Commit 62a37f6b authored by Justin TerAvest's avatar Justin TerAvest Committed by Jens Axboe
Browse files

cfq-iosched: Don't clear queue stats when preempt. 



For v2, I added back lines to cfq_preempt_queue() that were removed
during updates for accounting unaccounted_time. Thanks for pointing out
that I'd missed these, Vivek.

Previous commit "cfq-iosched: Don't set active queue in preempt" wrongly
cleared stats for preempting queues when it shouldn't have, because when
we choose a queue to preempt, it still isn't necessarily scheduled next.

Thanks to Vivek Goyal for figuring this out and understanding how the
preemption code works.

Signed-off-by: default avatarJustin TerAvest <teravest@google.com>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
parent 04521db0

block/cfq-iosched.c

+17 −22
Original line number Diff line number Diff line
@@ -1620,9 +1620,12 @@ static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) 
	cfq_blkiocg_update_idle_time_stats(&cfqq->cfqg->blkg);

}



static void cfq_clear_queue_stats(struct cfq_data *cfqd,

static void __cfq_set_active_queue(struct cfq_data *cfqd,

				   struct cfq_queue *cfqq)

{

	if (cfqq) {

		cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d",

				cfqd->serving_prio, cfqd->serving_type);

		cfq_blkiocg_update_avg_queue_size_stats(&cfqq->cfqg->blkg);

		cfqq->slice_start = 0;

		cfqq->dispatch_start = jiffies;
@@ -1640,15 +1643,6 @@ static void cfq_clear_queue_stats(struct cfq_data *cfqd, 
		cfq_del_timer(cfqd, cfqq);

	}



static void __cfq_set_active_queue(struct cfq_data *cfqd,

				   struct cfq_queue *cfqq)

{

	if (cfqq) {

		cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d",

				cfqd->serving_prio, cfqd->serving_type);

		cfq_clear_queue_stats(cfqd, cfqq);

	}



	cfqd->active_queue = cfqq;

}
@@ -3339,7 +3333,8 @@ static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) 


	cfq_service_tree_add(cfqd, cfqq, 1);



	cfq_clear_queue_stats(cfqd, cfqq);

	cfqq->slice_end = 0;

	cfq_mark_cfqq_slice_new(cfqq);

}



/*

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