Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752672Ab0DAExi (ORCPT ); Thu, 1 Apr 2010 00:53:38 -0400 Received: from e23smtp03.au.ibm.com ([202.81.31.145]:59151 "EHLO e23smtp03.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752483Ab0DAExb (ORCPT ); Thu, 1 Apr 2010 00:53:31 -0400 Date: Thu, 1 Apr 2010 10:23:10 +0530 From: Balbir Singh To: KAMEZAWA Hiroyuki Cc: Rik van Riel , Larry Woodman , "linux-kernel@vger.kernel.org" , "nishimura@mxp.nes.nec.co.jp" , "akpm@linux-foundation.org" Subject: Re: RFC [Patch] Remove "please try 'cgroup_disable=memory' option if you don't want memory cgroups" printk at boot time. Message-ID: <20100401045310.GB6337@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <1270049283.3551.281.camel@dhcp-100-19-198.bos.redhat.com> <1270050899.3551.283.camel@dhcp-100-19-198.bos.redhat.com> <4BB38D1A.7050204@redhat.com> <20100401104859.e0deeca8.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20100401104859.e0deeca8.kamezawa.hiroyu@jp.fujitsu.com> User-Agent: Mutt/1.5.20 (2009-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1817 Lines: 48 * KAMEZAWA Hiroyuki [2010-04-01 10:48:59]: > On Wed, 31 Mar 2010 13:57:46 -0400 > Rik van Riel wrote: > > > On 03/31/2010 11:54 AM, Larry Woodman wrote: > > > On Wed, 2010-03-31 at 11:28 -0400, Larry Woodman wrote: > > >> We are considering removing this printk at boot time from RHEL because > > >> it will confuse customers, encourage them to change the boot parameters > > >> and generate extraneous support calls. Its documented in > > >> Documentation/kernel-parameters.txt anyway. Any thoughts??? > > > > Yeah, that is a strange boot message... > > > > Acked-by: Rik van Riel > > > please CC linux-mm and maintainers. > > Acked-by: KAMEZAWA Hiroyuki > > It have been there for a year and I think memory usage by page_cgroup > will not surprise linux kernel users, more. > > Assume x86-32. > > RHEL allows amount of memory up to 16G, right? > > without memcg: memmap uses 32bytes * 16G/4k = 128M. > with memcg: memmap+page_cgroup uses (32+20) bytes * 16G/4k = 208M. > > I thought this may cause OOM in ZONE_NORMAL. Then, I added it when I wrote > original patch. This kind of memory eater can cause trouble when it pops > up suddenly. But I think 'one year' can be an excuse. > I've seen this issue come up on multiple machines, I think the printk is useful. However, we might need to change the panic() to a big fat warning and disable the memcg controller if we fail to allocate memory in page_cgroup_init_flatmem(). -- Three Cheers, Balbir -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/