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Tue, 10 Nov 2020 22:01:45 -0500 X-MC-Unique: NLclD9OwP_ybVC6RRTUqOw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 309E8803F60; Wed, 11 Nov 2020 03:01:43 +0000 (UTC) Received: from localhost (ovpn-12-35.pek2.redhat.com [10.72.12.35]) by smtp.corp.redhat.com (Postfix) with ESMTPS id ED71C5C1D0; Wed, 11 Nov 2020 03:01:38 +0000 (UTC) Date: Wed, 11 Nov 2020 11:01:36 +0800 From: Baoquan He To: Chen Zhou , bhsharma@redhat.com Subject: Re: [PATCH v13 0/8] support reserving crashkernel above 4G on arm64 kdump Message-ID: <20201111030136.GD8486@MiWiFi-R3L-srv> References: <20201031074437.168008-1-chenzhou10@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201031074437.168008-1-chenzhou10@huawei.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201110_220200_684614_18A60863 X-CRM114-Status: GOOD ( 31.46 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: horms@verge.net.au, John.P.donnelly@oracle.com, guohanjun@huawei.com, xiexiuqi@huawei.com, arnd@arndb.de, will@kernel.org, corbet@lwn.net, catalin.marinas@arm.com, linux-doc@vger.kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, robh+dt@kernel.org, wangkefeng.wang@huawei.com, mingo@redhat.com, james.morse@arm.com, linux-arm-kernel@lists.infradead.org, huawei.libin@huawei.com, prabhakar.pkin@gmail.com, tglx@linutronix.de, dyoung@redhat.com, nsaenzjulienne@suse.de Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Zhou, Bhupesh On 10/31/20 at 03:44pm, Chen Zhou 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. > 3. Since commit 1a8e1cef7603 ("arm64: use both ZONE_DMA and ZONE_DMA32"), > if the memory reserved for crash dump kernel falled in ZONE_DMA32, > the devices in crash dump kernel need to use ZONE_DMA will alloc > fail. I went through this patchset, mainly the x86 related and generic changes, the changes look great and no risk. And I know Bhupesh is following up this and helping review, thanks, both. So you have also tested crashkernel reservation on x86_64, with the normal reservation, and high/low reservation, it is working well, right? Asking this because I didn't see the test result description, and just note it. Thanks Baoquan > > To solve these issues, change the behavior of crashkernel=X. > crashkernel=X tries low allocation in DMA zone (or the DMA32 zone if > CONFIG_ZONE_DMA is disabled), 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 (or the DMA32 zone if CONFIG_ZONE_DMA is disabled). > "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 eight patches: > 0001-x86-kdump-replace-the-hard-coded-alignment-with-macr.patch > 0002-x86-kdump-make-the-lower-bound-of-crash-kernel-reser.patch > 0003-x86-kdump-use-macro-CRASH_ADDR_LOW_MAX-in-functions-.patch > 0004-x86-kdump-move-reserve_crashkernel-_low-into-crash_c.patch > 0005-arm64-kdump-introduce-some-macroes-for-crash-kernel-.patch > 0006-arm64-kdump-reimplement-crashkernel-X.patch > 0007-arm64-kdump-add-memory-for-devices-by-DT-property-li.patch > 0008-kdump-update-Documentation-about-crashkernel.patch > > 0001-0003 are some x86 cleanups which prepares for making > functionsreserve_crashkernel[_low]() generic. > 0004 makes functions reserve_crashkernel[_low]() generic. > 0005-0006 reimplements arm64 crashkernel=X. > 0007 adds memory for devices by DT property linux,usable-memory-range. > 0008 updates the doc. > > 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 > > Chen Zhou (8): > 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 reserve_crashkernel[_low]() into crash_core.c > arm64: kdump: introduce some macroes for crash kernel reservation > arm64: kdump: reimplement crashkernel=X > arm64: kdump: add memory for devices by DT property > linux,usable-memory-range > kdump: update Documentation about crashkernel > > Documentation/admin-guide/kdump/kdump.rst | 23 ++- > .../admin-guide/kernel-parameters.txt | 12 +- > arch/arm64/include/asm/kexec.h | 15 ++ > arch/arm64/include/asm/processor.h | 1 + > arch/arm64/kernel/setup.c | 13 +- > arch/arm64/mm/init.c | 105 ++++------- > arch/arm64/mm/mmu.c | 4 + > arch/x86/include/asm/kexec.h | 28 +++ > arch/x86/kernel/setup.c | 153 +--------------- > include/linux/crash_core.h | 4 + > include/linux/kexec.h | 2 - > kernel/crash_core.c | 168 ++++++++++++++++++ > kernel/kexec_core.c | 17 -- > 13 files changed, 301 insertions(+), 244 deletions(-) > > -- > 2.20.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel