cfq-iosched: Charge at least 1 jiffie instead of 1 ns

Commit 9a7f38c (cfq-iosched: Convert from jiffies to nanoseconds) could result in charging just 1 ns to a cgroup submitting IO instead of 1 jiffie we always charged before. It is arguable what is the right amount to change but for now lets retain the old behavior of always charging at least one jiffie. Fixes: 9a7f38c Signed-off-by: Jan Kara <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
ambv · Jun 28, 2016 · 0b31c10 · 0b31c10
1 parent 149321a
commit 0b31c10
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
@@ -1463,7 +1463,8 @@ static inline u64 cfq_cfqq_slice_usage(struct cfq_queue *cfqq,
 		 * a single request on seeky media and cause lots of seek time
 		 * and group will never know it.
 		 */
-		slice_used = max_t(u64, (now - cfqq->dispatch_start), 1);
+		slice_used = max_t(u64, (now - cfqq->dispatch_start),
+					jiffies_to_nsecs(1));
 	} else {
 		slice_used = now - cfqq->slice_start;
 		if (slice_used > cfqq->allocated_slice) {