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b=Mt3hXrxeKJoJfLibADZIcsXR7rI+NO9d5jFB7CsWQi7wKkA7Ivi+NuujoLsu6N0Sj xeAk+R1NrRVYx1sYEncPNYK1tOB4gOmoV/soXvOeMmPj9evSIL4UZE8ME5ru4NQo5h rdmao/ez90tKUwo3/XUgCH2iLLiz95UkX5/e2YrP1miGaCfo8O/R8cfIYLVig3VVnr r1iNDVPFLS7bpM7kU7EAqqH+8hkxOiLRbqqi3tb+hZaOnZwWSQEHk7khqjrR4q7t3A S0lU2etMBYUN25UboD24fjrlEjMmDt+fIwEsaB4T+GmpTzCmxcQVMevggk/I2FaJ6K 4dRr3m+UTBq7A== Date: Wed, 21 Oct 2026 08:23:08 -0500 From: Rob Herring To: Wandun Chen Cc: baoquan.he@linux.dev, rppt@kernel.org, m.szyprowski@samsung.com, catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, chenhuacai@kernel.org, kernel@xen0n.name, pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, saravanak@kernel.org, akpm@linux-foundation.org, pasha.tatashin@soleen.com, pratyush@kernel.org, ruirui.yang@linux.dev, robin.murphy@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, kexec@lists.infradead.org, linux-mm@kvack.org, iommu@lists.linux.dev Subject: Re: [PATCH v9 0/8] kdump: reduce vmcore size and capture time Message-ID: <20261021132308.GB3667411-robh@kernel.org> References: <20261021083011.2170525-1-chenwandun1@gmail.com> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261021083011.2170525-1-chenwandun1@gmail.com> X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 5CECD4000E X-Stat-Signature: 9ustt7gm6fk9i6x95pjakt73ah6q999t X-Rspam-User: X-Spam-Status: No, score=-6.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-HE-Tag: 1792588991-359761 X-HE-Meta: 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 ky7u9vLD jhk2LJ8ulkR5GFOxEWZvX/swc0CUDGkqBYHtIZ3LisPkDiJ/OnuRGjSp5/hUVhWI/5SXEOwn7/aQ2a/0cZD8LexzPj1JWe1/2HAYEVNSHTXJNGsx7Q5f9gFrIwzmPU3B0lioIHDB7h146r1JUUWLGEM0Crp7NEnODdDmZUiDDdXxdV9eHZuUFiTbrNw+MXwBZ5YPz6Lr5Pl2DS5F0AfjegmJq1JKobszMU0e/HxbtdS77SbbGf4mJ1/3sxW8Sl6nuWTo/eXr2GS3n/UIqXN/+A4DPwzWIBoTi51tQLf9bRQjbq9k1g5iaRnM91LecmZgH648fR04J0F/pccIfwCdjb8ikazfMUmu+3BzdwcVGqJ8hmAk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Wed, Oct 21, 2026 at 04:30:03PM +0800, Wandun Chen wrote: > From: Wandun Chen > > On SoCs that carve out large firmware-owned reserved memory (GPU, > camera ISP, ...), kdump currently dumps those carveouts as part of > system RAM even though their contents are firmware state that is not > useful for kernel crash analysis. > > ACPI systems already filter reserved memory out of the vmcore through > their existing path: firmware reports those carveouts as unusable in > the EFI memory map, they get MEMBLOCK_NOMAP set in memblock.memory > (is_usable_memory(), efi-init.c), and the ELF header builder has > always skipped nomap regions; only DT-based systems currently fail > to filter these regions, which is what this series addresses. > > This series introduces a MEMBLOCK_NODUMP flag (suggested by Rob) in > memblock to filter reserved memory on DT-based architectures. A new > flag is needed because MEMBLOCK_NOMAP can only express regions without > a linear mapping, while MEMBLOCK_NODUMP can filter regions that are > linearly mapped. Reserved regions are marked MEMBLOCK_NODUMP by default > so kdump omits them; reusable CMA regions are different because their > pages are handed back to the buddy allocator and may carry crash-relevant > data. There is little point in continuing to send new versions until Mike agrees with MEMBLOCK_NODUMP being added. You didn't answer him on v7. Also, I intend to apply this[1] before any further reserved memory changes which will greatly simplify the code. Rob [1] https://lore.kernel.org/all/20261015082315.56876-1-m.szyprowski@samsung.com/