From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 826F4CAC592 for ; Tue, 16 Sep 2025 20:20:11 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C99678E0003; Tue, 16 Sep 2025 16:20:10 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C495A8E0001; Tue, 16 Sep 2025 16:20:10 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B37FD8E0003; Tue, 16 Sep 2025 16:20:10 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 9BDC78E0001 for ; Tue, 16 Sep 2025 16:20:10 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 47DBF1DD9D1 for ; Tue, 16 Sep 2025 20:20:10 +0000 (UTC) X-FDA: 83896230180.13.3AC29A5 Received: from mail-wm1-f52.google.com (mail-wm1-f52.google.com [209.85.128.52]) by imf03.hostedemail.com (Postfix) with ESMTP id 3328C20008 for ; Tue, 16 Sep 2025 20:20:07 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=linaro.org header.s=google header.b="ETu/EElK"; spf=pass (imf03.hostedemail.com: domain of eugen.hristev@linaro.org designates 209.85.128.52 as permitted sender) smtp.mailfrom=eugen.hristev@linaro.org; dmarc=pass (policy=none) header.from=linaro.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1758054008; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=N+HzBTD2N3JCRvAB6oxwbdGwQ+4oKdqc9xdspcyNKo4=; b=A27cf/l9sfHga9Um8eNRWQDLGnSnVhfuV8v1uI8aIa60n/mT5I9VXwm0vrA1xGvr0FaEuA KVBqFQj3mjdoHA3MIzVYUbWZNHyCdfxBHyRw+lDJMOwlvigOwTgGkhM8vrrT9xkRiLpowY TkoA+oiDaWsmPRUjoU8eUDx+qLWZGvs= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1758054008; a=rsa-sha256; cv=none; b=kdq7THESg33mwT/hZQWcgx4kFLyDIse1gSHmB8zYdlPF5vELI6t6rWHUUmekNiNE/e8XYB Im5bazSScFAnNbEWrHIN8c41WcL3EJbSyjL2wpH0nm4xzn2MJFcJaTfJGMhM5XdX74tf0I IM1Vu8EBttAd4tb0MgvIzodfPqy2eUU= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=linaro.org header.s=google header.b="ETu/EElK"; spf=pass (imf03.hostedemail.com: domain of eugen.hristev@linaro.org designates 209.85.128.52 as permitted sender) smtp.mailfrom=eugen.hristev@linaro.org; dmarc=pass (policy=none) header.from=linaro.org Received: by mail-wm1-f52.google.com with SMTP id 5b1f17b1804b1-45f2f7ae386so19695655e9.3 for ; Tue, 16 Sep 2025 13:20:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1758054006; x=1758658806; darn=kvack.org; h=content-transfer-encoding:in-reply-to:content-language:from :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=N+HzBTD2N3JCRvAB6oxwbdGwQ+4oKdqc9xdspcyNKo4=; b=ETu/EElKw6o4l1xZvKJNFfcUf9wXp8/JlomlPFmvA7kMFrMa5JVv0fB0Yt/cTHP53I Qf+3BuvbFNrmWf0C9tftwYsx4jMughbkKdoNvPymH5eOChDm2zRBRbIGoFzLJswfo6iD RYK+qGl8cjn0rFLEuvfkFxXzphbJ/cH5acUIwzBod4qjQ1RMVAy2M/7EVMG/whW9vYMb AmW+27nClRK+cddihG3YR9aBnunGdGvakdoMjAayZhuWe6avTf0vJ92zBozAhxsm867L suEaTVzV5uAk7la2mb7ZPj3T316ivkz8JSDVrRKCT234uu5/4p8oYgmtPrfxY7m8lpmp NB8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1758054006; x=1758658806; h=content-transfer-encoding:in-reply-to:content-language:from :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=N+HzBTD2N3JCRvAB6oxwbdGwQ+4oKdqc9xdspcyNKo4=; b=uxBw6qP82KbgqE1FXJP/WZZXaRKlW/t5NoDXJikBTkjJDCkDf7dN5RwgOE3fparwES gPwr3/Z1XiVFfSaCyu01DlDq7BUTbaFiSfrtosMPO+3Z4L4XqQXXekpEjEhFl5Q1eNV3 BBXmhHI7KsycTNOcoJRuVZa6ZFtAsnk+8GXw2F8/okO/rfXvliTir4HvWoEb3wCYqqQj gjRfF0+n1IA8cD+BNBCuENCQaR7VynpYIN/aG17QpZjEoF/OVivNNPmmdBulGbEDLIg1 WRxBzUMVhlMHtEDzOgEU/VU9qT1yuwGRvkC+h/Wcqg3ZGAaMcY85PJGO6j27cuVqJq/b aEew== X-Forwarded-Encrypted: i=1; AJvYcCXYVl+9arUso8CiIgq638p73eFMMw4dQgspW3855E7GOTVoTKFkysmFe5kqMHYtBkU4wu3JDiEsfw==@kvack.org X-Gm-Message-State: AOJu0YwXTt793VoDhCYw73yAgRgIkq//k6gp55Gg/hnA1dj3qvieMzXA /dNXCPa/Sfh9pAQwarL8nDMnQyUG1LOM/u5IZvZp+nFkUqjYkCz8JgfwscLrAcUyfbY= X-Gm-Gg: ASbGnctTSF7DhOpViE8S6MqM/zSpZy+KNNG+yqEADtv57hdy7UlYmldXbFgTIInxzZF cgsE3xluZEqFvL4MUCqIA6eJ5pstqhqGYngd2nmCsHqohJNeo9GmNIfOyaKDnsRDmrL2l2JnCUT HcIexJALbsZDF+SDwLcugpDHHqS4INUGBcveM20yMKtUAnYi0T3QKyWrkkcXpO3LBRQ37GFiF9L sF/NAVT3voteUUvk4B9bLISDuTIA7TYJl1cr5JXLo3lyMWfWwIjLTjqxq/FMBNbSmH3fHeD/cFp SjlL3EG7fHX49dR6gGHTk32YaW24mWFBSTaZICzPADvWq+GQlEMRcX/oDYSg6a/UNYF6KgQ4sDq qi5m9dXl38S+2SQwcsjTqzmAGIYnzaQ== X-Google-Smtp-Source: AGHT+IGcnQ6MGxag1NEEIYuYJVLpZTLnzAxoZ0Qb6L436YEus+DLZOYlhdl12Vu/LiBk6DmaVXtczA== X-Received: by 2002:a05:600c:3154:b0:45b:83fe:9cf7 with SMTP id 5b1f17b1804b1-45f211c9c63mr186776255e9.6.1758054006410; Tue, 16 Sep 2025 13:20:06 -0700 (PDT) Received: from [192.168.0.24] ([82.76.24.202]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3ecdc967411sm1345667f8f.46.2025.09.16.13.20.04 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 16 Sep 2025 13:20:05 -0700 (PDT) Message-ID: Date: Tue, 16 Sep 2025 23:20:04 +0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [Invitation] Linux MM Alignment Session on kmemdump on Wednesday To: David Rientjes Cc: Matthew Wilcox , Amit Shah , Andrew Morton , Aneesh Kumar , Christoph Lameter , Dave Hansen , David Hildenbrand , Davidlohr Bueso , Hugh Dickins , Johannes Weiner , John Hubbard , Kirill Shutemov , Mel Gorman , Michal Hocko , Mike Rapoport , Peter Xu , Raghavendra K T , "Rao, Bharata Bhasker" , Rik van Riel , Roman Gushchin , Shivank Garg , Sterling Alexander , Suren Baghdasaryan , Tejun Heo , Vlastimil Babka , Yang Shi , Zi Yan , linux-mm@kvack.org, rdunlap@infradead.org, Shakeel Butt References: <426751f4-428b-ed01-509b-d13e719a2006@google.com> <50b566d6-aeda-48cc-bd67-362cb29b214a@linaro.org> <08c0b550-0a78-0b25-308d-18b143999599@google.com> From: Eugen Hristev Content-Language: en-US In-Reply-To: <08c0b550-0a78-0b25-308d-18b143999599@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: zjz46xec6cbrbkd57pg8syihb65ynfbs X-Rspamd-Queue-Id: 3328C20008 X-Rspam-User: X-Rspamd-Server: rspam03 X-HE-Tag: 1758054007-662502 X-HE-Meta: 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 xhlCv7pg 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/16/25 22:27, David Rientjes wrote: > On Tue, 16 Sep 2025, Shakeel Butt wrote: > >>>>>>> This week's topic will be kmemdump led by Eugen Hristev. See the latest >>>>>>> proposal at https://lwn.net/Articles/1031319/. >>>>>> >>>>>> I don't understand what this has to do with mm, to be honest. >>>>>> It looks like a debugging aid. >>>>> >>>>> It was suggested to move it to mm/ : >>>>> >>>>> https://lore.kernel.org/all/0fa9e4e7-1247-4c82-8c0b-fa65b7fbb56d@infradead.org/ >>>> >>>> I feel like you should be able to explain this rather better than >>>> "somebody else told me to move it". As of this moment, I still don't >>>> know what kmemdump even is. >>>> >>>>>> >>>>>> https://lore.kernel.org/lkml/20250422113156.575971-2-eugen.hristev@linaro.org/ >>>>>> >>>>>> is a great example of how to write a lot of documentation that doesn't >>>>>> actually tell the reader what anything is. >>>>>> >>>>>> >>>>> >>>>> Here is a link to the v3 where I changed it a little bit : >>>>> >>>>> https://lore.kernel.org/all/20250912150855.2901211-1-eugen.hristev@linaro.org/ >>>>> >>>>> I am eager to improve the documentation to make more sense out of it, I >>>>> am happy with suggestions. >>>> >>>> Start by telling me what it is. >>> >>> A way to select memory areas from the kernel that can be used to debug >>> the kernel, instead of saving the whole memory dump which is mostly not >>> of interest and takes a lot of space. >>> Anyone can register a pointer and a size, these are placed into a list, >>> and a dedicated firmware can parse it and save it in case of a crash. >>> Does this make sense ? >> >> Is it only for kernel or is available for userspace as well? And the >> crashes here, we are talking about kernel crashes or includes process >> crashes as well? >> > > Yeah, I think understanding the scope of this work, both in the current > RFC as well as the long term vision, is going to be useful. > > In this case of kmemdump, which I agree is not core mm, it's likely best > to use this alignment session to first describe the problem statement: > what are we trying to solve? The reference to dedicated firmware above > piques at least my curiosity. > > I see some interaction on the latest RFC, asking questions, and deciding > the interaction with pstore, I think the goal of this session would be to > determine if (1) the problem is worth solving, (2) if there are existing > mechanisms that can already get us there, and (3) if the current approach > makes sense long term or if any pivots are needed. > > Hopefully an interactive discussion will save time in the long term by > ensuring alignment in this area even if the feedback turns out to be "no, > we're not doing this." That would likely best be done by first > describing, thoroughly, the problem statement before jumping into > implementation specifics. Thank you David for getting everyone's expectations more aligned. I am happy to present everything tomorrow and get feedback on how to find the best way to get this moving forward with the community. Eugen