diff options
| author | Bart Van Assche <bart.vanassche@sandisk.com> | 2017-04-07 16:50:44 -0700 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2017-04-24 15:06:19 -0400 |
| commit | 06eb061f48594aa369f6e852b352410298b317a8 (patch) | |
| tree | 02c868ed14c9682c49a4f469edad71d730413fd8 | |
| parent | 117aceb030307dcd431fdcff87ce988d3016c34a (diff) | |
dm mpath: requeue after a small delay if blk_get_request() fails
If blk_get_request() returns ENODEV then multipath_clone_and_map()
causes a request to be requeued immediately. This can cause a kworker
thread to spend 100% of the CPU time of a single core in
__blk_mq_run_hw_queue() and also can cause device removal to never
finish.
Avoid this by only requeuing after a delay if blk_get_request() fails.
Additionally, reduce the requeue delay.
Cc: stable@vger.kernel.org # 4.9+
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| -rw-r--r-- | drivers/md/dm-mpath.c | 5 | ||||
| -rw-r--r-- | drivers/md/dm-rq.c | 2 |
2 files changed, 3 insertions, 4 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 7f223dbed49f..a4cc4d42117b 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -484,7 +484,6 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, struct request **__clone) { struct multipath *m = ti->private; - int r = DM_MAPIO_REQUEUE; size_t nr_bytes = blk_rq_bytes(rq); struct pgpath *pgpath; struct block_device *bdev; @@ -503,7 +502,7 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, } else if (test_bit(MPATHF_QUEUE_IO, &m->flags) || test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) { pg_init_all_paths(m); - return r; + return DM_MAPIO_REQUEUE; } memset(mpio, 0, sizeof(*mpio)); @@ -517,7 +516,7 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, GFP_ATOMIC); if (IS_ERR(clone)) { /* EBUSY, ENODEV or EWOULDBLOCK: requeue */ - return r; + return DM_MAPIO_DELAY_REQUEUE; } clone->bio = clone->biotail = NULL; clone->rq_disk = bdev->bd_disk; diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c index 28955b94d2b2..90756a56c4d3 100644 --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -280,7 +280,7 @@ static void dm_requeue_original_request(struct dm_rq_target_io *tio, bool delay_ if (!rq->q->mq_ops) dm_old_requeue_request(rq); else - dm_mq_delay_requeue_request(rq, delay_requeue ? 5000 : 0); + dm_mq_delay_requeue_request(rq, delay_requeue ? 100/*ms*/ : 0); rq_completed(md, rw, false); } |