From: Christoph Hellwig <hch@infradead.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Subject: Re: [PATCH 3/6] blk-mq: embed blk_mq_ops directly in the request queue
Date: Wed, 14 Nov 2018 07:20:53 -0800 [thread overview]
Message-ID: <20181114152053.GA22186@infradead.org> (raw)
In-Reply-To: <20181110151317.3813-4-axboe@kernel.dk>
On Sat, Nov 10, 2018 at 08:13:14AM -0700, Jens Axboe wrote:
> This saves an indirect function call everytime we have to
> call one of the strategy functions. We keep it const, and just
> hack around that a bit in blk_mq_init_allocated_queue(), which
> is where we copy the ops in.
What amount of difference does this patch make?
This really defeats the whole constification, which doesn't hinge
on the const attribute itself, but on having the static ops in
a read-only mapped section. So unless it is a real measurable
and big enough difference I'm against this patch, and if there is
a real an measurable difference we might have to find other ways
to archive this goal.
next prev parent reply other threads:[~2018-11-14 15:20 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-10 15:13 [PATCHSET 0/6] Various block optimizations Jens Axboe
2018-11-10 15:13 ` [PATCH 1/6] nvme: don't disable local ints for polled queue Jens Axboe
2018-11-14 8:43 ` Christoph Hellwig
2018-11-14 15:31 ` Jens Axboe
2018-11-14 15:37 ` Keith Busch
2018-11-14 10:18 ` Max Gurtovoy
2018-11-10 15:13 ` [PATCH 2/6] block: add queue_is_mq() helper Jens Axboe
2018-11-10 15:13 ` [PATCH 3/6] blk-mq: embed blk_mq_ops directly in the request queue Jens Axboe
2018-11-14 15:20 ` Christoph Hellwig [this message]
2018-11-14 15:33 ` Jens Axboe
2018-11-14 15:39 ` Christoph Hellwig
2018-11-14 15:47 ` Jens Axboe
2018-11-14 15:58 ` Christoph Hellwig
2018-11-10 15:13 ` [PATCH 4/6] block: avoid ordered task state change for polled IO Jens Axboe
2018-11-12 9:35 ` jianchao.wang
2018-11-12 16:26 ` Jens Axboe
2018-11-12 16:26 ` Jens Axboe
2018-11-13 2:02 ` jianchao.wang
2018-11-10 15:13 ` [PATCH 5/6] blk-rq-qos: inline check for q->rq_qos functions Jens Axboe
2018-11-14 15:21 ` Christoph Hellwig
2018-11-14 15:33 ` Jens Axboe
2018-11-14 15:40 ` Christoph Hellwig
2018-11-14 17:16 ` Jens Axboe
2018-11-10 15:13 ` [PATCH 6/6] block: add polled wakeup task helper Jens Axboe
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