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Date:   Tue, 22 Feb 2022 00:12:15 -0800
From:   Christoph Hellwig <hch@infradead.org>
To:     Wang Jianchao <jianchao.wan9@gmail.com>
Cc:     Christoph Hellwig <hch@infradead.org>,
        Jens Axboe <axboe@kernel.dk>, Josef Bacik <jbacik@fb.com>,
        Tejun Heo <tj@kernel.org>,
        Bart Van Assche <bvanassche@acm.org>,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC V4 2/6] blk-wbt: make wbt pluggable
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On Fri, Feb 18, 2022 at 11:41:11AM +0800, Wang Jianchao wrote:
> 
> 
> On 2022/2/17 4:50 下午, Christoph Hellwig wrote:
> >> +struct rq_qos *wbt_rq_qos(struct request_queue *q);
> >>  int wbt_init(struct request_queue *);
> > 
> > 
> > Please move the wb_lat sysfs attribute into blk-wbt.c as well, which
> > removes the need to expose these two functions.
> > 
> 
> Given this patchset:
> (1) Do we need to reserve the wb_lat sysfs when we turn off the wbt ?
> (2) Do we need to disable wbt automatically when switch io scheduler
>     to bfq ? Or just tell the user turn off the wbt by themselves ?

I don't think this needs any changes to what is done there today,
i.e. keep the sysfs attribute around.