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| author |   Joe Thornber <ejt@redhat.com> | 2017-05-03 12:01:27 -0400 |
|---|---|---|
| committer |   Mike Snitzer <snitzer@redhat.com> | 2017-05-04 10:27:47 -0400 |
| commit | ce1d64e84dbea98d41deaf5db0fe91fd729ad2cd (patch) | |
| tree | 7d56b14e5ae0e3eccdbf8c6bb1d197072250ce6b /drivers/md/dm-cache-policy-smq.c | |
| parent | Merge tag 'for-4.12/dm-post-merge-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm (diff) | |
| download | wireguard-linux-ce1d64e84dbea98d41deaf5db0fe91fd729ad2cd.tar.xz wireguard-linux-ce1d64e84dbea98d41deaf5db0fe91fd729ad2cd.zip | |
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: b29d4986d0 ("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>
Diffstat (limited to 'drivers/md/dm-cache-policy-smq.c')
| -rw-r--r-- | drivers/md/dm-cache-policy-smq.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/md/dm-cache-policy-smq.c b/drivers/md/dm-cache-policy-smq.c index e0c40aec5e96..d13d9edf8dfe 100644 --- a/drivers/md/dm-cache-policy-smq.c +++ b/drivers/md/dm-cache-policy-smq.c @@ -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; } |