Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757189Ab2KHWFd (ORCPT ); Thu, 8 Nov 2012 17:05:33 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:41008 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756595Ab2KHWFc (ORCPT ); Thu, 8 Nov 2012 17:05:32 -0500 Date: Thu, 8 Nov 2012 14:05:29 -0800 From: Andrew Morton To: KY Srinivasan Cc: David Rientjes , 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: <20121108140529.af7849c8.akpm@linux-foundation.org> In-Reply-To: <426367E2313C2449837CD2DE46E7EAF930E0D0CC@CH1PRD0310MB381.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> <20121105134456.f655b85a.akpm@linux-foundation.org> <426367E2313C2449837CD2DE46E7EAF930DFA7B8@SN2PRD0310MB382.namprd03.prod.outlook.com> <426367E2313C2449837CD2DE46E7EAF930E0D0CC@CH1PRD0310MB381.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: 2164 Lines: 52 On Thu, 8 Nov 2012 22:01:33 +0000 KY Srinivasan wrote: > > > > -----Original Message----- > > From: David Rientjes [mailto:rientjes@google.com] > > Sent: Monday, November 05, 2012 5:33 PM > > To: KY Srinivasan > > Cc: Andrew Morton; 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 > > > > On Mon, 5 Nov 2012, KY Srinivasan wrote: > > > > > The Hyper-V host has a policy engine for managing available physical memory > > across > > > competing virtual machines. This policy decision is based on a number of > > parameters > > > including the memory pressure reported by the guest. Currently, the pressure > > calculation is > > > based on the memory commitment made by the guest. From what I can tell, > > the ratio of > > > currently allocated physical memory to the current memory commitment made > > by the guest > > > (vm_committed_as) is used as one of the parameters in making the memory > > balancing decision on > > > the host. This is what Windows guests report to the host. So, I need some > > measure of memory > > > commitments made by the Linux guest. This is the reason I want export > > vm_committed_as. > > > > > > > I don't think you should export the symbol itself to modules but rather a > > helper function that returns s64 that just wraps > > percpu_counter_read_positive() which your driver could use instead. > > > > (And why percpu_counter_read_positive() returns a signed type is a > > mystery.) > > Yes, this makes sense. I just want to access (read) this metric. Andrew, if you are willing to > take this patch, I could send one. Sure. I suppose that's better, although any module which modifies committed_as would never pass review (rofl). -- 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/