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>
This commit is contained in:
Brian Foster 2014-12-04 09:43:17 +11:00 committed by Dave Chinner
parent 32296f865e
commit b29c70f598
4 changed files with 18 additions and 7 deletions

View File

@ -1041,7 +1041,7 @@ xfs_buf_ioend_work(
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 @@ void
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 @@ _xfs_buf_ioapply(
*/
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;

View File

@ -164,7 +164,8 @@ typedef struct xfs_buf {
struct xfs_perag *b_pag; /* contains rbtree root */
xfs_buftarg_t *b_target; /* buffer target (device) */
void *b_addr; /* virtual address of buffer */
struct work_struct b_iodone_work;
struct work_struct b_ioend_work;
struct workqueue_struct *b_ioend_wq; /* I/O completion wq */
xfs_buf_iodone_t b_iodone; /* I/O completion function */
struct completion b_iowait; /* queue for I/O waiters */
void *b_fspriv;

View File

@ -1808,6 +1808,8 @@ xlog_sync(
XFS_BUF_ZEROFLAGS(bp);
XFS_BUF_ASYNC(bp);
bp->b_flags |= XBF_SYNCIO;
/* use high priority completion wq */
bp->b_ioend_wq = log->l_mp->m_log_workqueue;
if (log->l_mp->m_flags & XFS_MOUNT_BARRIER) {
bp->b_flags |= XBF_FUA;
@ -1856,6 +1858,8 @@ xlog_sync(
bp->b_flags |= XBF_SYNCIO;
if (log->l_mp->m_flags & XFS_MOUNT_BARRIER)
bp->b_flags |= XBF_FUA;
/* use high priority completion wq */
bp->b_ioend_wq = log->l_mp->m_log_workqueue;
ASSERT(XFS_BUF_ADDR(bp) <= log->l_logBBsize-1);
ASSERT(XFS_BUF_ADDR(bp) + BTOBB(count) <= log->l_logBBsize);

View File

@ -842,8 +842,7 @@ xfs_init_mount_workqueues(
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 @@ xfs_init_mount_workqueues(
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;