2 * include/linux/writeback.h
7 #include <linux/sched.h>
10 struct backing_dev_info
;
12 extern spinlock_t inode_lock
;
13 extern struct list_head inode_in_use
;
14 extern struct list_head inode_unused
;
17 * Yes, writeback.h requires sched.h
18 * No, sched.h is not included from here.
20 static inline int task_is_pdflush(struct task_struct
*task
)
22 return task
->flags
& PF_FLUSHER
;
25 #define current_is_pdflush() task_is_pdflush(current)
30 enum writeback_sync_modes
{
31 WB_SYNC_NONE
, /* Don't wait on anything */
32 WB_SYNC_ALL
, /* Wait on every mapping */
33 WB_SYNC_HOLD
, /* Hold the inode on sb_dirty for sys_sync() */
37 * A control structure which tells the writeback code what to do. These are
38 * always on the stack, and hence need no locking. They are always initialised
39 * in a manner such that unspecified fields are set to zero.
41 struct writeback_control
{
42 struct backing_dev_info
*bdi
; /* If !NULL, only write back this
44 enum writeback_sync_modes sync_mode
;
45 unsigned long *older_than_this
; /* If !NULL, only write back inodes
47 long nr_to_write
; /* Write this many pages, and decrement
48 this for each page written */
49 long pages_skipped
; /* Pages which were not written */
52 * For a_ops->writepages(): is start or end are non-zero then this is
53 * a hint that the filesystem need only write out the pages inside that
54 * byterange. The byte at `end' is included in the writeout request.
59 unsigned nonblocking
:1; /* Don't get stuck on request queues */
60 unsigned encountered_congestion
:1; /* An output: a queue is full */
61 unsigned for_kupdate
:1; /* A kupdate writeback */
62 unsigned for_reclaim
:1; /* Invoked from the page allocator */
63 unsigned for_writepages
:1; /* This is a writepages() call */
64 unsigned range_cyclic
:1; /* range_start is cyclic */
65 unsigned more_io
:1; /* more io to be dispatched */
67 * write_cache_pages() won't update wbc->nr_to_write and
68 * mapping->writeback_index if no_nrwrite_index_update
69 * is set. write_cache_pages() may write more than we
70 * requested and we want to make sure nr_to_write and
71 * writeback_index are updated in a consistent manner
72 * so we use a single control to update them
74 unsigned no_nrwrite_index_update
:1;
80 void writeback_inodes(struct writeback_control
*wbc
);
81 int inode_wait(void *);
82 void sync_inodes_sb(struct super_block
*, int wait
);
83 void sync_inodes(int wait
);
85 /* writeback.h requires fs.h; it, too, is not included from here. */
86 static inline void wait_on_inode(struct inode
*inode
)
89 wait_on_bit(&inode
->i_state
, __I_LOCK
, inode_wait
,
90 TASK_UNINTERRUPTIBLE
);
92 static inline void inode_sync_wait(struct inode
*inode
)
95 wait_on_bit(&inode
->i_state
, __I_SYNC
, inode_wait
,
96 TASK_UNINTERRUPTIBLE
);
101 * mm/page-writeback.c
103 int wakeup_pdflush(long nr_pages
);
104 void laptop_io_completion(void);
105 void laptop_sync_completion(void);
106 void throttle_vm_writeout(gfp_t gfp_mask
);
108 /* These are exported to sysctl. */
109 extern int dirty_background_ratio
;
110 extern int vm_dirty_ratio
;
111 extern int dirty_writeback_interval
;
112 extern int dirty_expire_interval
;
113 extern int vm_highmem_is_dirtyable
;
114 extern int block_dump
;
115 extern int laptop_mode
;
117 extern unsigned long determine_dirtyable_memory(void);
119 extern int dirty_ratio_handler(struct ctl_table
*table
, int write
,
120 struct file
*filp
, void __user
*buffer
, size_t *lenp
,
125 int dirty_writeback_centisecs_handler(struct ctl_table
*, int, struct file
*,
126 void __user
*, size_t *, loff_t
*);
128 void get_dirty_limits(long *pbackground
, long *pdirty
, long *pbdi_dirty
,
129 struct backing_dev_info
*bdi
);
131 void page_writeback_init(void);
132 void balance_dirty_pages_ratelimited_nr(struct address_space
*mapping
,
133 unsigned long nr_pages_dirtied
);
136 balance_dirty_pages_ratelimited(struct address_space
*mapping
)
138 balance_dirty_pages_ratelimited_nr(mapping
, 1);
141 typedef int (*writepage_t
)(struct page
*page
, struct writeback_control
*wbc
,
144 int pdflush_operation(void (*fn
)(unsigned long), unsigned long arg0
);
145 int generic_writepages(struct address_space
*mapping
,
146 struct writeback_control
*wbc
);
147 int write_cache_pages(struct address_space
*mapping
,
148 struct writeback_control
*wbc
, writepage_t writepage
,
150 int do_writepages(struct address_space
*mapping
, struct writeback_control
*wbc
);
151 int sync_page_range(struct inode
*inode
, struct address_space
*mapping
,
152 loff_t pos
, loff_t count
);
153 int sync_page_range_nolock(struct inode
*inode
, struct address_space
*mapping
,
154 loff_t pos
, loff_t count
);
155 void set_page_dirty_balance(struct page
*page
, int page_mkwrite
);
156 void writeback_set_ratelimit(void);
159 extern int nr_pdflush_threads
; /* Global so it can be exported to sysctl
163 #endif /* WRITEBACK_H */