Commit ce1d64e8 authored May 03, 2017 by Joe Thornber Committed by Mike Snitzer May 04, 2017

dm cache policy smq: allow demotions to happen even during continuous IO

dm-cache's smq policy tries hard to do it's work during the idle periods
when there is no IO. But if there are no idle periods (eg, a long fio
run) we still need to allow some demotions and promotions to occur.

To achieve this, pass @idle=true to queue_promotion()'s
free_target_met() call so that free_target_met() doesn't short-circuit
the possibility of demotion simply because it isn't an idle period.

Fixes: b29d4986 ("dm cache: significant rework to leverage dm-bio-prison-v2")
Reported-by: John Harrigan <jharriga@redhat.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

parent 7b66f132

drivers/md/dm-cache-policy-smq.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -1214,7 +1214,11 @@ static void queue_promotion(struct smq_policy *mq, dm_oblock_t oblock,
		return;

		if (allocator_empty(&mq->cache_alloc)) {
		if (!free_target_met(mq, false))
		/*
		* We always claim to be 'idle' to ensure some demotions happen
		* with continuous loads.
		*/
		if (!free_target_met(mq, true))
		queue_demotion(mq);
		return;
		}