dect
/
linux-2.6
Archived
13
0
Fork 0
Code Releases Activity

writeback: Add a 'reason' to wb_writeback_work 

This creates a new 'reason' field in a wb_writeback_work
structure, which unambiguously identifies who initiates
writeback activity.  A 'wb_reason' enumeration has been
added to writeback.h, to enumerate the possible reasons.

The 'writeback_work_class' and tracepoint event class and
'writeback_queue_io' tracepoints are updated to include the
symbolic 'reason' in all trace events.

And the 'writeback_inodes_sbXXX' family of routines has had
a wb_stats parameter added to them, so callers can specify
why writeback is being started.

Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Curt Wohlgemuth <curtw@google.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
This commit is contained in:
Curt Wohlgemuth 2011-10-07 21:54:10 -06:00 committed by Wu Fengguang
parent ad4e38dd6a
commit 0e175a1835
13 changed files with 88 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
fs/btrfs/extent-tree.c
View File

@ -3340,7 +3340,8 @@ static int shrink_delalloc(struct btrfs_trans_handle *trans,
smp_mb();
nr_pages = min_t(unsigned long, nr_pages,
root->fs_info->delalloc_bytes >> PAGE_CACHE_SHIFT);
writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages);
writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages,
WB_REASON_FS_FREE_SPACE);
spin_lock(&space_info->lock);
if (reserved > space_info->bytes_reserved)

2
fs/buffer.c
View File

@ -285,7 +285,7 @@ static void free_more_memory(void)
struct zone *zone;
int nid;
wakeup_flusher_threads(1024);
wakeup_flusher_threads(1024, WB_REASON_FREE_MORE_MEM);
yield();
for_each_online_node(nid) {

2
fs/ext4/inode.c
View File

@ -2241,7 +2241,7 @@ static int ext4_nonda_switch(struct super_block *sb)
* start pushing delalloc when 1/2 of free blocks are dirty.
*/
if (free_blocks < 2 * dirty_blocks)
writeback_inodes_sb_if_idle(sb);
writeback_inodes_sb_if_idle(sb, WB_REASON_FS_FREE_SPACE);
return 0;
}

49
fs/fs-writeback.c
View File

@ -41,11 +41,23 @@ struct wb_writeback_work {
unsigned int for_kupdate:1;
unsigned int range_cyclic:1;
unsigned int for_background:1;
enum wb_reason reason; /* why was writeback initiated? */
struct list_head list; /* pending work list */
struct completion *done; /* set if the caller waits */
};
const char *wb_reason_name[] = {
[WB_REASON_BACKGROUND] = "background",
[WB_REASON_TRY_TO_FREE_PAGES] = "try_to_free_pages",
[WB_REASON_SYNC] = "sync",
[WB_REASON_PERIODIC] = "periodic",
[WB_REASON_LAPTOP_TIMER] = "laptop_timer",
[WB_REASON_FREE_MORE_MEM] = "free_more_memory",
[WB_REASON_FS_FREE_SPACE] = "fs_free_space",
[WB_REASON_FORKER_THREAD] = "forker_thread"
};
/*
* Include the creation of the trace points after defining the
* wb_writeback_work structure so that the definition remains local to this
@ -115,7 +127,7 @@ static void bdi_queue_work(struct backing_dev_info *bdi,
static void
__bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
bool range_cyclic)
bool range_cyclic, enum wb_reason reason)
{
struct wb_writeback_work *work;
@ -135,6 +147,7 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
work->sync_mode = WB_SYNC_NONE;
work->nr_pages = nr_pages;
work->range_cyclic = range_cyclic;
work->reason = reason;
bdi_queue_work(bdi, work);
}
@ -150,9 +163,10 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
* completion. Caller need not hold sb s_umount semaphore.
*
*/
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages)
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
enum wb_reason reason)
{
__bdi_start_writeback(bdi, nr_pages, true);
__bdi_start_writeback(bdi, nr_pages, true, reason);
}
/**
@ -641,12 +655,14 @@ static long __writeback_inodes_wb(struct bdi_writeback *wb,
return wrote;
}
long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages)
long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages,
enum wb_reason reason)
{
struct wb_writeback_work work = {
.nr_pages = nr_pages,
.sync_mode = WB_SYNC_NONE,
.range_cyclic = 1,
.reason = reason,
};
spin_lock(&wb->list_lock);
@ -825,6 +841,7 @@ static long wb_check_background_flush(struct bdi_writeback *wb)
.sync_mode = WB_SYNC_NONE,
.for_background = 1,
.range_cyclic = 1,
.reason = WB_REASON_BACKGROUND,
};
return wb_writeback(wb, &work);
@ -858,6 +875,7 @@ static long wb_check_old_data_flush(struct bdi_writeback *wb)
.sync_mode = WB_SYNC_NONE,
.for_kupdate = 1,
.range_cyclic = 1,
.reason = WB_REASON_PERIODIC,
};
return wb_writeback(wb, &work);
@ -976,7 +994,7 @@ int bdi_writeback_thread(void *data)
* Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back
* the whole world.
*/
void wakeup_flusher_threads(long nr_pages)
void wakeup_flusher_threads(long nr_pages, enum wb_reason reason)
{
struct backing_dev_info *bdi;
@ -989,7 +1007,7 @@ void wakeup_flusher_threads(long nr_pages)
list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) {
if (!bdi_has_dirty_io(bdi))
continue;
__bdi_start_writeback(bdi, nr_pages, false);
__bdi_start_writeback(bdi, nr_pages, false, reason);
}
rcu_read_unlock();
}
@ -1210,7 +1228,9 @@ static void wait_sb_inodes(struct super_block *sb)
* on how many (if any) will be written, and this function does not wait
* for IO completion of submitted IO.
*/
void writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr)
void writeback_inodes_sb_nr(struct super_block *sb,
unsigned long nr,
enum wb_reason reason)
{
DECLARE_COMPLETION_ONSTACK(done);
struct wb_writeback_work work = {
@ -1219,6 +1239,7 @@ void writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr)
.tagged_writepages = 1,
.done = &done,
.nr_pages = nr,
.reason = reason,
};
WARN_ON(!rwsem_is_locked(&sb->s_umount));
@ -1235,9 +1256,9 @@ EXPORT_SYMBOL(writeback_inodes_sb_nr);
* on how many (if any) will be written, and this function does not wait
* for IO completion of submitted IO.
*/
void writeback_inodes_sb(struct super_block *sb)
void writeback_inodes_sb(struct super_block *sb, enum wb_reason reason)
{
return writeback_inodes_sb_nr(sb, get_nr_dirty_pages());
return writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason);
}
EXPORT_SYMBOL(writeback_inodes_sb);
@ -1248,11 +1269,11 @@ EXPORT_SYMBOL(writeback_inodes_sb);
* Invoke writeback_inodes_sb if no writeback is currently underway.
* Returns 1 if writeback was started, 0 if not.
*/
int writeback_inodes_sb_if_idle(struct super_block *sb)
int writeback_inodes_sb_if_idle(struct super_block *sb, enum wb_reason reason)
{
if (!writeback_in_progress(sb->s_bdi)) {
down_read(&sb->s_umount);
writeback_inodes_sb(sb);
writeback_inodes_sb(sb, reason);
up_read(&sb->s_umount);
return 1;
} else
@ -1269,11 +1290,12 @@ EXPORT_SYMBOL(writeback_inodes_sb_if_idle);
* Returns 1 if writeback was started, 0 if not.
*/
int writeback_inodes_sb_nr_if_idle(struct super_block *sb,
unsigned long nr)
unsigned long nr,
enum wb_reason reason)
{
if (!writeback_in_progress(sb->s_bdi)) {
down_read(&sb->s_umount);
writeback_inodes_sb_nr(sb, nr);
writeback_inodes_sb_nr(sb, nr, reason);
up_read(&sb->s_umount);
return 1;
} else
@ -1297,6 +1319,7 @@ void sync_inodes_sb(struct super_block *sb)
.nr_pages = LONG_MAX,
.range_cyclic = 0,
.done = &done,
.reason = WB_REASON_SYNC,
};
WARN_ON(!rwsem_is_locked(&sb->s_umount));

2
fs/quota/quota.c
View File

@ -286,7 +286,7 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
/* caller already holds s_umount */
if (sb->s_flags & MS_RDONLY)
return -EROFS;
writeback_inodes_sb(sb);
writeback_inodes_sb(sb, WB_REASON_SYNC);
return 0;
default:
return -EINVAL;

4
fs/sync.c
View File

@ -43,7 +43,7 @@ static int __sync_filesystem(struct super_block *sb, int wait)
if (wait)
sync_inodes_sb(sb);
else
writeback_inodes_sb(sb);
writeback_inodes_sb(sb, WB_REASON_SYNC);
if (sb->s_op->sync_fs)
sb->s_op->sync_fs(sb, wait);
@ -98,7 +98,7 @@ static void sync_filesystems(int wait)
*/
SYSCALL_DEFINE0(sync)
{
wakeup_flusher_threads(0);
wakeup_flusher_threads(0, WB_REASON_SYNC);
sync_filesystems(0);
sync_filesystems(1);
if (unlikely(laptop_mode))

2
fs/ubifs/budget.c
View File

@ -63,7 +63,7 @@
static void shrink_liability(struct ubifs_info *c, int nr_to_write)
{
down_read(&c->vfs_sb->s_umount);
writeback_inodes_sb(c->vfs_sb);
writeback_inodes_sb(c->vfs_sb, WB_REASON_FS_FREE_SPACE);
up_read(&c->vfs_sb->s_umount);
}

3
include/linux/backing-dev.h
View File

@ -118,7 +118,8 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
void bdi_unregister(struct backing_dev_info *bdi);
int bdi_setup_and_register(struct backing_dev_info *, char *, unsigned int);
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages);
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
enum wb_reason reason);
void bdi_start_background_writeback(struct backing_dev_info *bdi);
int bdi_writeback_thread(void *data);
int bdi_has_dirty_io(struct backing_dev_info *bdi);

32
include/linux/writeback.h
View File

@ -38,6 +38,23 @@ enum writeback_sync_modes {
WB_SYNC_ALL, /* Wait on every mapping */
};
/*
* why some writeback work was initiated
*/
enum wb_reason {
WB_REASON_BACKGROUND,
WB_REASON_TRY_TO_FREE_PAGES,
WB_REASON_SYNC,
WB_REASON_PERIODIC,
WB_REASON_LAPTOP_TIMER,
WB_REASON_FREE_MORE_MEM,
WB_REASON_FS_FREE_SPACE,
WB_REASON_FORKER_THREAD,
WB_REASON_MAX,
};
extern const char *wb_reason_name[];
/*
* 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
@ -69,14 +86,17 @@ struct writeback_control {
*/
struct bdi_writeback;
int inode_wait(void *);
void writeback_inodes_sb(struct super_block *);
void writeback_inodes_sb_nr(struct super_block *, unsigned long nr);
int writeback_inodes_sb_if_idle(struct super_block *);
int writeback_inodes_sb_nr_if_idle(struct super_block *, unsigned long nr);
void writeback_inodes_sb(struct super_block *, enum wb_reason reason);
void writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
enum wb_reason reason);
int writeback_inodes_sb_if_idle(struct super_block *, enum wb_reason reason);
int writeback_inodes_sb_nr_if_idle(struct super_block *, unsigned long nr,
enum wb_reason reason);
void sync_inodes_sb(struct super_block *);
long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages);
long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages,
enum wb_reason reason);
long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
void wakeup_flusher_threads(long nr_pages);
void wakeup_flusher_threads(long nr_pages, enum wb_reason reason);
/* writeback.h requires fs.h; it, too, is not included from here. */
static inline void wait_on_inode(struct inode *inode)

14
include/trace/events/writeback.h
View File

@ -34,6 +34,7 @@ DECLARE_EVENT_CLASS(writeback_work_class,
__field(int, for_kupdate)
__field(int, range_cyclic)
__field(int, for_background)
__field(int, reason)
),
TP_fast_assign(
strncpy(__entry->name, dev_name(bdi->dev), 32);
@ -43,16 +44,18 @@ DECLARE_EVENT_CLASS(writeback_work_class,
__entry->for_kupdate = work->for_kupdate;
__entry->range_cyclic = work->range_cyclic;
__entry->for_background = work->for_background;
__entry->reason = work->reason;
),
TP_printk("bdi %s: sb_dev %d:%d nr_pages=%ld sync_mode=%d "
"kupdate=%d range_cyclic=%d background=%d",
"kupdate=%d range_cyclic=%d background=%d reason=%s",
__entry->name,
MAJOR(__entry->sb_dev), MINOR(__entry->sb_dev),
__entry->nr_pages,
__entry->sync_mode,
__entry->for_kupdate,
__entry->range_cyclic,
__entry->for_background
__entry->for_background,
wb_reason_name[__entry->reason]
)
);
#define DEFINE_WRITEBACK_WORK_EVENT(name) \
@ -165,6 +168,7 @@ TRACE_EVENT(writeback_queue_io,
__field(unsigned long, older)
__field(long, age)
__field(int, moved)
__field(int, reason)
),
TP_fast_assign(
unsigned long *older_than_this = work->older_than_this;
@ -173,12 +177,14 @@ TRACE_EVENT(writeback_queue_io,
__entry->age = older_than_this ?
(jiffies - *older_than_this) * 1000 / HZ : -1;
__entry->moved = moved;
__entry->reason = work->reason;
),
TP_printk("bdi %s: older=%lu age=%ld enqueue=%d",
TP_printk("bdi %s: older=%lu age=%ld enqueue=%d reason=%s",
__entry->name,
__entry->older, /* older_than_this in jiffies */
__entry->age, /* older_than_this in relative milliseconds */
__entry->moved)
__entry->moved,
wb_reason_name[__entry->reason])
);
TRACE_EVENT(global_dirty_state,

3
mm/backing-dev.c
View File

@ -476,7 +476,8 @@ static int bdi_forker_thread(void *ptr)
* the bdi from the thread. Hopefully 1024 is
* large enough for efficient IO.
*/
writeback_inodes_wb(&bdi->wb, 1024);
writeback_inodes_wb(&bdi->wb, 1024,
WB_REASON_FORKER_THREAD);
} else {
/*
* The spinlock makes sure we do not lose

3
mm/page-writeback.c
View File

@ -1301,7 +1301,8 @@ void laptop_mode_timer_fn(unsigned long data)
* threshold
*/
if (bdi_has_dirty_io(&q->backing_dev_info))
bdi_start_writeback(&q->backing_dev_info, nr_pages);
bdi_start_writeback(&q->backing_dev_info, nr_pages,
WB_REASON_LAPTOP_TIMER);
}
/*

3
mm/vmscan.c
View File

@ -2181,7 +2181,8 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
*/
writeback_threshold = sc->nr_to_reclaim + sc->nr_to_reclaim / 2;
if (total_scanned > writeback_threshold) {
wakeup_flusher_threads(laptop_mode ? 0 : total_scanned);
wakeup_flusher_threads(laptop_mode ? 0 : total_scanned,
WB_REASON_TRY_TO_FREE_PAGES);
sc->may_writepage = 1;
}