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=-7.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 CCB78C433EF for ; Tue, 7 Sep 2021 16:43:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A581F60E77 for ; Tue, 7 Sep 2021 16:43:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344063AbhIGQo7 (ORCPT ); Tue, 7 Sep 2021 12:44:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46176 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238089AbhIGQoz (ORCPT ); Tue, 7 Sep 2021 12:44:55 -0400 Received: from mail-il1-x12c.google.com (mail-il1-x12c.google.com [IPv6:2607:f8b0:4864:20::12c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1DB1EC061575 for ; Tue, 7 Sep 2021 09:43:49 -0700 (PDT) Received: by mail-il1-x12c.google.com with SMTP id u7so10740258ilk.7 for ; Tue, 07 Sep 2021 09:43:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=3KTSECMQ89sSb/89xBh9CeoozoL34Ed1QNjuTkUfkOs=; b=QyXDKfAD8zjNlfoWIRh+yxEfBJgzD+PngynPGAoCY8A8nPq0p2no9hMirpaPNiwbnc PvcihJ+Hi64vaSH2hCaf5dtNnWw5cQjUj76CftD8bKAueAtDWzvJ8J1v2dAT7IQWW+vq QNgZJUvkw4HjGBs8FScbp+bgS8xRD2XjK0CxjnadreCK9849sXTRTXAtDl46uCGjaPwa dKbErC381J6uGS1muBokbVos+X0CU154fURDUgGHgBMLGuXrA+Q+xxsdigj4SYDIK3Lp y5GRf+g4CAshcUT/H2lxHThmX+xV0hq8YzWrcEFlEBJBgJBEPCndbUpH8ak9uSFzU3CT +jGQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=3KTSECMQ89sSb/89xBh9CeoozoL34Ed1QNjuTkUfkOs=; b=F6TypPD5lpo4sNW7SmcwjPL/5DSrIB45MGPvG7f0NDohoY3+6o4NkhHxnZkA5kgY79 7pgm8CSWPASNFRXuOe/an7O7keigVumblfV/Jh8XEKw0X436PE8beNtCkYRp6m8IsFJw sHJBT4uEER0DzcD2gU2T9O+7awc/4ypOnRcOTYKK9dykbInqTeNuVPCUlbLS6Opzu/7S rvq5yelNJ5cDHEMLiJN0ZGlSKWnzQizyDAsE++1AL4bHjNTXO4/ttIru6WJc3tQNta6g BOShebAInN5YkVhitXa9ji9q9LRDPR9qNKYZmZTTJRHZsabSveNVvdcoI0vNZMa8mx4O HZdw== X-Gm-Message-State: AOAM53077dDS8J/SBaxKqU4SLwLLE9861KcUVEU5EfvR6ENixKqCGJ27 fm7nJR0oMKpZgb1Ml0ZaUP8evQ== X-Google-Smtp-Source: ABdhPJydgmex2AVNNZBm6S5H+yBNtfc6E4tKAvdERShRVi5efwE1Gu/s8rPZ/hyTim9QMsb2dR1fvA== X-Received: by 2002:a92:c5ac:: with SMTP id r12mr12191376ilt.279.1631033028454; Tue, 07 Sep 2021 09:43:48 -0700 (PDT) Received: from [192.168.1.30] ([207.135.234.126]) by smtp.gmail.com with ESMTPSA id c25sm7103722iom.9.2021.09.07.09.43.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 07 Sep 2021 09:43:48 -0700 (PDT) Subject: Re: [memcg] 0f12156dff: will-it-scale.per_process_ops -33.6% regression To: Linus Torvalds Cc: kernel test robot , Vasily Averin , Shakeel Butt , Alexander Viro , Alexey Dobriyan , Andrei Vagin , Borislav Petkov , Borislav Petkov , Christian Brauner , Dmitry Safonov <0x7f454c46@gmail.com>, "Eric W. Biederman" , Greg Kroah-Hartman , "H. Peter Anvin" , Ingo Molnar , "J. Bruce Fields" , Jeff Layton , Jiri Slaby , Johannes Weiner , Kirill Tkhai , Michal Hocko , Oleg Nesterov , Roman Gushchin , Serge Hallyn , Tejun Heo , Thomas Gleixner , Vladimir Davydov , Yutian Yang , Zefan Li , Andrew Morton , LKML , lkp@lists.01.org, kernel test robot , "Huang, Ying" , Feng Tang , Zhengjun Xing References: <20210907150757.GE17617@xsang-OptiPlex-9020> From: Jens Axboe Message-ID: <774dee70-69bd-9f95-d197-4cff83e4e633@kernel.dk> Date: Tue, 7 Sep 2021 10:43:46 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/7/21 10:39 AM, Linus Torvalds wrote: > On Tue, Sep 7, 2021 at 8:46 AM Jens Axboe wrote: >> >> Are we at all worried about these? There's been a number of them >> reported, basically for all the accounting enablements that have been >> done in this merge window. > > We are worried about them. I'm considering reverting several of them > because I think the problems are > > (a) big > > (b) nontrivial > > and the patches clearly weren't ready and people weren't aware of this issue. I think that is prudent. When I first enabled it for io_uring it was a bit of a shit show in terms of performance degradations, and some work had to be done before it could get enabled in a sane fashion. The accounting needs to be more efficient if we're seeing 30-50% slowdowns simply by enabling it on a kmem cache. -- Jens Axboe