From: Ariel Levkovich <lariel@mellanox.com>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>,
Jiri Pirko <jiri@resnulli.us>, Jakub Kicinski <kuba@kernel.org>,
Jamal Hadi Salim <jhs@mojatatu.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Jiri Pirko <jiri@mellanox.com>
Subject: Re: [PATCH net-next v3 2/4] net/sched: Introduce action hash
Date: Mon, 13 Jul 2020 23:17:50 -0400 [thread overview]
Message-ID: <b4099188-cd5d-cbca-001b-3b0e4b2bb98a@mellanox.com> (raw)
In-Reply-To: <CAM_iQpXy-_qVUangkd-V8V_shLRMjRNUpJkrWTZ=xv3sYzzaKQ@mail.gmail.com>
On 7/13/20 6:04 PM, Cong Wang wrote:
> On Sat, Jul 11, 2020 at 2:28 PM Ariel Levkovich <lariel@mellanox.com> wrote:
>> Allow user to set a packet's hash value using a bpf program.
>>
>> The user provided BPF program is required to compute and return
>> a hash value for the packet which is then stored in skb->hash.
> Can be done by act_bpf, right?
Right. We already agreed on that.
Nevertheless, as I mentioned, act_bpf is not offloadable.
Device driver has no clue what the program does.
>
>> Using this action to set the skb->hash is an alternative to setting
>> it with act_skbedit and can be useful for future HW offload support
>> when the HW hash function is different then the kernel's hash
>> function.
>> By using a bpg program that emulates the HW hash function user
>> can ensure hash consistency between the SW and the HW.
> It sounds weird that the sole reason to add a new action is
> because of HW offloading. What prevents us extending the
> existing actions to support HW offloading?
>
> Thanks.
Something like adding a parameter to act_bpf that provides information
on the program
and what it does?
Ariel
next prev parent reply other threads:[~2020-07-14 3:18 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-11 21:28 [PATCH net-next v3 0/4] ] TC datapath hash api Ariel Levkovich
2020-07-11 21:28 ` [PATCH net-next v3 1/4] net/sched: Add skb->hash field editing via act_skbedit Ariel Levkovich
2020-07-13 17:11 ` Davide Caratti
2020-07-15 14:25 ` Ariel Levkovich
2020-07-15 1:14 ` David Ahern
2020-07-11 21:28 ` [PATCH net-next v3 2/4] net/sched: Introduce action hash Ariel Levkovich
2020-07-13 22:04 ` Cong Wang
2020-07-14 3:17 ` Ariel Levkovich [this message]
2020-07-15 6:12 ` Cong Wang
2020-07-15 13:30 ` Ariel Levkovich
2020-07-15 18:49 ` Daniel Borkmann
2020-07-16 15:40 ` Ariel Levkovich
2020-07-11 21:28 ` [PATCH net-next v3 3/4] net/flow_dissector: add packet hash dissection Ariel Levkovich
2020-07-11 21:28 ` [PATCH net-next v3 4/4] net/sched: cls_flower: Add hash info to flow classification Ariel Levkovich
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