From: Rob Herring <robh@kernel.org>
To: Chen Wandun <chenwandun1@gmail.com>
Cc: kexec@lists.infradead.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev,
linux-riscv@lists.infradead.org, devicetree@vger.kernel.org,
akpm@linux-foundation.org, bhe@redhat.com, rppt@kernel.org,
pasha.tatashin@soleen.com, pratyush@kernel.org,
ruirui.yang@linux.dev, corbet@lwn.net, skhan@linuxfoundation.org,
catalin.marinas@arm.com, will@kernel.org, chenhuacai@kernel.org,
kernel@xen0n.name, pjw@kernel.org, palmer@dabbelt.com,
aou@eecs.berkeley.edu, saravanak@kernel.org,
chenwandun@lixiang.com, zhaomeijing@lixiang.com,
everyzhao@126.com
Subject: Re: [PATCH 05/11] of: reserved_mem: add linux,no-dump property support for reserved memory regions
Date: Wed, 6 May 2026 09:45:42 -0500 [thread overview]
Message-ID: <20260506144542.GA2072596-robh@kernel.org> (raw)
In-Reply-To: <20260429065831.1510858-6-chenwandun@lixiang.com>
On Wed, Apr 29, 2026 at 02:58:25PM +0800, Chen Wandun wrote:
> Add a 'no_dump' field to struct reserved_mem and parse the
> 'linux,no-dump' device tree property during reserved memory node
> initialization. This property allows device tree authors to mark
> specific reserved memory regions that should be excluded from kdump
> vmcore dumps.
>
> Reserved memory regions used by device firmware (e.g., GPU, DSP, modem)
> typically contain data that is not useful for kernel crash analysis and
> can significantly increase vmcore size. The 'linux,no-dump' property
> provides a declarative way to indicate these regions should be filtered
> out when constructing the elfcorehdr for kdump.
>
> The property is named with a 'linux,' prefix because kdump/vmcore is
> Linux-specific and the property is an OS hint rather than a hardware
> description, matching existing properties such as 'linux,cma-default'
> and 'linux,usable-memory-range'.
>
> The 'linux,no-dump' property is only effective when the region:
> - Does not have 'no-map': these regions are already excluded from
> vmcore since they are removed from the linear mapping (MEMBLOCK_NOMAP).
> - Does not have 'reusable': CMA reusable regions are actively used by
> the kernel for movable page allocations, and their contents are
> valuable for crash analysis.
>
> The no-dump status is also printed in the boot log alongside the
> existing nomap and reusable flags for diagnostic purposes.
I think this property is the wrong way around and probably not needed.
The default should be exclude the regions, but if Linux is using the
regions (like CMA) then it can decide on its own to include them.
With the restructuring that went into 7.1, it should be possible for the
CMA code (and code for any other regions) to set some flag for the
region.
Rob
next prev parent reply other threads:[~2026-05-06 14:45 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-29 6:58 [PATCH 00/11] kdump: reduce vmcore size and capture time via linux,no-dump Chen Wandun
2026-04-29 6:58 ` [PATCH 01/11] of: reserved_mem: fix region count for nodes with multiple reg entries Chen Wandun
2026-05-06 1:47 ` Rob Herring
2026-04-29 6:58 ` [PATCH 02/11] of: reserved_mem: reject reserved memory outside physical address range Chen Wandun
2026-05-06 1:51 ` Rob Herring
2026-04-29 6:58 ` [PATCH 03/11] of: reserved_mem: avoid unconditional save of reg entries in fdt_scan_reserved_mem_late() Chen Wandun
2026-04-29 6:58 ` [PATCH 04/11] of: reserved_mem: skip reserved_mem array allocation when there is nothing to save Chen Wandun
2026-04-29 6:58 ` [PATCH 05/11] of: reserved_mem: add linux,no-dump property support for reserved memory regions Chen Wandun
2026-05-06 14:45 ` Rob Herring [this message]
2026-04-29 6:58 ` [PATCH 06/11] of: reserved_mem: save /memreserve/ entries into reserved_mem array Chen Wandun
2026-04-29 6:58 ` [PATCH 07/11] of: reserved_mem: add no-dump crash_mem exclusion helpers Chen Wandun
2026-05-06 14:50 ` Rob Herring
2026-04-29 6:58 ` [PATCH 08/11] arm64: kdump: exclude no-dump reserved memory regions from vmcore Chen Wandun
2026-04-29 6:58 ` [PATCH 09/11] riscv: " Chen Wandun
2026-04-29 6:58 ` [PATCH 10/11] loongarch: " Chen Wandun
2026-04-29 6:58 ` [PATCH 11/11] Documentation: admin-guide: kdump: document linux,no-dump DT property Chen Wandun
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