From: Paolo Valente <paolo.valente@linaro.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
ulf.hansson@linaro.org, linus.walleij@linaro.org,
broonie@kernel.org, bfq-iosched@googlegroups.com,
oleksandr@natalenko.name, fra.fra.800@gmail.com,
alessio.masola@gmail.com, holger@applied-asynchrony.com,
Paolo Valente <paolo.valente@linaro.org>
Subject: [PATCH BUGFIX IMPROVEMENT V3 8/9] block, bfq: save & resume weight on a queue merge/split
Date: Tue, 12 Mar 2019 09:59:34 +0100 [thread overview]
Message-ID: <20190312085935.11340-9-paolo.valente@linaro.org> (raw)
In-Reply-To: <20190312085935.11340-1-paolo.valente@linaro.org>
From: Francesco Pollicino <fra.fra.800@gmail.com>
bfq saves the state of a queue each time a merge occurs, to be
able to resume such a state when the queue is associated again
with its original process, on a split.
Unfortunately bfq does not save & restore also the weight of the
queue. If the weight is not correctly resumed when the queue is
recycled, then the weight of the recycled queue could differ
from the weight of the original queue.
This commit adds the missing save & resume of the weight.
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Francesco Pollicino <fra.fra.800@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
---
block/bfq-iosched.c | 2 ++
block/bfq-iosched.h | 9 +++++++++
2 files changed, 11 insertions(+)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 7d95d9c01036..1712d12340c0 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -1028,6 +1028,7 @@ bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_data *bfqd,
else
bfq_clear_bfqq_IO_bound(bfqq);
+ bfqq->entity.new_weight = bic->saved_weight;
bfqq->ttime = bic->saved_ttime;
bfqq->wr_coeff = bic->saved_wr_coeff;
bfqq->wr_start_at_switch_to_srt = bic->saved_wr_start_at_switch_to_srt;
@@ -2502,6 +2503,7 @@ static void bfq_bfqq_save_state(struct bfq_queue *bfqq)
if (!bic)
return;
+ bic->saved_weight = bfqq->entity.orig_weight;
bic->saved_ttime = bfqq->ttime;
bic->saved_has_short_ttime = bfq_bfqq_has_short_ttime(bfqq);
bic->saved_IO_bound = bfq_bfqq_IO_bound(bfqq);
diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
index 67e63c276c7a..60c148728cc5 100644
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -404,6 +404,15 @@ struct bfq_io_cq {
*/
bool was_in_burst_list;
+ /*
+ * Save the weight when a merge occurs, to be able
+ * to restore it in case of split. If the weight is not
+ * correctly resumed when the queue is recycled,
+ * then the weight of the recycled queue could differ
+ * from the weight of the original queue.
+ */
+ unsigned int saved_weight;
+
/*
* Similar to previous fields: save wr information.
*/
--
2.20.1
next prev parent reply other threads:[~2019-03-12 9:00 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-12 8:59 [PATCH BUGFIX IMPROVEMENT V3 0/9] lock, bfq: fix bugs, reduce exec time and boost performance Paolo Valente
2019-03-12 8:59 ` [PATCH BUGFIX IMPROVEMENT V3 1/9] block, bfq: increase idling for weight-raised queues Paolo Valente
2019-03-12 8:59 ` [PATCH BUGFIX IMPROVEMENT V3 2/9] block, bfq: do not idle for lowest-weight queues Paolo Valente
2019-03-12 8:59 ` [PATCH BUGFIX IMPROVEMENT V3 3/9] block, bfq: tune service injection basing on request service times Paolo Valente
2019-03-12 8:59 ` [PATCH BUGFIX IMPROVEMENT V3 4/9] block, bfq: do not merge queues on flash storage with queueing Paolo Valente
2019-03-12 8:59 ` [PATCH BUGFIX IMPROVEMENT V3 5/9] block, bfq: do not tag totally seeky queues as soft rt Paolo Valente
2019-03-12 8:59 ` [PATCH BUGFIX IMPROVEMENT V3 6/9] block, bfq: always protect newly-created queues from existing active queues Paolo Valente
2019-03-12 8:59 ` [PATCH BUGFIX IMPROVEMENT V3 7/9] block, bfq: print SHARED instead of pid for shared queues in logs Paolo Valente
2019-03-12 8:59 ` Paolo Valente [this message]
2019-03-12 8:59 ` [PATCH BUGFIX IMPROVEMENT V3 9/9] doc, block, bfq: add information on bfq execution time Paolo Valente
2019-03-26 11:53 ` [PATCH BUGFIX IMPROVEMENT V3 0/9] lock, bfq: fix bugs, reduce exec time and boost performance Paolo Valente
2019-03-26 14:13 ` Jens Axboe
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