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block, bfq: fix delayed stable merge check 

When attempting to schedule a merge of a given bfq_queue with the currently
in-service bfq_queue or with a cooperating bfq_queue among the scheduled
bfq_queues, delayed stable merge is checked for rotational or non-queueing
devs. For this stable merge to be performed, some conditions must be met.
If the current bfq_queue underwent some split from some merged bfq_queue,
one of these conditions is that two hundred milliseconds must elapse from
split, otherwise this condition is always met.

Unfortunately, by mistake, time_is_after_jiffies() was written instead of
time_is_before_jiffies() for this check, verifying that less than two
hundred milliseconds have elapsed instead of verifying that at least two
hundred milliseconds have elapsed.

Fix this issue by replacing time_is_after_jiffies() with
time_is_before_jiffies().

Signed-off-by: Luca Mariotti <mariottiluca1@hotmail.it>
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Pietro Pedroni <pedroni.pietro.96@gmail.com>
Link: https://lore.kernel.org/r/20210619140948.98712-3-paolo.valente@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Luca Mariotti 2021-06-19 16:09:43 +02:00 committed by Jens Axboe
parent 511a269923
commit e03f2ab78a
1 changed files with 1 additions and 1 deletions
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2
block/bfq-iosched.c
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@ -2710,7 +2710,7 @@ bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq,
if (unlikely(!bfqd->nonrot_with_queueing)) {
if (bic->stable_merge_bfqq &&
!bfq_bfqq_just_created(bfqq) &&
time_is_after_jiffies(bfqq->split_time +
time_is_before_jiffies(bfqq->split_time +
msecs_to_jiffies(200))) {
struct bfq_queue *stable_merge_bfqq =
bic->stable_merge_bfqq;