Add proper blk_start_plug/blk_finish_plug pairs for the two places where
we issue buffer I/O, and remove the blk_flush_plug in xfs_buf_lock and
xfs_buf_iowait, given that context switches already flush the per-process
plugging lists.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Index: xfs/fs/xfs/linux-2.6/xfs_buf.c
===================================================================
--- xfs.orig/fs/xfs/linux-2.6/xfs_buf.c 2011-03-29 21:55:12.863724557 +0200
+++ xfs/fs/xfs/linux-2.6/xfs_buf.c 2011-03-29 21:58:39.028224204 +0200
@@ -919,8 +919,6 @@ xfs_buf_lock(
if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE))
xfs_log_force(bp->b_target->bt_mount, 0);
- if (atomic_read(&bp->b_io_remaining))
- blk_flush_plug(current);
down(&bp->b_sema);
XB_SET_OWNER(bp);
@@ -1309,8 +1307,6 @@ xfs_buf_iowait(
{
trace_xfs_buf_iowait(bp, _RET_IP_);
- if (atomic_read(&bp->b_io_remaining))
- blk_flush_plug(current);
wait_for_completion(&bp->b_iowait);
trace_xfs_buf_iowait_done(bp, _RET_IP_);
@@ -1747,8 +1743,8 @@ xfsbufd(
do {
long age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
long tout = xfs_buf_timer_centisecs * msecs_to_jiffies(10);
- int count = 0;
struct list_head tmp;
+ struct blk_plug plug;
if (unlikely(freezing(current))) {
set_bit(XBT_FORCE_SLEEP, &target->bt_flags);
@@ -1764,16 +1760,15 @@ xfsbufd(
xfs_buf_delwri_split(target, &tmp, age);
list_sort(NULL, &tmp, xfs_buf_cmp);
+
+ blk_start_plug(&plug);
while (!list_empty(&tmp)) {
struct xfs_buf *bp;
bp = list_first_entry(&tmp, struct xfs_buf, b_list);
list_del_init(&bp->b_list);
xfs_bdstrat_cb(bp);
- count++;
}
- if (count)
- blk_flush_plug(current);
-
+ blk_finish_plug(&plug);
} while (!kthread_should_stop());
return 0;
@@ -1793,6 +1788,7 @@ xfs_flush_buftarg(
int pincount = 0;
LIST_HEAD(tmp_list);
LIST_HEAD(wait_list);
+ struct blk_plug plug;
xfs_buf_runall_queues(xfsconvertd_workqueue);
xfs_buf_runall_queues(xfsdatad_workqueue);
@@ -1807,6 +1803,8 @@ xfs_flush_buftarg(
* we do that after issuing all the IO.
*/
list_sort(NULL, &tmp_list, xfs_buf_cmp);
+
+ blk_start_plug(&plug);
while (!list_empty(&tmp_list)) {
bp = list_first_entry(&tmp_list, struct xfs_buf, b_list);
ASSERT(target == bp->b_target);
@@ -1817,10 +1815,10 @@ xfs_flush_buftarg(
}
xfs_bdstrat_cb(bp);
}
+ blk_finish_plug(&plug);
if (wait) {
- /* Expedite and wait for IO to complete. */
- blk_flush_plug(current);
+ /* Wait for IO to complete. */
while (!list_empty(&wait_list)) {
bp = list_first_entry(&wait_list, struct xfs_buf, b_list);
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