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 C78DFC3DA49 for ; Tue, 16 Jul 2024 20:00:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3DABC6B0088; Tue, 16 Jul 2024 16:00:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 38B186B0089; Tue, 16 Jul 2024 16:00:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 252946B008A; Tue, 16 Jul 2024 16:00:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 01FF86B0088 for ; Tue, 16 Jul 2024 16:00:15 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 4EFD6A0757 for ; Tue, 16 Jul 2024 20:00:15 +0000 (UTC) X-FDA: 82346682390.08.EF9EADB Received: from mail-oi1-f178.google.com (mail-oi1-f178.google.com [209.85.167.178]) by imf10.hostedemail.com (Postfix) with ESMTP id 4BAA7C001D for ; Tue, 16 Jul 2024 20:00:13 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=aq2KMNsg; spf=pass (imf10.hostedemail.com: domain of htejun@gmail.com designates 209.85.167.178 as permitted sender) smtp.mailfrom=htejun@gmail.com; dmarc=fail reason="SPF not aligned (relaxed), DKIM not aligned (relaxed)" header.from=kernel.org (policy=none) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1721159974; h=from:from:sender: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=0A5eNeu1koPgDi+YMtCXJr0UJyxu69RXmGV7v4l255I=; b=DmYPvzNX7GXeNH5knyEp4AWXaKLvkZ++M2lu7NZtjlDE1J2op3BZWasoQIq43N9MtxX+YS bfPLQ8ja3qZ9F1PkVGpspUDTgGEpAzNzNxZam+ObSbhvemjIak0lp7fzUm+0oYC/uDYjgs mqI30kiVu+qD6zDtRRKzz8mmjmPW9vM= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1721159974; a=rsa-sha256; cv=none; b=pcfKsgQ1F8Dcj95wAISs0JRDFf2Xm2U8Lnbr62y234xkfigq9H4xffmvX7MsoGzVZXUQCY rmHJV+ilWW5SVfNPMl4LKxvvX38b9krHR7qvDoBdewsUNeo+xgbcCH065nAuJWJpcoZJfc vpRScQhmOknIv99bT9aZioNkDfWNVcg= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=aq2KMNsg; spf=pass (imf10.hostedemail.com: domain of htejun@gmail.com designates 209.85.167.178 as permitted sender) smtp.mailfrom=htejun@gmail.com; dmarc=fail reason="SPF not aligned (relaxed), DKIM not aligned (relaxed)" header.from=kernel.org (policy=none) Received: by mail-oi1-f178.google.com with SMTP id 5614622812f47-3c9cc681ee0so3378408b6e.0 for ; Tue, 16 Jul 2024 13:00:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1721160012; x=1721764812; darn=kvack.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:from:to:cc:subject:date:message-id :reply-to; bh=0A5eNeu1koPgDi+YMtCXJr0UJyxu69RXmGV7v4l255I=; b=aq2KMNsg5YM00/C4MqrPpJJgczGZYidUuBFxrHWyBGohE0R+0ame/53MzAm/PTuvPk OCMUjn6cq5gqLlvJ3gKhEuDk+n64h6s07nPjSlPo7RXbmnVNaqhih6ys1UdRiI3wHNf5 f9ZVXJvzv3EDwCIUgs7jc3EQaM6Dxe4skb//ik4K+hRlamTk44o9hwKCii7zvacvtk8S W5Z3POxQ1KgX7di1F5pRmv8wKCih85Z2DYyjwsigB3iNX/5cCdZ4eCk7yS/QaF9BYu+v LGa/8UPDAoqksexmwqW8xPqaaun4i9XnKWfc0MuSIORzBo1JeyxnzqI+xpm79ozFeGvr Xoug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1721160012; x=1721764812; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=0A5eNeu1koPgDi+YMtCXJr0UJyxu69RXmGV7v4l255I=; b=AeYH7KjGIQ1mjj2WOddDrAD9QhvXQUVlRg6/bWe13Sxp1YZ9Iq0sDlsqr6G+VE6pMJ xthRuuSoVeX9iIfSDQXm7lVV87sjwUgYooxkFXFALPYTvjnHms/rnlqkisxs2YzHTOVE dD8uZIhaEDb4em9UCKgv/GJ8P+h4xwxY2ELQ/klSahm70kCpVwcOdFDUQ3N3SJbUS3Bv +fPT7lTH8fvTNbwC/LCh8+WB4J0hvzLeTleGuALQCjaKVECyVx/KyHE0eqv6RqlWqafQ pWJdVFvmcGcqEMbi2J7QjgFLq+Ixr+/wktDUqgaJUBk9h0ivPDH4Iy1SRJxhiQx6ENaC DrXA== X-Forwarded-Encrypted: i=1; AJvYcCUtGwNDz3HmjKZc/af0TqKz9sp2d4jJ66CBvkRYpNiveZGQsMEpm1q3Nt62a4250XvxODpodBRKTSvB2wy7agTUv9A= X-Gm-Message-State: AOJu0Yy+VbS9LNLZq5fYqLkf4EEknLbB4rNTbs/wOQ2HadDuavWt+a4K HwKnT1aKtTBB6v+1s321PKj0CnQ+qfuvFC1tPuaTpLmsgCxPqz9l X-Google-Smtp-Source: AGHT+IF/MPQE8ZNQ6Zj3W4mfQ7FqcdlhVcA5/FWQ02lDg3e7Ex4EoBWszBDbyZ/WyYrEnG6vXLAAmQ== X-Received: by 2002:a05:6358:339a:b0:1aa:c9ba:4336 with SMTP id e5c5f4694b2df-1ac90325cffmr324198455d.3.1721160011871; Tue, 16 Jul 2024 13:00:11 -0700 (PDT) Received: from localhost (dhcp-141-239-149-160.hawaiiantel.net. [141.239.149.160]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-78e386d7d14sm4384150a12.73.2024.07.16.13.00.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Jul 2024 13:00:11 -0700 (PDT) Date: Tue, 16 Jul 2024 10:00:10 -1000 From: Tejun Heo To: Michal Hocko Cc: David Finkel , Muchun Song , Andrew Morton , core-services@vimeo.com, Jonathan Corbet , Roman Gushchin , Shakeel Butt , Shuah Khan , Johannes Weiner , Zefan Li , cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH] mm, memcg: cg2 memory{.swap,}.peak write handlers Message-ID: References: <20240715203625.1462309-1-davidf@vimeo.com> <20240715203625.1462309-2-davidf@vimeo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 4BAA7C001D X-Stat-Signature: jojpncwq5k5s6s1hthybxonwira98yak X-HE-Tag: 1721160013-515028 X-HE-Meta: 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 Ju+Z+fVF iIhw8NMe6aDSd6xV2IFTSSubZI3LLk6SSv5pW3fCDvso63e13nou2gQaH/Tu4lI6MXHESITM/QELoRGCyF1P0O8P4T4UQj4A7sjwBrgyRyWNSHChWzVZN9izRkO19jACCja9cW497G6JGu4DDiJSGayacp2czlAStzzY8/BDMw0fcw7QGX+z4KFmtXX7gB+Gt+t9OGqt5DguCCkvGI5cPXQg+qlRWoh0ZapuNfxnJs2cXbLCGXqw5tdNpJV373ntAzQZNuwTldaPy1dKC9tqZL0ZlkqQ6ZuaYvV2jl7Bop4nPuX8QkvUZ2vbN7EGgLBsW+MkJM4p4af0EoEr7AA1XngBFfRchqpdq2aKnOOTWB5548TU3oyOawOPFgoG1k4pvc/tsyN6hTi0m1JvrBzIJZ2FyeiRPR+Ugx2WH87YYqgbtMTI/VMdHg7OfwvV23uwqItu1 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: Hello, On Tue, Jul 16, 2024 at 08:00:52PM +0200, Michal Hocko wrote: ... > > If we want to allow peak measurement of time periods, I wonder whether we > > could do something similar to pressure triggers - ie. let users register > > watchers so that each user can define their own watch periods. This is more > > involved but more useful and less error-inducing than adding reset to a > > single counter. > > I would rather not get back to that unless we have many more users that > really need that. Absolute value of the memory consumption is a long > living concept that doesn't make much sense most of the time. People > just tend to still use it because it is much simpler to compare two different > values rather than something as dynamic as PSI similar metrics. The initial justification for adding memory.peak was that it's mostly to monitor short lived cgroups. Adding reset would make it used more widely, which isn't necessarily a bad thing and people most likely will find ways to use it creatively. I'm mostly worried that that's going to create a mess down the road. Yeah, so, it's not widely useful now but adding reset makes it more useful and in a way which can potentially paint us into a corner. But then again, maybe this is really niche, future usages will still remain very restricted, and adding something more akin to PSI triggers is way over-engineering it. Thanks. -- tejun