From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4336BC43441 for ; Tue, 27 Nov 2018 02:59:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 123F7208E4 for ; Tue, 27 Nov 2018 02:59:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 123F7208E4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728474AbeK0NzT (ORCPT ); Tue, 27 Nov 2018 08:55:19 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44294 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727741AbeK0NzT (ORCPT ); Tue, 27 Nov 2018 08:55:19 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8886630820CE; Tue, 27 Nov 2018 02:58:58 +0000 (UTC) Received: from localhost.localdomain (ovpn-12-79.pek2.redhat.com [10.72.12.79]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 438F060BE8; Tue, 27 Nov 2018 02:58:43 +0000 (UTC) Subject: Re: [PATCH 0/2 RESEND v7] add reserved e820 ranges to the kdump kernel e820 table To: Dave Hansen , linux-kernel@vger.kernel.org Cc: kexec@lists.infradead.org, x86@kernel.org, linux-ia64@vger.kernel.org, linux-efi@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, akpm@linux-foundation.org, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, ard.biesheuvel@linaro.org, tony.luck@intel.com, fenghua.yu@intel.com, dyoung@redhat.com, bhe@redhat.com References: <20181124051223.19994-1-lijiang@redhat.com> <35e8ade5-d5a8-b5e4-180b-44b4ff0a83b1@intel.com> From: lijiang Message-ID: <463c284b-115e-0784-ca07-a430127e6176@redhat.com> Date: Tue, 27 Nov 2018 10:58:38 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <35e8ade5-d5a8-b5e4-180b-44b4ff0a83b1@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Tue, 27 Nov 2018 02:58:58 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2018年11月27日 02:54, Dave Hansen 写道: > On 11/23/18 9:12 PM, Lianbo Jiang wrote: >> These patches add the new I/O resource descriptor 'IORES_DESC_RESERVED' >> for the iomem resources search interfaces, and in order to make it still >> work after the new descriptor is added, these codes originally related >> to 'IORES_DESC_NONE' have been updated. > > This is rather anemic "0/" text. Could you please include some more > background in here? The 2/2 patch is pretty good in this regard, but it > needs to be here, too. > Thanks for your comment. Originally, this patch added the e820 reserved ranges by accurately comparing a string. It only modifies fewer code paths. Please refer to patch v6. https://lore.kernel.org/lkml/20181114072926.13312-2-lijiang@redhat.com/ Because the string comparison is fragile and error-prone, this patch used the solution that adds a new descriptor 'IORES_DESC_RESERVED'. Please refer to this link: https://lore.kernel.org/lkml/20181120192935.GK2527@zn.tnic/ When passing the e820 reserved ranges to the second kernel, why does it need to compare strings accurately or add a new descriptor 'IORES_DESC_RESERVED'? -The reason is that it can not exactly match the e820 reserved resource ranges when walking through iomem resources with the descriptor 'IORES_DESC_NONE'. Thanks. Lianbo