2 * include/linux/writeback.h
7 #include <linux/sched.h>
8 #include <linux/workqueue.h>
11 DECLARE_PER_CPU(int, dirty_throttle_leaks
);
14 * The 1/4 region under the global dirty thresh is for smooth dirty throttling:
16 * (thresh - thresh/DIRTY_FULL_SCOPE, thresh)
18 * Further beyond, all dirtier tasks will enter a loop waiting (possibly long
19 * time) for the dirty pages to drop, unless written enough pages.
21 * The global dirty threshold is normally equal to the global dirty limit,
22 * except when the system suddenly allocates a lot of anonymous memory and
23 * knocks down the global dirty threshold quickly, in which case the global
24 * dirty limit will follow down slowly to prevent livelocking all dirtier tasks.
27 #define DIRTY_FULL_SCOPE (DIRTY_SCOPE / 2)
29 struct backing_dev_info
;
34 enum writeback_sync_modes
{
35 WB_SYNC_NONE
, /* Don't wait on anything */
36 WB_SYNC_ALL
, /* Wait on every mapping */
40 * why some writeback work was initiated
44 WB_REASON_TRY_TO_FREE_PAGES
,
47 WB_REASON_LAPTOP_TIMER
,
48 WB_REASON_FREE_MORE_MEM
,
49 WB_REASON_FS_FREE_SPACE
,
50 WB_REASON_FORKER_THREAD
,
54 extern const char *wb_reason_name
[];
57 * A control structure which tells the writeback code what to do. These are
58 * always on the stack, and hence need no locking. They are always initialised
59 * in a manner such that unspecified fields are set to zero.
61 struct writeback_control
{
62 long nr_to_write
; /* Write this many pages, and decrement
63 this for each page written */
64 long pages_skipped
; /* Pages which were not written */
67 * For a_ops->writepages(): if start or end are non-zero then this is
68 * a hint that the filesystem need only write out the pages inside that
69 * byterange. The byte at `end' is included in the writeout request.
74 enum writeback_sync_modes sync_mode
;
76 unsigned for_kupdate
:1; /* A kupdate writeback */
77 unsigned for_background
:1; /* A background writeback */
78 unsigned tagged_writepages
:1; /* tag-and-write to avoid livelock */
79 unsigned for_reclaim
:1; /* Invoked from the page allocator */
80 unsigned range_cyclic
:1; /* range_start is cyclic */
81 unsigned for_sync
:1; /* sync(2) WB_SYNC_ALL writeback */
88 int inode_wait(void *);
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 try_to_writeback_inodes_sb(struct super_block
*, enum wb_reason reason
);
93 int try_to_writeback_inodes_sb_nr(struct super_block
*, unsigned long nr
,
94 enum wb_reason reason
);
95 void sync_inodes_sb(struct super_block
*);
96 long writeback_inodes_wb(struct bdi_writeback
*wb
, long nr_pages
,
97 enum wb_reason reason
);
98 long wb_do_writeback(struct bdi_writeback
*wb
, int force_wait
);
99 void wakeup_flusher_threads(long nr_pages
, enum wb_reason reason
);
100 void inode_wait_for_writeback(struct inode
*inode
);
102 /* writeback.h requires fs.h; it, too, is not included from here. */
103 static inline void wait_on_inode(struct inode
*inode
)
106 wait_on_bit(&inode
->i_state
, __I_NEW
, inode_wait
, TASK_UNINTERRUPTIBLE
);
110 * mm/page-writeback.c
113 void laptop_io_completion(struct backing_dev_info
*info
);
114 void laptop_sync_completion(void);
115 void laptop_mode_sync(struct work_struct
*work
);
116 void laptop_mode_timer_fn(unsigned long data
);
118 static inline void laptop_sync_completion(void) { }
120 void throttle_vm_writeout(gfp_t gfp_mask
);
121 bool zone_dirty_ok(struct zone
*zone
);
123 extern unsigned long global_dirty_limit
;
125 /* These are exported to sysctl. */
126 extern int dirty_background_ratio
;
127 extern unsigned long dirty_background_bytes
;
128 extern int vm_dirty_ratio
;
129 extern unsigned long vm_dirty_bytes
;
130 extern unsigned int dirty_writeback_interval
;
131 extern unsigned int dirty_expire_interval
;
132 extern int vm_highmem_is_dirtyable
;
133 extern int block_dump
;
134 extern int laptop_mode
;
136 extern int dirty_background_ratio_handler(struct ctl_table
*table
, int write
,
137 void __user
*buffer
, size_t *lenp
,
139 extern int dirty_background_bytes_handler(struct ctl_table
*table
, int write
,
140 void __user
*buffer
, size_t *lenp
,
142 extern int dirty_ratio_handler(struct ctl_table
*table
, int write
,
143 void __user
*buffer
, size_t *lenp
,
145 extern int dirty_bytes_handler(struct ctl_table
*table
, int write
,
146 void __user
*buffer
, size_t *lenp
,
150 int dirty_writeback_centisecs_handler(struct ctl_table
*, int,
151 void __user
*, size_t *, loff_t
*);
153 void global_dirty_limits(unsigned long *pbackground
, unsigned long *pdirty
);
154 unsigned long bdi_dirty_limit(struct backing_dev_info
*bdi
,
155 unsigned long dirty
);
157 void __bdi_update_bandwidth(struct backing_dev_info
*bdi
,
158 unsigned long thresh
,
159 unsigned long bg_thresh
,
161 unsigned long bdi_thresh
,
162 unsigned long bdi_dirty
,
163 unsigned long start_time
);
165 void page_writeback_init(void);
166 void balance_dirty_pages_ratelimited(struct address_space
*mapping
);
168 typedef int (*writepage_t
)(struct page
*page
, struct writeback_control
*wbc
,
171 int generic_writepages(struct address_space
*mapping
,
172 struct writeback_control
*wbc
);
173 void tag_pages_for_writeback(struct address_space
*mapping
,
174 pgoff_t start
, pgoff_t end
);
175 int write_cache_pages(struct address_space
*mapping
,
176 struct writeback_control
*wbc
, writepage_t writepage
,
178 int do_writepages(struct address_space
*mapping
, struct writeback_control
*wbc
);
179 void set_page_dirty_balance(struct page
*page
, int page_mkwrite
);
180 void writeback_set_ratelimit(void);
181 void tag_pages_for_writeback(struct address_space
*mapping
,
182 pgoff_t start
, pgoff_t end
);
184 void account_page_redirty(struct page
*page
);
186 #endif /* WRITEBACK_H */