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Subject: Re: [PATCH RFC -next 0/7] blk-iocost: support to build iocost as
 kernel module
To: Greg KH <gregkh@linuxfoundation.org>, Yu Kuai <yukuai1@huaweicloud.com>
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, yi.zhang@huawei.com,
 yangerkun@huawei.com, "yukuai (C)" <yukuai3@huawei.com>
References: <20240613014937.1326020-1-yukuai1@huaweicloud.com>
 <2024061342-walk-cavalier-7e48@gregkh>
From: Yu Kuai <yukuai1@huaweicloud.com>
Message-ID: <278e27fd-ff5f-660a-5173-b0cff6c55821@huaweicloud.com>
Date: Thu, 13 Jun 2024 14:53:49 +0800
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Hi,

?? 2024/06/13 13:54, Greg KH д??:
> On Thu, Jun 13, 2024 at 09:49:30AM +0800, Yu Kuai wrote:
>> From: Yu Kuai <yukuai3@huawei.com>
>>
>> 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.

Yes, we discussed this before and this is actually an general question.
Main advantages are:

- Flexibility and Maintainability, allows for dynamic loading and
unloading of modules at runtime without the need to recompile and
restart the kernel, for example fixing iocost CVE in our production
environment.

- Kernel Size and Resource Usage, modules are loaded only when their
specific functionality is required.

Thanks,
Kuai

> 
> Why do this at all?
> 
> thanks,
> 
> greg k-h
> 
> .
>