From: Jens Axboe <axboe@kernel.dk>
To: Gabriel Krisman Bertazi <krisman@collabora.com>
Cc: linux-block@vger.kernel.org, kernel@collabora.com
Subject: Re: [PATCH] block: Fix inflight statistic for MQ submission with !elevator
Date: Mon, 31 Aug 2020 09:33:55 -0600 [thread overview]
Message-ID: <7a4669a1-7633-6acc-e06d-86992245dfee@kernel.dk> (raw)
In-Reply-To: <20200831153127.3561733-1-krisman@collabora.com>
On 8/31/20 9:31 AM, Gabriel Krisman Bertazi wrote:
> According to Documentation/block/stat.rst, inflight should not include
> I/O requests that are in the queue but not yet dispatched to the device,
> but blk-mq identifies as inflight any request that has a tag allocated,
> which, for queues without elevator, happens at request allocation time
> and before it is queued in the ctx (default case in blk_mq_submit_bio).
>
> A more precise approach would be to only consider requests with state
> MQ_RQ_IN_FLIGHT.
We've had some churn here, last change in this area was:
commit 6131837b1de66116459ef4413e26fdbc70d066dc
Author: Omar Sandoval <osandov@fb.com>
Date: Thu Apr 26 00:21:58 2018 -0700
blk-mq: count allocated but not started requests in iostats inflight
which your patch basically just reverts. So more testing/explanation
needed on why it's necessary.
--
Jens Axboe
next prev parent reply other threads:[~2020-08-31 15:34 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-31 15:31 [PATCH] block: Fix inflight statistic for MQ submission with !elevator Gabriel Krisman Bertazi
2020-08-31 15:33 ` Jens Axboe [this message]
2020-08-31 15:50 ` Gabriel Krisman Bertazi
2020-09-01 1:18 ` Ming Lei
2020-09-01 3:42 ` Jens Axboe
2020-09-01 6:36 ` Ming Lei
2020-09-01 22:37 ` Jens Axboe
2020-09-01 18:37 ` Gabriel Krisman Bertazi
2020-09-01 22:39 ` Jens Axboe
2020-09-02 20:19 ` [PATCH v2] block: Consider only dispatched requests for inflight statistic Gabriel Krisman Bertazi
2020-09-15 16:11 ` Gabriel Krisman Bertazi
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