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Date: Fri, 12 Jan 2024 15:25:09 +0100
From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>, Ming Lei <ming.lei@redhat.com>,
	linux-block@vger.kernel.org, Ulf Hansson <ulf.hansson@linaro.org>,
	linux-mmc@vger.kernel.org
Subject: Re: [PATCH 2/2] blk-mq: ensure a q_usage_counter reference is held
 when splitting bios
Message-ID: <20240112142509.GA6899@lst.de>
References: <20240112054449.GA6829@lst.de> <9eb0f18e-f3ce-497c-931d-339efee2190d@kernel.dk>
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On Fri, Jan 12, 2024 at 07:22:18AM -0700, Jens Axboe wrote:
> Yep it is pretty cheap, but it's not free. Here's a test where we just
> grab a ref and drop it, which should arguably be cheaper than doing a
> ref at the top and dropping it at the bottom due to temporal locality:
> 
>      5.01%     +0.86%  [kernel.vmlinux]  [k] blk_mq_submit_bio

Ok.  Do you want to send out your version formally?