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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no 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 74C3FC3A5AA for ; Wed, 4 Sep 2019 17:18:14 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 38E5521726 for ; Wed, 4 Sep 2019 17:18:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Rlc1qhvZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 38E5521726 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id CB8F16B0003; Wed, 4 Sep 2019 13:18:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C699C6B0006; Wed, 4 Sep 2019 13:18:13 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B58A46B0007; Wed, 4 Sep 2019 13:18:13 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0200.hostedemail.com [216.40.44.200]) by kanga.kvack.org (Postfix) with ESMTP id 97F2B6B0003 for ; Wed, 4 Sep 2019 13:18:13 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 411AC181AC9BF for ; Wed, 4 Sep 2019 17:18:13 +0000 (UTC) X-FDA: 75897896466.22.feast37_47b3cfb25d42a X-HE-Tag: feast37_47b3cfb25d42a X-Filterd-Recvd-Size: 4220 Received: from mail-ot1-f67.google.com (mail-ot1-f67.google.com [209.85.210.67]) by imf13.hostedemail.com (Postfix) with ESMTP for ; Wed, 4 Sep 2019 17:18:12 +0000 (UTC) Received: by mail-ot1-f67.google.com with SMTP id o101so21349693ota.8 for ; Wed, 04 Sep 2019 10:18:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=fWAo+cPvJp3pRuv/EjTjzujk+3Lx4B3tuClNVfFzxqE=; b=Rlc1qhvZ/ZQZfeXisjWKvvbzrb0mPj0GtsVSCztE1V6gBxbgVkBtlwBpQfC2Ws0iBt j4bJSkCe2TVLeJe5NK/C6H5I6WMPrjn2HB/p4HGS4lLapqisnUcpYcsHcOvLEXufOiOS /Rxvb97yf7u2LLniuekAdg3DDYKhLMQQEx4l4CR7VYkoEEETOko7EYgS9GpF9q0C/2r2 dvVVNg9ufoLzzbx/qnE1LgO1GRYro3b/T25vZuduFuyj1S3ATJ9kKptK/TWQwnUUnEId EIySB20LH9efVW3/EMHOaxC/bSdaLLY2mfjzFeoqVQWPb5Tyj8/Q733yJqVbiiK1ODNC HxmA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=fWAo+cPvJp3pRuv/EjTjzujk+3Lx4B3tuClNVfFzxqE=; b=TKoIG2azPbQeaMz7vOwYy3Jkhyyal233Lb/HBW30nzPNivZEjeGC2uezAMYzZLm8vi ywYvvu3zqs2NwtztvL2E9i8Xvz75KFCJVOCxjC9fS/wZxScfxNUFVJbINO7kxx6xJ+u1 YagA8o87yG5R3a6hA/0X6pWGHRihLm7ENJ6QpAXZEUyZTCBD2gN7cBB4rYHP5I71d0BD 59Jdk4mcv9WZMoYcBGhCWRy/UBONHsP9CS9Z9pt3Vhzd6X0+mcCL5OoEKyZC0MvzJGzq frWEwGxUOc7KZnlUUkwv0yNxnc0reCBZfDH2MWUYD98AuRntGW6WYvwAJsDv0TX2fWyd PYZg== X-Gm-Message-State: APjAAAWgZvDPDQYq9937MWvoxIh2Hv/c5Ud1pss7LQHa7oFbEE0xXODf M2DRl2y7UlzEapPj9NgHXsO6Vokf1bGl6/jEDKpqkA== X-Google-Smtp-Source: APXvYqxB6/QFXnZ/bEnS1j2lA+AClqCX06L5cZV7XAFcGub2RVPZyKFEhbHeaZgG1pDQGqQfQ9P+zjb+4LI/qsUMqOE= X-Received: by 2002:a9d:30c2:: with SMTP id r2mr17813816otg.186.1567617491603; Wed, 04 Sep 2019 10:18:11 -0700 (PDT) MIME-Version: 1.0 References: <20190903200905.198642-1-joel@joelfernandes.org> <20190904084508.GL3838@dhcp22.suse.cz> <20190904153258.GH240514@google.com> <20190904153759.GC3838@dhcp22.suse.cz> In-Reply-To: <20190904153759.GC3838@dhcp22.suse.cz> From: Daniel Colascione Date: Wed, 4 Sep 2019 10:17:33 -0700 Message-ID: Subject: Re: [PATCH v2] mm: emit tracepoint when RSS changes by threshold To: Michal Hocko Cc: Joel Fernandes , linux-kernel , Tim Murray , Carmen Jackson , Mayank Gupta , Steven Rostedt , Minchan Kim , Andrew Morton , Android Kernel Team , "Aneesh Kumar K.V" , Dan Williams , Jerome Glisse , linux-mm , Matthew Wilcox , Ralph Campbell , Vlastimil Babka Content-Type: text/plain; charset="UTF-8" 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 Wed, Sep 4, 2019 at 8:38 AM Michal Hocko wrote: > > but also for reducing > > tracing noise. Flooding the traces makes it less useful for long traces and > > post-processing of traces. IOW, the overhead reduction is a bonus. > > This is not really anything special for this tracepoint though. > Basically any tracepoint in a hot path is in the same situation and I do > not see a point why each of them should really invent its own way to > throttle. Maybe there is some way to do that in the tracing subsystem > directly. I agree. I'd rather not special-case RSS in this way, especially not with a hardcoded aggregation and thresholding configuration. It should be possible to handle high-frequency trace data point aggregation in a general way. Why shouldn't we be able to get a time series for, say, dirty pages? Or various slab counts? IMHO, any counter on the system ought to be observable in a uniform way.