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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: Justin TerAvest <teravest@google.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This commit is contained in:
Justin TerAvest 2011-03-23 08:25:44 +01:00 committed by Jens Axboe
parent 04521db04e
commit 62a37f6bad
1 changed files with 17 additions and 22 deletions
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39
block/cfq-iosched.c
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@ -1620,33 +1620,27 @@ 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,
struct cfq_queue *cfqq)
{
cfq_blkiocg_update_avg_queue_size_stats(&cfqq->cfqg->blkg);
cfqq->slice_start = 0;
cfqq->dispatch_start = jiffies;
cfqq->allocated_slice = 0;
cfqq->slice_end = 0;
cfqq->slice_dispatch = 0;
cfqq->nr_sectors = 0;
cfq_clear_cfqq_wait_request(cfqq);
cfq_clear_cfqq_must_dispatch(cfqq);
cfq_clear_cfqq_must_alloc_slice(cfqq);
cfq_clear_cfqq_fifo_expire(cfqq);
cfq_mark_cfqq_slice_new(cfqq);
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);
cfq_blkiocg_update_avg_queue_size_stats(&cfqq->cfqg->blkg);
cfqq->slice_start = 0;
cfqq->dispatch_start = jiffies;
cfqq->allocated_slice = 0;
cfqq->slice_end = 0;
cfqq->slice_dispatch = 0;
cfqq->nr_sectors = 0;
cfq_clear_cfqq_wait_request(cfqq);
cfq_clear_cfqq_must_dispatch(cfqq);
cfq_clear_cfqq_must_alloc_slice(cfqq);
cfq_clear_cfqq_fifo_expire(cfqq);
cfq_mark_cfqq_slice_new(cfqq);
cfq_del_timer(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);
}
/*