From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id 64DDA6B006A for ; Thu, 15 Jan 2009 05:28:23 -0500 (EST) Received: from m5.gw.fujitsu.co.jp ([10.0.50.75]) by fgwmail6.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n0FASKSg000516 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Thu, 15 Jan 2009 19:28:21 +0900 Received: from smail (m5 [127.0.0.1]) by outgoing.m5.gw.fujitsu.co.jp (Postfix) with ESMTP id CCA0145DE4F for ; Thu, 15 Jan 2009 19:28:20 +0900 (JST) Received: from s5.gw.fujitsu.co.jp (s5.gw.fujitsu.co.jp [10.0.50.95]) by m5.gw.fujitsu.co.jp (Postfix) with ESMTP id AB2D945DE4D for ; Thu, 15 Jan 2009 19:28:20 +0900 (JST) Received: from s5.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s5.gw.fujitsu.co.jp (Postfix) with ESMTP id 92B701DB803F for ; Thu, 15 Jan 2009 19:28:20 +0900 (JST) Received: from m108.s.css.fujitsu.com (m108.s.css.fujitsu.com [10.249.87.108]) by s5.gw.fujitsu.co.jp (Postfix) with ESMTP id 3E3771DB803C for ; Thu, 15 Jan 2009 19:28:17 +0900 (JST) Date: Thu, 15 Jan 2009 19:27:12 +0900 From: KAMEZAWA Hiroyuki Subject: [PATCH 2/4] cgroup:add css_is_populated Message-Id: <20090115192712.33b533c3.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090115192120.9956911b.kamezawa.hiroyu@jp.fujitsu.com> References: <20090115192120.9956911b.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "menage@google.com" , "lizf@cn.fujitsu.com" , "balbir@linux.vnet.ibm.com" , "nishimura@mxp.nes.nec.co.jp" , "akpm@linux-foundation.org" List-ID: From: KAMEZAWA Hiroyuki cgroup creation is done in several stages. After allocated and linked to cgroup's hierarchy tree, all necessary control files are created. When using CSS_ID, scanning cgroups without cgrouo_lock(), status of cgroup is important. At removal of cgroup/css, css_tryget() works fine and we can write a safe code. At creation, we need some flag to show "This cgroup is not ready yet" This patch adds CSS_POPULATED flag. Signed-off-by: KAMEZAWA Hiroyuki --- Index: mmotm-2.6.29-Jan14/include/linux/cgroup.h =================================================================== --- mmotm-2.6.29-Jan14.orig/include/linux/cgroup.h +++ mmotm-2.6.29-Jan14/include/linux/cgroup.h @@ -69,6 +69,7 @@ struct cgroup_subsys_state { enum { CSS_ROOT, /* This CSS is the root of the subsystem */ CSS_REMOVED, /* This CSS is dead */ + CSS_POPULATED, /* This CSS finished all initialization */ }; /* @@ -90,6 +91,11 @@ static inline bool css_is_removed(struct return test_bit(CSS_REMOVED, &css->flags); } +static inline bool css_is_populated(struct cgroup_subsys_state *css) +{ + return test_bit(CSS_POPULATED, &css->flags); +} + /* * Call css_tryget() to take a reference on a css if your existing * (known-valid) reference isn't already ref-counted. Returns false if Index: mmotm-2.6.29-Jan14/kernel/cgroup.c =================================================================== --- mmotm-2.6.29-Jan14.orig/kernel/cgroup.c +++ mmotm-2.6.29-Jan14/kernel/cgroup.c @@ -2326,8 +2326,10 @@ static int cgroup_populate_dir(struct cg } for_each_subsys(cgrp->root, ss) { + struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id]; if (ss->populate && (err = ss->populate(ss, cgrp)) < 0) return err; + set_bit(CSS_POPULATED, &css->flags); } return 0; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org