Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753338Ab0LQEq4 (ORCPT ); Thu, 16 Dec 2010 23:46:56 -0500 Received: from rcsinet10.oracle.com ([148.87.113.121]:62314 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753170Ab0LQEqz (ORCPT ); Thu, 16 Dec 2010 23:46:55 -0500 Message-ID: <4D0AEB0F.5020909@kernel.org> Date: Thu, 16 Dec 2010 20:46:07 -0800 From: Yinghai Lu User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.16) Gecko/20101125 SUSE/3.0.11 Thunderbird/3.0.11 MIME-Version: 1.0 To: "H. Peter Anvin" CC: Vivek Goyal , Stanislaw Gruszka , Ingo Molnar , Thomas Gleixner , Maxim Uvarov , "linux-kernel@vger.kernel.org" , Neil Horman Subject: Re: kdump broken on 2.6.37-rc4 References: <20101207105053.GA2803@redhat.com> <4CFE89FE.1090901@kernel.org> <20101208141942.GA2335@redhat.com> <4D00823A.9050808@kernel.org> <20101209124117.GA6032@redhat.com> <4D01377B.5070809@kernel.org> <20101213100848.GA2237@redhat.com> <4D0663F0.2060103@kernel.org> <4D06783C.6040009@zytor.com> <20101214224135.GB19693@redhat.com> <20101215103954.GA2243@redhat.com> <4D09958D.2040907@kernel.org> <4D0AD976.3020504@zytor.com> <3C6B7683-9CDC-4C4A-A32A-56227DE01387@kernel.org> <4D0AE231.4010804@zytor.com> In-Reply-To: <4D0AE231.4010804@zytor.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2191 Lines: 60 On 12/16/2010 08:08 PM, H. Peter Anvin wrote: > On 12/16/2010 07:58 PM, Yinghai wrote: >> Please don't do that to 64 bit >> >> My big system with 1024g memory and a lot of cards with rhel 6 to make kdump work must have crashkernel=512m and second kernel need to take pci=nomsi >> >> Thanks >> > > Hm, this seems like an epic FAIL. > > First of all, the current code still limits it to 896 MiB, so 512 MiB is > not a significant restriction. You only have chance to get 512M under 896M but not under 512M. > > Second, this patch only applies if "crashkernel=" is not specified, so > it doesn't even apply to your situation. current code: /* 0 means: find the address automatically */ if (crash_base <= 0) { const unsigned long long alignment = 16<<20; /* 16M */ /* * kexec want bzImage is below DEFAULT_BZIMAGE_ADDR_MAX */ crash_base = memblock_find_in_range(alignment, DEFAULT_BZIMAGE_ADDR_MAX, crash_size, alignment); if (crash_base == MEMBLOCK_ERROR) { pr_info("crashkernel reservation failed - No suitable area found.\n"); return; } } else { unsigned long long start; start = memblock_find_in_range(crash_base, crash_base + crash_size, crash_size, 1<<20); if (start != crash_base) { pr_info("crashkernel reservation failed - memory is in use.\n"); return; } } first branch : will take only crash_size. second branch : will need to specify crash_base and crash_size. > > Third, if you have to specify "crashkernel=" that means that there is > yet another problem here that should be fixed. no, every kdump need to specify crashkernel=128M or more. Yinghai -- 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/