~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/include/linux/backing-dev.h

Version: ~ [ linux-5.1-rc1 ] ~ [ linux-5.0.3 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.30 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.107 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.164 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.176 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.136 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.63 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /* SPDX-License-Identifier: GPL-2.0 */
  2 /*
  3  * include/linux/backing-dev.h
  4  *
  5  * low-level device information and state which is propagated up through
  6  * to high-level code.
  7  */
  8 
  9 #ifndef _LINUX_BACKING_DEV_H
 10 #define _LINUX_BACKING_DEV_H
 11 
 12 #include <linux/kernel.h>
 13 #include <linux/fs.h>
 14 #include <linux/sched.h>
 15 #include <linux/blkdev.h>
 16 #include <linux/writeback.h>
 17 #include <linux/blk-cgroup.h>
 18 #include <linux/backing-dev-defs.h>
 19 #include <linux/slab.h>
 20 
 21 static inline struct backing_dev_info *bdi_get(struct backing_dev_info *bdi)
 22 {
 23         kref_get(&bdi->refcnt);
 24         return bdi;
 25 }
 26 
 27 void bdi_put(struct backing_dev_info *bdi);
 28 
 29 __printf(2, 3)
 30 int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...);
 31 __printf(2, 0)
 32 int bdi_register_va(struct backing_dev_info *bdi, const char *fmt,
 33                     va_list args);
 34 int bdi_register_owner(struct backing_dev_info *bdi, struct device *owner);
 35 void bdi_unregister(struct backing_dev_info *bdi);
 36 
 37 struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id);
 38 static inline struct backing_dev_info *bdi_alloc(gfp_t gfp_mask)
 39 {
 40         return bdi_alloc_node(gfp_mask, NUMA_NO_NODE);
 41 }
 42 
 43 void wb_start_background_writeback(struct bdi_writeback *wb);
 44 void wb_workfn(struct work_struct *work);
 45 void wb_wakeup_delayed(struct bdi_writeback *wb);
 46 
 47 extern spinlock_t bdi_lock;
 48 extern struct list_head bdi_list;
 49 
 50 extern struct workqueue_struct *bdi_wq;
 51 
 52 static inline bool wb_has_dirty_io(struct bdi_writeback *wb)
 53 {
 54         return test_bit(WB_has_dirty_io, &wb->state);
 55 }
 56 
 57 static inline bool bdi_has_dirty_io(struct backing_dev_info *bdi)
 58 {
 59         /*
 60          * @bdi->tot_write_bandwidth is guaranteed to be > 0 if there are
 61          * any dirty wbs.  See wb_update_write_bandwidth().
 62          */
 63         return atomic_long_read(&bdi->tot_write_bandwidth);
 64 }
 65 
 66 static inline void __add_wb_stat(struct bdi_writeback *wb,
 67                                  enum wb_stat_item item, s64 amount)
 68 {
 69         percpu_counter_add_batch(&wb->stat[item], amount, WB_STAT_BATCH);
 70 }
 71 
 72 static inline void inc_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
 73 {
 74         __add_wb_stat(wb, item, 1);
 75 }
 76 
 77 static inline void dec_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
 78 {
 79         __add_wb_stat(wb, item, -1);
 80 }
 81 
 82 static inline s64 wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
 83 {
 84         return percpu_counter_read_positive(&wb->stat[item]);
 85 }
 86 
 87 static inline s64 wb_stat_sum(struct bdi_writeback *wb, enum wb_stat_item item)
 88 {
 89         return percpu_counter_sum_positive(&wb->stat[item]);
 90 }
 91 
 92 extern void wb_writeout_inc(struct bdi_writeback *wb);
 93 
 94 /*
 95  * maximal error of a stat counter.
 96  */
 97 static inline unsigned long wb_stat_error(void)
 98 {
 99 #ifdef CONFIG_SMP
100         return nr_cpu_ids * WB_STAT_BATCH;
101 #else
102         return 1;
103 #endif
104 }
105 
106 int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
107 int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
108 
109 /*
110  * Flags in backing_dev_info::capability
111  *
112  * The first three flags control whether dirty pages will contribute to the
113  * VM's accounting and whether writepages() should be called for dirty pages
114  * (something that would not, for example, be appropriate for ramfs)
115  *
116  * WARNING: these flags are closely related and should not normally be
117  * used separately.  The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these
118  * three flags into a single convenience macro.
119  *
120  * BDI_CAP_NO_ACCT_DIRTY:  Dirty pages shouldn't contribute to accounting
121  * BDI_CAP_NO_WRITEBACK:   Don't write pages back
122  * BDI_CAP_NO_ACCT_WB:     Don't automatically account writeback pages
123  * BDI_CAP_STRICTLIMIT:    Keep number of dirty pages below bdi threshold.
124  *
125  * BDI_CAP_CGROUP_WRITEBACK: Supports cgroup-aware writeback.
126  * BDI_CAP_SYNCHRONOUS_IO: Device is so fast that asynchronous IO would be
127  *                         inefficient.
128  */
129 #define BDI_CAP_NO_ACCT_DIRTY   0x00000001
130 #define BDI_CAP_NO_WRITEBACK    0x00000002
131 #define BDI_CAP_NO_ACCT_WB      0x00000004
132 #define BDI_CAP_STABLE_WRITES   0x00000008
133 #define BDI_CAP_STRICTLIMIT     0x00000010
134 #define BDI_CAP_CGROUP_WRITEBACK 0x00000020
135 #define BDI_CAP_SYNCHRONOUS_IO  0x00000040
136 
137 #define BDI_CAP_NO_ACCT_AND_WRITEBACK \
138         (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB)
139 
140 extern struct backing_dev_info noop_backing_dev_info;
141 
142 /**
143  * writeback_in_progress - determine whether there is writeback in progress
144  * @wb: bdi_writeback of interest
145  *
146  * Determine whether there is writeback waiting to be handled against a
147  * bdi_writeback.
148  */
149 static inline bool writeback_in_progress(struct bdi_writeback *wb)
150 {
151         return test_bit(WB_writeback_running, &wb->state);
152 }
153 
154 static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
155 {
156         struct super_block *sb;
157 
158         if (!inode)
159                 return &noop_backing_dev_info;
160 
161         sb = inode->i_sb;
162 #ifdef CONFIG_BLOCK
163         if (sb_is_blkdev_sb(sb))
164                 return I_BDEV(inode)->bd_bdi;
165 #endif
166         return sb->s_bdi;
167 }
168 
169 static inline int wb_congested(struct bdi_writeback *wb, int cong_bits)
170 {
171         struct backing_dev_info *bdi = wb->bdi;
172 
173         if (bdi->congested_fn)
174                 return bdi->congested_fn(bdi->congested_data, cong_bits);
175         return wb->congested->state & cong_bits;
176 }
177 
178 long congestion_wait(int sync, long timeout);
179 long wait_iff_congested(int sync, long timeout);
180 
181 static inline bool bdi_cap_synchronous_io(struct backing_dev_info *bdi)
182 {
183         return bdi->capabilities & BDI_CAP_SYNCHRONOUS_IO;
184 }
185 
186 static inline bool bdi_cap_stable_pages_required(struct backing_dev_info *bdi)
187 {
188         return bdi->capabilities & BDI_CAP_STABLE_WRITES;
189 }
190 
191 static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
192 {
193         return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
194 }
195 
196 static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
197 {
198         return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
199 }
200 
201 static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
202 {
203         /* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */
204         return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB |
205                                       BDI_CAP_NO_WRITEBACK));
206 }
207 
208 static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
209 {
210         return bdi_cap_writeback_dirty(inode_to_bdi(mapping->host));
211 }
212 
213 static inline bool mapping_cap_account_dirty(struct address_space *mapping)
214 {
215         return bdi_cap_account_dirty(inode_to_bdi(mapping->host));
216 }
217 
218 static inline int bdi_sched_wait(void *word)
219 {
220         schedule();
221         return 0;
222 }
223 
224 #ifdef CONFIG_CGROUP_WRITEBACK
225 
226 struct bdi_writeback_congested *
227 wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp);
228 void wb_congested_put(struct bdi_writeback_congested *congested);
229 struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi,
230                                     struct cgroup_subsys_state *memcg_css,
231                                     gfp_t gfp);
232 void wb_memcg_offline(struct mem_cgroup *memcg);
233 void wb_blkcg_offline(struct blkcg *blkcg);
234 int inode_congested(struct inode *inode, int cong_bits);
235 
236 /**
237  * inode_cgwb_enabled - test whether cgroup writeback is enabled on an inode
238  * @inode: inode of interest
239  *
240  * cgroup writeback requires support from both the bdi and filesystem.
241  * Also, both memcg and iocg have to be on the default hierarchy.  Test
242  * whether all conditions are met.
243  *
244  * Note that the test result may change dynamically on the same inode
245  * depending on how memcg and iocg are configured.
246  */
247 static inline bool inode_cgwb_enabled(struct inode *inode)
248 {
249         struct backing_dev_info *bdi = inode_to_bdi(inode);
250 
251         return cgroup_subsys_on_dfl(memory_cgrp_subsys) &&
252                 cgroup_subsys_on_dfl(io_cgrp_subsys) &&
253                 bdi_cap_account_dirty(bdi) &&
254                 (bdi->capabilities & BDI_CAP_CGROUP_WRITEBACK) &&
255                 (inode->i_sb->s_iflags & SB_I_CGROUPWB);
256 }
257 
258 /**
259  * wb_find_current - find wb for %current on a bdi
260  * @bdi: bdi of interest
261  *
262  * Find the wb of @bdi which matches both the memcg and blkcg of %current.
263  * Must be called under rcu_read_lock() which protects the returend wb.
264  * NULL if not found.
265  */
266 static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi)
267 {
268         struct cgroup_subsys_state *memcg_css;
269         struct bdi_writeback *wb;
270 
271         memcg_css = task_css(current, memory_cgrp_id);
272         if (!memcg_css->parent)
273                 return &bdi->wb;
274 
275         wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id);
276 
277         /*
278          * %current's blkcg equals the effective blkcg of its memcg.  No
279          * need to use the relatively expensive cgroup_get_e_css().
280          */
281         if (likely(wb && wb->blkcg_css == task_css(current, io_cgrp_id)))
282                 return wb;
283         return NULL;
284 }
285 
286 /**
287  * wb_get_create_current - get or create wb for %current on a bdi
288  * @bdi: bdi of interest
289  * @gfp: allocation mask
290  *
291  * Equivalent to wb_get_create() on %current's memcg.  This function is
292  * called from a relatively hot path and optimizes the common cases using
293  * wb_find_current().
294  */
295 static inline struct bdi_writeback *
296 wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
297 {
298         struct bdi_writeback *wb;
299 
300         rcu_read_lock();
301         wb = wb_find_current(bdi);
302         if (wb && unlikely(!wb_tryget(wb)))
303                 wb = NULL;
304         rcu_read_unlock();
305 
306         if (unlikely(!wb)) {
307                 struct cgroup_subsys_state *memcg_css;
308 
309                 memcg_css = task_get_css(current, memory_cgrp_id);
310                 wb = wb_get_create(bdi, memcg_css, gfp);
311                 css_put(memcg_css);
312         }
313         return wb;
314 }
315 
316 /**
317  * inode_to_wb_is_valid - test whether an inode has a wb associated
318  * @inode: inode of interest
319  *
320  * Returns %true if @inode has a wb associated.  May be called without any
321  * locking.
322  */
323 static inline bool inode_to_wb_is_valid(struct inode *inode)
324 {
325         return inode->i_wb;
326 }
327 
328 /**
329  * inode_to_wb - determine the wb of an inode
330  * @inode: inode of interest
331  *
332  * Returns the wb @inode is currently associated with.  The caller must be
333  * holding either @inode->i_lock, the i_pages lock, or the
334  * associated wb's list_lock.
335  */
336 static inline struct bdi_writeback *inode_to_wb(const struct inode *inode)
337 {
338 #ifdef CONFIG_LOCKDEP
339         WARN_ON_ONCE(debug_locks &&
340                      (!lockdep_is_held(&inode->i_lock) &&
341                       !lockdep_is_held(&inode->i_mapping->i_pages.xa_lock) &&
342                       !lockdep_is_held(&inode->i_wb->list_lock)));
343 #endif
344         return inode->i_wb;
345 }
346 
347 /**
348  * unlocked_inode_to_wb_begin - begin unlocked inode wb access transaction
349  * @inode: target inode
350  * @cookie: output param, to be passed to the end function
351  *
352  * The caller wants to access the wb associated with @inode but isn't
353  * holding inode->i_lock, the i_pages lock or wb->list_lock.  This
354  * function determines the wb associated with @inode and ensures that the
355  * association doesn't change until the transaction is finished with
356  * unlocked_inode_to_wb_end().
357  *
358  * The caller must call unlocked_inode_to_wb_end() with *@cookie afterwards and
359  * can't sleep during the transaction.  IRQs may or may not be disabled on
360  * return.
361  */
362 static inline struct bdi_writeback *
363 unlocked_inode_to_wb_begin(struct inode *inode, struct wb_lock_cookie *cookie)
364 {
365         rcu_read_lock();
366 
367         /*
368          * Paired with store_release in inode_switch_wbs_work_fn() and
369          * ensures that we see the new wb if we see cleared I_WB_SWITCH.
370          */
371         cookie->locked = smp_load_acquire(&inode->i_state) & I_WB_SWITCH;
372 
373         if (unlikely(cookie->locked))
374                 xa_lock_irqsave(&inode->i_mapping->i_pages, cookie->flags);
375 
376         /*
377          * Protected by either !I_WB_SWITCH + rcu_read_lock() or the i_pages
378          * lock.  inode_to_wb() will bark.  Deref directly.
379          */
380         return inode->i_wb;
381 }
382 
383 /**
384  * unlocked_inode_to_wb_end - end inode wb access transaction
385  * @inode: target inode
386  * @cookie: @cookie from unlocked_inode_to_wb_begin()
387  */
388 static inline void unlocked_inode_to_wb_end(struct inode *inode,
389                                             struct wb_lock_cookie *cookie)
390 {
391         if (unlikely(cookie->locked))
392                 xa_unlock_irqrestore(&inode->i_mapping->i_pages, cookie->flags);
393 
394         rcu_read_unlock();
395 }
396 
397 #else   /* CONFIG_CGROUP_WRITEBACK */
398 
399 static inline bool inode_cgwb_enabled(struct inode *inode)
400 {
401         return false;
402 }
403 
404 static inline struct bdi_writeback_congested *
405 wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp)
406 {
407         refcount_inc(&bdi->wb_congested->refcnt);
408         return bdi->wb_congested;
409 }
410 
411 static inline void wb_congested_put(struct bdi_writeback_congested *congested)
412 {
413         if (refcount_dec_and_test(&congested->refcnt))
414                 kfree(congested);
415 }
416 
417 static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi)
418 {
419         return &bdi->wb;
420 }
421 
422 static inline struct bdi_writeback *
423 wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
424 {
425         return &bdi->wb;
426 }
427 
428 static inline bool inode_to_wb_is_valid(struct inode *inode)
429 {
430         return true;
431 }
432 
433 static inline struct bdi_writeback *inode_to_wb(struct inode *inode)
434 {
435         return &inode_to_bdi(inode)->wb;
436 }
437 
438 static inline struct bdi_writeback *
439 unlocked_inode_to_wb_begin(struct inode *inode, struct wb_lock_cookie *cookie)
440 {
441         return inode_to_wb(inode);
442 }
443 
444 static inline void unlocked_inode_to_wb_end(struct inode *inode,
445                                             struct wb_lock_cookie *cookie)
446 {
447 }
448 
449 static inline void wb_memcg_offline(struct mem_cgroup *memcg)
450 {
451 }
452 
453 static inline void wb_blkcg_offline(struct blkcg *blkcg)
454 {
455 }
456 
457 static inline int inode_congested(struct inode *inode, int cong_bits)
458 {
459         return wb_congested(&inode_to_bdi(inode)->wb, cong_bits);
460 }
461 
462 #endif  /* CONFIG_CGROUP_WRITEBACK */
463 
464 static inline int inode_read_congested(struct inode *inode)
465 {
466         return inode_congested(inode, 1 << WB_sync_congested);
467 }
468 
469 static inline int inode_write_congested(struct inode *inode)
470 {
471         return inode_congested(inode, 1 << WB_async_congested);
472 }
473 
474 static inline int inode_rw_congested(struct inode *inode)
475 {
476         return inode_congested(inode, (1 << WB_sync_congested) |
477                                       (1 << WB_async_congested));
478 }
479 
480 static inline int bdi_congested(struct backing_dev_info *bdi, int cong_bits)
481 {
482         return wb_congested(&bdi->wb, cong_bits);
483 }
484 
485 static inline int bdi_read_congested(struct backing_dev_info *bdi)
486 {
487         return bdi_congested(bdi, 1 << WB_sync_congested);
488 }
489 
490 static inline int bdi_write_congested(struct backing_dev_info *bdi)
491 {
492         return bdi_congested(bdi, 1 << WB_async_congested);
493 }
494 
495 static inline int bdi_rw_congested(struct backing_dev_info *bdi)
496 {
497         return bdi_congested(bdi, (1 << WB_sync_congested) |
498                                   (1 << WB_async_congested));
499 }
500 
501 #endif  /* _LINUX_BACKING_DEV_H */
502 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp