From c1d7ecf7ca11d0edd3085262c8597203440d056c Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Thu, 27 Apr 2017 10:11:16 -0700 Subject: [PATCH] dm mpath: delay requeuing while path initialization is in progress 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 Reviewed-by: Hannes Reinecke Cc: Christoph Hellwig Cc: Signed-off-by: Mike Snitzer --- drivers/md/dm-mpath.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index f3c79f1..d85baff 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) { + int ret; unsigned long flags; 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) @@ -503,7 +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); + if (pg_init_all_paths(m)) + return DM_MAPIO_DELAY_REQUEUE; return DM_MAPIO_REQUEUE; } -- 2.7.4