c63c7b0513
Currently we do write coalescing in a very inefficient manner: one pass in generic_writepages() in order to lock the pages for writing, then one pass in nfs_flush_mapping() and/or nfs_sync_mapping_wait() in order to gather the locked pages for coalescing into RPC requests of size "wsize". In fact, it turns out there is actually a deadlock possible here since we only start I/O on the second pass. If the user signals the process while we're in nfs_sync_mapping_wait(), for instance, then we may exit before starting I/O on all the requests that have been queued up. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
130 lines
3.9 KiB
C
130 lines
3.9 KiB
C
/*
|
|
* include/linux/writeback.h
|
|
*/
|
|
#ifndef WRITEBACK_H
|
|
#define WRITEBACK_H
|
|
|
|
struct backing_dev_info;
|
|
|
|
extern spinlock_t inode_lock;
|
|
extern struct list_head inode_in_use;
|
|
extern struct list_head inode_unused;
|
|
|
|
/*
|
|
* Yes, writeback.h requires sched.h
|
|
* No, sched.h is not included from here.
|
|
*/
|
|
static inline int task_is_pdflush(struct task_struct *task)
|
|
{
|
|
return task->flags & PF_FLUSHER;
|
|
}
|
|
|
|
#define current_is_pdflush() task_is_pdflush(current)
|
|
|
|
/*
|
|
* fs/fs-writeback.c
|
|
*/
|
|
enum writeback_sync_modes {
|
|
WB_SYNC_NONE, /* Don't wait on anything */
|
|
WB_SYNC_ALL, /* Wait on every mapping */
|
|
WB_SYNC_HOLD, /* Hold the inode on sb_dirty for sys_sync() */
|
|
};
|
|
|
|
/*
|
|
* A control structure which tells the writeback code what to do. These are
|
|
* always on the stack, and hence need no locking. They are always initialised
|
|
* in a manner such that unspecified fields are set to zero.
|
|
*/
|
|
struct writeback_control {
|
|
struct backing_dev_info *bdi; /* If !NULL, only write back this
|
|
queue */
|
|
enum writeback_sync_modes sync_mode;
|
|
unsigned long *older_than_this; /* If !NULL, only write back inodes
|
|
older than this */
|
|
long nr_to_write; /* Write this many pages, and decrement
|
|
this for each page written */
|
|
long pages_skipped; /* Pages which were not written */
|
|
|
|
/*
|
|
* For a_ops->writepages(): is start or end are non-zero then this is
|
|
* a hint that the filesystem need only write out the pages inside that
|
|
* byterange. The byte at `end' is included in the writeout request.
|
|
*/
|
|
loff_t range_start;
|
|
loff_t range_end;
|
|
|
|
unsigned nonblocking:1; /* Don't get stuck on request queues */
|
|
unsigned encountered_congestion:1; /* An output: a queue is full */
|
|
unsigned for_kupdate:1; /* A kupdate writeback */
|
|
unsigned for_reclaim:1; /* Invoked from the page allocator */
|
|
unsigned for_writepages:1; /* This is a writepages() call */
|
|
unsigned range_cyclic:1; /* range_start is cyclic */
|
|
|
|
void *fs_private; /* For use by ->writepages() */
|
|
};
|
|
|
|
/*
|
|
* fs/fs-writeback.c
|
|
*/
|
|
void writeback_inodes(struct writeback_control *wbc);
|
|
void wake_up_inode(struct inode *inode);
|
|
int inode_wait(void *);
|
|
void sync_inodes_sb(struct super_block *, int wait);
|
|
void sync_inodes(int wait);
|
|
|
|
/* writeback.h requires fs.h; it, too, is not included from here. */
|
|
static inline void wait_on_inode(struct inode *inode)
|
|
{
|
|
might_sleep();
|
|
wait_on_bit(&inode->i_state, __I_LOCK, inode_wait,
|
|
TASK_UNINTERRUPTIBLE);
|
|
}
|
|
|
|
/*
|
|
* mm/page-writeback.c
|
|
*/
|
|
int wakeup_pdflush(long nr_pages);
|
|
void laptop_io_completion(void);
|
|
void laptop_sync_completion(void);
|
|
void throttle_vm_writeout(gfp_t gfp_mask);
|
|
|
|
/* These are exported to sysctl. */
|
|
extern int dirty_background_ratio;
|
|
extern int vm_dirty_ratio;
|
|
extern int dirty_writeback_interval;
|
|
extern int dirty_expire_interval;
|
|
extern int block_dump;
|
|
extern int laptop_mode;
|
|
|
|
struct ctl_table;
|
|
struct file;
|
|
int dirty_writeback_centisecs_handler(struct ctl_table *, int, struct file *,
|
|
void __user *, size_t *, loff_t *);
|
|
|
|
void page_writeback_init(void);
|
|
void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
|
|
unsigned long nr_pages_dirtied);
|
|
|
|
static inline void
|
|
balance_dirty_pages_ratelimited(struct address_space *mapping)
|
|
{
|
|
balance_dirty_pages_ratelimited_nr(mapping, 1);
|
|
}
|
|
|
|
int pdflush_operation(void (*fn)(unsigned long), unsigned long arg0);
|
|
extern int generic_writepages(struct address_space *mapping,
|
|
struct writeback_control *wbc);
|
|
int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
|
|
int sync_page_range(struct inode *inode, struct address_space *mapping,
|
|
loff_t pos, loff_t count);
|
|
int sync_page_range_nolock(struct inode *inode, struct address_space *mapping,
|
|
loff_t pos, loff_t count);
|
|
void set_page_dirty_balance(struct page *page);
|
|
void writeback_set_ratelimit(void);
|
|
|
|
/* pdflush.c */
|
|
extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
|
|
read-only. */
|
|
|
|
|
|
#endif /* WRITEBACK_H */
|