Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E738EC433F5 for ; Fri, 10 Dec 2021 07:15:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237341AbhLJHSk (ORCPT ); Fri, 10 Dec 2021 02:18:40 -0500 Received: from szxga03-in.huawei.com ([45.249.212.189]:29171 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232025AbhLJHSi (ORCPT ); Fri, 10 Dec 2021 02:18:38 -0500 Received: from dggpemm500021.china.huawei.com (unknown [172.30.72.54]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4J9MYf5c15z8vnk; Fri, 10 Dec 2021 15:12:54 +0800 (CST) Received: from dggpemm500001.china.huawei.com (7.185.36.107) by dggpemm500021.china.huawei.com (7.185.36.109) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Fri, 10 Dec 2021 15:15:02 +0800 Received: from [10.174.177.243] (10.174.177.243) by dggpemm500001.china.huawei.com (7.185.36.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2308.20; Fri, 10 Dec 2021 15:15:01 +0800 Message-ID: Date: Fri, 10 Dec 2021 15:15:00 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [PATCH v17 00/10] support reserving crashkernel above 4G on arm64 kdump Content-Language: en-US To: Zhen Lei , Thomas Gleixner , Ingo Molnar , Borislav Petkov , , "H . Peter Anvin" , , Dave Young , Baoquan He , Vivek Goyal , Eric Biederman , , Catalin Marinas , Will Deacon , , Rob Herring , Frank Rowand , , "Jonathan Corbet" , CC: Randy Dunlap , Feng Zhou , Chen Zhou References: <20211210065533.2023-1-thunder.leizhen@huawei.com> From: Kefeng Wang In-Reply-To: <20211210065533.2023-1-thunder.leizhen@huawei.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggeme710-chm.china.huawei.com (10.1.199.106) To dggpemm500001.china.huawei.com (7.185.36.107) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/12/10 14:55, Zhen Lei wrote: > There are following issues in arm64 kdump: > 1. We use crashkernel=X to reserve crashkernel below 4G, which > will fail when there is no enough low memory. > 2. If reserving crashkernel above 4G, in this case, crash dump > kernel will boot failure because there is no low memory available > for allocation. > > To solve these issues, change the behavior of crashkernel=X. > crashkernel=X tries low allocation in DMA zone and fall back to high > allocation if it fails. > > We can also use "crashkernel=X,high" to select a high region above > DMA zone, which also tries to allocate at least 256M low memory in > DMA zone automatically and "crashkernel=Y,low" can be used to allocate > specified size low memory. > > When reserving crashkernel in high memory, some low memory is reserved > for crash dump kernel devices. So there may be two regions reserved for > crash dump kernel. > In order to distinct from the high region and make no effect to the use > of existing kexec-tools, rename the low region as "Crash kernel (low)", > and pass the low region by reusing DT property > "linux,usable-memory-range". We made the low memory region as the last > range of "linux,usable-memory-range" to keep compatibility with existing > user-space and older kdump kernels. > > Besides, we need to modify kexec-tools: > arm64: support more than one crash kernel regions(see [1]) > > Another update is document about DT property 'linux,usable-memory-range': > schemas: update 'linux,usable-memory-range' node schema(see [2]) > > This patchset contains the following 10 patches: > > 0001-0004 are some x86 cleanups which prepares for making functionsreserve_crashkernel[_low]() generic. > 0005 makes functions reserve_crashkernel[_low]() generic. > 0006-0007 reimplements arm64 crashkernel=X. > 0008-0009 adds memory for devices by DT property linux,usable-memory-range. > 0010 updates the doc. > > Changes since [v16] > - Because no functional changes in this version, so add > "Tested-by: Dave Kleikamp " for patch 1-9 > - Add "Reviewed-by: Rob Herring " for patch 8 > - Update patch 9 based on the review comments of Rob Herring > - As Catalin Marinas's suggestion, merge the implementation of > ARCH_WANT_RESERVE_CRASH_KERNEL into patch 5. Ensure that the > contents of X86 and ARM64 do not overlap, and reduce unnecessary > temporary differences. An Internal review has been done, so for this series, Reviewed-by: Kefeng Wang