From: Jan Kara <jack@suse.cz>
To: "yukuai (C)" <yukuai3@huawei.com>
Cc: Jan Kara <jack@suse.cz>,
tj@kernel.org, axboe@kernel.dk, paolo.valente@linaro.org,
fchecconi@gmail.com, avanzini.arianna@gmail.com,
cgroups@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, yi.zhang@huawei.com
Subject: Re: [PATCH 2/4] block, bfq: avoid moving bfqq to it's parent bfqg
Date: Tue, 21 Dec 2021 12:52:47 +0100 [thread overview]
Message-ID: <20211221115247.GE24748@quack2.suse.cz> (raw)
In-Reply-To: <d1c91a5f-33f3-ffad-e1ad-fb91482eb864@huawei.com>
On Tue 21-12-21 19:08:44, yukuai (C) wrote:
> 在 2021/12/21 18:16, Jan Kara 写道:
> > On Tue 21-12-21 11:21:33, Yu Kuai wrote:
> > > Moving bfqq to it's parent bfqg is pointless.
> > >
> > > Signed-off-by: Yu Kuai <yukuai3@huawei.com>
> >
> > Did you notice that this is happening often enough that the check is worth
> > it? Where do we do this?
> >
>
> I noticed that this will happend when root group is offlined:
>
> bfq_pd_offline
> bfq_put_async_queues
> __bfq_put_async_bfqq
> bfq_bfqq_move
>
> I'm not sure if there are other situations. I think bfq_bfqq_move()
> is not happening often itself, thus the checking won't affect
> performance.
Yeah, OK, I was just wondering. I guess there's no harm in doing this
check. Maybe add a comment that this can sometimes happen when dealing with
the root cgroup. And then feel free to add:
Reviewed-by: Jan Kara <jack@suse.cz>
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2021-12-21 11:52 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-21 3:21 [PATCH 0/4] block, bfq: minor cleanup and fix Yu Kuai
2021-12-21 3:21 ` [PATCH 1/4] block, bfq: cleanup bfq_bfqq_to_bfqg() Yu Kuai
2021-12-21 10:15 ` Jan Kara
2021-12-21 3:21 ` [PATCH 2/4] block, bfq: avoid moving bfqq to it's parent bfqg Yu Kuai
2021-12-21 10:16 ` Jan Kara
2021-12-21 11:08 ` yukuai (C)
2021-12-21 11:52 ` Jan Kara [this message]
2021-12-21 3:21 ` [PATCH 3/4] block, bfq: don't move oom_bfqq Yu Kuai
2021-12-21 10:18 ` Jan Kara
2021-12-21 3:21 ` [PATCH 4/4] block, bfq: update pos_root for idle bfq_queue in bfq_bfqq_move() Yu Kuai
2021-12-21 11:50 ` Jan Kara
2021-12-22 3:12 ` yukuai (C)
2021-12-22 14:17 ` Jan Kara
2021-12-23 1:03 ` yukuai (C)
2021-12-25 1:19 ` yukuai (C)
2021-12-25 7:44 ` yukuai (C)
2022-01-03 15:37 ` Jan Kara
2022-01-07 1:04 ` yukuai (C)
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