From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f194.google.com (mail-pf1-f194.google.com [209.85.210.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7C64D3C3455 for ; Thu, 7 May 2026 09:42:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.194 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778146922; cv=none; b=nIRzEOA4/TXz6Yu/JzNmvEJySAEKt9XSM0h6mQJ9li9v7U2fWmxqIeS+J3TK/3rz/4/0jBmSN54exsA/PxsX2w7P2J5YOGPs+/5D4vJeQghxILUwK+zhq7Ul1lBequPW/qcwbd7OfuUWtvokPDFB0U2meCPB8sMHdORIAFJKhNE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778146922; c=relaxed/simple; bh=K1VCjRoLW0QcGM0dhJF4jAnQbIUr+A3+Rl8KKkOY/EQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=FtvctJZN3Fx8Z7gXn5ESLF7XfPJJm2fAO5O4ilrh6iZsBYc1NPcUjYciWH0YxKBDoJLshl7GuqinziQ1hISc/gplTCZetrLNmLzrOnaU5zjACeRVyjyxSJEHlS3h6cVQWJ2UROIvfaVOAxXJ5Hx4jQzEREnJ4YwbEXHPtdLB+Cc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=RfwUwx01; arc=none smtp.client-ip=209.85.210.194 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="RfwUwx01" Received: by mail-pf1-f194.google.com with SMTP id d2e1a72fcca58-83945063f70so854004b3a.0 for ; Thu, 07 May 2026 02:42:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1778146921; x=1778751721; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=JUrNwnrnHXKNK1Z+tsaGPk05Wyp59KKsZWMiHJkBCuY=; b=RfwUwx011PnAQCww545ZbYX91bbrYk2UfJ57++JfIXMjmyb0Eck3lgYjMPI+u5nH98 2u48n+FkDwdbdB7nfyOzqOJZ2u2TJeYLZdkNZkuVdWjfzlDIxbPQmui/NJINbfmtI6MQ 1RARiyUrlslScD7Ar/tQkKlbwAZyEBlDFhYEjslxv7XmtrpO35X/CDzAz8a/4hEMzRkT jBp307wJvS62s7mIxC7+j3x+BfggYwwHqcBtRJJyixFDUFgK8cAuK1GSj2cE1CKIqT1m 5/IXxTTAiV3q0do1TZdCCmh52uNbduY4tH6f9GvRc0bU+CM3ntqJV4tcGr9Jq0x9FnzS cvtw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778146921; x=1778751721; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=JUrNwnrnHXKNK1Z+tsaGPk05Wyp59KKsZWMiHJkBCuY=; b=dYT0JBe4Bg2PW31zDEhPjmEwN6TuuHV06noekyBK53kEXhA3KeDdjgtHSJxFYrM83R 5gSIpPTSuQrc43VhJPg/YTQmFcW+H9ArK+SvX0/8QlTHBaFUgljvWP2KswOZqCxBMIIm Eyz9UBblq5Euyct6UUcqoCLJWns29NXrfC308N6CgmWZyyLV77O6vvnMOfjrSoUbgb7A SQyrW8iIPjeTf4P4enSmQ+0bU6/bldW6y5+EgAeywMmWv1n54XQ3EKTM8d3J1g5itqew keF5hviEljseigC9GqwBsp9bzDVZBKsddE46XBhFAH+7l054AdopTzvFgsGMz3bILFf+ eh4A== X-Forwarded-Encrypted: i=1; AFNElJ8hAqFaaislmgKWOgJY6DSbYfNSAQcT1UvDS7T1WMY5C9kxQkm+oM/MOoZskXdNh+cV1jVqGBBmlD0zAcI=@vger.kernel.org X-Gm-Message-State: AOJu0YwZzDAvv8XLu8/uxSTPFAAH7SDP1qNHPhWskqYLpVy12+GUV2yG p3q1rGXaetdzFawWrVKkot3A8b+mfiO+kM+zHHp/Yg9m/Q7nS4nFeDlQ X-Gm-Gg: AeBDietN4+RYsA8h4SpH+Hm/YmjnB8rWZKQ+Mp0fnsanav07ibaZO1Cw8ORLazLjiOG +qe6wu+extDK91SXz/nR0cZn/UzydDqlOHV63ccwJI0ocbNkmK2MWuJYUGyL/ntB83vISlOwDpu sbbdnDSYQXh8gdZ0KgIbhVGTt1fGB6CofUh3iccMBujqxrb3zqH8vEIZ5hPudkwmTCVoealPGux CrMSEq8vHMTOl6Hefa1X0G28IHMZ0CYtXlA1BnGf9+HRvRsaJxK+BxMhGrqONaTSXP7k/58yajg NZtJhBgG8kRP9M+4xDLjL7ugrl8jksW4g8UJwsGR1KhbmYgZrCeBed7clI3T7MbZ63vfYCqzFXi VIJ/a4HYjdRD7P28t9nZ2FWq9zjgos3LTUsYAXOe3CP7ViDanp/KMt1hMRx1Ro3tgJbgSNmZb99 3G6jdJCNUYZfZKSRGZv1ZM+ObxXQv89ayoQBkfzWM5mt60CMkkwRMK X-Received: by 2002:a05:6a00:4093:b0:82f:3e9:7bec with SMTP id d2e1a72fcca58-83bb7abceeemr1949432b3a.12.1778146920796; Thu, 07 May 2026 02:42:00 -0700 (PDT) Received: from [10.125.112.20] ([210.184.73.204]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-83965c30ddasm10264549b3a.21.2026.05.07.02.41.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 07 May 2026 02:42:00 -0700 (PDT) Message-ID: Date: Thu, 7 May 2026 17:41:49 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 05/11] of: reserved_mem: add linux,no-dump property support for reserved memory regions To: Rob Herring 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 References: <20260429065831.1510858-1-chenwandun@lixiang.com> <20260429065831.1510858-6-chenwandun@lixiang.com> <20260506144542.GA2072596-robh@kernel.org> Content-Language: en-US From: Wandun In-Reply-To: <20260506144542.GA2072596-robh@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 5/6/26 22:45, Rob Herring wrote: > 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. Agree that the property direction is wrong. Rework in v2:   - Default: exclude reserved regions from vmcore   - CMA (reusable) setup path marks regions as kernel-managed general memory → include   - No DT binding needed; linux,no-dump proposal withdrawn Thanks. > > Rob