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Thu, 13 Jun 2024 16:15:13 +0000 (UTC) Message-ID: <97a2b888-4dac-451c-bb9c-40d8dc52cd60@acm.org> Date: Thu, 13 Jun 2024 09:15:11 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC -next 0/7] blk-iocost: support to build iocost as kernel module To: Greg KH , Yu Kuai Cc: axboe@kernel.dk, tj@kernel.org, josef@toxicpanda.com, lizefan.x@bytedance.com, hannes@cmpxchg.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, yukuai3@huawei.com, yi.zhang@huawei.com, yangerkun@huawei.com References: <20240613014937.1326020-1-yukuai1@huaweicloud.com> <2024061342-walk-cavalier-7e48@gregkh> Content-Language: en-US From: Bart Van Assche In-Reply-To: <2024061342-walk-cavalier-7e48@gregkh> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 6/12/24 10:54 PM, Greg KH wrote: > On Thu, Jun 13, 2024 at 09:49:30AM +0800, Yu Kuai wrote: >> From: Yu Kuai >> >> Yu Kuai (7): >> kernfs: export pr_cont_kernfs_path() >> cgroup: export cgroup_parse_float >> block: export some API >> blk-iocost: factor out helpers to handle params from ioc_qos_write() >> blk-iocost: parse params before initializing iocost >> blk-iocost: support to free iocost >> blk-iocost: support to build iocost as kernel module > > No where do you say _why_ building this as a module is a good idea. > > Why do this at all? With CONFIG_BLK_CGROUP_IOCOST=y (as in the Android kernel), the blk-iocost kernel module causes a (small) runtime overhead, even if it is not being used. Thanks, Bart.