BugLink: http://bugs.launchpad.net/bugs/1774063
[ Upstream commit
050af08ffb1b62af69196d61c22a0755f9a3cdbd ]
blk-mq will rerun queue via RESTART or dispatch wake after one request
is completed, so not necessary to wait random time for requeuing, we
should trust blk-mq to do it.
More importantly, we need to return BLK_STS_RESOURCE to blk-mq so that
dequeuing from the I/O scheduler can be stopped, this results in
improved I/O merging.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
if (queue_dying) {
atomic_inc(&m->pg_init_in_progress);
activate_or_offline_path(pgpath);
if (queue_dying) {
atomic_inc(&m->pg_init_in_progress);
activate_or_offline_path(pgpath);
+ return DM_MAPIO_DELAY_REQUEUE;
- return DM_MAPIO_DELAY_REQUEUE;
+
+ /*
+ * blk-mq's SCHED_RESTART can cover this requeue, so we
+ * needn't deal with it by DELAY_REQUEUE. More importantly,
+ * we have to return DM_MAPIO_REQUEUE so that blk-mq can
+ * get the queue busy feedback (via BLK_STS_RESOURCE),
+ * otherwise I/O merging can suffer.
+ */
+ if (q->mq_ops)
+ return DM_MAPIO_REQUEUE;
+ else
+ return DM_MAPIO_DELAY_REQUEUE;
}
clone->bio = clone->biotail = NULL;
clone->rq_disk = bdev->bd_disk;
}
clone->bio = clone->biotail = NULL;
clone->rq_disk = bdev->bd_disk;