Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757665Ab0GVHIL (ORCPT ); Thu, 22 Jul 2010 03:08:11 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:33032 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752004Ab0GVHIK (ORCPT ); Thu, 22 Jul 2010 03:08:10 -0400 To: Cong Wang Cc: linux-kernel@vger.kernel.org, nhorman@redhat.com, akpm@linux-foundation.org Subject: Re: [Patch] kexec: increase max of kexec segments and use dynamic allocation References: <20100722061810.5659.87609.sendpatchset@localhost.localdomain> <4C47E7C9.60608@redhat.com> From: ebiederm@xmission.com (Eric W. Biederman) Date: Thu, 22 Jul 2010 00:08:05 -0700 In-Reply-To: <4C47E7C9.60608@redhat.com> (Cong Wang's message of "Thu\, 22 Jul 2010 14\:40\:09 +0800") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-XM-SPF: eid=;;;mid=;;;hst=in01.mta.xmission.com;;;ip=67.188.4.80;;;frm=ebiederm@xmission.com;;;spf=neutral X-SA-Exim-Connect-IP: 67.188.4.80 X-SA-Exim-Mail-From: ebiederm@xmission.com X-SA-Exim-Scanned: No (on in01.mta.xmission.com); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1555 Lines: 40 Cong Wang writes: > On 07/22/10 14:28, Eric W. Biederman wrote: >> Amerigo Wang writes: >> >>> Currently KEXEC_SEGMENT_MAX is only 16 which is too small for machine with >>> many memory ranges. Increase this hard limit to 1024 which is reasonably large, >>> and change ->segment from a static array to a dynamically allocated memory. >> >> ??? >> >> This should be about segments in the executable being loaded. What >> executable has one segment for each range of physical memory? >> >> Not that generalizing this is a bad idea but with a comment that >> seems entirely wrong I am wondering what the problem really is. >> > > Ah, I think Neil should explain this. > > He made a patch which includes many memory ranges, caused kexec > fails to load the kernel. Increasing this limit and the corresponding > one in kexec-tools fixes the problem. His patch is not in upstream > kexec-tools, AFAIK. > > However, even if we don't consider that patch, isn't 16 too small too? Generally you just need one physical hunk for the code, maybe a second for the initrd. It is perfectly fine to raise the number of segments as it doesn't affect the ABI, but it wants a good explanation of what kind of weird application wants to write to all over memory when it is loaded. Eric -- 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/