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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 671DAC433E2 for ; Tue, 26 May 2020 02:28:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5050920823 for ; Tue, 26 May 2020 02:28:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388536AbgEZC2c (ORCPT ); Mon, 25 May 2020 22:28:32 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:5280 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2388459AbgEZC2c (ORCPT ); Mon, 25 May 2020 22:28:32 -0400 Received: from DGGEMS413-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id E1699FB94B3AC18B0138; Tue, 26 May 2020 10:28:28 +0800 (CST) Received: from [127.0.0.1] (10.166.213.90) by DGGEMS413-HUB.china.huawei.com (10.3.19.213) with Microsoft SMTP Server id 14.3.487.0; Tue, 26 May 2020 10:28:19 +0800 Subject: Re: [PATCH v8 0/5] support reserving crashkernel above 4G on arm64 kdump To: Baoquan He References: <20200521093805.64398-1-chenzhou10@huawei.com> <20200526014242.GF20045@MiWiFi-R3L-srv> CC: , , , , , , , , , , , , , , , From: chenzhou Message-ID: <7b17448f-ab1d-1849-3302-2446f4eb8710@huawei.com> Date: Tue, 26 May 2020 10:28:18 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <20200526014242.GF20045@MiWiFi-R3L-srv> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.166.213.90] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Baoquan, Thanks for your suggestions. You are right, some details should be made in the commit log. Thanks, Chen Zhou On 2020/5/26 9:42, Baoquan He wrote: > On 05/21/20 at 05:38pm, Chen Zhou wrote: >> This patch series enable reserving crashkernel above 4G in arm64. >> >> 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. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G, >> in this case, if swiotlb or DMA buffers are required, crash dump kernel >> will boot failure because there is no low memory available for allocation. >> >> To solve these issues, introduce crashkernel=X,low to reserve specified >> size low memory. >> Crashkernel=X tries to reserve memory for the crash dump kernel under >> 4G. If crashkernel=Y,low is specified simultaneously, reserve spcified >> size low memory for crash kdump kernel devices firstly and then reserve >> memory above 4G. >> >> When crashkernel is reserved above 4G in memory, that is, crashkernel=X,low >> is specified simultaneously, kernel should reserve specified size low memory >> for crash dump kernel devices. So there may be two crash kernel regions, one >> is below 4G, the other is above 4G. >> In order to distinct from the high region and make no effect to the use of >> kexec-tools, rename the low region as "Crash kernel (low)", and add DT property >> "linux,low-memory-range" to crash dump kernel's dtb to pass the low region. >> >> Besides, we need to modify kexec-tools: >> arm64: kdump: add another DT property to crash dump kernel's dtb(see [1]) >> >> The previous changes and discussions can be retrieved from: >> >> Changes since [v7] >> - Move x86 CRASH_ALIGN to 2M >> Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M. > OK, moving x86 CRASH_ALIGN to 2M is suggested by Dave. Because > CONFIG_PHYSICAL_ALIGN can be selected from 2M to 16M. So 2M seems good. > But, anyway, we should tell the reason why it need be changed in commit > log. > > > arch/x86/Kconfig: > config PHYSICAL_ALIGN > hex "Alignment value to which kernel should be aligned" > default "0x200000" > range 0x2000 0x1000000 if X86_32 > range 0x200000 0x1000000 if X86_64 > >> - Update Documentation/devicetree/bindings/chosen.txt >> Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt suggested by Arnd. >> - Add Tested-by from Jhon and pk >> >> Changes since [v6] >> - Fix build errors reported by kbuild test robot. >> >> Changes since [v5] >> - Move reserve_crashkernel_low() into kernel/crash_core.c. >> - Delete crashkernel=X,high. > And the crashkernel=X,high being deleted need be told too. Otherwise > people reading the commit have to check why themselves. I didn't follow > the old version, can't see why ,high can't be specified explicitly. > >> - Modify crashkernel=X,low. >> If crashkernel=X,low is specified simultaneously, reserve spcified size low >> memory for crash kdump kernel devices firstly and then reserve memory above 4G. >> In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then >> pass to crash dump kernel by DT property "linux,low-memory-range". >> - Update Documentation/admin-guide/kdump/kdump.rst. >> >> Changes since [v4] >> - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike. >> >> Changes since [v3] >> - Add memblock_cap_memory_ranges back for multiple ranges. >> - Fix some compiling warnings. >> >> Changes since [v2] >> - Split patch "arm64: kdump: support reserving crashkernel above 4G" as >> two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate >> patch. >> >> Changes since [v1]: >> - Move common reserve_crashkernel_low() code into kernel/kexec_core.c. >> - Remove memblock_cap_memory_ranges() i added in v1 and implement that >> in fdt_enforce_memory_region(). >> There are at most two crash kernel regions, for two crash kernel regions >> case, we cap the memory range [min(regs[*].start), max(regs[*].end)] >> and then remove the memory range in the middle. >> >> [1]: http://lists.infradead.org/pipermail/kexec/2020-May/025128.html >> [v1]: https://lkml.org/lkml/2019/4/2/1174 >> [v2]: https://lkml.org/lkml/2019/4/9/86 >> [v3]: https://lkml.org/lkml/2019/4/9/306 >> [v4]: https://lkml.org/lkml/2019/4/15/273 >> [v5]: https://lkml.org/lkml/2019/5/6/1360 >> [v6]: https://lkml.org/lkml/2019/8/30/142 >> [v7]: https://lkml.org/lkml/2019/12/23/411 >> >> Chen Zhou (5): >> x86: kdump: move reserve_crashkernel_low() into crash_core.c >> arm64: kdump: reserve crashkenel above 4G for crash dump kernel >> arm64: kdump: add memory for devices by DT property, low-memory-range >> kdump: update Documentation about crashkernel on arm64 >> dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump >> >> Documentation/admin-guide/kdump/kdump.rst | 13 ++- >> .../admin-guide/kernel-parameters.txt | 12 ++- >> Documentation/devicetree/bindings/chosen.txt | 25 ++++++ >> arch/arm64/kernel/setup.c | 8 +- >> arch/arm64/mm/init.c | 61 ++++++++++++- >> arch/x86/kernel/setup.c | 66 ++------------ >> include/linux/crash_core.h | 3 + >> include/linux/kexec.h | 2 - >> kernel/crash_core.c | 85 +++++++++++++++++++ >> kernel/kexec_core.c | 17 ---- >> 10 files changed, 208 insertions(+), 84 deletions(-) >> >> -- >> 2.20.1 >> >> >> _______________________________________________ >> kexec mailing list >> kexec@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/kexec >> > > . >