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