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authorCurt Wohlgemuth <curtw@google.com>2011-10-07 21:54:10 -0600
committerWu Fengguang <fengguang.wu@intel.com>2011-10-31 00:33:36 +0800
commit0e175a1835ffc979e55787774e58ec79e41957d7 (patch)
tree6ec4b65a8de4e9d1c12d26a1079079ed81d79450 /fs/fs-writeback.c
parentad4e38dd6a33bb3a4882c487d7abe621e583b982 (diff)
downloadlinux-0e175a1835ffc979e55787774e58ec79e41957d7.tar.bz2
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>
Diffstat (limited to 'fs/fs-writeback.c')
-rw-r--r--fs/fs-writeback.c49
1 files changed, 36 insertions, 13 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index c51029693600..73c3992b2bb4 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -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));