netdev - Re: [RFC net-next] net/flow_offload: allow user to offload tc action to net device

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Message-ID: <CALnP8ZaZQAbvm1girLUSLcFZTKV5MvBMEtN67OiA55OAvsO_1Q@mail.gmail.com>
Date:   Thu, 29 Apr 2021 19:47:13 -0700
From:   Marcelo Ricardo Leitner <mleitner@...hat.com>
To:     Simon Horman <simon.horman@...ronome.com>
Cc:     Jamal Hadi Salim <jhs@...atatu.com>,
        Cong Wang <xiyou.wangcong@...il.com>,
        Jiri Pirko <jiri@...lanox.com>, netdev@...r.kernel.org,
        oss-drivers@...ronome.com,
        Baowen Zheng <baowen.zheng@...igine.com>,
        Louis Peens <louis.peens@...ronome.com>, dcaratti@...hat.com,
        ozsh@...dia.com
Subject: Re: [RFC net-next] net/flow_offload: allow user to offload tc action
 to net device

On Thu, Apr 29, 2021 at 10:10:14AM +0200, Simon Horman wrote:
> From: Baowen Zheng <baowen.zheng@...igine.com>
>
> Allow use of flow_indr_dev_register/flow_indr_dev_setup_offload to offload
> tc actions independent of flows.
>
> The motivation for this work is to prepare for using TC police action
> instances to provide hardware offload of OVS metering feature - which calls
> for policers that may be used my multiple flows and whose lifecycle is
> independent of any flows that use them.

Makes sense to me.

>
> This patch includes basic changes to offload drivers to return EOPNOTSUPP
> if this feature is used - it is not yet supported by any driver.

I miss indications on whether the action is offloaded or not. That's
really useful for debugging. extacks are nice but they may not be
logged and are not present in dumps later on.

As the offloading is optional here (it will fill in the extack but not
error out), seems that it's up to the driver then to ensure that the
action is offloaded when offloading a flow that uses such action,
right? With that, all the skip_sw/skip_hw dealing is left to the
flow/classifier.

  Marcelo