Commit Graph

4 Commits

Author SHA1 Message Date
Mike Snitzer 280884fadc dm cache background tracker: fix sparse warning
Fix drivers/md/dm-cache-background-tracker.c:169:16: warning: symbol
'alloc_work' was not declared. Should it be static?

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-04-30 15:40:40 -04:00
Joe Thornber 64748b1645 dm cache background tracker: limit amount of background work that may be issued at once
On large systems the cache policy can be over enthusiastic and queue far
too much dirty data to be written back.  This consumes memory.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-11-10 15:45:03 -05:00
Colin Ian King 7e1b9521f5 dm cache: handle kmalloc failure allocating background_tracker struct
Currently there is no kmalloc failure check on the allocation of
the background_tracker struct in btracker_create(), and so a NULL return
will lead to a NULL pointer dereference.  Add a NULL check.

Detected by CoverityScan, CID#1416587 ("Dereference null return value")

Fixes: b29d4986d ("dm cache: significant rework to leverage dm-bio-prison-v2")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-05-17 09:44:53 -04:00
Joe Thornber b29d4986d0 dm cache: significant rework to leverage dm-bio-prison-v2
The cache policy interfaces have been updated to work well with the new
bio-prison v2 interface's ability to queue work immediately (promotion,
demotion, etc) -- overriding benefit being reduced latency on processing
IO through the cache.  Previously such work would be left for the DM
cache core to queue on various lists and then process in batches later
-- this caused a serious delay in latency for IO driven by the cache.

The background tracker code was factored out so that all cache policies
can make use of it.

Also, the "cleaner" policy has been removed and is now a variant of the
smq policy that simply disallows migrations.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-03-07 13:28:31 -05:00