[V2,02/10] Btrfs: wake up the tasks that wait for the io earlier
diff mbox

Message ID 1394085304-32589-2-git-send-email-miaox@cn.fujitsu.com
State Accepted
Headers show

Commit Message

Miao Xie March 6, 2014, 5:54 a.m. UTC
The tasks that wait for the IO_DONE flag just care about the io of the dirty
pages, so it is better to wake up them immediately after all the pages are
written, not the whole process of the io completes.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
Changelog v1 -> v2:
- None.
---
 fs/btrfs/ordered-data.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

Comments

David Sterba March 27, 2014, 4:57 p.m. UTC | #1
On Thu, Mar 06, 2014 at 01:54:56PM +0800, Miao Xie wrote:
> @@ -349,10 +349,13 @@ int btrfs_dec_test_first_ordered_pending(struct inode *inode,
>  	if (!uptodate)
>  		set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
>  
> -	if (entry->bytes_left == 0)
> +	if (entry->bytes_left == 0) {
>  		ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
> -	else

waitqueue_active() should be preceded by a barrier (either implicit or
explicit), which is missing here and below. Though this could lead to a
missed wakeup, I don't think it's required here, but for consistency I
suggest to add it or put a comment why it's not needed.

> +		if (waitqueue_active(&entry->wait))
> +			wake_up(&entry->wait);
> +	} else {
>  		ret = 1;
> +	}
>  out:
>  	if (!ret && cached && entry) {
>  		*cached = entry;
> @@ -410,10 +413,13 @@ have_entry:
>  	if (!uptodate)
>  		set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
>  
> -	if (entry->bytes_left == 0)
> +	if (entry->bytes_left == 0) {
>  		ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
> -	else
> +		if (waitqueue_active(&entry->wait))

^^^

> +			wake_up(&entry->wait);
> +	} else {
>  		ret = 1;
> +	}
>  out:
>  	if (!ret && cached && entry) {
>  		*cached = entry;
--
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Patch
diff mbox

diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index a6ba75e..067e129 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -349,10 +349,13 @@  int btrfs_dec_test_first_ordered_pending(struct inode *inode,
 	if (!uptodate)
 		set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 
-	if (entry->bytes_left == 0)
+	if (entry->bytes_left == 0) {
 		ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
-	else
+		if (waitqueue_active(&entry->wait))
+			wake_up(&entry->wait);
+	} else {
 		ret = 1;
+	}
 out:
 	if (!ret && cached && entry) {
 		*cached = entry;
@@ -410,10 +413,13 @@  have_entry:
 	if (!uptodate)
 		set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 
-	if (entry->bytes_left == 0)
+	if (entry->bytes_left == 0) {
 		ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
-	else
+		if (waitqueue_active(&entry->wait))
+			wake_up(&entry->wait);
+	} else {
 		ret = 1;
+	}
 out:
 	if (!ret && cached && entry) {
 		*cached = entry;