netdev - Re: [Patch net 0/5] net_sched: tc action fixes and updates

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Message-ID: <ee17984e-35ec-3331-9143-4e00c06f21c9@mojatatu.com>
Date:	Wed, 10 Aug 2016 09:54:31 -0400
From:	Jamal Hadi Salim <jhs@...atatu.com>
To:	Cong Wang <xiyou.wangcong@...il.com>
Cc:	netdev@...r.kernel.org, David Miller <davem@...emloft.net>
Subject: Re: [Patch net 0/5] net_sched: tc action fixes and updates

On 16-08-08 04:46 PM, Cong Wang wrote:
> This patchset fixes several regressions caused by the previous
> code refactor. Thanks to Jamal for catching them!
>
> Note, patch 3/5 and 4/5 are not strictly necessary, I just
> want to carry them together.

Cong - there's good news and bad news.
The good news is that the oopses are fixed.
The bad news is you have now slowed down the system. It is noticeable
at high speed.
I narrowed it down to your use of flex arrays. In particular
tcf_exts_exec() call:
This is the fast path - was flexarray really necessary?
The conversion to list is slowing things down.

As hard as this is for me to say:
I am actually beginning to question this whole patch series.
Either you have a plan to fix this regression or lets just
pull this out for now to regain stability until we get our
act together. I think it would make a lot of sense to just pass
an array instead of a list.

cheers,
jamal