From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from terminus.zytor.com ([2001:1868:205::10] helo=mail.zytor.com) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1Tzzjj-0006JO-2G for kexec@lists.infradead.org; Tue, 29 Jan 2013 01:11:43 +0000 Message-ID: <510721C6.6080705@zytor.com> Date: Mon, 28 Jan 2013 17:11:34 -0800 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: [PATCH 2/2] x86 e820: Introduce memmap=resetusablemap for kdump usage References: <1358868049-19884-1-git-send-email-trenn@suse.de> <6950516.1uefDuthAH@hammer82.arch.suse.de> In-Reply-To: <6950516.1uefDuthAH@hammer82.arch.suse.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Thomas Renninger Cc: x86@kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, horms@verge.net.au, Yinghai Lu , vgoyal@redhat.com On 01/28/2013 05:05 PM, Thomas Renninger wrote: > > But this (converting usable memory to reserved one before usable kdump memory > is added) will let machines run into problems again for which the check: > "mmconf area must be in reserved memory" got added? > > If, then memory which was usable before has to be converted to a special > E820_KUMP (or whatever type) to make sure existing checks which look for > "is reserved memory" still work the same way as in a productive kernel. > > Advantage of this would be that the info what originally was usable > memory is preserved and can be used in future kdump related patches. > > So I guess the final patch should be: > - Add a new e820 type: > E820_KDUMP_RESERVED /* Originally usable memory where the crashed > kernel kernel resided in */ > - Use Yinghai's last posted patch, but instead of: > + e820_update_range(0, ULLONG_MAX, E820_RAM, > + E820_RESERVED); > ... > + e820_remove_range(start_at, mem_size, E820_RESERVED, 0); > do: > + e820_update_range(0, ULLONG_MAX, E820_RAM, > + E820_KDUMP_RESERVED); > ... > + e820_remove_range(start_at, mem_size, E820_KDUMP_RESERVED, 0); > > - Come up with another memmap=kdump_reserve_ram memmap option name > or however it should get named... > > If this proposal gets accepted, I can send a tested patch... > Yes, this is much saner. There really shouldn't need to be an option, even; since the tools need to be modified anyway, just modify the actual memory map data structure itself. -hpa _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec