Linux kernel mirror (for testing)
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1/*
2 * include/linux/writeback.h
3 */
4#ifndef WRITEBACK_H
5#define WRITEBACK_H
6
7#include <linux/sched.h>
8#include <linux/fs.h>
9
10struct backing_dev_info;
11
12extern spinlock_t inode_lock;
13extern struct list_head inode_in_use;
14extern struct list_head inode_unused;
15
16/*
17 * fs/fs-writeback.c
18 */
19enum writeback_sync_modes {
20 WB_SYNC_NONE, /* Don't wait on anything */
21 WB_SYNC_ALL, /* Wait on every mapping */
22};
23
24/*
25 * A control structure which tells the writeback code what to do. These are
26 * always on the stack, and hence need no locking. They are always initialised
27 * in a manner such that unspecified fields are set to zero.
28 */
29struct writeback_control {
30 struct backing_dev_info *bdi; /* If !NULL, only write back this
31 queue */
32 struct super_block *sb; /* if !NULL, only write inodes from
33 this super_block */
34 enum writeback_sync_modes sync_mode;
35 unsigned long *older_than_this; /* If !NULL, only write back inodes
36 older than this */
37 unsigned long wb_start; /* Time writeback_inodes_wb was
38 called. This is needed to avoid
39 extra jobs and livelock */
40 long nr_to_write; /* Write this many pages, and decrement
41 this for each page written */
42 long pages_skipped; /* Pages which were not written */
43
44 /*
45 * For a_ops->writepages(): is start or end are non-zero then this is
46 * a hint that the filesystem need only write out the pages inside that
47 * byterange. The byte at `end' is included in the writeout request.
48 */
49 loff_t range_start;
50 loff_t range_end;
51
52 unsigned nonblocking:1; /* Don't get stuck on request queues */
53 unsigned encountered_congestion:1; /* An output: a queue is full */
54 unsigned for_kupdate:1; /* A kupdate writeback */
55 unsigned for_background:1; /* A background writeback */
56 unsigned for_reclaim:1; /* Invoked from the page allocator */
57 unsigned range_cyclic:1; /* range_start is cyclic */
58 unsigned more_io:1; /* more io to be dispatched */
59 /*
60 * write_cache_pages() won't update wbc->nr_to_write and
61 * mapping->writeback_index if no_nrwrite_index_update
62 * is set. write_cache_pages() may write more than we
63 * requested and we want to make sure nr_to_write and
64 * writeback_index are updated in a consistent manner
65 * so we use a single control to update them
66 */
67 unsigned no_nrwrite_index_update:1;
68};
69
70/*
71 * fs/fs-writeback.c
72 */
73struct bdi_writeback;
74int inode_wait(void *);
75void writeback_inodes_sb(struct super_block *);
76int writeback_inodes_sb_if_idle(struct super_block *);
77void sync_inodes_sb(struct super_block *);
78void writeback_inodes_wbc(struct writeback_control *wbc);
79long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
80void wakeup_flusher_threads(long nr_pages);
81
82/* writeback.h requires fs.h; it, too, is not included from here. */
83static inline void wait_on_inode(struct inode *inode)
84{
85 might_sleep();
86 wait_on_bit(&inode->i_state, __I_NEW, inode_wait, TASK_UNINTERRUPTIBLE);
87}
88static inline void inode_sync_wait(struct inode *inode)
89{
90 might_sleep();
91 wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
92 TASK_UNINTERRUPTIBLE);
93}
94
95
96/*
97 * mm/page-writeback.c
98 */
99void laptop_io_completion(void);
100void laptop_sync_completion(void);
101void throttle_vm_writeout(gfp_t gfp_mask);
102
103/* These are exported to sysctl. */
104extern int dirty_background_ratio;
105extern unsigned long dirty_background_bytes;
106extern int vm_dirty_ratio;
107extern unsigned long vm_dirty_bytes;
108extern unsigned int dirty_writeback_interval;
109extern unsigned int dirty_expire_interval;
110extern int vm_highmem_is_dirtyable;
111extern int block_dump;
112extern int laptop_mode;
113
114extern unsigned long determine_dirtyable_memory(void);
115
116extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
117 void __user *buffer, size_t *lenp,
118 loff_t *ppos);
119extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
120 void __user *buffer, size_t *lenp,
121 loff_t *ppos);
122extern int dirty_ratio_handler(struct ctl_table *table, int write,
123 void __user *buffer, size_t *lenp,
124 loff_t *ppos);
125extern int dirty_bytes_handler(struct ctl_table *table, int write,
126 void __user *buffer, size_t *lenp,
127 loff_t *ppos);
128
129struct ctl_table;
130int dirty_writeback_centisecs_handler(struct ctl_table *, int,
131 void __user *, size_t *, loff_t *);
132
133void get_dirty_limits(unsigned long *pbackground, unsigned long *pdirty,
134 unsigned long *pbdi_dirty, struct backing_dev_info *bdi);
135
136void page_writeback_init(void);
137void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
138 unsigned long nr_pages_dirtied);
139
140static inline void
141balance_dirty_pages_ratelimited(struct address_space *mapping)
142{
143 balance_dirty_pages_ratelimited_nr(mapping, 1);
144}
145
146typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
147 void *data);
148
149int generic_writepages(struct address_space *mapping,
150 struct writeback_control *wbc);
151int write_cache_pages(struct address_space *mapping,
152 struct writeback_control *wbc, writepage_t writepage,
153 void *data);
154int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
155void set_page_dirty_balance(struct page *page, int page_mkwrite);
156void writeback_set_ratelimit(void);
157
158/* pdflush.c */
159extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
160 read-only. */
161
162
163#endif /* WRITEBACK_H */