Requeuing a request immediately while path initialization is ongoing causes high CPU usage, something that is undesired. Hence delay requeuing while path initialization is in progress. Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx> Cc: Hannes Reinecke <hare@xxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> --- drivers/md/dm-mpath.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 6d4333fdddf5..e38c92178746 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -322,13 +322,16 @@ static int __pg_init_all_paths(struct multipath *m) return atomic_read(&m->pg_init_in_progress); } -static void pg_init_all_paths(struct multipath *m) +static int pg_init_all_paths(struct multipath *m) { unsigned long flags; + int ret; spin_lock_irqsave(&m->lock, flags); - __pg_init_all_paths(m); + ret = __pg_init_all_paths(m); spin_unlock_irqrestore(&m->lock, flags); + + return ret; } static void __switch_pg(struct multipath *m, struct priority_group *pg) @@ -485,7 +488,6 @@ 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; @@ -504,8 +506,8 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, return -EIO; /* Failed */ } 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 pg_init_all_paths(m) == 0 ? DM_MAPIO_REQUEUE : + DM_MAPIO_DELAY_REQUEUE; } memset(mpio, 0, sizeof(*mpio)); -- 2.12.2 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel