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| author | Paolo Valente <paolo.valente@linaro.org> | 2018-08-16 18:51:15 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-08-16 21:08:10 +0200 |
| commit | 8a511ba5feec5947bee0635cff8bd796d5f77e3e (patch) | |
| tree | 207364ee03acae3e83532d35146021316202f40b /block | |
| parent | blk-wbt: fix IO hang in wbt_wait() (diff) | |
| download | linux-8a511ba5feec5947bee0635cff8bd796d5f77e3e.tar.xz linux-8a511ba5feec5947bee0635cff8bd796d5f77e3e.zip | |
block, bfq: readd missing reset of parent-entity service
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: 9fae8dd59ff3 ("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>
Diffstat (limited to 'block')
| -rw-r--r-- | block/bfq-iosched.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 41d9036b1822..62efc1b97afb 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -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; } /* |