From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752978Ab2A2Uh4 (ORCPT ); Sun, 29 Jan 2012 15:37:56 -0500 Received: from mail-pw0-f46.google.com ([209.85.160.46]:61565 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751220Ab2A2Uhz (ORCPT ); Sun, 29 Jan 2012 15:37:55 -0500 Date: Sun, 29 Jan 2012 12:37:49 -0800 From: Tejun Heo To: Mandeep Singh Baines Cc: Li Zefan , linux-kernel@vger.kernel.org, Frederic Weisbecker , containers@lists.linux-foundation.org, cgroups@vger.kernel.org, KAMEZAWA Hiroyuki , Oleg Nesterov , Andrew Morton , Paul Menage Subject: Re: [PATCH] cgroup: remove extra calls to find_existing_css_set Message-ID: <20120129203749.GE17211@htj.dyndns.org> References: <1327429591-8507-1-git-send-email-msb@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1327429591-8507-1-git-send-email-msb@chromium.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Manddep. On Tue, Jan 24, 2012 at 10:26:31AM -0800, Mandeep Singh Baines wrote: > In cgroup_attach_proc, we indirectly call find_existing_css_set 3 > times. It is an expensive call so we want to call it a minimum > of times. This patch only calls it once and stores the result so > that it can be used later on when we call cgroup_task_migrate. > > This required modifying cgroup_task_migrate to take the new css_set > (which we obtained from find_css_set) as a parameter. The nice side > effect of this is that cgroup_task_migrate is now identical for > cgroup_attach_task and cgroup_attach_proc. It also now returns a > void since it can never fail. > > Changes in V5: > * https://lkml.org/lkml/2012/1/20/344 (Tejun Heo) > * Remove css_set_refs ^^^^^^^^^^^^ > static int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader) > { > - int retval, i, group_size; > + int retval, i, group_size, css_set_refs = 0; ^^^^^^^^^^^^ Wrong patch? Thanks. -- tejun