From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752574Ab3AUJx6 (ORCPT ); Mon, 21 Jan 2013 04:53:58 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:8651 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751833Ab3AUJx4 (ORCPT ); Mon, 21 Jan 2013 04:53:56 -0500 Message-ID: <50FD0FED.7070204@huawei.com> Date: Mon, 21 Jan 2013 17:52:45 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130107 Thunderbird/17.0.2 MIME-Version: 1.0 To: John Fastabend CC: Daniel Wagner , John Fastabend , Neil Horman , Daniel Wagner , LKML , , Cgroups Subject: Re: [BUG] Bug in netprio_cgroup and netcls_cgroup ? References: <50FCDB5C.4050608@huawei.com> <50FD0144.1000401@monom.org> <50FD0402.6060400@huawei.com> <50FD0893.1050805@gmail.com> In-Reply-To: <50FD0893.1050805@gmail.com> Content-Type: text/plain; charset="GB2312" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.135.68.215] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2013/1/21 17:21, John Fastabend wrote: > On 01/21/2013 01:01 AM, Li Zefan wrote: >> On 2013/1/21 16:50, Daniel Wagner wrote: >>> Hi Li, >>> >>> On 21.01.2013 07:08, Li Zefan wrote: >>>> I'm not a network developer, so correct me if I'm wrong. >>>> >>>> Since commit 7955490f732c2b8 >>>> ("net: netprio_cgroup: rework update socket logic"), sock->sk->sk_cgrp_prioidx >>>> is set when the socket is created, and won't be updated unless the task is >>>> moved to another cgroup. >>>> >>>> Now the problem is, a socket can be _shared_ by multiple processes (fork, SCM_RIGHT). >>>> If we place those processes in different cgroups, and each cgroup has >>>> different configs, but all of the processes will send data via this socket >>>> with the same network priority. >>> >>> Wouldn't that be addressed by 48a87cc26c13b68f6cce4e9d769fcb17a6b3e4b8 >>> >>> net: netprio: fd passed in SCM_RIGHTS datagram not set correctly >>> >>> A socket fd passed in a SCM_RIGHTS datagram was not getting >>> updated with the new tasks cgrp prioidx. This leaves IO on >>> the socket tagged with the old tasks priority. >>> >>> To fix this add a check in the scm recvmsg path to update the >>> sock cgrp prioidx with the new tasks value. >>> >>> As I read this this should work for net_prio. >>> >> >> But after process A passed the socket fd to B, both A and B can use the >> same socket to send data, right? Then if A and B were placed in different >> cgroups with differnt configs, A's config won't take effect anymore. >> >> Am I missing something? >> >> > > Hi Zefan, > > Neil and I discusses this here, http://patchwork.ozlabs.org/patch/172343/ > look towards the bottom of the thread. Quoted here. > So this is a known issue. Why not document this behavior in Documentation/cgroups/netprio.txt?