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]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC989C27C54 for ; Thu, 6 Jun 2024 18:15:19 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 73A576B00BD; Thu, 6 Jun 2024 14:15:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6EB036B00BE; Thu, 6 Jun 2024 14:15:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5B2976B00BF; Thu, 6 Jun 2024 14:15:19 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 3CF206B00BD for ; Thu, 6 Jun 2024 14:15:19 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 0230DA082F for ; Thu, 6 Jun 2024 18:15:18 +0000 (UTC) X-FDA: 82201265958.09.68B8F9D Received: from out-182.mta0.migadu.com (out-182.mta0.migadu.com [91.218.175.182]) by imf02.hostedemail.com (Postfix) with ESMTP id 7572B80018 for ; Thu, 6 Jun 2024 18:15:16 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=If2w5F5Z; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf02.hostedemail.com: domain of roman.gushchin@linux.dev designates 91.218.175.182 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1717697716; 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=Zm43uA+FFLHcQl+sDCvd8VPxTBF9+LzpAfW+SfYXKcA=; b=u8pwEeuaNCZaQ/AyOShmTH/penYgda8oXGp0VofqMoKVsF/1Pu/9w77b1f5Aj75iNryONC WjzPd19ykde07bcUEEH0FITtKtiXCUiwnJ9hf6BGXLBouMjfMY9/pJzb/+brdAJs3iKg6Q Oo0EfOh1+JfTHPfff7XfXF7KCQOwEVA= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1717697716; a=rsa-sha256; cv=none; b=RRgIbN4ew/EJ7qFeAa7P4Tj2kTZv1TkKBlE/Q14XxAdjs5o7LuMi8ZyJg0TBupSr3Qc2Qe bzftuosuSIXDZx3JyJ8LjgLc6jlnsScNGpJyJL+FQ/o/ZeNtgbAd5FZq2ZqP9EJ9zsI48/ RMBetentLa+bENaggEH2wJR6ZS0L/WM= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=If2w5F5Z; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf02.hostedemail.com: domain of roman.gushchin@linux.dev designates 91.218.175.182 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev X-Envelope-To: mkoutny@suse.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1717697714; h=from:from: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; bh=Zm43uA+FFLHcQl+sDCvd8VPxTBF9+LzpAfW+SfYXKcA=; b=If2w5F5Zph9CPlLmSbDtKOFaWOdch41r+lhhzrRFSq3r8BF8SWCpDg8bIfa6Qm0usWedal SHHmp+IAtel164h1JJDc9izUSVY3Z4JE9sy4y3KFtJbcEMaoQZ/dxaYGQACssHxbulRoXj cnBeRCdKm0Ms6sR8G818cpPUl2nSbhA= X-Envelope-To: cgroups@vger.kernel.org X-Envelope-To: linux-doc@vger.kernel.org X-Envelope-To: linux-kernel@vger.kernel.org X-Envelope-To: linux-mm@kvack.org X-Envelope-To: tj@kernel.org X-Envelope-To: lizefan.x@bytedance.com X-Envelope-To: hannes@cmpxchg.org X-Envelope-To: corbet@lwn.net X-Envelope-To: mhocko@kernel.org X-Envelope-To: shakeel.butt@linux.dev X-Envelope-To: muchun.song@linux.dev X-Envelope-To: akpm@linux-foundation.org X-Envelope-To: jkratochvil@azul.com Date: Thu, 6 Jun 2024 11:15:00 -0700 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Roman Gushchin To: Michal =?iso-8859-1?Q?Koutn=FD?= Cc: cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Michal Hocko , Shakeel Butt , Muchun Song , Andrew Morton , "Jan Kratochvil (Azul)" Subject: Re: [RFC PATCH v5 0/3] Add memory.max.effective for application's allocators Message-ID: References: <20240606152232.20253-1-mkoutny@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240606152232.20253-1-mkoutny@suse.com> X-Migadu-Flow: FLOW_OUT X-Stat-Signature: gp6coixj8sg7pqipob1qam9mdnt98zp7 X-Rspamd-Queue-Id: 7572B80018 X-Rspam-User: X-Rspamd-Server: rspam01 X-HE-Tag: 1717697716-783340 X-HE-Meta: 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 GmhFcVBV 4FA8BmErWXFS1SaTvaXS1TyezRuZ2RZLZdRDi3PtXge0WJyOT7RgZ4BNeg8HnWru4qWamWFBlQVFzcLNQPNyUSDRQT+c+tewRqJo2RaskcZi1AS3tjqTc+IVrkg== 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, Jun 06, 2024 at 05:22:29PM +0200, Michal Koutný wrote: > Some applications use memory cgroup limits to scale their own memory > needs. Reading of the immediate membership cgroup's memory.max is not > sufficient because of possible ancestral limits. The application could > traverse upwards to figure out the tightest limit but this would not > work in cgroup namespace where the view of cgroup hierarchy is > incomplete and the limit may apply from outer world. > Additionally, applications should respond to limit changes. If the goal is to detect how much memory would it be possible to allocate, I'm not sure that knowing all memory.max limits upper in the hierarchy really buys anything without knowing actual usages and a potential for memory reclaim across the entire tree. E.g.: A (max = 100G) | \ B C C's effective max will come out as 100G, but if B.anon_usage = 100G and there is no swap, the actual number is 0. But if it's more about exploring the "invisible" part of the cgroup tree configuration, it makes sense to me. Not sure about the naming, maybe something like memory.tree.max or memory.parent.max or even memory.hierarchical.max is a better fit. Thanks!