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 X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 48742C2B9F8 for ; Tue, 25 May 2021 13:00:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2C7D56141C for ; Tue, 25 May 2021 13:00:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232917AbhEYNCF (ORCPT ); Tue, 25 May 2021 09:02:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232979AbhEYNCE (ORCPT ); Tue, 25 May 2021 09:02:04 -0400 Received: from mail-qk1-x72f.google.com (mail-qk1-x72f.google.com [IPv6:2607:f8b0:4864:20::72f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 00953C06138A for ; Tue, 25 May 2021 06:00:33 -0700 (PDT) Received: by mail-qk1-x72f.google.com with SMTP id v8so30286360qkv.1 for ; Tue, 25 May 2021 06:00:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=Y28saWW4RbQx7WFyioP30Xg1gnMSgGnjvex8TrgoAmQ=; b=SmfdiXxkr36Ea/32dUzc9goah/P/GDAmfDbfC23QxapWU+TYijU+tfipqVELo7UnNb kCjW74Q30JDB5fgFGsHqgJCEmxBDKG9IApVbKABuX/KOwPBR0S9vlJjymq+MrMGk51h3 6ydpK/iuWp9N2XdHcbwhGAfcdpizobjsabPIpm0tzrNvmu9Bxekatij9qaP2uru6JWkm 9Q/bdYcBQsR1yN1XYUK+IHclcbpDWwfEhDxrstMqMj+GfnNWOoDjxxvTrZpSn3pYUBV+ tBirFOf/cNxOyaXXED4cDuzfXDrAdEmlM6leYVvOPcAJrsNxmqDTUvm5putYq5K3bzNj AP8g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=Y28saWW4RbQx7WFyioP30Xg1gnMSgGnjvex8TrgoAmQ=; b=tFR2rppOeZ1hvZKeH/CQznV19yjEM21fBKBPNLiwhRfHTwRmrk5qdpmAHMLSxbf+ro SixTKH7gyeJmCRHzvAZ21j2Brwkoa+0PvmTub6bGjJOc5qBbnqS/43lgBIn2elM2IhT8 xDjUHrhSpDCV4QSgORWdJD3+tHOADl0PfV7KkiESxwkqKbUzXuAoorUCthmw8peY4IOQ 0FrxtyItS7HV/ciIgTywzu778kS4pVBBdN2rzeclg7LLTP7ZIA9pxAk34c/FGMc1AzLK Q2E/gr5MVkeJwGnuHUfMSErkUPLsB21yfX4EdEPgjPl27qNI4ce3deRoYXJdWS1Kjr4d uo2g== X-Gm-Message-State: AOAM532hydQsiU9AhKaErcbMb4opEMA6xjKK2f5JBZNeAy0B+4cIqyUw ZuzG1k91+ySpDqcrDvW9FGHP1Q== X-Google-Smtp-Source: ABdhPJweYIK4QVt1oGBJstiLAQCOmbfbqmVA42aSLZNXQ/Hhy/JZ23PoCnqA1TrO1jkKqaIdstwAUA== X-Received: by 2002:a37:9a44:: with SMTP id c65mr23489338qke.152.1621947632397; Tue, 25 May 2021 06:00:32 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::1:4f4e]) by smtp.gmail.com with ESMTPSA id o5sm4565264qkl.25.2021.05.25.06.00.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 May 2021 06:00:31 -0700 (PDT) Date: Tue, 25 May 2021 09:00:30 -0400 From: Johannes Weiner To: Suren Baghdasaryan Cc: tj@kernel.org, lizefan.x@bytedance.com, mingo@redhat.com, peterz@infradead.org, shakeelb@google.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, minchan@kernel.org, corbet@lwn.net, bristot@redhat.com, paulmck@kernel.org, rdunlap@infradead.org, akpm@linux-foundation.org, tglx@linutronix.de, macro@orcam.me.uk, viresh.kumar@linaro.org, mike.kravetz@oracle.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH v3 1/1] cgroup: make per-cgroup pressure stall tracking configurable Message-ID: References: <20210524195339.1233449-1-surenb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210524195339.1233449-1-surenb@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Mon, May 24, 2021 at 12:53:39PM -0700, Suren Baghdasaryan wrote: > PSI accounts stalls for each cgroup separately and aggregates it at each > level of the hierarchy. This causes additional overhead with psi_avgs_work > being called for each cgroup in the hierarchy. psi_avgs_work has been > highly optimized, however on systems with large number of cgroups the > overhead becomes noticeable. > Systems which use PSI only at the system level could avoid this overhead > if PSI can be configured to skip per-cgroup stall accounting. > Add "cgroup_disable=pressure" kernel command-line option to allow > requesting system-wide only pressure stall accounting. When set, it > keeps system-wide accounting under /proc/pressure/ but skips accounting > for individual cgroups and does not expose PSI nodes in cgroup hierarchy. > > Signed-off-by: Suren Baghdasaryan Acked-by: Johannes Weiner