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From:   Jens Axboe <axboe@kernel.dk>
To:     linux-block@vger.kernel.org, Hou Tao <houtao@huaweicloud.com>
Cc:     Bart Van Assche <bvanassche@acm.org>, Jan Kara <jack@suse.cz>,
        Bagas Sanjaya <bagasdotme@gmail.com>,
        Chaitanya Kulkarni <kch@nvidia.com>, cgroups@vger.kernel.org,
        Tejun Heo <tj@kernel.org>, Zefan Li <lizefan.x@bytedance.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Jonathan Corbet <corbet@lwn.net>, linux-kernel@vger.kernel.org,
        linux-doc@vger.kernel.org, houtao1@huawei.com
In-Reply-To: <20230428074404.280532-1-houtao@huaweicloud.com>
References: <20230428074404.280532-1-houtao@huaweicloud.com>
Subject: Re: [PATCH v4] blk-ioprio: Introduce promote-to-rt policy
Message-Id: <168611202214.121141.17298993524876974749.b4-ty@kernel.dk>
Date:   Tue, 06 Jun 2023 22:27:02 -0600
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Precedence: bulk


On Fri, 28 Apr 2023 15:44:04 +0800, Hou Tao wrote:
> Since commit a78418e6a04c ("block: Always initialize bio IO priority on
> submit"), bio->bi_ioprio will never be IOPRIO_CLASS_NONE when calling
> blkcg_set_ioprio(), so there will be no way to promote the io-priority
> of one cgroup to IOPRIO_CLASS_RT, because bi_ioprio will always be
> greater than or equals to IOPRIO_CLASS_RT.
> 
> It seems possible to call blkcg_set_ioprio() first then try to
> initialize bi_ioprio later in bio_set_ioprio(), but this doesn't work
> for bio in which bi_ioprio is already initialized (e.g., direct-io), so
> introduce a new promote-to-rt policy to promote the iopriority of bio to
> IOPRIO_CLASS_RT if the ioprio is not already RT.
> 
> [...]

Applied, thanks!

[1/1] blk-ioprio: Introduce promote-to-rt policy
      commit: ddf63516d8d37528dc6834c7f19b55084e956068

Best regards,
-- 
Jens Axboe