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 4CFB7C433F5 for ; Wed, 16 Mar 2022 16:31:26 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B772B6B0071; Wed, 16 Mar 2022 12:31:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B26138D0003; Wed, 16 Mar 2022 12:31:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9C7858D0002; Wed, 16 Mar 2022 12:31:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0050.hostedemail.com [216.40.44.50]) by kanga.kvack.org (Postfix) with ESMTP id 8E9D76B0071 for ; Wed, 16 Mar 2022 12:31:25 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 3E9A9A15EC for ; Wed, 16 Mar 2022 16:31:25 +0000 (UTC) X-FDA: 79250789730.30.0D20E1D Received: from mail-pj1-f41.google.com (mail-pj1-f41.google.com [209.85.216.41]) by imf24.hostedemail.com (Postfix) with ESMTP id B14F718002B for ; Wed, 16 Mar 2022 16:31:24 +0000 (UTC) Received: by mail-pj1-f41.google.com with SMTP id v4so2596282pjh.2 for ; Wed, 16 Mar 2022 09:31:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=0li51S2j9zx6touwa3lalaBuNLB+ApBmTIWJmdTR4CI=; b=CMYlilISkpmT9u93kuzE80ilYUmxO8tZDHP6kRvGqaeCD3IgCfRgtxtt4ui3m8C8N3 9QtIz4konuRNXrXD0iyToy2A4HfrIhnctNOUmpZYxsjwupqLpl7K0F3OdK7bv76ZfG3S d7I15BTZRPEIinQ3m0FkfvWkUcwSGR1Kc3/jiio7PtNWUUHFlqir/2VM7IQD1imzBbID DSr03q7fwGP/+dxbERzS+cdO5t1v3YENg18f8jVBEZpwv4qnrRc58kP/y7mbEgt4vj+L LHrdRCBMigiHY3BFJ70y/qpNf8P39NsI9ElYBYDeI1G4SH0cV9bcMzQpwjbmUyBVJ7Ta M/lQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=0li51S2j9zx6touwa3lalaBuNLB+ApBmTIWJmdTR4CI=; b=bVTIjXJ6mOs6Ggr4h6B5aqH49lPG/DAtxb6O38QhfE1mB1prONDXG0VJ5rRUf2y56g HsDI/Zp0vuRVo511/nx4j0Ew5NVh6tG2ZVxKPu1rNK+E+R/KIox7rmUM9nJsOXACcVrM c+UgEd/7Tzn5xHORZFDZM1bJEg2/cVVN7n/1rnwwdD/214+0uJIgzGMDZshNaDoCTO6v GWpimAbH0QmGL/7La4YyJKE5ckHGrk8ec3Fdd60aaAR4+Dqo2OxcyXQcO8V9xY/TE8q2 bzK2YhPqqOisjOFlGsjihhbBBz5BQBcyHwWpJtw8GLf67y7f142m40WtdX3xQzJamz6V wxMg== X-Gm-Message-State: AOAM530tidBFmsQ878HLMXsu0j6G/KwKsqfxCpxNR8eHaOUhzUqqiErv dzsRYncx9eXwNx6MMmM7PwGH6lSAu7/skQ== X-Google-Smtp-Source: ABdhPJzEVxA0lPXRLR3lK6epsQ90ZVHK5W+GGO82avyXJSn6CEsL4VYY2Tdi1UmAoEVuQTAdoHvncw== X-Received: by 2002:a17:902:bcca:b0:153:88c7:a02 with SMTP id o10-20020a170902bcca00b0015388c70a02mr338759pls.112.1647448283647; Wed, 16 Mar 2022 09:31:23 -0700 (PDT) Received: from localhost (2603-800c-1a02-1bae-e24f-43ff-fee6-449f.res6.spectrum.com. [2603:800c:1a02:1bae:e24f:43ff:fee6:449f]) by smtp.gmail.com with ESMTPSA id j23-20020a17090a841700b001c678ac3b4bsm81977pjn.14.2022.03.16.09.31.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Mar 2022 09:31:22 -0700 (PDT) Date: Wed, 16 Mar 2022 06:31:21 -1000 From: Tejun Heo To: Song Liu Cc: Yosry Ahmed , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Johannes Weiner , Hao Luo , Shakeel Butt , Stanislav Fomichev , David Rientjes , bpf , KP Singh , cgroups@vger.kernel.org, Linux-MM Subject: Re: [RFC bpf-next] Hierarchical Cgroup Stats Collection Using BPF Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: B14F718002B X-Stat-Signature: xqkznaj5qt5rdg9ej66ew8d8rza6y9dn Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=CMYlilIS; spf=pass (imf24.hostedemail.com: domain of htejun@gmail.com designates 209.85.216.41 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) X-Rspam-User: X-HE-Tag: 1647448284-1553 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: On Tue, Mar 15, 2022 at 11:04:56PM -0700, Song Liu wrote: > Lookups invoke a rstat flush, so we still walk every node of a subtree for > each lookup, no? So the actual cost should be similar than walking the > subtree with some BPF program? Did I miss something? rstat only walks cgroups / cpus which have been active since the flush. Thanks. -- tejun