From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id 7CCD66B007B for ; Tue, 12 Jan 2010 08:36:16 -0500 (EST) Date: Tue, 12 Jan 2010 21:35:56 +0800 From: Wu Fengguang Subject: Re: [PATCH - resend] Memory-Hotplug: Fix the bug on interface /dev/mem for 64-bit kernel(v1) Message-ID: <20100112133556.GB7647@localhost> References: <20100108124851.GB6153@localhost> <20100111124303.GA21408@localhost> <20100112093031.0fc6877f.kamezawa.hiroyu@jp.fujitsu.com> <20100112023307.GA16661@localhost> <20100112113903.89163c46.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100112113903.89163c46.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: "Zheng, Shaohui" , "linux-mm@kvack.org" , "akpm@linux-foundation.org" , "linux-kernel@vger.kernel.org" , "ak@linux.intel.com" , "y-goto@jp.fujitsu.com" , Dave Hansen , "x86@kernel.org" , Yinghai Lu List-ID: On Tue, Jan 12, 2010 at 10:39:03AM +0800, KAMEZAWA Hiroyuki wrote: > On Tue, 12 Jan 2010 10:33:08 +0800 > Wu Fengguang wrote: > > > Sure, here it is :) > > --- > > x86: use the generic page_is_ram() > > > > The generic resource based page_is_ram() works better with memory > > hotplug/hotremove. So switch the x86 e820map based code to it. > > > > CC: Andi Kleen > > CC: KAMEZAWA Hiroyuki > > Signed-off-by: Wu Fengguang > > Ack. Thank you. > > > +#ifdef CONFIG_X86 > > + /* > > + * A special case is the first 4Kb of memory; > > + * This is a BIOS owned area, not kernel ram, but generally > > + * not listed as such in the E820 table. > > + */ > > + if (pfn == 0) > > + return 0; > > + > > + /* > > + * Second special case: Some BIOSen report the PC BIOS > > + * area (640->1Mb) as ram even though it is not. > > + */ > > + if (pfn >= (BIOS_BEGIN >> PAGE_SHIFT) && > > + pfn < (BIOS_END >> PAGE_SHIFT)) > > + return 0; > > +#endif > > I'm glad if this part is sorted out in clean way ;) Two possible solutions are: - to exclude the above two ranges directly in e820 map; - to not add the above two ranges into iomem_resource. Yinghai, do you have any suggestions? We want to get rid of the two explicit tests from page_is_ram(). Thanks, Fengguang -- 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