This is a note to let you know that I've just added the patch titled dm mpath: delay requeuing while path initialization is in progress to the 4.11-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: dm-mpath-delay-requeuing-while-path-initialization-is-in-progress.patch and it can be found in the queue-4.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From c1d7ecf7ca11d0edd3085262c8597203440d056c Mon Sep 17 00:00:00 2001 From: Bart Van Assche <bart.vanassche@xxxxxxxxxxx> Date: Thu, 27 Apr 2017 10:11:16 -0700 Subject: dm mpath: delay requeuing while path initialization is in progress From: Bart Van Assche <bart.vanassche@xxxxxxxxxxx> commit c1d7ecf7ca11d0edd3085262c8597203440d056c upstream. 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> Reviewed-by: Hannes Reinecke <hare@xxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/md/dm-mpath.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -322,13 +322,16 @@ static int __pg_init_all_paths(struct mu 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(struc 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; } Patches currently in stable-queue which might be from bart.vanassche@xxxxxxxxxxx are queue-4.11/dm-mpath-requeue-after-a-small-delay-if-blk_get_request-fails.patch queue-4.11/dm-mpath-avoid-that-path-removal-can-trigger-an-infinite-loop.patch queue-4.11/dm-mpath-split-and-rename-activate_path-to-prepare-for-its-expanded-use.patch queue-4.11/dm-mpath-delay-requeuing-while-path-initialization-is-in-progress.patch