Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
f30c2269 | 2 | * include/linux/writeback.h |
1da177e4 LT |
3 | */ |
4 | #ifndef WRITEBACK_H | |
5 | #define WRITEBACK_H | |
6 | ||
e8edc6e0 | 7 | #include <linux/sched.h> |
f5ff8422 | 8 | #include <linux/fs.h> |
e8edc6e0 | 9 | |
ffd1f609 | 10 | /* |
1a12d8bd WF |
11 | * The 1/4 region under the global dirty thresh is for smooth dirty throttling: |
12 | * | |
13 | * (thresh - thresh/DIRTY_FULL_SCOPE, thresh) | |
14 | * | |
ffd1f609 WF |
15 | * Further beyond, all dirtier tasks will enter a loop waiting (possibly long |
16 | * time) for the dirty pages to drop, unless written enough pages. | |
17 | * | |
18 | * The global dirty threshold is normally equal to the global dirty limit, | |
19 | * except when the system suddenly allocates a lot of anonymous memory and | |
20 | * knocks down the global dirty threshold quickly, in which case the global | |
21 | * dirty limit will follow down slowly to prevent livelocking all dirtier tasks. | |
22 | */ | |
1a12d8bd WF |
23 | #define DIRTY_SCOPE 8 |
24 | #define DIRTY_FULL_SCOPE (DIRTY_SCOPE / 2) | |
ffd1f609 | 25 | |
1a12d8bd WF |
26 | /* |
27 | * 4MB minimal write chunk size | |
28 | */ | |
29 | #define MIN_WRITEBACK_PAGES (4096UL >> (PAGE_CACHE_SHIFT - 10)) | |
30 | ||
1da177e4 LT |
31 | struct backing_dev_info; |
32 | ||
1da177e4 LT |
33 | /* |
34 | * fs/fs-writeback.c | |
35 | */ | |
36 | enum writeback_sync_modes { | |
37 | WB_SYNC_NONE, /* Don't wait on anything */ | |
38 | WB_SYNC_ALL, /* Wait on every mapping */ | |
1da177e4 LT |
39 | }; |
40 | ||
0e175a18 CW |
41 | /* |
42 | * why some writeback work was initiated | |
43 | */ | |
44 | enum wb_reason { | |
45 | WB_REASON_BACKGROUND, | |
46 | WB_REASON_TRY_TO_FREE_PAGES, | |
47 | WB_REASON_SYNC, | |
48 | WB_REASON_PERIODIC, | |
49 | WB_REASON_LAPTOP_TIMER, | |
50 | WB_REASON_FREE_MORE_MEM, | |
51 | WB_REASON_FS_FREE_SPACE, | |
52 | WB_REASON_FORKER_THREAD, | |
53 | ||
54 | WB_REASON_MAX, | |
55 | }; | |
56 | extern const char *wb_reason_name[]; | |
57 | ||
1da177e4 LT |
58 | /* |
59 | * A control structure which tells the writeback code what to do. These are | |
60 | * always on the stack, and hence need no locking. They are always initialised | |
61 | * in a manner such that unspecified fields are set to zero. | |
62 | */ | |
63 | struct writeback_control { | |
1da177e4 | 64 | enum writeback_sync_modes sync_mode; |
1da177e4 LT |
65 | long nr_to_write; /* Write this many pages, and decrement |
66 | this for each page written */ | |
67 | long pages_skipped; /* Pages which were not written */ | |
68 | ||
69 | /* | |
70 | * For a_ops->writepages(): is start or end are non-zero then this is | |
71 | * a hint that the filesystem need only write out the pages inside that | |
72 | * byterange. The byte at `end' is included in the writeout request. | |
73 | */ | |
111ebb6e OH |
74 | loff_t range_start; |
75 | loff_t range_end; | |
1da177e4 | 76 | |
22905f77 | 77 | unsigned for_kupdate:1; /* A kupdate writeback */ |
b17621fe | 78 | unsigned for_background:1; /* A background writeback */ |
6e6938b6 | 79 | unsigned tagged_writepages:1; /* tag-and-write to avoid livelock */ |
22905f77 | 80 | unsigned for_reclaim:1; /* Invoked from the page allocator */ |
111ebb6e | 81 | unsigned range_cyclic:1; /* range_start is cyclic */ |
1da177e4 LT |
82 | }; |
83 | ||
1da177e4 LT |
84 | /* |
85 | * fs/fs-writeback.c | |
86 | */ | |
03ba3782 | 87 | struct bdi_writeback; |
1da177e4 | 88 | int inode_wait(void *); |
0e175a18 CW |
89 | void writeback_inodes_sb(struct super_block *, enum wb_reason reason); |
90 | void writeback_inodes_sb_nr(struct super_block *, unsigned long nr, | |
91 | enum wb_reason reason); | |
92 | int writeback_inodes_sb_if_idle(struct super_block *, enum wb_reason reason); | |
93 | int writeback_inodes_sb_nr_if_idle(struct super_block *, unsigned long nr, | |
94 | enum wb_reason reason); | |
b6e51316 | 95 | void sync_inodes_sb(struct super_block *); |
0e175a18 CW |
96 | long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages, |
97 | enum wb_reason reason); | |
03ba3782 | 98 | long wb_do_writeback(struct bdi_writeback *wb, int force_wait); |
0e175a18 | 99 | void wakeup_flusher_threads(long nr_pages, enum wb_reason reason); |
1da177e4 LT |
100 | |
101 | /* writeback.h requires fs.h; it, too, is not included from here. */ | |
102 | static inline void wait_on_inode(struct inode *inode) | |
103 | { | |
104 | might_sleep(); | |
eaff8079 | 105 | wait_on_bit(&inode->i_state, __I_NEW, inode_wait, TASK_UNINTERRUPTIBLE); |
1da177e4 | 106 | } |
1c0eeaf5 JE |
107 | static inline void inode_sync_wait(struct inode *inode) |
108 | { | |
109 | might_sleep(); | |
110 | wait_on_bit(&inode->i_state, __I_SYNC, inode_wait, | |
111 | TASK_UNINTERRUPTIBLE); | |
112 | } | |
113 | ||
1da177e4 LT |
114 | |
115 | /* | |
116 | * mm/page-writeback.c | |
117 | */ | |
c2c4986e | 118 | #ifdef CONFIG_BLOCK |
31373d09 | 119 | void laptop_io_completion(struct backing_dev_info *info); |
1da177e4 | 120 | void laptop_sync_completion(void); |
31373d09 MG |
121 | void laptop_mode_sync(struct work_struct *work); |
122 | void laptop_mode_timer_fn(unsigned long data); | |
c2c4986e JA |
123 | #else |
124 | static inline void laptop_sync_completion(void) { } | |
125 | #endif | |
232ea4d6 | 126 | void throttle_vm_writeout(gfp_t gfp_mask); |
1da177e4 | 127 | |
c42843f2 WF |
128 | extern unsigned long global_dirty_limit; |
129 | ||
1da177e4 LT |
130 | /* These are exported to sysctl. */ |
131 | extern int dirty_background_ratio; | |
2da02997 | 132 | extern unsigned long dirty_background_bytes; |
1da177e4 | 133 | extern int vm_dirty_ratio; |
2da02997 | 134 | extern unsigned long vm_dirty_bytes; |
704503d8 AD |
135 | extern unsigned int dirty_writeback_interval; |
136 | extern unsigned int dirty_expire_interval; | |
195cf453 | 137 | extern int vm_highmem_is_dirtyable; |
1da177e4 LT |
138 | extern int block_dump; |
139 | extern int laptop_mode; | |
140 | ||
3eefae99 SR |
141 | extern unsigned long determine_dirtyable_memory(void); |
142 | ||
2da02997 | 143 | extern int dirty_background_ratio_handler(struct ctl_table *table, int write, |
8d65af78 | 144 | void __user *buffer, size_t *lenp, |
2da02997 DR |
145 | loff_t *ppos); |
146 | extern int dirty_background_bytes_handler(struct ctl_table *table, int write, | |
8d65af78 | 147 | void __user *buffer, size_t *lenp, |
2da02997 | 148 | loff_t *ppos); |
04fbfdc1 | 149 | extern int dirty_ratio_handler(struct ctl_table *table, int write, |
8d65af78 | 150 | void __user *buffer, size_t *lenp, |
04fbfdc1 | 151 | loff_t *ppos); |
2da02997 | 152 | extern int dirty_bytes_handler(struct ctl_table *table, int write, |
8d65af78 | 153 | void __user *buffer, size_t *lenp, |
2da02997 | 154 | loff_t *ppos); |
04fbfdc1 | 155 | |
1da177e4 | 156 | struct ctl_table; |
8d65af78 | 157 | int dirty_writeback_centisecs_handler(struct ctl_table *, int, |
1da177e4 LT |
158 | void __user *, size_t *, loff_t *); |
159 | ||
16c4042f WF |
160 | void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty); |
161 | unsigned long bdi_dirty_limit(struct backing_dev_info *bdi, | |
162 | unsigned long dirty); | |
cf0ca9fe | 163 | |
e98be2d5 | 164 | void __bdi_update_bandwidth(struct backing_dev_info *bdi, |
c42843f2 | 165 | unsigned long thresh, |
af6a3113 | 166 | unsigned long bg_thresh, |
c42843f2 WF |
167 | unsigned long dirty, |
168 | unsigned long bdi_thresh, | |
169 | unsigned long bdi_dirty, | |
e98be2d5 WF |
170 | unsigned long start_time); |
171 | ||
1da177e4 | 172 | void page_writeback_init(void); |
fa5a734e AM |
173 | void balance_dirty_pages_ratelimited_nr(struct address_space *mapping, |
174 | unsigned long nr_pages_dirtied); | |
175 | ||
176 | static inline void | |
177 | balance_dirty_pages_ratelimited(struct address_space *mapping) | |
178 | { | |
179 | balance_dirty_pages_ratelimited_nr(mapping, 1); | |
180 | } | |
181 | ||
0ea97180 MS |
182 | typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc, |
183 | void *data); | |
184 | ||
0ea97180 MS |
185 | int generic_writepages(struct address_space *mapping, |
186 | struct writeback_control *wbc); | |
5b41d924 ES |
187 | void tag_pages_for_writeback(struct address_space *mapping, |
188 | pgoff_t start, pgoff_t end); | |
0ea97180 MS |
189 | int write_cache_pages(struct address_space *mapping, |
190 | struct writeback_control *wbc, writepage_t writepage, | |
191 | void *data); | |
1da177e4 | 192 | int do_writepages(struct address_space *mapping, struct writeback_control *wbc); |
a200ee18 | 193 | void set_page_dirty_balance(struct page *page, int page_mkwrite); |
2d1d43f6 | 194 | void writeback_set_ratelimit(void); |
92c09c04 NK |
195 | void tag_pages_for_writeback(struct address_space *mapping, |
196 | pgoff_t start, pgoff_t end); | |
1da177e4 LT |
197 | |
198 | /* pdflush.c */ | |
199 | extern int nr_pdflush_threads; /* Global so it can be exported to sysctl | |
200 | read-only. */ | |
201 | ||
202 | ||
203 | #endif /* WRITEBACK_H */ |