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Date: Thu, 18 Apr 2024 20:21:53 +0800
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Subject: Re: [PATCH] blk-iocost: do not WARNING if iocg has already offlined
To: Yu Kuai <yukuai1@huaweicloud.com>, linan666@huaweicloud.com,
 tj@kernel.org, josef@toxicpanda.com, axboe@kernel.dk
Cc: hch@lst.de, cgroups@vger.kernel.org, linux-block@vger.kernel.org,
 linux-kernel@vger.kernel.org, yi.zhang@huawei.com, houtao1@huawei.com,
 yangerkun@huawei.com, "yukuai (C)" <yukuai3@huawei.com>
References: <20240418072340.2090877-1-linan666@huaweicloud.com>
 <75a8212a-a6ff-416c-7bce-0f4036a4abc0@huaweicloud.com>
From: Li Nan <linan666@huaweicloud.com>
In-Reply-To: <75a8212a-a6ff-416c-7bce-0f4036a4abc0@huaweicloud.com>
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在 2024/4/18 16:52, Yu Kuai 写道:
> 
> 
> 在 2024/04/18 15:23, linan666@huaweicloud.com 写道:
>> From: Li Nan <linan122@huawei.com>
>>
>> In iocg_pay_debt(), warn is triggered if 'active_list' is empty, which
>> is intended to confirm iocg is avitve when it has debt. However, warn
>> can be triggered during removing cgroup controller, as
>> iocg_waitq_timer_fn() is awakened at that time.
>>
>>    WARNING: CPU: 0 PID: 2344971 at block/blk-iocost.c:1402 
>> iocg_pay_debt+0x14c/0x190
> 
> This line doesn't match the code from mainline, please mention that
> which kernel release you're testing.
> 

Thanks for your review.
I tested at 5.10, but mainline has the same issue.

> Other than that, ioc_pd_free() indeed clear 'active_list' before
> canceling the timer, this patch looks good to me.
> 
> Reviewed-by: Yu Kuai <yukuai3@huawei.com>

-- 
Thanks,
Nan