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block, bfq: give a better name to bfq_bfqq_may_idle

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The actual goal of the function bfq_bfqq_may_idle is to tell whether
it is better to perform device idling (more precisely: I/O-dispatch
plugging) for the input bfq_queue, either to boost throughput or to
preserve service guarantees. This commit improves the name of the
function accordingly.

Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Paolo Valente 2018-06-25 21:55:37 +02:00 committed by Jens Axboe
parent 9fae8dd59f
commit 277a4a9b56
1 changed files with 8 additions and 8 deletions
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16
block/bfq-iosched.c
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@ -634,7 +634,7 @@ static bool bfq_differentiated_weights(struct bfq_data *bfqd)
* The following function returns true if every queue must receive the
* same share of the throughput (this condition is used when deciding
* whether idling may be disabled, see the comments in the function
* bfq_bfqq_may_idle()).
* bfq_better_to_idle()).
*
* Such a scenario occurs when:
* 1) all active queues have the same weight,
@ -3355,7 +3355,7 @@ static bool bfq_may_expire_for_budg_timeout(struct bfq_queue *bfqq)
* issues taken into account are not trivial. We discuss these issues
* individually while introducing the variables.
*/
static bool bfq_bfqq_may_idle(struct bfq_queue *bfqq)
static bool bfq_better_to_idle(struct bfq_queue *bfqq)
{
struct bfq_data *bfqd = bfqq->bfqd;
bool rot_without_queueing =
@ -3588,19 +3588,19 @@ static bool bfq_bfqq_may_idle(struct bfq_queue *bfqq)
}
/*
* If the in-service queue is empty but the function bfq_bfqq_may_idle
* If the in-service queue is empty but the function bfq_better_to_idle
* returns true, then:
* 1) the queue must remain in service and cannot be expired, and
* 2) the device must be idled to wait for the possible arrival of a new
* request for the queue.
* See the comments on the function bfq_bfqq_may_idle for the reasons
* See the comments on the function bfq_better_to_idle for the reasons
* why performing device idling is the best choice to boost the throughput
* and preserve service guarantees when bfq_bfqq_may_idle itself
* and preserve service guarantees when bfq_better_to_idle itself
* returns true.
*/
static bool bfq_bfqq_must_idle(struct bfq_queue *bfqq)
{
return RB_EMPTY_ROOT(&bfqq->sort_list) && bfq_bfqq_may_idle(bfqq);
return RB_EMPTY_ROOT(&bfqq->sort_list) && bfq_better_to_idle(bfqq);
}
/*
@ -3686,7 +3686,7 @@ static struct bfq_queue *bfq_select_queue(struct bfq_data *bfqd)
* may idle after their completion, then keep it anyway.
*/
if (bfq_bfqq_wait_request(bfqq) ||
(bfqq->dispatched != 0 && bfq_bfqq_may_idle(bfqq))) {
(bfqq->dispatched != 0 && bfq_better_to_idle(bfqq))) {
bfqq = NULL;
goto keep_queue;
}
@ -4734,7 +4734,7 @@ static void bfq_completed_request(struct bfq_queue *bfqq, struct bfq_data *bfqd)
BFQQE_BUDGET_TIMEOUT);
else if (RB_EMPTY_ROOT(&bfqq->sort_list) &&
(bfqq->dispatched == 0 ||
!bfq_bfqq_may_idle(bfqq)))
!bfq_better_to_idle(bfqq)))
bfq_bfqq_expire(bfqd, bfqq, false,
BFQQE_NO_MORE_REQUESTS);
}