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_super.c b/fs/xfs/xfs_super.c
index 45fa5b5..b5aacfc 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -842,8 +842,7 @@
struct xfs_mount *mp)
{
mp->m_buf_workqueue = alloc_workqueue("xfs-buf/%s",
- WQ_MEM_RECLAIM|WQ_HIGHPRI|WQ_FREEZABLE, 1,
- mp->m_fsname);
+ WQ_MEM_RECLAIM|WQ_FREEZABLE, 1, mp->m_fsname);
if (!mp->m_buf_workqueue)
goto out;
@@ -868,7 +867,7 @@
goto out_destroy_cil;
mp->m_log_workqueue = alloc_workqueue("xfs-log/%s",
- WQ_FREEZABLE, 0, mp->m_fsname);
+ WQ_FREEZABLE|WQ_HIGHPRI, 0, mp->m_fsname);
if (!mp->m_log_workqueue)
goto out_destroy_reclaim;