From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Lameter Subject: Re: [RFC PATCH v3 0/13] memory-hotplug : hot-remove physical memory Date: Mon, 9 Jul 2012 10:18:54 -0500 (CDT) Message-ID: References: <4FFAB0A2.8070304@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: In-Reply-To: <4FFAB0A2.8070304@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: Yasuaki Ishimatsu Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, benh@kernel.crashing.org, paulus@samba.org, minchan.kim@gmail.com, akpm@linux-foundation.org, kosaki.motohiro@jp.fujitsu.com, wency@cn.fujitsu.com List-Id: linux-acpi@vger.kernel.org On Mon, 9 Jul 2012, Yasuaki Ishimatsu wrote: > Even if you apply these patches, you cannot remove the physical memory > completely since these patches are still under development. I want you to > cooperate to improve the physical memory hot-remove. So please review these > patches and give your comment/idea. Could you at least give a method on how you want to do physical memory removal? You would have to remove all objects from the range you want to physically remove. That is only possible under special circumstances and with a limited set of objects. Even if you exclusively use ZONE_MOVEABLE you still may get cases where pages are pinned for a long time. I am not sure that these patches are useful unless we know where you are going with this. If we end up with a situation where we still cannot remove physical memory then this patchset is not helpful. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755251Ab2GIPTA (ORCPT ); Mon, 9 Jul 2012 11:19:00 -0400 Received: from smtp108.prem.mail.ac4.yahoo.com ([76.13.13.47]:35911 "HELO smtp108.prem.mail.ac4.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1755025Ab2GIPS7 (ORCPT ); Mon, 9 Jul 2012 11:18:59 -0400 X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: JDAqHwMVM1nvr.tmefhqEY5Z_8GbzwHt7.IhBkNlNxA8IPK V0GPHs4au7x7STJ9WXSAh7KA2Sad1EAuAef_yj6ayM2ra2dCnO08bEHCTZQE SAA.KTQHyW.WVm26hPXOHHbxDphuU7A9eTGbcp_23qNB_4y0_iGf5pA.c.u. a4eTtncGvMvqTKFsPXL_DqEmcOJgagvR2CPumVQVspyIo4o1E0JoTWg_ZwHD t95za6lem0eaIzrVm19gnPp8euPFOoiX.6sUcLh2RfzTltU96mCkkbj.SrCk qI7PGzYwbis1RqOIzJiEVTO_NL7Z9OSfdnjcnvFDnAKDUS_CbeuPnWzubrdv sNs4E1HlNeeQ2oZFIAAPkuElrE6pMNS9pDROMT4wu7Mo1SHv8ELe1Xs7QHQ2 .RycZMhPcRLJPdmnYCgqSQgL_hEzUnZkTR8xI X-Yahoo-SMTP: _Dag8S.swBC1p4FJKLCXbs8NQzyse1SYSgnAbY0- Date: Mon, 9 Jul 2012 10:18:54 -0500 (CDT) From: Christoph Lameter X-X-Sender: cl@router.home To: Yasuaki Ishimatsu cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, benh@kernel.crashing.org, paulus@samba.org, minchan.kim@gmail.com, akpm@linux-foundation.org, kosaki.motohiro@jp.fujitsu.com, wency@cn.fujitsu.com Subject: Re: [RFC PATCH v3 0/13] memory-hotplug : hot-remove physical memory In-Reply-To: <4FFAB0A2.8070304@jp.fujitsu.com> Message-ID: References: <4FFAB0A2.8070304@jp.fujitsu.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 9 Jul 2012, Yasuaki Ishimatsu wrote: > Even if you apply these patches, you cannot remove the physical memory > completely since these patches are still under development. I want you to > cooperate to improve the physical memory hot-remove. So please review these > patches and give your comment/idea. Could you at least give a method on how you want to do physical memory removal? You would have to remove all objects from the range you want to physically remove. That is only possible under special circumstances and with a limited set of objects. Even if you exclusively use ZONE_MOVEABLE you still may get cases where pages are pinned for a long time. I am not sure that these patches are useful unless we know where you are going with this. If we end up with a situation where we still cannot remove physical memory then this patchset is not helpful. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp108.prem.mail.ac4.yahoo.com (smtp108.prem.mail.ac4.yahoo.com [76.13.13.47]) by ozlabs.org (Postfix) with SMTP id 0F0712C0203 for ; Tue, 10 Jul 2012 01:19:00 +1000 (EST) Date: Mon, 9 Jul 2012 10:18:54 -0500 (CDT) From: Christoph Lameter To: Yasuaki Ishimatsu Subject: Re: [RFC PATCH v3 0/13] memory-hotplug : hot-remove physical memory In-Reply-To: <4FFAB0A2.8070304@jp.fujitsu.com> Message-ID: References: <4FFAB0A2.8070304@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: len.brown@intel.com, wency@cn.fujitsu.com, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, paulus@samba.org, minchan.kim@gmail.com, kosaki.motohiro@jp.fujitsu.com, rientjes@google.com, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org, liuj97@gmail.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, 9 Jul 2012, Yasuaki Ishimatsu wrote: > Even if you apply these patches, you cannot remove the physical memory > completely since these patches are still under development. I want you to > cooperate to improve the physical memory hot-remove. So please review these > patches and give your comment/idea. Could you at least give a method on how you want to do physical memory removal? You would have to remove all objects from the range you want to physically remove. That is only possible under special circumstances and with a limited set of objects. Even if you exclusively use ZONE_MOVEABLE you still may get cases where pages are pinned for a long time. I am not sure that these patches are useful unless we know where you are going with this. If we end up with a situation where we still cannot remove physical memory then this patchset is not helpful.