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cfq-iosched: don't schedule a dispatch for a non-idle queue

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Vivek suggests we don't need schedule a dispatch when an idle queue
becomes nonidle. And he is right, cfq_should_preempt already covers
the logic.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This commit is contained in:
Shaohua Li 2010-11-09 14:51:13 +01:00 committed by Jens Axboe
parent 8e1ac66551
commit 2b9408a459
1 changed files with 1 additions and 18 deletions
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19
block/cfq-iosched.c
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@ -3523,25 +3523,8 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
} }
} }
if (!cfqd->rq_in_driver) { if (!cfqd->rq_in_driver)
cfq_schedule_dispatch(cfqd); cfq_schedule_dispatch(cfqd);
return;
}
/*
* A queue is idle at cfq_dispatch_requests(), but it gets noidle
* later. We schedule a dispatch if the queue has no requests,
* otherwise the disk is actually in idle till all requests
* are finished even cfq_arm_slice_timer doesn't make the queue idle
* */
cfqq = cfqd->active_queue;
if (!cfqq)
return;
if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq) &&
(!cfqd->cfq_group_idle || cfqq->cfqg->nr_cfqq > 1)) {
cfq_del_timer(cfqd, cfqq);
cfq_schedule_dispatch(cfqd);
}
} }
/* /*