samsung_sm8750/android_kernel_samsung_sm8750
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

dm cache: age and write back cache entries even without active IO

Browse Source 
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>
This commit is contained in:
Joe Thornber
2015-05-29 10:20:56 +01:00
committed by Mike Snitzer
parent b61d950962
commit fba10109a4
5 changed files with 20 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/md/dm-cache-target.c
View File

@@ -2271,7 +2271,7 @@ static void do_worker(struct work_struct *ws)
static void do_waker(struct work_struct *ws)
{
struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker);
policy_tick(cache->policy);
policy_tick(cache->policy, true);
wake_worker(cache);
queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD);
}
@@ -3148,7 +3148,7 @@ static int cache_end_io(struct dm_target *ti, struct bio *bio, int error)
struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
if (pb->tick) {
policy_tick(cache->policy);
policy_tick(cache->policy, false);
spin_lock_irqsave(&cache->lock, flags);
cache->need_tick_bio = true;