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 D28E0CCF9FF for ; Fri, 31 Oct 2025 09:31:43 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1A41A8E00A0; Fri, 31 Oct 2025 05:31:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1547E8E0042; Fri, 31 Oct 2025 05:31:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 01C088E00A0; Fri, 31 Oct 2025 05:31:42 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id DF9468E0042 for ; Fri, 31 Oct 2025 05:31:42 -0400 (EDT) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 555B112AFA6 for ; Fri, 31 Oct 2025 09:31:42 +0000 (UTC) X-FDA: 84057892044.29.2EE5DA7 Received: from mail-wr1-f49.google.com (mail-wr1-f49.google.com [209.85.221.49]) by imf21.hostedemail.com (Postfix) with ESMTP id 4371C1C0007 for ; Fri, 31 Oct 2025 09:31:40 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=suse.com header.s=google header.b=CU0PE6Ir; spf=pass (imf21.hostedemail.com: domain of mhocko@suse.com designates 209.85.221.49 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1761903100; a=rsa-sha256; cv=none; b=mmiev1InV7tVVGwW4vG9zr4sbKlwHZrbR9e9q5FJKJmJQ4O+0hb/QQTUxKSg1Ud63fn1yD 8TbPjNgPwneZeKAmY92uohMkunLrAFMo39xN8NHZnNsFQYDT8uWitb3cxE9UgvZCjjyDHD lED/hVghw/xCZKlX/PpOSvKMmPTT1yg= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=suse.com header.s=google header.b=CU0PE6Ir; spf=pass (imf21.hostedemail.com: domain of mhocko@suse.com designates 209.85.221.49 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1761903100; 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=eZqsIXX4i9fDMKAO6vBiIA93QUBSotAqCxkbGp8FfSY=; b=p7xfRNAotX3htb18+EPzYPwlLcNDZq2pfc0KtshN8pyC6wiwA/CjlUxmpA65ug9OtSFZos j9MLp9zDJg8Ob16O+n94UJO+/89onoK6u3n4BDKLmEM3NszjOvbpkGI6uVRBOXs+WPbezF CvFTGrz2bMjZV6GIx4hRn5b2CxCgmYU= Received: by mail-wr1-f49.google.com with SMTP id ffacd0b85a97d-421851bca51so1790864f8f.1 for ; Fri, 31 Oct 2025 02:31:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1761903099; x=1762507899; darn=kvack.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=eZqsIXX4i9fDMKAO6vBiIA93QUBSotAqCxkbGp8FfSY=; b=CU0PE6Irj8xopgpcCw60CasIKW3URawaNP9uDMLvk+zBo5fZOynileBTkafipEqp/Y y0ZJtAP5SM0xHASAIfFifT6DaxgIT/zjBLr0PBq5T2Ghr14tINfk92/45vWsZiQf8i1l z0GRAGwliUp/seYq5YCjWSrZhUwRBnjfgG4GIEUlvkUezpB6jVg+EeLgqT3CBgzxWnLt tsifgRNevCWdZJSSHtAbYJ/MYmmT1gB8oVygLrxxfA8YKRtp5sWem6rlthCPnped4jsJ FTQArJWgfDstolXY+l9iMJhdaOJUlOhU4v8Iwm9OHzQANUD202a7eJaRv7YYhqvqLRLb DI5w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761903099; x=1762507899; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=eZqsIXX4i9fDMKAO6vBiIA93QUBSotAqCxkbGp8FfSY=; b=PB+LkwB5AyvbFNo7oTQIdhnyY4R5nzflmG5OL3O/bMu7WXkEgVIADC+SSj9ukKM3Ae Gobx34KV1idcPd0uTNqO3xagnof1MfaxwgPa8ikWAUHUOWDJ2KJwQxapSBMgwGoDo40k at0NAAmpoLSqkW0VTLhjMaBLOVb/QvOL3gB8bG+nrh2+cGsHVUW8vmgmWWXsOK9pqqh0 MESW6GrRBVYAfdh6S64FYNxa0Q+gkMZtIgAGvfZweWaEAWuFF4BvayorHliWYubziCfh aqGC7ioPyY6w/fN+ev9alenF9HGTKKtGz5LBzTregLFMBiwOn1lHR7kTvlaXm79cnywD yB2g== X-Forwarded-Encrypted: i=1; AJvYcCVquGtMjEq9R5seoDOH+yvlf6a6gFhw/tTNi3YXG6YPaxLLYepbqydaYHebeEllsZsH8M6QmSJPYw==@kvack.org X-Gm-Message-State: AOJu0YzdTSFmuYCGH2x0wLnvwf75BFrt57spdSCNPQkYNqHNhDyi4go9 1ZUFuiHPw5b2zkOq+p3D46TF0EcYgcwMIEWsGFDzCoObKVzQ0GA8obuzRhUxAn3y1Ao= X-Gm-Gg: ASbGncuSGv5bRwAPa1UgsI0zw+/9rNDj5YSzumfH2Qw1r2xPUHJ8smcGiM1dvka11kJ Ix5ZS45EwPT2iL7gNaQanSle52GovIZv5orWYpEqaXvG2OkNToIobS922E2TxapGdogdDkJkOyD TQf2duzfAKe2lffyLYT/tIYdYRue5o2vpV2xFcZJGBlUw1l3Nb4t5kA3E22SsqIfEVJh/eKBfnE PAsLnl/m8cJ4Mtxr7jQ0Sxvn5K4s8cMkta3mHP4VUsvolNp+1wffLyFRuHtYQyQG5UJJztTyJoa XrS3URMLZNF+ychw1W38ajicmIQEoYuXHUfaKOXENnAm/sClLd2/x6TUjERl0R3HxmPpFtQapQh YcH0fXYbA9IUxWIsMbOLGEQjVtnB3NLZ79BulgxiP7u71vkbIWqcun7s3J9chJGXFnGqV/9RhrC 0CGjrXwCS91T+sUg== X-Google-Smtp-Source: AGHT+IG50zQtJd3CIUQKj9ncFkPdrH/t/rsOh53ftoZJnLGX9Bc7esexz1A2xxBb08Zp7FtUCXSR/Q== X-Received: by 2002:a5d:588a:0:b0:429:b52e:351c with SMTP id ffacd0b85a97d-429bd69ff31mr2719399f8f.38.1761903098515; Fri, 31 Oct 2025 02:31:38 -0700 (PDT) Received: from localhost (109-81-31-109.rct.o2.cz. [109.81.31.109]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-429c13edc36sm2536910f8f.37.2025.10.31.02.31.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 31 Oct 2025 02:31:37 -0700 (PDT) Date: Fri, 31 Oct 2025 10:31:36 +0100 From: Michal Hocko To: Roman Gushchin Cc: Andrew Morton , linux-kernel@vger.kernel.org, Alexei Starovoitov , Suren Baghdasaryan , Shakeel Butt , Johannes Weiner , Andrii Nakryiko , JP Kobryn , linux-mm@kvack.org, cgroups@vger.kernel.org, bpf@vger.kernel.org, Martin KaFai Lau , Song Liu , Kumar Kartikeya Dwivedi , Tejun Heo Subject: Re: [PATCH v2 00/23] mm: BPF OOM Message-ID: References: <20251027231727.472628-1-roman.gushchin@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251027231727.472628-1-roman.gushchin@linux.dev> X-Rspam-User: X-Stat-Signature: b1mu1oj5i68inrm45nec6qkf8y9syk5c X-Rspamd-Queue-Id: 4371C1C0007 X-Rspamd-Server: rspam09 X-HE-Tag: 1761903100-656301 X-HE-Meta: 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 sPg/+ENC Qvrly/GCnWvWCDtbOXGLtPmb7mXidEaFEl6S/qnuCAFQnFGXgcZav1hRUDUZDON7/tHleDgr/ZOO8kZf4Vhy+CIv0MHHZlyirp7MnVNI6M98CNV7yNZXDmudYcAANZyWUlSoWABZMFiBBZB3VX2J87zO3Sobs2727Djs4uzMwz93cmJk5W6S8R5rq+unHXiK0VxFthUbrpdhyZcHP1xbRi7pMk7kGuNJ+r0h/VGNsOvNGKpY0789UOXG45xVEbyPxvxFfDs63UcAAJ0jwJ3k2iSraNkD4OZiq5s3vkVYjs6G5mKVyBgjc8UIpYiY/gcyn9PG83ntLZ3lO9QBjJ4K2xNlU5/5dgr5Uk8kZVpHjakkwwj0= 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 Mon 27-10-25 16:17:03, Roman Gushchin wrote: > The second part is related to the fundamental question on when to > declare the OOM event. It's a trade-off between the risk of > unnecessary OOM kills and associated work losses and the risk of > infinite trashing and effective soft lockups. In the last few years > several PSI-based userspace solutions were developed (e.g. OOMd [3] or > systemd-OOMd [4]). The common idea was to use userspace daemons to > implement custom OOM logic as well as rely on PSI monitoring to avoid > stalls. In this scenario the userspace daemon was supposed to handle > the majority of OOMs, while the in-kernel OOM killer worked as the > last resort measure to guarantee that the system would never deadlock > on the memory. But this approach creates additional infrastructure > churn: userspace OOM daemon is a separate entity which needs to be > deployed, updated, monitored. A completely different pipeline needs to > be built to monitor both types of OOM events and collect associated > logs. A userspace daemon is more restricted in terms on what data is > available to it. Implementing a daemon which can work reliably under a > heavy memory pressure in the system is also tricky. I do not see this part addressed in the series. Am I just missing something or this will follow up once the initial (plugging to the existing OOM handling) is merged? -- Michal Hocko SUSE Labs