From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754816AbZLCCbR (ORCPT ); Wed, 2 Dec 2009 21:31:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753506AbZLCCbR (ORCPT ); Wed, 2 Dec 2009 21:31:17 -0500 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:34665 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753482AbZLCCbQ (ORCPT ); Wed, 2 Dec 2009 21:31:16 -0500 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Thu, 3 Dec 2009 11:28:22 +0900 From: KAMEZAWA Hiroyuki To: Wu Fengguang Cc: Andi Kleen , Andrew Morton , KOSAKI Motohiro , Hugh Dickins , Daisuke Nishimura , Balbir Singh , Li Zefan , Paul Menage , Nick Piggin , "linux-mm@kvack.org" , LKML Subject: Re: [PATCH 22/24] HWPOISON: add memory cgroup filter Message-Id: <20091203112822.ecee5bf5.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20091203021915.GA13587@localhost> References: <20091202031231.735876003@intel.com> <20091202043046.519053333@intel.com> <20091202124446.GA18989@one.firstfloor.org> <20091202125842.GA13277@localhost> <20091203105229.afb0efc4.kamezawa.hiroyu@jp.fujitsu.com> <20091203021915.GA13587@localhost> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 2.5.0 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 3 Dec 2009 10:19:15 +0800 Wu Fengguang wrote: > On Thu, Dec 03, 2009 at 09:52:29AM +0800, KAMEZAWA Hiroyuki wrote: > > On Wed, 2 Dec 2009 20:58:42 +0800 > > Wu Fengguang wrote: > > > > > On Wed, Dec 02, 2009 at 08:44:46PM +0800, Andi Kleen wrote: > > > > > > > > > > +static int hwpoison_filter_task(struct page *p) > > > > > +{ > > > > > > > > Can we make that ifdef instead of depends on ? > > > > > > Sure. Here is the updated patch. > > > > > > --- > > > HWPOISON: add memory cgroup filter > > > > > > The hwpoison test suite need to inject hwpoison to a collection of > > > selected task pages, and must not touch pages not owned by them and > > > thus kill important system processes such as init. (But it's OK to > > > mis-hwpoison free/unowned pages as well as shared clean pages. > > > Mis-hwpoison of shared dirty pages will kill all tasks, so the test > > > suite will target all or non of such tasks in the first place.) > > > > > > The memory cgroup serves this purpose well. We can put the target > > > processes under the control of a memory cgroup, and tell the hwpoison > > > injection code to only kill pages associated with some active memory > > > cgroup. > > > > > > The prerequisite for doing hwpoison stress tests with mem_cgroup is, > > > the mem_cgroup code tracks task pages _accurately_ (unless page is > > > locked). Which we believe is/should be true. > > > > > > The benifits are simplification of hwpoison injector code. Also the > > > mem_cgroup code will automatically be tested by hwpoison test cases. > > > > > > The alternative interfaces pin-pfn/unpin-pfn can also delegate the > > > (process and page flags) filtering functions reliably to user space. > > > However prototype implementation shows that this scheme adds more > > > complexity than we wanted. > > > > > > CC: KOSAKI Motohiro > > > CC: Hugh Dickins > > > CC: Daisuke Nishimura > > > CC: Balbir Singh > > > CC: KAMEZAWA Hiroyuki > > > CC: Li Zefan > > > CC: Paul Menage > > > CC: Nick Piggin > > > CC: Andi Kleen > > > Signed-off-by: Wu Fengguang > > > --- > > > mm/Kconfig | 2 +- > > > mm/hwpoison-inject.c | 7 +++++++ > > > mm/internal.h | 1 + > > > mm/memory-failure.c | 28 ++++++++++++++++++++++++++++ > > > 4 files changed, 37 insertions(+), 1 deletion(-) > > > > > > --- linux-mm.orig/mm/memory-failure.c 2009-12-01 09:56:06.000000000 +0800 > > > +++ linux-mm/mm/memory-failure.c 2009-12-02 20:56:55.000000000 +0800 > > > @@ -96,6 +96,31 @@ static int hwpoison_filter_flags(struct > > > return -EINVAL; > > > } > > > > > > +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP > > > +u32 hwpoison_filter_memcg; > > > +static int hwpoison_filter_task(struct page *p) > > > +{ > > > + struct mem_cgroup *mem; > > > + struct cgroup_subsys_state *css; > > > + > > > + if (!hwpoison_filter_memcg) > > > + return 0; > > > + > > > + mem = try_get_mem_cgroup_from_page(p); > > > + if (!mem) > > > + return -EINVAL; > > > + > > > + css = mem_cgroup_css(mem); > > > + if (!css) > > > + return -EINVAL; > > > > > + > > > + css_put(css); > > > + return 0; > > > +} > > > > > > Hmm..can you adds comment ? What does this function is for ? > > Good idea. How about this one? > > /* > * This allows stress tests to limit test scope to a collection of tasks > * by putting them under some memcg. This prevents killing unrelated/important > * processes such as /sbin/init. Note that the target task may share clean > * pages with init (eg. libc text), which is harmless. If the target task > * share _dirty_ pages with another task B, the test scheme must make sure B > * is also included in the memcg. At last, due to race conditions this filter > * can only guarantee that the page either belongs to the memcg tasks, or is > * a freed page. > */ > Hmm. seems good but..by what means "avoiding killing /sbin/init" is done ? All process are under some memcg.. If you have more patches to be usable the function above, I recommend you to post this with some real-use patches, in step by step. patch 19,20 is ok for me. Thanks, -Kame