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Subject: Re: [patch v11 0/6] support concurrent sync io for bfq on a specail
 occasion
To:     Yu Kuai <yukuai1@huaweicloud.com>, tj@kernel.org, axboe@kernel.dk,
        paolo.valente@linaro.org, jack@suse.cz
Cc:     cgroups@vger.kernel.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, yi.zhang@huawei.com,
        "yukuai (C)" <yukuai3@huawei.com>
References: <20220916071942.214222-1-yukuai1@huaweicloud.com>
From:   Yu Kuai <yukuai1@huaweicloud.com>
Message-ID: <b2099166-5386-d60b-0b31-e5cd40ef97da@huaweicloud.com>
Date:   Tue, 1 Nov 2022 19:32:45 +0800
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Hi, Jens

?? 2022/09/16 15:19, Yu Kuai д??:
> From: Yu Kuai <yukuai3@huawei.com>
>
> 
> Currently, bfq can't handle sync io concurrently as long as they
> are not issued from root group. This is because
> 'bfqd->num_groups_with_pending_reqs > 0' is always true in
> bfq_asymmetric_scenario().
> 
> The way that bfqg is counted into 'num_groups_with_pending_reqs':
> 
> Before this patchset:
>   1) root group will never be counted.
>   2) Count if bfqg or it's child bfqgs have pending requests.
>   3) Don't count if bfqg and it's child bfqgs complete all the requests.
> 
> After this patchset:
>   1) root group is counted.
>   2) Count if bfqg has pending requests.
>   3) Don't count if bfqg complete all the requests.
> 
> With the above changes, concurrent sync io can be supported if only
> one group is activated.

Can you apply this patchset?

Thanks,
Kuai