netdev - Re: [PATCH net-next] openvswitch: avoid deferred execution of recirc actions

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Date:   Tue, 13 Sep 2016 13:52:32 -0700
From:   pravin shelar <pshelar@....org>
To:     Lance Richardson <lrichard@...hat.com>
Cc:     Linux Kernel Network Developers <netdev@...r.kernel.org>,
        ovs dev <dev@...nvswitch.org>, sramamur@...ux.vnet.ibm.com
Subject: Re: [PATCH net-next] openvswitch: avoid deferred execution of recirc actions

On Tue, Sep 13, 2016 at 7:08 AM, Lance Richardson <lrichard@...hat.com> wrote:
> The ovs kernel data path currently defers the execution of all
> recirc actions until stack utilization is at a minimum.
> This is too limiting for some packet forwarding scenarios due to
> the small size of the deferred action FIFO (10 entries). For
> example, broadcast traffic sent out more than 10 ports with
> recirculation results in packet drops when the deferred action
> FIFO becomes full, as reported here:
>
>      http://openvswitch.org/pipermail/dev/2016-March/067672.html
>
> Since the current recursion depth is available (it is already tracked
> by the exec_actions_level pcpu variable), we can use it to determine
> whether to execute recirculation actions immediately (safe when
> recursion depth is low) or defer execution until more stack space is
> available.
>
> With this change, the deferred action fifo size becomes a non-issue
> for currently failing scenarios because it is no longer used when
> there are three or fewer recursions through ovs_execute_actions().
>
> Suggested-by: Pravin Shelar <pshelar@....org>
> Signed-off-by: Lance Richardson <lrichard@...hat.com>

Thanks for working on it.

Acked-by: Pravin B Shelar <pshelar@....org>