Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753284Ab2FLQKe (ORCPT ); Tue, 12 Jun 2012 12:10:34 -0400 Received: from terminus.zytor.com ([198.137.202.10]:43150 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751745Ab2FLQKd (ORCPT ); Tue, 12 Jun 2012 12:10:33 -0400 References: <4FD5AFF2.3040306@cn.fujitsu.com> <4FD65FD4.4060705@zytor.com> <4FD6E101.3010106@cn.fujitsu.com> User-Agent: K-9 Mail for Android In-Reply-To: <4FD6E101.3010106@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: Re: [PATCH 1/2 v2] x86: add max_addr boot option From: "H. Peter Anvin" Date: Tue, 12 Jun 2012 09:10:05 -0700 To: Wen Congyang CC: rob@landley.net, tglx@linutronix.de, Ingo Molnar , x86@kernel.org, "linux-kernel@vger.kernel.org" , bhelgaas@google.com Message-ID: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2045 Lines: 56 If what you care about is nodes, why not have an option to specify a map? Wen Congyang wrote: >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/ >> -- Sent from my mobile phone. Please excuse brevity and lack of formatting. -- 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/