From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH net-next 1/6] net: skbuff: don't use union for napi_id and sender_cpu Date: Fri, 1 Apr 2016 12:49:31 +0800 Message-ID: <56FDFDDB.7090606@redhat.com> References: <1459403439-6011-1-git-send-email-jasowang@redhat.com> <1459403439-6011-2-git-send-email-jasowang@redhat.com> <1459420341.6473.225.camel@edumazet-glaptop3.roam.corp.google.com> <56FDD94E.8090908@redhat.com> <1459479325.6473.260.camel@edumazet-glaptop3.roam.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: davem@davemloft.net, mst@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Eric Dumazet Return-path: Received: from mx1.redhat.com ([209.132.183.28]:60133 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750741AbcDAEtg (ORCPT ); Fri, 1 Apr 2016 00:49:36 -0400 In-Reply-To: <1459479325.6473.260.camel@edumazet-glaptop3.roam.corp.google.com> Sender: netdev-owner@vger.kernel.org List-ID: On 04/01/2016 10:55 AM, Eric Dumazet wrote: > On Fri, 2016-04-01 at 10:13 +0800, Jason Wang wrote: > > >> The problem is we want to support busy polling for tun. This needs >> napi_id to be passed to tun socket by sk_mark_napi_id() during >> tun_net_xmit(). But before reaching this, XPS will set sender_cpu will >> make us can't see correct napi_id. >> > Looks like napi_id should have precedence then ? But then when busy polling is enabled, we may still hit the issue before commit 2bd82484bb4c5db1d5dc983ac7c409b2782e0154? So looks like sometimes (e.g for tun), we need both two fields. > > Only forwarding should allow the field to be cleared to allow XPS to do > its job. > > Maybe skb_sender_cpu_clear() was removed too early (commit > 64d4e3431e686dc37ce388ba531c4c4e866fb141) Not sure I get you, but this will clear napi_id too. > Look, it is 8pm here, I am pretty sure a solution can be found, > but I am also need to take a break, I started at 3am today... > > >