From: Felix Fietkau <nbd@nbd.name>
To: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>
Cc: Cong Wang <xiyou.wangcong@gmail.com>,
Eric Dumazet <edumazet@google.com>, Jiri Pirko <jiri@resnulli.us>
Subject: Re: [PATCH RFC] net_sched/codel: do not defer queue length update
Date: Sun, 11 Mar 2018 08:58:25 +0100 [thread overview]
Message-ID: <efdb1e4a-6c7e-a0ed-059b-cb2eb7b1c92c@nbd.name> (raw)
In-Reply-To: <150330325401.155105.30496752582836861.stgit@buzz>
On 2017-08-21 10:14, Konstantin Khlebnikov wrote:
> When codel wants to drop last packet in ->dequeue() it cannot call
> qdisc_tree_reduce_backlog() right away - it will notify parent qdisc
> about zero qlen and HTB/HFSC will deactivate class. The same class will
> be deactivated second time by caller of ->dequeue(). Currently codel and
> fq_codel defer update. This triggers warning in HFSC when it's qlen != 0
> but there is no active classes.
>
> This patch update parent queue length immediately: just temporary increase
> qlen around qdisc_tree_reduce_backlog() to prevent first class deactivation
> if we have skb to return.
>
> This might open another problem in HFSC - now operation peek could fail and
> deactivate parent class.
>
> Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=109581
This has been tested by several people and it seems to be working well.
Please make sure this gets merged soon.
Thanks,
- Felix
prev parent reply other threads:[~2018-03-11 7:58 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-21 8:14 [PATCH RFC] net_sched/codel: do not defer queue length update Konstantin Khlebnikov
2018-03-11 7:58 ` Felix Fietkau [this message]
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