From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-6.0 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=unavailable autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 2C5747D8BB for ; Thu, 15 Nov 2018 14:13:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732953AbeKPAVI (ORCPT ); Thu, 15 Nov 2018 19:21:08 -0500 Received: from mail.skyhub.de ([5.9.137.197]:56794 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729010AbeKPAVI (ORCPT ); Thu, 15 Nov 2018 19:21:08 -0500 X-Virus-Scanned: Nedap ESD1 at mail.skyhub.de Received: from mail.skyhub.de ([127.0.0.1]) by localhost (blast.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id QPo6znDV46Cx; Thu, 15 Nov 2018 15:13:06 +0100 (CET) Received: from zn.tnic (p200300EC2BD00900D5714500C00E26FD.dip0.t-ipconnect.de [IPv6:2003:ec:2bd0:900:d571:4500:c00e:26fd]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 900891EC00CD; Thu, 15 Nov 2018 15:13:06 +0100 (CET) Date: Thu, 15 Nov 2018 15:13:07 +0100 From: Borislav Petkov To: Michal Hocko Cc: David Hildenbrand , Dave Young , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, devel@linuxdriverproject.org, linux-fsdevel@vger.kernel.org, linux-pm@vger.kernel.org, xen-devel@lists.xenproject.org, Andrew Morton , "Kirill A. Shutemov" , Baoquan He , Omar Sandoval , Arnd Bergmann , Matthew Wilcox , Lianbo Jiang , "Michael S. Tsirkin" Subject: Re: [PATCH RFC 3/6] kexec: export PG_offline to VMCOREINFO Message-ID: <20181115141307.GH26448@zn.tnic> References: <20181114211704.6381-1-david@redhat.com> <20181114211704.6381-4-david@redhat.com> <20181115061923.GA3971@dhcp-128-65.nay.redhat.com> <20181115111023.GC26448@zn.tnic> <4aa5d39d-a923-87de-d646-70b9cbfe62f0@redhat.com> <20181115115213.GE26448@zn.tnic> <20181115121102.GP23831@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20181115121102.GP23831@dhcp22.suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Thu, Nov 15, 2018 at 01:11:02PM +0100, Michal Hocko wrote: > I am not familiar with kexec to judge this particular patch but we > cannot simply define any range for these pages (same as for hwpoison > ones) because they can be almost anywhere in the available memory range. > Then there can be countless of them. There is no other way to rule them > out but to check the page state. I guess, especially if it is a monster box with a lot of memory in it. > I am not really sure what is the concern here exactly. Kdump is so > closly tight to the specific kernel version that the api exported > specifically for its purpose cannot be seriously considered an ABI. > Kdump has to adopt all the time. Right... Except, when people start ogling vmcoreinfo for other things and start exporting all kinds of kernel internals in there, my alarm bells start ringing. But ok, kdump *is* special and I guess that's fine. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.