Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752648Ab2FLGWK (ORCPT ); Tue, 12 Jun 2012 02:22:10 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:53388 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751670Ab2FLGWH (ORCPT ); Tue, 12 Jun 2012 02:22:07 -0400 X-IronPort-AV: E=Sophos;i="4.77,394,1336320000"; d="scan'208";a="5166319" Message-ID: <4FD6E101.3010106@cn.fujitsu.com> Date: Tue, 12 Jun 2012 14:26:09 +0800 From: Wen Congyang User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100413 Fedora/3.0.4-2.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: "H. Peter Anvin" CC: rob@landley.net, tglx@linutronix.de, Ingo Molnar , x86@kernel.org, "linux-kernel@vger.kernel.org" , bhelgaas@google.com Subject: Re: [PATCH 1/2 v2] x86: add max_addr boot option References: <4FD5AFF2.3040306@cn.fujitsu.com> <4FD65FD4.4060705@zytor.com> In-Reply-To: <4FD65FD4.4060705@zytor.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/06/12 14:22:39, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/06/12 14:22:40, Serialize complete at 2012/06/12 14:22:40 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1805 Lines: 43 At 06/12/2012 05:15 AM, H. Peter Anvin Wrote: > On 06/11/2012 01:44 AM, Wen Congyang wrote: >> Currently, the boot option max_addr is only supported on ia64 platform. >> We also need it on x86 platform. >> For example: >> There are two nodes: >> NODE#0 address range 0x00000000 00000000 - 0x00010000 00000000 >> NODE#1 address range 0x00010000 00000000 - 0x00020000 00000000 >> If we only want to use node0, we can specify the max_addr. The boot >> option "mem=" can do the same thing now. But the boot option "mem=" >> means the total memory used by the system. If we tell the user >> that the boot option "mem=" can do this, it will confuse the user. >> So we need an new boot option "max_addr" on x86 platform. >> > > I fail to see what this does that cannot be done with the > since-long-existing memmap= option. Could you address why memmap= > doesn't match your needs? The memmap= option is very diffcult to use. The end user should know the memory map in the system. The end user can get the max address of NODE#0, but he may not know the memory map for NODE#0. If the end user give the wrong memory map, the kernel can not boot. For example: I add memmap=16G@0 in the kernel parameter, and the kernel cannot boot. The max_addr is more easier to use. Thanks Wen Congyang > > -hpa > > -- > 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/ > -- 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/