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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * include/linux/backing-dev.h | |
3 | * | |
4 | * low-level device information and state which is propagated up through | |
5 | * to high-level code. | |
6 | */ | |
7 | ||
8 | #ifndef _LINUX_BACKING_DEV_H | |
9 | #define _LINUX_BACKING_DEV_H | |
10 | ||
cf0ca9fe | 11 | #include <linux/kernel.h> |
e4ad08fe | 12 | #include <linux/fs.h> |
03ba3782 | 13 | #include <linux/sched.h> |
a212b105 | 14 | #include <linux/blkdev.h> |
03ba3782 | 15 | #include <linux/writeback.h> |
52ebea74 | 16 | #include <linux/blk-cgroup.h> |
66114cad | 17 | #include <linux/backing-dev-defs.h> |
1da177e4 | 18 | |
8077c0d9 | 19 | int __must_check bdi_init(struct backing_dev_info *bdi); |
b2e8fb6e PZ |
20 | void bdi_destroy(struct backing_dev_info *bdi); |
21 | ||
d2cc4dde | 22 | __printf(3, 4) |
cf0ca9fe PZ |
23 | int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
24 | const char *fmt, ...); | |
25 | int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev); | |
26 | void bdi_unregister(struct backing_dev_info *bdi); | |
b4caecd4 | 27 | int __must_check bdi_setup_and_register(struct backing_dev_info *, char *); |
c00ddad3 TH |
28 | void wb_start_writeback(struct bdi_writeback *wb, long nr_pages, |
29 | bool range_cyclic, enum wb_reason reason); | |
9ecf4866 | 30 | void wb_start_background_writeback(struct bdi_writeback *wb); |
f0054bb1 | 31 | void wb_workfn(struct work_struct *work); |
f0054bb1 | 32 | void wb_wakeup_delayed(struct bdi_writeback *wb); |
cf0ca9fe | 33 | |
03ba3782 | 34 | extern spinlock_t bdi_lock; |
66f3b8e2 JA |
35 | extern struct list_head bdi_list; |
36 | ||
839a8e86 TH |
37 | extern struct workqueue_struct *bdi_wq; |
38 | ||
d6c10f1f | 39 | static inline bool wb_has_dirty_io(struct bdi_writeback *wb) |
03ba3782 | 40 | { |
d6c10f1f | 41 | return test_bit(WB_has_dirty_io, &wb->state); |
03ba3782 JA |
42 | } |
43 | ||
95a46c65 TH |
44 | static inline bool bdi_has_dirty_io(struct backing_dev_info *bdi) |
45 | { | |
46 | /* | |
47 | * @bdi->tot_write_bandwidth is guaranteed to be > 0 if there are | |
48 | * any dirty wbs. See wb_update_write_bandwidth(). | |
49 | */ | |
50 | return atomic_long_read(&bdi->tot_write_bandwidth); | |
51 | } | |
52 | ||
93f78d88 TH |
53 | static inline void __add_wb_stat(struct bdi_writeback *wb, |
54 | enum wb_stat_item item, s64 amount) | |
b2e8fb6e | 55 | { |
93f78d88 | 56 | __percpu_counter_add(&wb->stat[item], amount, WB_STAT_BATCH); |
b2e8fb6e PZ |
57 | } |
58 | ||
93f78d88 TH |
59 | static inline void __inc_wb_stat(struct bdi_writeback *wb, |
60 | enum wb_stat_item item) | |
b2e8fb6e | 61 | { |
93f78d88 | 62 | __add_wb_stat(wb, item, 1); |
b2e8fb6e PZ |
63 | } |
64 | ||
93f78d88 | 65 | static inline void inc_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) |
b2e8fb6e PZ |
66 | { |
67 | unsigned long flags; | |
68 | ||
69 | local_irq_save(flags); | |
93f78d88 | 70 | __inc_wb_stat(wb, item); |
b2e8fb6e PZ |
71 | local_irq_restore(flags); |
72 | } | |
73 | ||
93f78d88 TH |
74 | static inline void __dec_wb_stat(struct bdi_writeback *wb, |
75 | enum wb_stat_item item) | |
b2e8fb6e | 76 | { |
93f78d88 | 77 | __add_wb_stat(wb, item, -1); |
b2e8fb6e PZ |
78 | } |
79 | ||
93f78d88 | 80 | static inline void dec_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) |
b2e8fb6e PZ |
81 | { |
82 | unsigned long flags; | |
83 | ||
84 | local_irq_save(flags); | |
93f78d88 | 85 | __dec_wb_stat(wb, item); |
b2e8fb6e PZ |
86 | local_irq_restore(flags); |
87 | } | |
88 | ||
93f78d88 | 89 | static inline s64 wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) |
b2e8fb6e | 90 | { |
93f78d88 | 91 | return percpu_counter_read_positive(&wb->stat[item]); |
b2e8fb6e PZ |
92 | } |
93 | ||
93f78d88 TH |
94 | static inline s64 __wb_stat_sum(struct bdi_writeback *wb, |
95 | enum wb_stat_item item) | |
b2e8fb6e | 96 | { |
93f78d88 | 97 | return percpu_counter_sum_positive(&wb->stat[item]); |
b2e8fb6e PZ |
98 | } |
99 | ||
93f78d88 | 100 | static inline s64 wb_stat_sum(struct bdi_writeback *wb, enum wb_stat_item item) |
e0bf68dd | 101 | { |
b2e8fb6e PZ |
102 | s64 sum; |
103 | unsigned long flags; | |
104 | ||
105 | local_irq_save(flags); | |
93f78d88 | 106 | sum = __wb_stat_sum(wb, item); |
b2e8fb6e PZ |
107 | local_irq_restore(flags); |
108 | ||
109 | return sum; | |
e0bf68dd PZ |
110 | } |
111 | ||
93f78d88 | 112 | extern void wb_writeout_inc(struct bdi_writeback *wb); |
dd5656e5 | 113 | |
b2e8fb6e PZ |
114 | /* |
115 | * maximal error of a stat counter. | |
116 | */ | |
93f78d88 | 117 | static inline unsigned long wb_stat_error(struct bdi_writeback *wb) |
e0bf68dd | 118 | { |
b2e8fb6e | 119 | #ifdef CONFIG_SMP |
93f78d88 | 120 | return nr_cpu_ids * WB_STAT_BATCH; |
b2e8fb6e PZ |
121 | #else |
122 | return 1; | |
123 | #endif | |
e0bf68dd | 124 | } |
1da177e4 | 125 | |
189d3c4a | 126 | int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio); |
a42dde04 | 127 | int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); |
189d3c4a | 128 | |
1da177e4 LT |
129 | /* |
130 | * Flags in backing_dev_info::capability | |
e4ad08fe MS |
131 | * |
132 | * The first three flags control whether dirty pages will contribute to the | |
133 | * VM's accounting and whether writepages() should be called for dirty pages | |
134 | * (something that would not, for example, be appropriate for ramfs) | |
135 | * | |
136 | * WARNING: these flags are closely related and should not normally be | |
137 | * used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these | |
138 | * three flags into a single convenience macro. | |
139 | * | |
140 | * BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting | |
141 | * BDI_CAP_NO_WRITEBACK: Don't write pages back | |
142 | * BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages | |
5a537485 | 143 | * BDI_CAP_STRICTLIMIT: Keep number of dirty pages below bdi threshold. |
89e9b9e0 TH |
144 | * |
145 | * BDI_CAP_CGROUP_WRITEBACK: Supports cgroup-aware writeback. | |
1da177e4 | 146 | */ |
e4ad08fe MS |
147 | #define BDI_CAP_NO_ACCT_DIRTY 0x00000001 |
148 | #define BDI_CAP_NO_WRITEBACK 0x00000002 | |
b4caecd4 CH |
149 | #define BDI_CAP_NO_ACCT_WB 0x00000004 |
150 | #define BDI_CAP_STABLE_WRITES 0x00000008 | |
151 | #define BDI_CAP_STRICTLIMIT 0x00000010 | |
89e9b9e0 | 152 | #define BDI_CAP_CGROUP_WRITEBACK 0x00000020 |
1da177e4 | 153 | |
e4ad08fe MS |
154 | #define BDI_CAP_NO_ACCT_AND_WRITEBACK \ |
155 | (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB) | |
156 | ||
5129a469 | 157 | extern struct backing_dev_info noop_backing_dev_info; |
1da177e4 | 158 | |
bc05873d TH |
159 | /** |
160 | * writeback_in_progress - determine whether there is writeback in progress | |
161 | * @wb: bdi_writeback of interest | |
162 | * | |
163 | * Determine whether there is writeback waiting to be handled against a | |
164 | * bdi_writeback. | |
165 | */ | |
166 | static inline bool writeback_in_progress(struct bdi_writeback *wb) | |
167 | { | |
168 | return test_bit(WB_writeback_running, &wb->state); | |
169 | } | |
1da177e4 | 170 | |
a212b105 TH |
171 | static inline struct backing_dev_info *inode_to_bdi(struct inode *inode) |
172 | { | |
173 | struct super_block *sb; | |
174 | ||
175 | if (!inode) | |
176 | return &noop_backing_dev_info; | |
177 | ||
178 | sb = inode->i_sb; | |
179 | #ifdef CONFIG_BLOCK | |
180 | if (sb_is_blkdev_sb(sb)) | |
181 | return blk_get_backing_dev_info(I_BDEV(inode)); | |
182 | #endif | |
183 | return sb->s_bdi; | |
184 | } | |
185 | ||
ec8a6f26 | 186 | static inline int wb_congested(struct bdi_writeback *wb, int cong_bits) |
1da177e4 | 187 | { |
ec8a6f26 | 188 | struct backing_dev_info *bdi = wb->bdi; |
1da177e4 | 189 | |
ec8a6f26 TH |
190 | if (bdi->congested_fn) |
191 | return bdi->congested_fn(bdi->congested_data, cong_bits); | |
192 | return wb->congested->state & cong_bits; | |
1da177e4 LT |
193 | } |
194 | ||
8aa7e847 | 195 | long congestion_wait(int sync, long timeout); |
0e093d99 | 196 | long wait_iff_congested(struct zone *zone, int sync, long timeout); |
3965c9ae WL |
197 | int pdflush_proc_obsolete(struct ctl_table *table, int write, |
198 | void __user *buffer, size_t *lenp, loff_t *ppos); | |
1da177e4 | 199 | |
7d311cda DW |
200 | static inline bool bdi_cap_stable_pages_required(struct backing_dev_info *bdi) |
201 | { | |
202 | return bdi->capabilities & BDI_CAP_STABLE_WRITES; | |
203 | } | |
204 | ||
e4ad08fe MS |
205 | static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi) |
206 | { | |
207 | return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK); | |
208 | } | |
209 | ||
210 | static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi) | |
211 | { | |
212 | return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY); | |
213 | } | |
1da177e4 | 214 | |
e4ad08fe MS |
215 | static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi) |
216 | { | |
217 | /* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */ | |
218 | return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB | | |
219 | BDI_CAP_NO_WRITEBACK)); | |
220 | } | |
1da177e4 | 221 | |
e4ad08fe MS |
222 | static inline bool mapping_cap_writeback_dirty(struct address_space *mapping) |
223 | { | |
de1414a6 | 224 | return bdi_cap_writeback_dirty(inode_to_bdi(mapping->host)); |
e4ad08fe | 225 | } |
1da177e4 | 226 | |
e4ad08fe MS |
227 | static inline bool mapping_cap_account_dirty(struct address_space *mapping) |
228 | { | |
de1414a6 | 229 | return bdi_cap_account_dirty(inode_to_bdi(mapping->host)); |
e4ad08fe | 230 | } |
1da177e4 | 231 | |
03ba3782 JA |
232 | static inline int bdi_sched_wait(void *word) |
233 | { | |
234 | schedule(); | |
235 | return 0; | |
236 | } | |
237 | ||
89e9b9e0 TH |
238 | #ifdef CONFIG_CGROUP_WRITEBACK |
239 | ||
52ebea74 TH |
240 | struct bdi_writeback_congested * |
241 | wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp); | |
242 | void wb_congested_put(struct bdi_writeback_congested *congested); | |
243 | struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi, | |
244 | struct cgroup_subsys_state *memcg_css, | |
245 | gfp_t gfp); | |
52ebea74 TH |
246 | void wb_memcg_offline(struct mem_cgroup *memcg); |
247 | void wb_blkcg_offline(struct blkcg *blkcg); | |
703c2708 | 248 | int inode_congested(struct inode *inode, int cong_bits); |
52ebea74 | 249 | |
89e9b9e0 TH |
250 | /** |
251 | * inode_cgwb_enabled - test whether cgroup writeback is enabled on an inode | |
252 | * @inode: inode of interest | |
253 | * | |
254 | * cgroup writeback requires support from both the bdi and filesystem. | |
255 | * Test whether @inode has both. | |
256 | */ | |
257 | static inline bool inode_cgwb_enabled(struct inode *inode) | |
258 | { | |
259 | struct backing_dev_info *bdi = inode_to_bdi(inode); | |
260 | ||
261 | return bdi_cap_account_dirty(bdi) && | |
262 | (bdi->capabilities & BDI_CAP_CGROUP_WRITEBACK) && | |
263 | (inode->i_sb->s_type->fs_flags & FS_CGROUP_WRITEBACK); | |
264 | } | |
265 | ||
52ebea74 TH |
266 | /** |
267 | * wb_find_current - find wb for %current on a bdi | |
268 | * @bdi: bdi of interest | |
269 | * | |
270 | * Find the wb of @bdi which matches both the memcg and blkcg of %current. | |
271 | * Must be called under rcu_read_lock() which protects the returend wb. | |
272 | * NULL if not found. | |
273 | */ | |
274 | static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi) | |
275 | { | |
276 | struct cgroup_subsys_state *memcg_css; | |
277 | struct bdi_writeback *wb; | |
278 | ||
279 | memcg_css = task_css(current, memory_cgrp_id); | |
280 | if (!memcg_css->parent) | |
281 | return &bdi->wb; | |
282 | ||
283 | wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id); | |
284 | ||
285 | /* | |
286 | * %current's blkcg equals the effective blkcg of its memcg. No | |
287 | * need to use the relatively expensive cgroup_get_e_css(). | |
288 | */ | |
289 | if (likely(wb && wb->blkcg_css == task_css(current, blkio_cgrp_id))) | |
290 | return wb; | |
291 | return NULL; | |
292 | } | |
293 | ||
294 | /** | |
295 | * wb_get_create_current - get or create wb for %current on a bdi | |
296 | * @bdi: bdi of interest | |
297 | * @gfp: allocation mask | |
298 | * | |
299 | * Equivalent to wb_get_create() on %current's memcg. This function is | |
300 | * called from a relatively hot path and optimizes the common cases using | |
301 | * wb_find_current(). | |
302 | */ | |
303 | static inline struct bdi_writeback * | |
304 | wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp) | |
305 | { | |
306 | struct bdi_writeback *wb; | |
307 | ||
308 | rcu_read_lock(); | |
309 | wb = wb_find_current(bdi); | |
310 | if (wb && unlikely(!wb_tryget(wb))) | |
311 | wb = NULL; | |
312 | rcu_read_unlock(); | |
313 | ||
314 | if (unlikely(!wb)) { | |
315 | struct cgroup_subsys_state *memcg_css; | |
316 | ||
317 | memcg_css = task_get_css(current, memory_cgrp_id); | |
318 | wb = wb_get_create(bdi, memcg_css, gfp); | |
319 | css_put(memcg_css); | |
320 | } | |
321 | return wb; | |
322 | } | |
323 | ||
52ebea74 TH |
324 | /** |
325 | * inode_to_wb - determine the wb of an inode | |
326 | * @inode: inode of interest | |
327 | * | |
328 | * Returns the wb @inode is currently associated with. | |
329 | */ | |
330 | static inline struct bdi_writeback *inode_to_wb(struct inode *inode) | |
331 | { | |
332 | return inode->i_wb; | |
333 | } | |
334 | ||
ebe41ab0 TH |
335 | struct wb_iter { |
336 | int start_blkcg_id; | |
337 | struct radix_tree_iter tree_iter; | |
338 | void **slot; | |
339 | }; | |
340 | ||
341 | static inline struct bdi_writeback *__wb_iter_next(struct wb_iter *iter, | |
342 | struct backing_dev_info *bdi) | |
343 | { | |
344 | struct radix_tree_iter *titer = &iter->tree_iter; | |
345 | ||
346 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
347 | ||
348 | if (iter->start_blkcg_id >= 0) { | |
349 | iter->slot = radix_tree_iter_init(titer, iter->start_blkcg_id); | |
350 | iter->start_blkcg_id = -1; | |
351 | } else { | |
352 | iter->slot = radix_tree_next_slot(iter->slot, titer, 0); | |
353 | } | |
354 | ||
355 | if (!iter->slot) | |
356 | iter->slot = radix_tree_next_chunk(&bdi->cgwb_tree, titer, 0); | |
357 | if (iter->slot) | |
358 | return *iter->slot; | |
359 | return NULL; | |
360 | } | |
361 | ||
362 | static inline struct bdi_writeback *__wb_iter_init(struct wb_iter *iter, | |
363 | struct backing_dev_info *bdi, | |
364 | int start_blkcg_id) | |
365 | { | |
366 | iter->start_blkcg_id = start_blkcg_id; | |
367 | ||
368 | if (start_blkcg_id) | |
369 | return __wb_iter_next(iter, bdi); | |
370 | else | |
371 | return &bdi->wb; | |
372 | } | |
373 | ||
374 | /** | |
375 | * bdi_for_each_wb - walk all wb's of a bdi in ascending blkcg ID order | |
376 | * @wb_cur: cursor struct bdi_writeback pointer | |
377 | * @bdi: bdi to walk wb's of | |
378 | * @iter: pointer to struct wb_iter to be used as iteration buffer | |
379 | * @start_blkcg_id: blkcg ID to start iteration from | |
380 | * | |
381 | * Iterate @wb_cur through the wb's (bdi_writeback's) of @bdi in ascending | |
382 | * blkcg ID order starting from @start_blkcg_id. @iter is struct wb_iter | |
383 | * to be used as temp storage during iteration. rcu_read_lock() must be | |
384 | * held throughout iteration. | |
385 | */ | |
386 | #define bdi_for_each_wb(wb_cur, bdi, iter, start_blkcg_id) \ | |
387 | for ((wb_cur) = __wb_iter_init(iter, bdi, start_blkcg_id); \ | |
388 | (wb_cur); (wb_cur) = __wb_iter_next(iter, bdi)) | |
389 | ||
89e9b9e0 TH |
390 | #else /* CONFIG_CGROUP_WRITEBACK */ |
391 | ||
392 | static inline bool inode_cgwb_enabled(struct inode *inode) | |
393 | { | |
394 | return false; | |
395 | } | |
396 | ||
52ebea74 TH |
397 | static inline struct bdi_writeback_congested * |
398 | wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp) | |
399 | { | |
400 | return bdi->wb.congested; | |
401 | } | |
402 | ||
403 | static inline void wb_congested_put(struct bdi_writeback_congested *congested) | |
404 | { | |
405 | } | |
406 | ||
52ebea74 TH |
407 | static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi) |
408 | { | |
409 | return &bdi->wb; | |
410 | } | |
411 | ||
412 | static inline struct bdi_writeback * | |
413 | wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp) | |
414 | { | |
415 | return &bdi->wb; | |
416 | } | |
417 | ||
52ebea74 TH |
418 | static inline struct bdi_writeback *inode_to_wb(struct inode *inode) |
419 | { | |
420 | return &inode_to_bdi(inode)->wb; | |
421 | } | |
422 | ||
423 | static inline void wb_memcg_offline(struct mem_cgroup *memcg) | |
424 | { | |
425 | } | |
426 | ||
427 | static inline void wb_blkcg_offline(struct blkcg *blkcg) | |
428 | { | |
429 | } | |
430 | ||
ebe41ab0 TH |
431 | struct wb_iter { |
432 | int next_id; | |
433 | }; | |
434 | ||
435 | #define bdi_for_each_wb(wb_cur, bdi, iter, start_blkcg_id) \ | |
436 | for ((iter)->next_id = (start_blkcg_id); \ | |
437 | ({ (wb_cur) = !(iter)->next_id++ ? &(bdi)->wb : NULL; }); ) | |
438 | ||
703c2708 TH |
439 | static inline int inode_congested(struct inode *inode, int cong_bits) |
440 | { | |
441 | return wb_congested(&inode_to_bdi(inode)->wb, cong_bits); | |
442 | } | |
443 | ||
89e9b9e0 TH |
444 | #endif /* CONFIG_CGROUP_WRITEBACK */ |
445 | ||
703c2708 TH |
446 | static inline int inode_read_congested(struct inode *inode) |
447 | { | |
448 | return inode_congested(inode, 1 << WB_sync_congested); | |
449 | } | |
450 | ||
451 | static inline int inode_write_congested(struct inode *inode) | |
452 | { | |
453 | return inode_congested(inode, 1 << WB_async_congested); | |
454 | } | |
455 | ||
456 | static inline int inode_rw_congested(struct inode *inode) | |
457 | { | |
458 | return inode_congested(inode, (1 << WB_sync_congested) | | |
459 | (1 << WB_async_congested)); | |
460 | } | |
461 | ||
ec8a6f26 TH |
462 | static inline int bdi_congested(struct backing_dev_info *bdi, int cong_bits) |
463 | { | |
464 | return wb_congested(&bdi->wb, cong_bits); | |
465 | } | |
466 | ||
467 | static inline int bdi_read_congested(struct backing_dev_info *bdi) | |
468 | { | |
469 | return bdi_congested(bdi, 1 << WB_sync_congested); | |
470 | } | |
471 | ||
472 | static inline int bdi_write_congested(struct backing_dev_info *bdi) | |
473 | { | |
474 | return bdi_congested(bdi, 1 << WB_async_congested); | |
475 | } | |
476 | ||
477 | static inline int bdi_rw_congested(struct backing_dev_info *bdi) | |
478 | { | |
479 | return bdi_congested(bdi, (1 << WB_sync_congested) | | |
480 | (1 << WB_async_congested)); | |
481 | } | |
482 | ||
89e9b9e0 | 483 | #endif /* _LINUX_BACKING_DEV_H */ |