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 B5DCDD5B160 for ; Sun, 14 Dec 2025 01:55:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8D4936B0005; Sat, 13 Dec 2025 20:55:41 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 885706B0007; Sat, 13 Dec 2025 20:55:41 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 79B146B0008; Sat, 13 Dec 2025 20:55:41 -0500 (EST) 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 67EDA6B0005 for ; Sat, 13 Dec 2025 20:55:41 -0500 (EST) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 9D0DA5B0B5 for ; Sun, 14 Dec 2025 01:55:40 +0000 (UTC) X-FDA: 84216410040.09.E728186 Received: from mail-pl1-f181.google.com (mail-pl1-f181.google.com [209.85.214.181]) by imf06.hostedemail.com (Postfix) with ESMTP id C02CF18000A for ; Sun, 14 Dec 2025 01:55:38 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=KC5JSIGY; spf=pass (imf06.hostedemail.com: domain of rientjes@google.com designates 209.85.214.181 as permitted sender) smtp.mailfrom=rientjes@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1765677338; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=QgtwyL2IOQsaRpXQUokhvGPgbhGzCSq0MlFT6kUkMw0=; b=hsZewmOQKiBoR3hIhXAUCTO3k+BBsp9jjedI1QcGcRGcxCS+Tv/iJTdzQO1LQXlNP/AWVe O98tNR2GvxZ+KGBxSie1GZB2zMqOjrXR0J0IjOL1ZRwvKl/XipJJNrw4fEHgMVOSzlETdk yoMzKnNEyW/V9AZobmxl5hiKUHK+N2Q= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=KC5JSIGY; spf=pass (imf06.hostedemail.com: domain of rientjes@google.com designates 209.85.214.181 as permitted sender) smtp.mailfrom=rientjes@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1765677338; a=rsa-sha256; cv=none; b=m2/lcwwZOU9b97UKFjjSYeCYboE+OO1d9JDZr6on1p1EMbzRLQbfjYf3dtk0xsRu+0xBKH /z8RG7kis13n61dIsRTb1Qo2zGdHRAzP1mLGhOLcb03R+x9rWfLPSQWYd2gJMJwD09nDOn hWFdKqbuFW2B4RvNURdZACuDW17/tpA= Received: by mail-pl1-f181.google.com with SMTP id d9443c01a7336-2a0d06cfa93so18385ad.1 for ; Sat, 13 Dec 2025 17:55:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1765677337; x=1766282137; darn=kvack.org; h=mime-version:references:message-id:in-reply-to:subject:cc:to:from :date:from:to:cc:subject:date:message-id:reply-to; bh=QgtwyL2IOQsaRpXQUokhvGPgbhGzCSq0MlFT6kUkMw0=; b=KC5JSIGYGvSyOokenf+7KGHQVFwI6rGeRSYIQt6uzd3mLyyCMHuPibyjYETGR+ej33 y8BTpy6Y+ngrLbUrrsnWSH73XH4tMvaRlE1QlStGaHad1RHvOCSd+5sMpu4VIabE3RI4 T10Mfcx3Gv6HNHzg4K8mA1LzOB3bersIX1c6eN2GFgg1KOHKAXq3HbvUHWoSu0p7xqJ4 ZtyIJuKMtgXsgVlOsCM7VSG8T2EQBsiQhhGTPZR2NSfCAMHl/3MA5zj8iGx/izpLuTMP zpqitGWbRFnI7oXefdoJRSGPez9iTsaCmXjAPc94r3Zm2Wfa0rk+KR87l17Cbjw/2aJW xiSg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1765677337; x=1766282137; h=mime-version:references:message-id:in-reply-to:subject:cc:to:from :date:x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=QgtwyL2IOQsaRpXQUokhvGPgbhGzCSq0MlFT6kUkMw0=; b=qt61gLMcVktJpeol8/IKE4th2JqMt5h918qrJEBPDKqJO4rKEo1ffYmiRhBt1y6nEu MusqympEwR0de66NB8BZz0009ES/U1VAXnV0x8yHXJZP2x0BhaRLk5iRD6RIdqSZBnHp O1pST7yHGtWPTK4A/YF5kaaJl820vvynielAD2pZ+cYK4JSDlZus7DrZiDffiZ+hsK05 cbYoOlraXK1Od9E5fnd+Ht/SkK3R4ebxpj/tHtqrvqq+WYkXFQv11LCE/geal2kLUIow rtxVs7nfK6QI5GY9vAryBTPw3GY3EBWuzqRY3R5LblbXwTUU3bcWDCIYnpgk7b4KW8k+ iFJw== X-Forwarded-Encrypted: i=1; AJvYcCVa9U+2ZG5cMq+bwhL6BCuC9b9ZITmdTXUhPYcACu4j/o9i18fAbmdkFSye2j4fK2p2kcCTLuJ7LA==@kvack.org X-Gm-Message-State: AOJu0Yw9hLT5BX4oR9mAeveLHtGaT6pioM6D0UKESa8pGOjpBv4whXFC T5GFsEZhZYjMPN88NQqGAMK8qvlC0Mg1aUbHBBeNAoWg1xOad+cQK64s/MLgtGoOSw== X-Gm-Gg: AY/fxX6uq6zdXPqBg72+VWauwxM5XAUNKkrWmgxnzWB0D3G41GePZZzDgknsdYKiuxA KB+XSs2ffNUvvMSZsWcdvG+OkucMlm5K7/ogBO55yueWzAiFpbAxyqqBhOjq9W+EsX/abg4F9Qs M1od/N1dVav6JHbWDIWLwS/Xog6UHjQ56hlDwRz7uN33Vtapx4Kd1jDvUzVJfBMb1z0F8IzoyxX SC72sTAg5jiikKL3eCaFk5zhuDaKubVcbUrWtEjwLGSguphQdLX9EcB5U+ZyhUrYlzp04ybnWrg gLl7hpljoy4OuG4/lTQDmgW5obhwyXnKbsIHgoIiOMhx8aOkUrU2QmKth5xGbl9Wn9LHUSxVFSW TDesUYyV/JLTLNtP1H9GvR//PirmqlgCjgm/t7FWOTcVgmVs7lJdYU7ymzR9QmAW8I/BKtbous2 0VRJtCNfkoQy6utNwi8wzIDpadT1me7t1d7pGsCLLagNAhMJ7Foxgk9pdr2SK5RmsR4TpQeukBR o5p8Tefvfssmm9D9f5qEJoHu4aT8R3htFrOf3g= X-Google-Smtp-Source: AGHT+IFM6b0dYNyFOMBGuCZFF0FeXHFTlS/LG7X4aAopwttF35Wi88j7hDAibJ75vZtBwKctVMpYJg== X-Received: by 2002:a17:902:e54f:b0:291:6858:ee60 with SMTP id d9443c01a7336-2a090572ebbmr2877745ad.4.1765677337122; Sat, 13 Dec 2025 17:55:37 -0800 (PST) Received: from [2a00:79e0:2eb0:8:ca83:e74:ec08:e2cc] ([2a00:79e0:2eb0:8:ca83:e74:ec08:e2cc]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-c0c2b9d81d2sm8664281a12.26.2025.12.13.17.55.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 13 Dec 2025 17:55:35 -0800 (PST) Date: Sat, 13 Dec 2025 17:55:34 -0800 (PST) From: David Rientjes To: Michal Hocko cc: Yang Xin , akpm@linux-foundation.org, shakeel.butt@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yang Xin Subject: Re: [PATCH] mm/oom_kill: add sysctl_oom_dump_stack to control kernel stack dumping on OOM In-Reply-To: Message-ID: References: <20251211202433.4495-1-redleaf@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: C02CF18000A X-Stat-Signature: f35ndnnnaorn1sujps69qbb97mhwcgyw X-HE-Tag: 1765677338-104487 X-HE-Meta: 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 j2L8LKW7 mcoptu7U/6Cn88SJNYWnObVu4aNeBxfbjd7pXT3TgWTLGemp56xDVs9X0l0qt7U7m3rw0TDBKOO8Nf8wRfy+1wBllUldaQrM297Nsuv8jGeMG1YNttTkqZeZ4tU/kAkAnVwfVWkuEmXg12CCefVbXhGXWd5CE4/sbICfVQWbPvxdJuLrjjpnjAubljzsY1vaNqJCgNGmTF/KWKspjXYGzh/uymSYG+iXEbt/b6l6JwKmmxMU4V6ske3R2QyUit1xQBJ8J7Lzms/fk/pMycnqehqb7IYUK/MXT7ffG5PNDgCVsC+LD7SsYSVa9+5lCIZuw+70hsWIKwhMUt55zv4osJXQWS0Rb8qGdbrhWSRylmrBkGUJMb0z/TL6CgCKgdY+i0jlhUc/T6u+a2wYko7vDo/6LghIYx4bJRPATQt0yORwnCQq+AQ8JP7j4rBEYoTvR0vxVZIqcajApzSZWkMIfW5oHw8CH/9S6r6M10FCnohlkEPI= 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 Thu, 11 Dec 2025, Michal Hocko wrote: > On Fri 12-12-25 04:24:33, Yang Xin wrote: > > Most OOM kills triggered by user-space processes produce kernel stack > > traces that are not helpful for diagnosing the root cause. These traces > > usually just show the page fault handler or system call entry. > > > > Furthermore, dump_stack() can be expensive. It often runs with > > interrupts disabled or holds the console lock for a long time, > > potentially causing system latencies and preventing the system from > > responding to other events. > > > > This patch adds a new sysctl vm.oom_dump_stack to control this > > behavior. Writing '0' to /proc/sys/vm/oom_dump_stack suppresses the > > kernel stack dump during OOM kills, while '1' (the default) preserves > > the existing behavior. > > While I fundamentally do not object to ways to suppress stacks traces > for OOM I would really like to hear more what kind of overhead we are > talking about here (stack traces are reported for tracing and other low > latency situations) and why does this matter for as cold of a path as > OOM is. > > Also we are getting way too many of these sysctls. Maybe it is time to > look for a more customizable way to configure oom output that doesn't > require sysctl per output feature. > Strongly agree, I don't think this requires yet another sysctl. It's also global, so it will affect all oom kills including the ones where you might find a stack to actually be really helpful to understand the issue.