block, bfq: readd missing reset of parent-entity service (8a511ba5) · Commits · 戴 / test

The received-service counter needs to be equal to 0 when an entity is set in service. Unfortunately, commit "block, bfq: fix service being wrongly set to zero in case of preemption" mistakenly removed the resetting of this counter for the parent entities of the bfq_queue being set in service. This commit fixes this issue by resetting service for parent entities, directly on the expiration of the in-service bfq_queue. Fixes: ("block, bfq: fix service being wrongly set to zero in case of preemption") Signed-off-by:

Paolo Valente <paolo.valente@linaro.org> Signed-off-by:

Jens Axboe <axboe@kernel.dk>

block/bfq-iosched.c

+21 −0

Original line number	Diff line number	Diff line
		@@ -3298,6 +3298,27 @@ void bfq_bfqq_expire(struct bfq_data *bfqd,
		*/
		} else
		entity->service = 0;

		/*
		* Reset the received-service counter for every parent entity.
		* Differently from what happens with bfqq->entity.service,
		* the resetting of this counter never needs to be postponed
		* for parent entities. In fact, in case bfqq may have a
		* chance to go on being served using the last, partially
		* consumed budget, bfqq->entity.service needs to be kept,
		* because if bfqq then actually goes on being served using
		* the same budget, the last value of bfqq->entity.service is
		* needed to properly decrement bfqq->entity.budget by the
		* portion already consumed. In contrast, it is not necessary
		* to keep entity->service for parent entities too, because
		* the bubble up of the new value of bfqq->entity.budget will
		* make sure that the budgets of parent entities are correct,
		* even in case bfqq and thus parent entities go on receiving
		* service with the same budget.
		*/
		entity = entity->parent;
		for_each_entity(entity)
		entity->service = 0;
		}

		/*

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