct inode *inode, struct page *page) | |
235 | { | |
236 | if (!inode->i_wb) | |
237 | __inode_attach_wb(inode, page); | |
238 | } | |
239 | ||
240 | /** | |
241 | * inode_detach_wb - disassociate an inode from its wb | |
242 | * @inode: inode of interest | |
243 | * | |
244 | * @inode is being freed. Detach from its wb. | |
245 | */ | |
246 | static inline void inode_detach_wb(struct inode *inode) | |
247 | { | |
248 | if (inode->i_wb) { | |
f759741d | 249 | WARN_ON_ONCE(!(inode->i_state & I_CLEAR)); |
21c6321f TH |
250 | wb_put(inode->i_wb); |
251 | inode->i_wb = NULL; | |
252 | } | |
253 | } | |
254 | ||
b16b1deb TH |
255 | /** |
256 | * wbc_attach_fdatawrite_inode - associate wbc and inode for fdatawrite | |
257 | * @wbc: writeback_control of interest | |
258 | * @inode: target inode | |
259 | * | |
260 | * This function is to be used by __filemap_fdatawrite_range(), which is an | |
261 | * alternative entry point into writeback code, and first ensures @inode is | |
262 | * associated with a bdi_writeback and attaches it to @wbc. | |
263 | */ | |
264 | static inline void wbc_attach_fdatawrite_inode(struct writeback_control *wbc, | |
265 | struct inode *inode) | |
266 | { | |
267 | spin_lock(&inode->i_lock); | |
268 | inode_attach_wb(inode, NULL); | |
269 | wbc_attach_and_unlock_inode(wbc, inode); | |
270 | } | |
271 | ||
272 | /** | |
273 | * wbc_init_bio - writeback specific initializtion of bio | |
274 | * @wbc: writeback_control for the writeback in progress | |
275 | * @bio: bio to be initialized | |
276 | * | |
277 | * @bio is a part of the writeback in progress controlled by @wbc. Perform | |
278 | * writeback specific initialization. This is used to apply the cgroup | |
fd42df30 DZ |
279 | * writeback context. Must be called after the bio has been associated with |
280 | * a device. | |
b16b1deb TH |
281 | */ |
282 | static inline void wbc_init_bio(struct writeback_control *wbc, struct bio *bio) | |
283 | { | |
284 | /* | |
285 | * pageout() path doesn't attach @wbc to the inode being written | |
286 | * out. This is intentional as we don't want the function to block | |
287 | * behind a slow cgroup. Ultimately, we want pageout() to kick off | |
288 | * regular writeback instead of writing things out itself. | |
289 | */ | |
290 | if (wbc->wb) | |
fd42df30 | 291 | bio_associate_blkg_from_css(bio, wbc->wb->blkcg_css); |
b16b1deb TH |
292 | } |
293 | ||
21c6321f TH |
294 | #else /* CONFIG_CGROUP_WRITEBACK */ |
295 | ||
296 | static inline void inode_attach_wb(struct inode *inode, struct page *page) | |
297 | { | |
298 | } | |
299 | ||
300 | static inline void inode_detach_wb(struct inode *inode) | |
301 | { | |
302 | } | |
303 | ||
b16b1deb TH |
304 | static inline void wbc_attach_and_unlock_inode(struct writeback_control *wbc, |
305 | struct inode *inode) | |
306 | __releases(&inode->i_lock) | |
307 | { | |
308 | spin_unlock(&inode->i_lock); | |
309 | } | |
310 | ||
311 | static inline void wbc_attach_fdatawrite_inode(struct writeback_control *wbc, | |
312 | struct inode *inode) | |
313 | { | |
314 | } | |
315 | ||
316 | static inline void wbc_detach_inode(struct writeback_control *wbc) | |
317 | { | |
318 | } | |
319 | ||
320 | static inline void wbc_init_bio(struct writeback_control *wbc, struct bio *bio) | |
321 | { | |
322 | } | |
323 | ||
34e51a5e TH |
324 | static inline void wbc_account_cgroup_owner(struct writeback_control *wbc, |
325 | struct page *page, size_t bytes) | |
2a814908 TH |
326 | { |
327 | } | |
328 | ||
a1a0e23e TH |
329 | static inline void cgroup_writeback_umount(void) |
330 | { | |
331 | } | |
332 | ||
21c6321f TH |
333 | #endif /* CONFIG_CGROUP_WRITEBACK */ |
334 | ||
1da177e4 LT |
335 | /* |
336 | * mm/page-writeback.c | |
337 | */ | |
c2c4986e | 338 | #ifdef CONFIG_BLOCK |
31373d09 | 339 | void laptop_io_completion(struct backing_dev_info *info); |
1da177e4 | 340 | void laptop_sync_completion(void); |
31373d09 | 341 | void laptop_mode_sync(struct work_struct *work); |
bca237a5 | 342 | void laptop_mode_timer_fn(struct timer_list *t); |
c2c4986e JA |
343 | #else |
344 | static inline void laptop_sync_completion(void) { } | |
345 | #endif | |
281e3726 | 346 | bool node_dirty_ok(struct pglist_data *pgdat); |
380c27ca | 347 | int wb_domain_init(struct wb_domain *dom, gfp_t gfp); |
841710aa TH |
348 | #ifdef CONFIG_CGROUP_WRITEBACK |
349 | void wb_domain_exit(struct wb_domain *dom); | |
350 | #endif | |
1da177e4 | 351 | |
dcc25ae7 | 352 | extern struct wb_domain global_wb_domain; |
c42843f2 | 353 | |
1da177e4 LT |
354 | /* These are exported to sysctl. */ |
355 | extern int dirty_background_ratio; | |
2da02997 | 356 | extern unsigned long dirty_background_bytes; |
1da177e4 | 357 | extern int vm_dirty_ratio; |
2da02997 | 358 | extern unsigned long vm_dirty_bytes; |
704503d8 AD |
359 | extern unsigned int dirty_writeback_interval; |
360 | extern unsigned int dirty_expire_interval; | |
1efff914 | 361 | extern unsigned int dirtytime_expire_interval; |
195cf453 | 362 | extern int vm_highmem_is_dirtyable; |
1da177e4 LT |
363 | extern int block_dump; |
364 | extern int laptop_mode; | |
365 | ||
32927393 CH |
366 | int dirty_background_ratio_handler(struct ctl_table *table, int write, |
367 | void *buffer, size_t *lenp, loff_t *ppos); | |
368 | int dirty_background_bytes_handler(struct ctl_table *table, int write, | |
369 | void *buffer, size_t *lenp, loff_t *ppos); | |
370 | int dirty_ratio_handler(struct ctl_table *table, int write, | |
371 | void *buffer, size_t *lenp, loff_t *ppos); | |
372 | int dirty_bytes_handler(struct ctl_table *table, int write, | |
373 | void *buffer, size_t *lenp, loff_t *ppos); | |
1efff914 | 374 | int dirtytime_interval_handler(struct ctl_table *table, int write, |
32927393 CH |
375 | void *buffer, size_t *lenp, loff_t *ppos); |
376 | int dirty_writeback_centisecs_handler(struct ctl_table *table, int write, | |
377 | void *buffer, size_t *lenp, loff_t *ppos); | |
1da177e4 | 378 | |
16c4042f | 379 | void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty); |
0d960a38 | 380 | unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh); |
a88a341a | 381 | |
8a731799 | 382 | void wb_update_bandwidth(struct bdi_writeback *wb, unsigned long start_time); |
d0e1d66b | 383 | void balance_dirty_pages_ratelimited(struct address_space *mapping); |
aa661bbe | 384 | bool wb_over_bg_thresh(struct bdi_writeback *wb); |
fa5a734e | 385 | |
0ea97180 MS |
386 | typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc, |
387 | void *data); | |
388 | ||
0ea97180 MS |
389 | int generic_writepages(struct address_space *mapping, |
390 | struct writeback_control *wbc); | |
5b41d924 ES |
391 | void tag_pages_for_writeback(struct address_space *mapping, |
392 | pgoff_t start, pgoff_t end); | |
0ea97180 MS |
393 | int write_cache_pages(struct address_space *mapping, |
394 | struct writeback_control *wbc, writepage_t writepage, | |
395 | void *data); | |
1da177e4 | 396 | int do_writepages(struct address_space *mapping, struct writeback_control *wbc); |
2d1d43f6 | 397 | void writeback_set_ratelimit(void); |
92c09c04 NK |
398 | void tag_pages_for_writeback(struct address_space *mapping, |
399 | pgoff_t start, pgoff_t end); | |
1da177e4 | 400 | |
2f800fbd WF |
401 | void account_page_redirty(struct page *page); |
402 | ||
6c60d2b5 DC |
403 | void sb_mark_inode_writeback(struct inode *inode); |
404 | void sb_clear_inode_writeback(struct inode *inode); | |
405 | ||
1da177e4 | 406 | #endif /* WRITEBACK_H */ |