From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E76B4C04AAF for ; Tue, 21 May 2019 04:47:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C34C421743 for ; Tue, 21 May 2019 04:47:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726042AbfEUErg (ORCPT ); Tue, 21 May 2019 00:47:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47604 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725982AbfEUErg (ORCPT ); Tue, 21 May 2019 00:47:36 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BE8CB81DEE; Tue, 21 May 2019 04:47:30 +0000 (UTC) Received: from [10.72.12.36] (ovpn-12-36.pek2.redhat.com [10.72.12.36]) by smtp.corp.redhat.com (Postfix) with ESMTP id DC7EE5DA34; Tue, 21 May 2019 04:47:25 +0000 (UTC) Subject: Re: [PATCH v2 net 2/2] net: core: generic XDP support for stacked device To: Jiri Pirko , Stephen Hemminger Cc: netdev@vger.kernel.org, davem@davemloft.net, xdp-newbies@vger.kernel.org, bpf@vger.kernel.org, Stephen Hemminger References: <20190519031046.4049-1-sthemmin@microsoft.com> <20190519031046.4049-3-sthemmin@microsoft.com> <20190520091105.GA2142@nanopsycho> From: Jason Wang Message-ID: Date: Tue, 21 May 2019 12:47:23 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190520091105.GA2142@nanopsycho> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 21 May 2019 04:47:35 +0000 (UTC) Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 2019/5/20 下午5:11, Jiri Pirko wrote: > Sun, May 19, 2019 at 05:10:46AM CEST, stephen@networkplumber.org wrote: >> When a device is stacked like (team, bonding, failsafe or netvsc) the >> XDP generic program for the parent device is not called. In these >> cases, the rx handler changes skb->dev to its own in the receive >> handler, and returns RX_HANDLER_ANOTHER. Fix this by calling >> do_xdp_generic if necessary before starting another round. >> >> Review of all the places RX_HANDLER_ANOTHER is returned >> show that the current devices do correctly change skb->dev. >> >> There was an older patch that got abandoned that did the >> same thing, this is just a rewrite. >> >> Suggested-by: Jason Wang >> Fixes: d445516966dc ("net: xdp: support xdp generic on virtual devices") >> Signed-off-by: Stephen Hemminger >> Acked-by: Jason Wang >> --- >> net/core/dev.c | 10 ++++++++++ >> 1 file changed, 10 insertions(+) >> >> diff --git a/net/core/dev.c b/net/core/dev.c >> index b6b8505cfb3e..240d0b2de1a8 100644 >> --- a/net/core/dev.c >> +++ b/net/core/dev.c >> @@ -4921,6 +4921,16 @@ static int __netif_receive_skb_core(struct sk_buff *skb, bool pfmemalloc, >> ret = NET_RX_SUCCESS; >> goto out; >> case RX_HANDLER_ANOTHER: >> + if (static_branch_unlikely(&generic_xdp_needed_key)) { >> + struct bpf_prog *xdp_prog; >> + >> + xdp_prog = rcu_dereference(skb->dev->xdp_prog); >> + ret = do_xdp_generic(xdp_prog, skb); >> + if (ret != XDP_PASS) { >> + ret = NET_RX_SUCCESS; >> + goto out; >> + } >> + } > I'm always scarred of changes like this. The history tells us that this > codepaths are very fragile. It took us non-trivial efford to fix bonding > here, not to mention vlans (that was pain). I may miss something, did you see any issue for bonding with this patch? > > The reason for troubles was often fact that different flows were treated > differently (vlan accel/non-accel). Do you mean we need do something similar after vlan_do_receive() returns true? > This patch calls do_xdp_generic for master device in different point in > the receive patch comparing to lower device. Would it be possible to > unify this? E.g. by moving do_xdp_generice() call from > netif_rx_internal()/netif_receive_skb_internal() here, > to the beginning of __netif_receive_skb_core()? Probably just after another_round label. And this means generic XDP is done after RPS which could be even better. Thanks > > > >> goto another_round; >> case RX_HANDLER_EXACT: >> deliver_exact = true; >> -- >> 2.20.1 >>