xfs: split metadata and log buffer completion to separate workqueues
XFS traditionally sends all buffer I/O completion work to a single
workqueue. This includes metadata buffer completion and log buffer
completion. The log buffer completion requires a high priority queue to
prevent stalls due to log forces getting stuck behind other queued work.
Rather than continue to prioritize all buffer I/O completion due to the
needs of log completion, split log buffer completion off to
m_log_workqueue and move the high priority flag from m_buf_workqueue to
m_log_workqueue.
Add a b_ioend_wq wq pointer to xfs_buf to allow completion workqueue
customization on a per-buffer basis. Initialize b_ioend_wq to
m_buf_workqueue by default in the generic buffer I/O submission path.
Finally, override the default wq with the high priority m_log_workqueue
in the log buffer I/O submission path.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index d083889..945bea9 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1041,7 +1041,7 @@
struct work_struct *work)
{
struct xfs_buf *bp =
- container_of(work, xfs_buf_t, b_iodone_work);
+ container_of(work, xfs_buf_t, b_ioend_work);
xfs_buf_ioend(bp);
}
@@ -1050,8 +1050,8 @@
xfs_buf_ioend_async(
struct xfs_buf *bp)
{
- INIT_WORK(&bp->b_iodone_work, xfs_buf_ioend_work);
- queue_work(bp->b_target->bt_mount->m_buf_workqueue, &bp->b_iodone_work);
+ INIT_WORK(&bp->b_ioend_work, xfs_buf_ioend_work);
+ queue_work(bp->b_ioend_wq, &bp->b_ioend_work);
}
void
@@ -1220,6 +1220,13 @@
*/
bp->b_error = 0;
+ /*
+ * Initialize the I/O completion workqueue if we haven't yet or the
+ * submitter has not opted to specify a custom one.
+ */
+ if (!bp->b_ioend_wq)
+ bp->b_ioend_wq = bp->b_target->bt_mount->m_buf_workqueue;
+
if (bp->b_flags & XBF_WRITE) {
if (bp->b_flags & XBF_SYNCIO)
rw = WRITE_SYNC;