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authorJoe Thornber <ejt@redhat.com>2015-05-29 12:20:56 +0300
committerMike Snitzer <snitzer@redhat.com>2015-06-12 00:13:01 +0300
commitfba10109a45d864bab98ae90dd63bcc2789352b3 (patch)
tree9cfe1ba112421a7b18515d7854836a1b76aacb0b /drivers/md/dm-cache-policy.h
parentb61d9509628fea995196a96b4c1713fa67dade88 (diff)
downloadlinux-fba10109a45d864bab98ae90dd63bcc2789352b3.tar.xz
dm cache: age and write back cache entries even without active IO
The policy tick() method is normally called from interrupt context. Both the mq and smq policies do some bottom half work for the tick method in their map functions. However if no IO is going through the cache, then that bottom half work doesn't occur. With these policies this means recently hit entries do not age and do not get written back as early as we'd like. Fix this by introducing a new 'can_block' parameter to the tick() method. When this is set the bottom half work occurs immediately. 'can_block' is set when the tick method is called every second by the core target (not in interrupt context). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-cache-policy.h')
-rw-r--r--drivers/md/dm-cache-policy.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/md/dm-cache-policy.h b/drivers/md/dm-cache-policy.h
index 74709129d856..05db56eedb6a 100644
--- a/drivers/md/dm-cache-policy.h
+++ b/drivers/md/dm-cache-policy.h
@@ -200,10 +200,10 @@ struct dm_cache_policy {
* Because of where we sit in the block layer, we can be asked to
* map a lot of little bios that are all in the same block (no
* queue merging has occurred). To stop the policy being fooled by
- * these the core target sends regular tick() calls to the policy.
+ * these, the core target sends regular tick() calls to the policy.
* The policy should only count an entry as hit once per tick.
*/
- void (*tick)(struct dm_cache_policy *p);
+ void (*tick)(struct dm_cache_policy *p, bool can_block);
/*
* Configuration.