From: Niklas Cassel <Niklas.Cassel@wdc.com>
To: Bart Van Assche <bvanassche@acm.org>
Cc: Jens Axboe <axboe@kernel.dk>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
Christoph Hellwig <hch@lst.de>, Jaegeuk Kim <jaegeuk@kernel.org>,
Damien Le Moal <Damien.LeMoal@wdc.com>,
Hannes Reinecke <hare@suse.de>
Subject: Re: [PATCH 1/4] block/mq-deadline: Improve request accounting further
Date: Mon, 27 Sep 2021 15:53:29 +0000 [thread overview]
Message-ID: <YVHo90gFgIpvjdSW@x1-carbon> (raw)
In-Reply-To: <20210923232655.3907383-1-bvanassche@acm.org>
On Thu, Sep 23, 2021 at 04:26:52PM -0700, Bart Van Assche wrote:
> The scheduler .insert_requests() callback is called when a request is
> queued for the first time and also when it is requeued. Only count a
> request the first time it is queued. Additionally, since the mq-deadline
> scheduler only performs zone locking for requests that have been
> inserted, skip the zone unlock code for requests that have not been
> inserted into the mq-deadline scheduler.
>
> Fixes: 38ba64d12d4c ("block/mq-deadline: Track I/O statistics")
> Cc: Damien Le Moal <damien.lemoal@wdc.com>
> Cc: Niklas Cassel <Niklas.Cassel@wdc.com>
> Cc: Hannes Reinecke <hare@suse.de>
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> ---
> block/mq-deadline.c | 17 ++++++++++-------
> 1 file changed, 10 insertions(+), 7 deletions(-)
>
> diff --git a/block/mq-deadline.c b/block/mq-deadline.c
> index 7f3c3932b723..b1175e4560ad 100644
> --- a/block/mq-deadline.c
> +++ b/block/mq-deadline.c
> @@ -677,8 +677,10 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
> blk_req_zone_write_unlock(rq);
>
> prio = ioprio_class_to_prio[ioprio_class];
> - dd_count(dd, inserted, prio);
> - rq->elv.priv[0] = (void *)(uintptr_t)1;
> + if (!rq->elv.priv[0]) {
> + dd_count(dd, inserted, prio);
> + rq->elv.priv[0] = (void *)(uintptr_t)1;
> + }
>
> if (blk_mq_sched_try_insert_merge(q, rq, &free)) {
> blk_mq_free_requests(&free);
> @@ -759,12 +761,13 @@ static void dd_finish_request(struct request *rq)
>
> /*
> * The block layer core may call dd_finish_request() without having
> - * called dd_insert_requests(). Hence only update statistics for
> - * requests for which dd_insert_requests() has been called. See also
> - * blk_mq_request_bypass_insert().
> + * called dd_insert_requests(). Skip requests that bypassed I/O
> + * scheduling. See also blk_mq_request_bypass_insert().
> */
> - if (rq->elv.priv[0])
> - dd_count(dd, completed, prio);
> + if (!rq->elv.priv[0])
> + return;
> +
> + dd_count(dd, completed, prio);
>
> if (blk_queue_is_zoned(q)) {
> unsigned long flags;
Reviewed-by: Niklas Cassel <niklas.cassel@wdc.com>
prev parent reply other threads:[~2021-09-27 15:53 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-23 23:23 [PATCH 0/4] Restore I/O priority support in the mq-deadline scheduler Bart Van Assche
2021-09-23 23:26 ` [PATCH 1/4] block/mq-deadline: Improve request accounting further Bart Van Assche
2021-09-23 23:26 ` [PATCH 2/4] block/mq-deadline: Add an invariant check Bart Van Assche
2021-09-24 10:54 ` Damien Le Moal
2021-09-27 15:53 ` Niklas Cassel
2021-09-23 23:26 ` [PATCH 3/4] block/mq-deadline: Stop using per-CPU counters Bart Van Assche
2021-09-24 10:58 ` Damien Le Moal
2021-09-25 2:59 ` Bart Van Assche
2021-09-27 0:19 ` Damien Le Moal
2021-09-27 2:38 ` Bart Van Assche
2021-09-27 3:41 ` Damien Le Moal
2021-09-27 15:53 ` Niklas Cassel
2021-09-23 23:26 ` [PATCH 4/4] block/mq-deadline: Prioritize high-priority requests Bart Van Assche
2021-09-24 11:08 ` Damien Le Moal
2021-09-27 20:03 ` Bart Van Assche
2021-09-24 10:54 ` [PATCH 1/4] block/mq-deadline: Improve request accounting further Damien Le Moal
2021-09-27 15:53 ` Niklas Cassel [this message]
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