summaryrefslogtreecommitdiffstats
path: root/block/cfq-iosched.c
diff options
context:
space:
mode:
authorJan Kara <jack@suse.com>2016-01-12 16:24:16 +0100
committerJens Axboe <axboe@fb.com>2016-02-04 09:50:12 -0700
commit6c80731c75bd3289d35b89a21a4e317cbcb306e3 (patch)
tree6436e8e33ca1f8cd62a46c900547bab559504384 /block/cfq-iosched.c
parente795421e40b39bf874c5ed9434365fb4a4b6c5d1 (diff)
downloadlinux-0-day-6c80731c75bd3289d35b89a21a4e317cbcb306e3.tar.gz
cfq-iosched: Reorder checks in cfq_should_preempt()
Move check for preemption by rt class up. There is no functional change but it makes arguing about conditions simpler since we can be sure both cfq queues are from the same ioprio class. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jan Kara <jack@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/cfq-iosched.c')
-rw-r--r--block/cfq-iosched.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 0a6a70a..2544c21 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3959,6 +3959,13 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
if (cfq_slice_used(cfqq))
return true;
+ /*
+ * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
+ */
+ if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
+ return true;
+
+ WARN_ON_ONCE(cfqq->ioprio_class != new_cfqq->ioprio_class);
/* Allow preemption only if we are idling on sync-noidle tree */
if (cfqd->serving_wl_type == SYNC_NOIDLE_WORKLOAD &&
cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD &&
@@ -3973,12 +3980,6 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
if ((rq->cmd_flags & REQ_PRIO) && !cfqq->prio_pending)
return true;
- /*
- * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
- */
- if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
- return true;
-
/* An idle queue should not be idle now for some reason */
if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq))
return true;