Commit 0b31c10c authored Jun 28, 2016 by Jan Kara Committed by Jens Axboe Jun 28, 2016

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



Commit 9a7f38c4 (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: 9a7f38c4
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>

parent 149321a6

block/cfq-iosched.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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) {

Admin message