From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@meta.com>
Cc: linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
joshi.k@samsung.com, axboe@kernel.dk, hch@lst.de,
xiaoguang.wang@linux.alibaba.com, Keith Busch <kbusch@kernel.org>
Subject: Re: [RFC 1/3] nvme: skip block cgroups for passthrough commands
Date: Wed, 3 May 2023 07:04:14 +0200 [thread overview]
Message-ID: <20230503050414.GA19301@lst.de> (raw)
In-Reply-To: <20230501153306.537124-2-kbusch@meta.com>
On Mon, May 01, 2023 at 08:33:04AM -0700, Keith Busch wrote:
> From: Keith Busch <kbusch@kernel.org>
>
> Passthrough requests don't go through the submit_bio() path, so all the
> overhead of setting up the bio's cgroup is wasted cycles. Provide a path
> to skip this setup.
These days we should not need to set bi_bdev at all for passthrough,
so I think we can just drop the assingment.
But instead of just optimizing for passthrough we really need to optimize
this assignment and get rid of the cost entirely. What is so expensive
about the cgroup lookup? Is this even for a device that uses cgroups
at all, or could we come up with a flag to bypass all the lookup unless
cgroup are anbled?
next prev parent reply other threads:[~2023-05-03 5:04 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20230501154403epcas5p388c607114ad6f9d20dfd3ec958d88947@epcas5p3.samsung.com>
2023-05-01 15:33 ` [RFC 0/3] nvme uring passthrough diet Keith Busch
2023-05-01 15:33 ` [RFC 1/3] nvme: skip block cgroups for passthrough commands Keith Busch
2023-05-03 5:04 ` Christoph Hellwig [this message]
2023-05-03 15:25 ` Keith Busch
2023-05-15 15:47 ` Keith Busch
2023-05-01 15:33 ` [RFC 2/3] nvme: fix cdev name leak Keith Busch
2023-05-01 15:33 ` [RFC 3/3] nvme: create special request queue for cdev Keith Busch
2023-05-02 12:20 ` Johannes Thumshirn
2023-05-03 5:04 ` Christoph Hellwig
2023-05-03 14:56 ` Keith Busch
2023-05-01 19:01 ` [RFC 0/3] nvme uring passthrough diet Kanchan Joshi
2023-05-01 19:31 ` Keith Busch
2023-05-03 7:27 ` Kanchan Joshi
2023-05-03 15:20 ` Keith Busch
2023-05-05 8:14 ` Kanchan Joshi
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