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Subject: Re: [PATCH BUGFIX] block, bfq: deschedule empty bfq_queues not
 referred by any process
From:   Paolo Valente <paolo.valente@linaro.org>
In-Reply-To: <5b0b07fc8e50a1beac215230ca84d955@natalenko.name>
Date:   Thu, 14 Nov 2019 10:23:24 +0100
Cc:     Jens Axboe <axboe@kernel.dk>,
        linux-block <linux-block@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Ulf Hansson <ulf.hansson@linaro.org>, linus.walleij@linaro.org,
        bfq-iosched@googlegroups.com, Chris Evich <cevich@redhat.com>,
        Patrick Dung <patdung100@gmail.com>,
        Thorsten Schubert <tschubert@bafh.org>
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Message-Id: <C824EC38-887E-45DB-A629-A75E99ED7454@linaro.org>
References: <20191112074856.40433-1-paolo.valente@linaro.org>
 <bb393dcaa426786e0963cf0e70f0b062@natalenko.name>
 <2FB3736A-693E-44B9-9D1F-39AE0D016644@linaro.org>
 <65fc0bffbcb2296d121b3d5a79108e76@natalenko.name>
 <5773ff54421ccf179ef57d96e19ef042@natalenko.name>
 <69B451DE-B04B-4E0E-9464-826C4A7619AD@linaro.org>
 <5b0b07fc8e50a1beac215230ca84d955@natalenko.name>
To:     Oleksandr Natalenko <oleksandr@natalenko.name>
Sender: linux-kernel-owner@vger.kernel.org
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> Il giorno 14 nov 2019, alle ore 09:53, Oleksandr Natalenko =
<oleksandr@natalenko.name> ha scritto:
>=20
> Hi.
>=20
> On 13.11.2019 18:42, Paolo Valente wrote:
>>> Il giorno 13 nov 2019, alle ore 16:01, Oleksandr Natalenko =
<oleksandr@natalenko.name> ha scritto:
>> Ok, you may have given me enough information, thank you very much.
>> Could you please apply the attached (compressed) patch on top of my
>> offending patch?  For review purposes, here is the simple change:
>> --- a/block/bfq-iosched.c
>> +++ b/block/bfq-iosched.c
>> @@ -2728,7 +2728,8 @@ void bfq_release_process_ref(struct bfq_data
>> *bfqd, struct bfq_queue *bfqq)
>>         * freed when dequeued from service. But this is assumed to
>>         * never happen.
>>         */
>> -       if (bfq_bfqq_busy(bfqq) && RB_EMPTY_ROOT(&bfqq->sort_list))
>> +       if (bfq_bfqq_busy(bfqq) && RB_EMPTY_ROOT(&bfqq->sort_list) &&
>> +           bfqq !=3D bfqd->in_service_queue)
>>                bfq_del_bfqq_busy(bfqd, bfqq, false);
>>        bfq_put_queue(bfqq);
>=20
> The issue is not reproducible for me after applying this patch.
>=20

Great! I'm sending a V2 with your Tested-by.

Thank you,
Paolo

> Thank you.
>=20
> --=20
>  Oleksandr Natalenko (post-factum)