On Tue 07-06-11 11:56:50, Tao Ma wrote:
> From: Tao Ma <boyu.mt@xxxxxxxxxx>
>
> In journal checkpoint, we write the buffer and wait for its finish.
> But in cfq, the async queue has a very low priority, and in our test,
> if there are too many sync queues and every queue is filled up with
> requests, and the process will hang waiting for the log space.
>
> So this patch tries to use WRITE_SYNC in __flush_batch so that the request will
> be moved into sync queue and handled by cfq timely. We also use the new plug,
> sot that all the WRITE_SYNC requests can be given as a whole when we unplug it.
>
> Cc: Jan Kara <jack@xxxxxxx>
> Reported-by: Robin Dong <sanbai@xxxxxxxxxx>
> Signed-off-by: Tao Ma <boyu.mt@xxxxxxxxxx>
OK, since Ted took ext4 patch, I took this one to my tree as well. Thanks
for your work.
Honza
> ---
> fs/jbd/checkpoint.c | 6 +++++-
> 1 files changed, 5 insertions(+), 1 deletions(-)
>
> diff --git a/fs/jbd/checkpoint.c b/fs/jbd/checkpoint.c
> index e4b87bc..a7ce053 100644
> --- a/fs/jbd/checkpoint.c
> +++ b/fs/jbd/checkpoint.c
> @@ -22,6 +22,7 @@
> #include <linux/jbd.h>
> #include <linux/errno.h>
> #include <linux/slab.h>
> +#include <linux/blkdev.h>
>
> /*
> * Unlink a buffer from a transaction checkpoint list.
> @@ -253,9 +254,12 @@ static void
> __flush_batch(journal_t *journal, struct buffer_head **bhs, int *batch_count)
> {
> int i;
> + struct blk_plug plug;
>
> + blk_start_plug(&plug);
> for (i = 0; i < *batch_count; i++)
> - write_dirty_buffer(bhs[i], WRITE);
> + write_dirty_buffer(bhs[i], WRITE_SYNC);
> + blk_finish_plug(&plug);
>
> for (i = 0; i < *batch_count; i++) {
> struct buffer_head *bh = bhs[i];
> --
> 1.7.4
>
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
