From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx182.postini.com [74.125.245.182]) by kanga.kvack.org (Postfix) with SMTP id 8953F6B0008 for ; Thu, 21 Feb 2013 13:21:48 -0500 (EST) Received: by mail-ve0-f178.google.com with SMTP id db10so8265052veb.9 for ; Thu, 21 Feb 2013 10:21:47 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <51242908.2050308@huawei.com> References: <51074786.5030007@huawei.com> <1359995565.7515.178.camel@mfleming-mobl1.ger.corp.intel.com> <51131248.3080203@huawei.com> <5113450C.1080109@huawei.com> <51242908.2050308@huawei.com> Date: Thu, 21 Feb 2013 10:21:46 -0800 Message-ID: Subject: Re: [PATCH V3] ia64/mm: fix a bad_page bug when crash kernel booting From: Tony Luck Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Xishi Qiu Cc: Matt Fleming , fenghua.yu@intel.com, Liujiang , Andrew Morton , linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, linux-mm@kvack.org, Hanjun Guo , WuJianguo , linux-arch@vger.kernel.org On Tue, Feb 19, 2013 at 5:38 PM, Xishi Qiu wrote: > Seems like a good idea, should we modify "\linux\Documentation\kernel-parameters.txt"? Perhaps in Documentation/kdump/kdump.txt (which the crashkernel entry in kernel-parameters.txt points at). The ia64 section of kdump.txt notes that the start address will be rounded up to a GRANULE boundary, but doesn't talk about restrictions on the size. I wonder if any other architectures have alignment restrictions on the addresses in "crashkernel" parameters? Does x86 like them to be 2MB aligned? Second question is whether we should check and warn in parse_crashkernel_mem()? I think the answer is "yes" (since the consequences of getting this wrong don't show up till much later, and the errors aren't all that obviously connected back to the original mistake). Perhaps each architecture that cares could provide defines: #define ARCH_CRASH_KERNEL_START_ALIGN (... arch value here ...) #define ARCH_CRASH_KERNEL_SIZE_ALIGN (... arch value here ...) [Suggestion provided mostly to provoke somebody to provide a more elegant solution] -Tony -- 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