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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Uwe Zeisbergerf30c2262006-10-03 23:01:26 +02002 * include/linux/writeback.h
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 */
4#ifndef WRITEBACK_H
5#define WRITEBACK_H
6
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +04007#include <linux/sched.h>
Jens Axboef5ff8422007-09-21 09:19:54 +02008#include <linux/fs.h>
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +04009
Wu Fengguang54848d72011-04-05 13:21:19 -060010DECLARE_PER_CPU(int, dirty_throttle_leaks);
11
Wu Fengguangffd1f602011-06-19 22:18:42 -060012/*
Wu Fengguang1a12d8b2010-08-29 13:28:09 -060013 * The 1/4 region under the global dirty thresh is for smooth dirty throttling:
14 *
15 * (thresh - thresh/DIRTY_FULL_SCOPE, thresh)
16 *
Wu Fengguangffd1f602011-06-19 22:18:42 -060017 * Further beyond, all dirtier tasks will enter a loop waiting (possibly long
18 * time) for the dirty pages to drop, unless written enough pages.
19 *
20 * The global dirty threshold is normally equal to the global dirty limit,
21 * except when the system suddenly allocates a lot of anonymous memory and
22 * knocks down the global dirty threshold quickly, in which case the global
23 * dirty limit will follow down slowly to prevent livelocking all dirtier tasks.
24 */
Wu Fengguang1a12d8b2010-08-29 13:28:09 -060025#define DIRTY_SCOPE 8
26#define DIRTY_FULL_SCOPE (DIRTY_SCOPE / 2)
Wu Fengguangffd1f602011-06-19 22:18:42 -060027
Linus Torvalds1da177e2005-04-16 15:20:36 -070028struct backing_dev_info;
29
Linus Torvalds1da177e2005-04-16 15:20:36 -070030/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070031 * fs/fs-writeback.c
32 */
33enum writeback_sync_modes {
34 WB_SYNC_NONE, /* Don't wait on anything */
35 WB_SYNC_ALL, /* Wait on every mapping */
Linus Torvalds1da177e2005-04-16 15:20:36 -070036};
37
38/*
Curt Wohlgemuth0e175a12011-10-07 21:54:10 -060039 * why some writeback work was initiated
40 */
41enum wb_reason {
42 WB_REASON_BACKGROUND,
43 WB_REASON_TRY_TO_FREE_PAGES,
44 WB_REASON_SYNC,
45 WB_REASON_PERIODIC,
46 WB_REASON_LAPTOP_TIMER,
47 WB_REASON_FREE_MORE_MEM,
48 WB_REASON_FS_FREE_SPACE,
49 WB_REASON_FORKER_THREAD,
50
51 WB_REASON_MAX,
52};
53extern const char *wb_reason_name[];
54
55/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 * A control structure which tells the writeback code what to do. These are
57 * always on the stack, and hence need no locking. They are always initialised
58 * in a manner such that unspecified fields are set to zero.
59 */
60struct writeback_control {
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 long nr_to_write; /* Write this many pages, and decrement
62 this for each page written */
63 long pages_skipped; /* Pages which were not written */
64
65 /*
Andrew Morton95468fd2012-03-05 15:06:02 -080066 * For a_ops->writepages(): if start or end are non-zero then this is
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 * a hint that the filesystem need only write out the pages inside that
68 * byterange. The byte at `end' is included in the writeout request.
69 */
OGAWA Hirofumi111ebb62006-06-23 02:03:26 -070070 loff_t range_start;
71 loff_t range_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -070072
Richard Kennedy4cd90692012-04-25 14:53:05 +010073 enum writeback_sync_modes sync_mode;
74
Andrew Morton22905f72005-11-16 15:07:01 -080075 unsigned for_kupdate:1; /* A kupdate writeback */
Wu Fengguangb17621f2009-12-03 13:54:25 +010076 unsigned for_background:1; /* A background writeback */
Wu Fengguang6e6938b2010-06-06 10:38:15 -060077 unsigned tagged_writepages:1; /* tag-and-write to avoid livelock */
Andrew Morton22905f72005-11-16 15:07:01 -080078 unsigned for_reclaim:1; /* Invoked from the page allocator */
OGAWA Hirofumi111ebb62006-06-23 02:03:26 -070079 unsigned range_cyclic:1; /* range_start is cyclic */
Linus Torvalds1da177e2005-04-16 15:20:36 -070080};
81
82/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 * fs/fs-writeback.c
84 */
Jens Axboe03ba3782009-09-09 09:08:54 +020085struct bdi_writeback;
Linus Torvalds1da177e2005-04-16 15:20:36 -070086int inode_wait(void *);
Curt Wohlgemuth0e175a12011-10-07 21:54:10 -060087void writeback_inodes_sb(struct super_block *, enum wb_reason reason);
88void writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
89 enum wb_reason reason);
90int writeback_inodes_sb_if_idle(struct super_block *, enum wb_reason reason);
91int writeback_inodes_sb_nr_if_idle(struct super_block *, unsigned long nr,
92 enum wb_reason reason);
Jens Axboeb6e51312009-09-16 15:13:54 +020093void sync_inodes_sb(struct super_block *);
Curt Wohlgemuth0e175a12011-10-07 21:54:10 -060094long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages,
95 enum wb_reason reason);
Jens Axboe03ba3782009-09-09 09:08:54 +020096long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
Curt Wohlgemuth0e175a12011-10-07 21:54:10 -060097void wakeup_flusher_threads(long nr_pages, enum wb_reason reason);
Jan Kara169ebd92012-05-03 14:48:03 +020098void inode_wait_for_writeback(struct inode *inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -070099
100/* writeback.h requires fs.h; it, too, is not included from here. */
101static inline void wait_on_inode(struct inode *inode)
102{
103 might_sleep();
Christoph Hellwigeaff8072009-12-17 14:25:01 +0100104 wait_on_bit(&inode->i_state, __I_NEW, inode_wait, TASK_UNINTERRUPTIBLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105}
Joern Engel1c0eeaf2007-10-16 23:30:44 -0700106
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107/*
108 * mm/page-writeback.c
109 */
Jens Axboec2c49862010-05-20 09:18:47 +0200110#ifdef CONFIG_BLOCK
Matthew Garrett31373d02010-04-06 14:25:14 +0200111void laptop_io_completion(struct backing_dev_info *info);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112void laptop_sync_completion(void);
Matthew Garrett31373d02010-04-06 14:25:14 +0200113void laptop_mode_sync(struct work_struct *work);
114void laptop_mode_timer_fn(unsigned long data);
Jens Axboec2c49862010-05-20 09:18:47 +0200115#else
116static inline void laptop_sync_completion(void) { }
117#endif
Andrew Morton232ea4d2007-02-28 20:13:21 -0800118void throttle_vm_writeout(gfp_t gfp_mask);
Johannes Weinera756cf52012-01-10 15:07:49 -0800119bool zone_dirty_ok(struct zone *zone);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120
Wu Fengguangc42843f2011-03-02 15:54:09 -0600121extern unsigned long global_dirty_limit;
122
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123/* These are exported to sysctl. */
124extern int dirty_background_ratio;
David Rientjes2da02992009-01-06 14:39:31 -0800125extern unsigned long dirty_background_bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126extern int vm_dirty_ratio;
David Rientjes2da02992009-01-06 14:39:31 -0800127extern unsigned long vm_dirty_bytes;
Alexey Dobriyan704503d2009-03-31 15:23:18 -0700128extern unsigned int dirty_writeback_interval;
129extern unsigned int dirty_expire_interval;
Bron Gondwana195cf4532008-02-04 22:29:20 -0800130extern int vm_highmem_is_dirtyable;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131extern int block_dump;
132extern int laptop_mode;
133
David Rientjes2da02992009-01-06 14:39:31 -0800134extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
Alexey Dobriyan8d65af72009-09-23 15:57:19 -0700135 void __user *buffer, size_t *lenp,
David Rientjes2da02992009-01-06 14:39:31 -0800136 loff_t *ppos);
137extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
Alexey Dobriyan8d65af72009-09-23 15:57:19 -0700138 void __user *buffer, size_t *lenp,
David Rientjes2da02992009-01-06 14:39:31 -0800139 loff_t *ppos);
Peter Zijlstra04fbfdc2007-10-16 23:25:50 -0700140extern int dirty_ratio_handler(struct ctl_table *table, int write,
Alexey Dobriyan8d65af72009-09-23 15:57:19 -0700141 void __user *buffer, size_t *lenp,
Peter Zijlstra04fbfdc2007-10-16 23:25:50 -0700142 loff_t *ppos);
David Rientjes2da02992009-01-06 14:39:31 -0800143extern int dirty_bytes_handler(struct ctl_table *table, int write,
Alexey Dobriyan8d65af72009-09-23 15:57:19 -0700144 void __user *buffer, size_t *lenp,
David Rientjes2da02992009-01-06 14:39:31 -0800145 loff_t *ppos);
Peter Zijlstra04fbfdc2007-10-16 23:25:50 -0700146
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147struct ctl_table;
Alexey Dobriyan8d65af72009-09-23 15:57:19 -0700148int dirty_writeback_centisecs_handler(struct ctl_table *, int,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 void __user *, size_t *, loff_t *);
150
Wu Fengguang16c40422010-08-11 14:17:39 -0700151void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty);
152unsigned long bdi_dirty_limit(struct backing_dev_info *bdi,
153 unsigned long dirty);
Peter Zijlstracf0ca9f2008-04-30 00:54:32 -0700154
Wu Fengguange98be2d2010-08-29 11:22:30 -0600155void __bdi_update_bandwidth(struct backing_dev_info *bdi,
Wu Fengguangc42843f2011-03-02 15:54:09 -0600156 unsigned long thresh,
Wu Fengguangaf6a3112011-10-03 20:46:17 -0600157 unsigned long bg_thresh,
Wu Fengguangc42843f2011-03-02 15:54:09 -0600158 unsigned long dirty,
159 unsigned long bdi_thresh,
160 unsigned long bdi_dirty,
Wu Fengguange98be2d2010-08-29 11:22:30 -0600161 unsigned long start_time);
162
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163void page_writeback_init(void);
Andrew Mortonfa5a7342006-03-24 03:18:10 -0800164void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
165 unsigned long nr_pages_dirtied);
166
167static inline void
168balance_dirty_pages_ratelimited(struct address_space *mapping)
169{
170 balance_dirty_pages_ratelimited_nr(mapping, 1);
171}
172
Miklos Szeredi0ea97182007-05-10 22:22:51 -0700173typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
174 void *data);
175
Miklos Szeredi0ea97182007-05-10 22:22:51 -0700176int generic_writepages(struct address_space *mapping,
177 struct writeback_control *wbc);
Eric Sandeen5b41d922010-10-27 21:30:13 -0400178void tag_pages_for_writeback(struct address_space *mapping,
179 pgoff_t start, pgoff_t end);
Miklos Szeredi0ea97182007-05-10 22:22:51 -0700180int write_cache_pages(struct address_space *mapping,
181 struct writeback_control *wbc, writepage_t writepage,
182 void *data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
Peter Zijlstraa200ee12007-10-08 18:54:37 +0200184void set_page_dirty_balance(struct page *page, int page_mkwrite);
Chandra Seetharaman2d1d43f2006-09-29 02:01:25 -0700185void writeback_set_ratelimit(void);
Namhyung Kim92c09c02010-10-26 14:22:03 -0700186void tag_pages_for_writeback(struct address_space *mapping,
187 pgoff_t start, pgoff_t end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188
Wu Fengguang2f800fb2011-08-08 15:22:00 -0600189void account_page_redirty(struct page *page);
190
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191#endif /* WRITEBACK_H */