From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from us-smtp-2.mimecast.com ([205.139.110.61] helo=us-smtp-delivery-1.mimecast.com) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jdOcU-0005es-Pi for kexec@lists.infradead.org; Tue, 26 May 2020 01:43:08 +0000 Date: Tue, 26 May 2020 09:42:42 +0800 From: Baoquan He Subject: Re: [PATCH v8 0/5] support reserving crashkernel above 4G on arm64 kdump Message-ID: <20200526014242.GF20045@MiWiFi-R3L-srv> References: <20200521093805.64398-1-chenzhou10@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200521093805.64398-1-chenzhou10@huawei.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Chen Zhou Cc: horms@verge.net.au, John.p.donnelly@oracle.com, arnd@arndb.de, will@kernel.org, devicetree@vger.kernel.org, catalin.marinas@arm.com, linux-doc@vger.kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, robh+dt@kernel.org, mingo@redhat.com, guohanjun@huawei.com, tglx@linutronix.de, pkushwaha@marvell.com, dyoung@redhat.com, linux-arm-kernel@lists.infradead.org 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 > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec