laptop-mode: Make flushes per-device
[linux-2.6.git] / include / linux / writeback.h
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
10 struct backing_dev_info;
11
12 extern spinlock_t inode_lock;
13 extern struct list_head inode_in_use;
14 extern struct list_head inode_unused;
15
16 /*
17  * fs/fs-writeback.c
18  */
19 enum 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  */
29 struct 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  */     
73 struct bdi_writeback;
74 int inode_wait(void *);
75 void writeback_inodes_sb(struct super_block *);
76 int writeback_inodes_sb_if_idle(struct super_block *);
77 void sync_inodes_sb(struct super_block *);
78 void writeback_inodes_wbc(struct writeback_control *wbc);
79 long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
80 void wakeup_flusher_threads(long nr_pages);
81
82 /* writeback.h requires fs.h; it, too, is not included from here. */
83 static 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 }
88 static 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  */
99 void laptop_io_completion(struct backing_dev_info *info);
100 void laptop_sync_completion(void);
101 void laptop_mode_sync(struct work_struct *work);
102 void laptop_mode_timer_fn(unsigned long data);
103 void throttle_vm_writeout(gfp_t gfp_mask);
104
105 /* These are exported to sysctl. */
106 extern int dirty_background_ratio;
107 extern unsigned long dirty_background_bytes;
108 extern int vm_dirty_ratio;
109 extern unsigned long vm_dirty_bytes;
110 extern unsigned int dirty_writeback_interval;
111 extern unsigned int dirty_expire_interval;
112 extern int vm_highmem_is_dirtyable;
113 extern int block_dump;
114 extern int laptop_mode;
115
116 extern unsigned long determine_dirtyable_memory(void);
117
118 extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
119                 void __user *buffer, size_t *lenp,
120                 loff_t *ppos);
121 extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
122                 void __user *buffer, size_t *lenp,
123                 loff_t *ppos);
124 extern int dirty_ratio_handler(struct ctl_table *table, int write,
125                 void __user *buffer, size_t *lenp,
126                 loff_t *ppos);
127 extern int dirty_bytes_handler(struct ctl_table *table, int write,
128                 void __user *buffer, size_t *lenp,
129                 loff_t *ppos);
130
131 struct ctl_table;
132 int dirty_writeback_centisecs_handler(struct ctl_table *, int,
133                                       void __user *, size_t *, loff_t *);
134
135 void get_dirty_limits(unsigned long *pbackground, unsigned long *pdirty,
136                       unsigned long *pbdi_dirty, struct backing_dev_info *bdi);
137
138 void page_writeback_init(void);
139 void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
140                                         unsigned long nr_pages_dirtied);
141
142 static inline void
143 balance_dirty_pages_ratelimited(struct address_space *mapping)
144 {
145         balance_dirty_pages_ratelimited_nr(mapping, 1);
146 }
147
148 typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
149                                 void *data);
150
151 int generic_writepages(struct address_space *mapping,
152                        struct writeback_control *wbc);
153 int write_cache_pages(struct address_space *mapping,
154                       struct writeback_control *wbc, writepage_t writepage,
155                       void *data);
156 int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
157 void set_page_dirty_balance(struct page *page, int page_mkwrite);
158 void writeback_set_ratelimit(void);
159
160 /* pdflush.c */
161 extern int nr_pdflush_threads;  /* Global so it can be exported to sysctl
162                                    read-only. */
163
164
165 #endif          /* WRITEBACK_H */