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 36CECC433F5 for ; Mon, 13 Dec 2021 18:57:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242042AbhLMS5H (ORCPT ); Mon, 13 Dec 2021 13:57:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47258 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236468AbhLMS5F (ORCPT ); Mon, 13 Dec 2021 13:57:05 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 341E3C0613FE; Mon, 13 Dec 2021 10:57:02 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D410DB81259; Mon, 13 Dec 2021 18:57:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 980D3C34605; Mon, 13 Dec 2021 18:56:55 +0000 (UTC) Date: Mon, 13 Dec 2021 18:56:52 +0000 From: Catalin Marinas To: john.p.donnelly@oracle.com Cc: Zhen Lei , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H . Peter Anvin" , linux-kernel@vger.kernel.org, Dave Young , Baoquan He , Vivek Goyal , Eric Biederman , kexec@lists.infradead.org, Will Deacon , linux-arm-kernel@lists.infradead.org, Rob Herring , Frank Rowand , devicetree@vger.kernel.org, Jonathan Corbet , linux-doc@vger.kernel.org, Randy Dunlap , Feng Zhou , Kefeng Wang , Chen Zhou Subject: Re: [PATCH v17 00/10] support reserving crashkernel above 4G on arm64 kdump Message-ID: References: <20211210065533.2023-1-thunder.leizhen@huawei.com> <5ef3ef54-33db-3cb2-4908-8bd1254749e3@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5ef3ef54-33db-3cb2-4908-8bd1254749e3@oracle.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 13, 2021 at 08:37:48AM -0600, john.p.donnelly@oracle.com wrote: > On 12/10/21 12:55 AM, 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. > > > > Changes since [v15] > > - Aggregate the processing of "linux,usable-memory-range" into one function. > > Only patch 9-10 have been updated. > > > > Changes since [v14] > > - Recovering the requirement that the CrashKernel memory regions on X86 > > only requires 1 MiB alignment. > > - Combine patches 5 and 6 in v14 into one. The compilation warning fixed > > by patch 6 was introduced by patch 5 in v14. > > - As with crashk_res, crashk_low_res is also processed by > > crash_exclude_mem_range() in patch 7. > > - Due to commit b261dba2fdb2 ("arm64: kdump: Remove custom linux,usable-memory-range handling") > > has removed the architecture-specific code, extend the property "linux,usable-memory-range" > > in the platform-agnostic FDT core code. See patch 9. > > - Discard the x86 description update in the document, because the description > > has been updated by commit b1f4c363666c ("Documentation: kdump: update kdump guide"). > > - Change "arm64" to "ARM64" in Doc. > > > > > > Changes since [v13] > > - Rebased on top of 5.11-rc5. > > - Introduce config CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL. > > Since reserve_crashkernel[_low]() implementations are quite similar on > > other architectures, so have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in > > arch/Kconfig and select this by X86 and ARM64. > > - Some minor cleanup. > > > > Changes since [v12] > > - Rebased on top of 5.10-rc1. > > - Keep CRASH_ALIGN as 16M suggested by Dave. > > - Drop patch "kdump: add threshold for the required memory". > > - Add Tested-by from John. > > > > Changes since [v11] > > - Rebased on top of 5.9-rc4. > > - Make the function reserve_crashkernel() of x86 generic. > > Suggested by Catalin, make the function reserve_crashkernel() of x86 generic > > and arm64 use the generic version to reimplement crashkernel=X. > > > > Changes since [v10] > > - Reimplement crashkernel=X suggested by Catalin, Many thanks to Catalin. > > > > Changes since [v9] > > - Patch 1 add Acked-by from Dave. > > - Update patch 5 according to Dave's comments. > > - Update chosen schema. > > > > Changes since [v8] > > - Reuse DT property "linux,usable-memory-range". > > Suggested by Rob, reuse DT property "linux,usable-memory-range" to pass the low > > memory region. > > - Fix kdump broken with ZONE_DMA reintroduced. > > - Update chosen schema. > > > > Changes since [v7] > > - Move x86 CRASH_ALIGN to 2M > > Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M. > > - 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. > > - 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-June/020737.html > > [2]: https://github.com/robherring/dt-schema/pull/19 > > [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 > > [v8]: https://lkml.org/lkml/2020/5/21/213 > > [v9]: https://lkml.org/lkml/2020/6/28/73 > > [v10]: https://lkml.org/lkml/2020/7/2/1443 > > [v11]: https://lkml.org/lkml/2020/8/1/150 > > [v12]: https://lkml.org/lkml/2020/9/7/1037 > > [v13]: https://lkml.org/lkml/2020/10/31/34 > > [v14]: https://lkml.org/lkml/2021/1/30/53 > > [v15]: https://lkml.org/lkml/2021/10/19/1405 > > [v16]: https://lkml.org/lkml/2021/11/23/435 > > > > > > Chen Zhou (9): > > x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN > > x86: kdump: make the lower bound of crash kernel reservation > > consistent > > x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions > > reserve_crashkernel() > > x86: kdump: move xen_pv_domain() check and insert_resource() to > > setup_arch() > > x86: kdump: move reserve_crashkernel[_low]() into crash_core.c > > arm64: kdump: introduce some macros for crash kernel reservation > > arm64: kdump: reimplement crashkernel=X > > of: fdt: Add memory for devices by DT property > > "linux,usable-memory-range" > > kdump: update Documentation about crashkernel > > > > Zhen Lei (1): > > of: fdt: Aggregate the processing of "linux,usable-memory-range" > > > > Documentation/admin-guide/kdump/kdump.rst | 11 +- > > .../admin-guide/kernel-parameters.txt | 11 +- > > arch/Kconfig | 3 + > > arch/arm64/Kconfig | 1 + > > arch/arm64/include/asm/kexec.h | 10 ++ > > arch/arm64/kernel/machine_kexec_file.c | 12 +- > > arch/arm64/kernel/setup.c | 13 +- > > arch/arm64/mm/init.c | 59 ++----- > > arch/x86/Kconfig | 2 + > > arch/x86/include/asm/elf.h | 3 + > > arch/x86/include/asm/kexec.h | 31 +++- > > arch/x86/kernel/setup.c | 163 ++---------------- > > drivers/of/fdt.c | 42 +++-- > > include/linux/crash_core.h | 3 + > > include/linux/kexec.h | 2 - > > kernel/crash_core.c | 156 +++++++++++++++++ > > kernel/kexec_core.c | 17 -- > > 17 files changed, 301 insertions(+), 238 deletions(-) > > After 2 years, and 17 versions, can we now get this series promoted into a > build ? We don't push patches to linux-next while there are still pending issues. The v17 looks alright though, I'll push it out for a bit more coverage and, if there are no objections, it should land in 5.17. -- Catalin