[{"id":3669632,"web_url":"http://patchwork.ozlabs.org/comment/3669632/","msgid":"","date":"2026-03-26T10:54:01","subject":"Re: [PATCH v10 6/8] arm64: kexec: Add support for crashkernel CMA\n reservation","submitter":{"id":938,"url":"http://patchwork.ozlabs.org/api/people/938/","name":"Catalin Marinas","email":"catalin.marinas@arm.com"},"content":"On Wed, Mar 25, 2026 at 10:59:02AM +0800, Jinjie Ruan wrote:\n> Commit 35c18f2933c5 (\"Add a new optional \",cma\" suffix to the\n> crashkernel= command line option\") and commit ab475510e042 (\"kdump:\n> implement reserve_crashkernel_cma\") added CMA support for kdump\n> crashkernel reservation.\n> \n> Crash kernel memory reservation wastes production resources if too\n> large, risks kdump failure if too small, and faces allocation difficulties\n> on fragmented systems due to contiguous block constraints. The new\n> CMA-based crashkernel reservation scheme splits the \"large fixed\n> reservation\" into a \"small fixed region + large CMA dynamic region\": the\n> CMA memory is available to userspace during normal operation to avoid\n> waste, and is reclaimed for kdump upon crash—saving memory while\n> improving reliability.\n> \n> So extend crashkernel CMA reservation support to arm64. The following\n> changes are made to enable CMA reservation:\n> \n> - Parse and obtain the CMA reservation size along with other crashkernel\n> parameters.\n> - Call reserve_crashkernel_cma() to allocate the CMA region for kdump.\n> - Include the CMA-reserved ranges for kdump kernel to use.\n> - Exclude the CMA-reserved ranges from the crash kernel memory to\n> prevent them from being exported through /proc/vmcore, which is already\n> done in the crash core.\n> \n> Update kernel-parameters.txt to document CMA support for crashkernel on\n> arm64 architecture.\n> \n> Acked-by: Rob Herring (Arm) \n> Acked-by: Baoquan He \n> Acked-by: Mike Rapoport (Microsoft) \n> Acked-by: Ard Biesheuvel \n> Signed-off-by: Jinjie Ruan \n\nAcked-by: Catalin Marinas ","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linuxppc-dev@lists.ozlabs.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=arm.com header.i=@arm.com header.a=rsa-sha256\n header.s=foss header.b=YVuxS70w;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org\n (client-ip=112.213.38.117; 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