From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756169AbYIJW5f (ORCPT ); Wed, 10 Sep 2008 18:57:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752801AbYIJW5H (ORCPT ); Wed, 10 Sep 2008 18:57:07 -0400 Received: from smtp-out.google.com ([216.239.33.17]:1986 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752360AbYIJW5F (ORCPT ); Wed, 10 Sep 2008 18:57:05 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=message-id:date:from:to:subject:cc:in-reply-to: mime-version:content-type:content-transfer-encoding: content-disposition:references; b=jX7SEMYVtNxG1b6cbmC5a0fQUF+l4eQahfZoGxiDO15caxlgVP5pzDWh5q1q6l7Nc uyP0XZfyw8TMHyM4CUO3Q== Message-ID: <166fe7950809101556q61cb7e30m2d5e758304618f61@mail.gmail.com> Date: Wed, 10 Sep 2008 15:56:55 -0700 From: "Ranjit Manomohan" To: "Thomas Graf" Subject: Re: [PATCH 1/2] Traffic control cgroups subsystem Cc: davem@davemloft.net, akpm@linux-foundation.org, kaber@trash.net, lizf@cn.fujitsu.com, menage@google.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org In-Reply-To: <20080910220115.GH20815@postel.suug.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080910220115.GH20815@postel.suug.ch> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 10, 2008 at 3:01 PM, Thomas Graf wrote: > * Ranjit Manomohan 2008-09-10 10:42 >> +void cgroup_tc_set_sock_classid(struct sock *sk) >> +{ >> + if (sk) >> + sk->sk_cgroup_classid = cgroup_tc_classid(current); >> +} >> + >> @@ -1170,6 +1171,8 @@ static int __sock_create(struct net *net, int family, int type, int protocol, >> if (err < 0) >> goto out_module_put; >> >> + cgroup_tc_set_sock_classid(sock->sk); >> + >> /* >> * Now to bump the refcnt of the [loadable] module that owns this >> * socket at sock_release time we decrement its refcnt. >> @@ -1444,6 +1447,8 @@ asmlinkage long sys_accept(int fd, struct sockaddr __user *upeer_sockaddr, >> if (err < 0) >> goto out_fd; >> >> + cgroup_tc_set_sock_classid(newsock->sk); >> + >> if (upeer_sockaddr) { >> if (newsock->ops->getname(newsock, (struct sockaddr *)address, >> &len, 2) < 0) { > > The big disadvantage of this method is that it does not allow to change > the classid for sockets which already exist. It inherits the classid > at socket creation time and then sticks to it. So if you want to follow > this approach I'd suggest to at least store a reference to the cgroup > state and reference count it properly. > I had considered adding support for moving tasks between cgroups by going through all the open fds of the task and updating the sockets (in the cgroup attach method). It is a very heavy weight operation and not considered a common use case (and even undesirable at times) so I dropped the idea. I can add it back in if it is considered essential. > As for the locking that you mentioned in the other thread. IMHO it is > not possible to lookup a socket without taking at least one lock, but > I might be wrong there. Actually I think it will take even more locks > as different locks are used to f.e. protect listening and established > tcp sockets. That is correct for ingress, for egress the sk is already available in the skb so should be fine. -Thanks, Ranjit >