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From: "Toke Høiland-Jørgensen" <toke@toke.dk>
To: cake@lists.bufferbloat.net
Subject: Re: [Cake] [PATCH net-next v7 3/7] sch_cake: Add optional ACK filter
Date: Thu, 03 May 2018 14:40:47 +0200	[thread overview]
Message-ID: <87po2czzcg.fsf@toke.dk> (raw)
In-Reply-To: <201805031629.vXyGm7Ql%fengguang.wu@intel.com>

kbuild test robot <lkp@intel.com> writes:

> Hi Toke,
>
> Thank you for the patch! Perhaps something to improve:
>
> [auto build test WARNING on net-next/master]
>
> url:    https://github.com/0day-ci/linux/commits/Toke-H-iland-J-rgensen/sched-Add-Common-Applications-Kept-Enhanced-cake-qdisc/20180503-073002
>
>
> coccinelle warnings: (new ones prefixed by >>)
>
>>> net/sched/sch_cake.c:1047:6-13: ERROR: PTR_ERR applied after
>>>initialization to constant on line 822

While attempting to fix this I realised that I didn't fully understand
the complex state keeping logic in the ACK filter. And rather than try
to do that, I thought I'd see what the simplest possible filter looks
like.

So lo and behold:
https://github.com/dtaht/sch_cake/commit/df5d38a0a38ffb35c7c18e2269ac73792267bd0e

This has the advantage of removing about a hundred lines of code, and
being way easier to follow (and thus review). And I think it still does
the right thing. The drawback is that it will loop from the head of the
queue every time it is invoked rather than try to "keep its place" as
the old version did.

I'm honestly not sure whether the efficiency gains are worth the complex
logic; we only gain something if there are both ACKs and non-ACKs in the
same queue.

Of course, if we *are* going to keep the old version, someone else is
going to step up to fix the warning above :)

What do you guys think?

-Toke

  reply	other threads:[~2018-05-03 12:40 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-02 15:10 [Cake] [PATCH net-next v7 0/7] sched: Add Common Applications Kept Enhanced (cake) qdisc Toke Høiland-Jørgensen
2018-05-02 15:11 ` [Cake] [PATCH net-next v7 1/7] " Toke Høiland-Jørgensen
2018-05-03  5:05   ` kbuild test robot
2018-05-03  5:05   ` [Cake] [PATCH] sched: fix semicolon.cocci warnings kbuild test robot
2018-05-03 15:24   ` [Cake] [PATCH net-next v7 1/7] sched: Add Common Applications Kept Enhanced (cake) qdisc David Miller
2018-05-03 15:28     ` Toke Høiland-Jørgensen
2018-05-02 15:11 ` [Cake] [PATCH net-next v7 2/7] sch_cake: Add ingress mode Toke Høiland-Jørgensen
2018-05-02 15:11 ` [Cake] [PATCH net-next v7 3/7] sch_cake: Add optional ACK filter Toke Høiland-Jørgensen
2018-05-03  8:26   ` kbuild test robot
2018-05-03 12:40     ` Toke Høiland-Jørgensen [this message]
2018-05-02 15:11 ` [Cake] [PATCH net-next v7 4/7] sch_cake: Add NAT awareness to packet classifier Toke Høiland-Jørgensen
2018-05-02 15:11 ` [Cake] [PATCH net-next v7 5/7] sch_cake: Add DiffServ handling Toke Høiland-Jørgensen
2018-05-02 15:11 ` [Cake] [PATCH net-next v7 6/7] sch_cake: Add overhead compensation support to the rate shaper Toke Høiland-Jørgensen
2018-05-02 15:25   ` Sebastian Moeller
2018-05-02 15:30     ` Toke Høiland-Jørgensen
2018-05-02 16:08       ` Sebastian Moeller
2018-05-02 16:15         ` Toke Høiland-Jørgensen
2018-05-02 15:11 ` [Cake] [PATCH net-next v7 7/7] sch_cake: Conditionally split GSO segments Toke Høiland-Jørgensen

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