Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754506Ab0ALBCW (ORCPT ); Mon, 11 Jan 2010 20:02:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751249Ab0ALBCV (ORCPT ); Mon, 11 Jan 2010 20:02:21 -0500 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:49490 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750940Ab0ALBCU (ORCPT ); Mon, 11 Jan 2010 20:02:20 -0500 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Tue, 12 Jan 2010 09:58:48 +0900 From: KAMEZAWA Hiroyuki To: Andi Kleen Cc: "H. Peter Anvin" , "Zheng, Shaohui" , "linux-mm@kvack.org" , "akpm@linux-foundation.org" , "linux-kernel@vger.kernel.org" , "y-goto@jp.fujitsu.com" , Dave Hansen , "Wu, Fengguang" , "x86@kernel.org" Subject: Re: [PATCH - resend] Memory-Hotplug: Fix the bug on interface /dev/mem for 64-bit kernel(v1) Message-Id: <20100112095848.b2cee1f3.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <4B478BEA.1010504@linux.intel.com> References: <4B46BC6F.5060607@kernel.org> <4B478BEA.1010504@linux.intel.com> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 2.7.1 (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 Content-Length: 1587 Lines: 41 On Fri, 08 Jan 2010 20:47:54 +0100 Andi Kleen wrote: > H. Peter Anvin wrote: > > On 01/07/2010 07:32 PM, Zheng, Shaohui wrote: > >> Resend the patch to the mailing-list, the original patch URL is > >> http://patchwork.kernel.org/patch/69075/, it is not accepted without comments, > >> sent it again to review. > >> > >> Memory-Hotplug: Fix the bug on interface /dev/mem for 64-bit kernel > >> > >> The new added memory can not be access by interface /dev/mem, because we do not > >> update the variable high_memory. This patch add a new e820 entry in e820 table, > >> and update max_pfn, max_low_pfn and high_memory. > >> > >> We add a function update_pfn in file arch/x86/mm/init.c to udpate these > >> varibles. Memory hotplug does not make sense on 32-bit kernel, so we did not > >> concern it in this function. > >> > > > > Memory hotplug makes sense on 32-bit kernels, at least in virtual > > environments. > > No VM currently supports it to my knowledge. They all use traditional > balooning. > > If someone adds that they can still fix it, but right now fixing it on 64bit > is the important part. > I wonder...with some modification, memory hotplug (or Mel's page coalescing) can be used for balloning in MAX_ORDER page size. I'm sorry if VM' baloon drivers has no fragmentaion problem. Thanks, -Kame -- 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/