From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner+w=401wt.eu-S1753472AbZBDAyz@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1753472AbZBDAyz (ORCPT <rfc822;w@1wt.eu>);
	Tue, 3 Feb 2009 19:54:55 -0500
Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751244AbZBDAyn
	(ORCPT <rfc822;linux-kernel-outgoing>);
	Tue, 3 Feb 2009 19:54:43 -0500
Received: from cn.fujitsu.com ([222.73.24.84]:56345 "EHLO song.cn.fujitsu.com"
	rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP
	id S1750866AbZBDAyn (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Tue, 3 Feb 2009 19:54:43 -0500
Message-ID: <4988E727.8030807@cn.fujitsu.com>
Date: Wed, 04 Feb 2009 08:53:59 +0800
From: Li Zefan <lizf@cn.fujitsu.com>
User-Agent: Thunderbird 2.0.0.9 (X11/20071115)
MIME-Version: 1.0
To: balbir@linux.vnet.ibm.com
CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
       Andrew Morton <akpm@linux-foundation.org>,
       "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
       "nishimura@mxp.nes.nec.co.jp" <nishimura@mxp.nes.nec.co.jp>,
       "linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [-mm patch] Show memcg information during OOM (v3)
References: <20090203172135.GF918@balbir.in.ibm.com>
In-Reply-To: <20090203172135.GF918@balbir.in.ibm.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

> @@ -104,6 +104,8 @@ struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
>  						      struct zone *zone);
>  struct zone_reclaim_stat*
>  mem_cgroup_get_reclaim_stat_from_page(struct page *page);
> +extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
> +					struct task_struct *p);
>  
>  #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
>  extern int do_swap_account;
> @@ -270,6 +272,10 @@ mem_cgroup_get_reclaim_stat_from_page(struct page *page)
>  	return NULL;
>  }
>  
> +void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
> +{

should be static inline, otherwise it won't compile if CONFIG_CGROUP_MEM_CONT=n

> +}
> +
>  #endif /* CONFIG_CGROUP_MEM_CONT */
>  

> +void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
> +{
> +	struct cgroup *task_cgrp;
> +	struct cgroup *mem_cgrp;
> +	/*
> +	 * Need a buffer on stack, can't rely on allocations. The code relies

I think it's in .bss section, but not on stack, and it's better to explain why
the static buffer is safe in the comment.

> +	 * on the assumption that OOM is serialized for memory controller.
> +	 * If this assumption is broken, revisit this code.
> +	 */
> +	static char task_memcg_name[PATH_MAX];
> +	static char memcg_name[PATH_MAX];
> +	int ret;