Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754904Ab2KEVo7 (ORCPT ); Mon, 5 Nov 2012 16:44:59 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:55436 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754830Ab2KEVo5 (ORCPT ); Mon, 5 Nov 2012 16:44:57 -0500 Date: Mon, 5 Nov 2012 13:44:56 -0800 From: Andrew Morton To: KY Srinivasan Cc: Greg KH , "olaf@aepfle.de" , "linux-kernel@vger.kernel.org" , "andi@firstfloor.org" , "apw@canonical.com" , "devel@linuxdriverproject.org" , linux-mm@kvack.org, Hiroyuki Kamezawa , Michal Hocko , Johannes Weiner , Ying Han Subject: Re: [PATCH 1/2] mm: Export vm_committed_as Message-Id: <20121105134456.f655b85a.akpm@linux-foundation.org> In-Reply-To: <426367E2313C2449837CD2DE46E7EAF930DF7FBB@SN2PRD0310MB382.namprd03.prod.outlook.com> References: <1349654347-18337-1-git-send-email-kys@microsoft.com> <1349654386-18378-1-git-send-email-kys@microsoft.com> <20121008004358.GA12342@kroah.com> <426367E2313C2449837CD2DE46E7EAF930A1FB31@SN2PRD0310MB382.namprd03.prod.outlook.com> <20121008133539.GA15490@kroah.com> <20121009124755.ce1087b4.akpm@linux-foundation.org> <426367E2313C2449837CD2DE46E7EAF930DF7FBB@SN2PRD0310MB382.namprd03.prod.outlook.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) 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 Content-Length: 1536 Lines: 43 On Sat, 3 Nov 2012 14:09:38 +0000 KY Srinivasan wrote: > > > > > > > > Ok, but you're going to have to get the -mm developers to agree that > > > this is ok before I can accept it. > > > > Well I guess it won't kill us. > > Andrew, > > I presumed this was an Ack from you with regards to exporting the > symbol. Looks like Greg is waiting to hear from you before he can check > these patches in. Could you provide an explicit Ack. > Well, I do have some qualms about exporting vm_committed_as to modules. vm_committed_as is a global thing and only really makes sense in a non-containerised system. If the application is running within a memory cgroup then vm_enough_memory() and the global overcommit policy are at best irrelevant and misleading. If use of vm_committed_as is indeed a bad thing, then exporting it to modules might increase the amount of badness in the kernel. I don't think these qualms are serious enough to stand in the way of this patch, but I'd be interested in hearing the memcg developers' thoughts on the matter? Perhaps you could provide a detailed description of why your module actually needs this? Precisely what information is it looking for and why? If we know that then perhaps a more comfortable alternative can be found. -- 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/