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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 163E1C6778F for ; Thu, 26 Jul 2018 00:55:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B119720852 for ; Thu, 26 Jul 2018 00:55:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ABE80zD5" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B119720852 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728653AbeGZCJc (ORCPT ); Wed, 25 Jul 2018 22:09:32 -0400 Received: from mail-pl0-f67.google.com ([209.85.160.67]:37950 "EHLO mail-pl0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728378AbeGZCJb (ORCPT ); Wed, 25 Jul 2018 22:09:31 -0400 Received: by mail-pl0-f67.google.com with SMTP id b1-v6so4729pls.5 for ; Wed, 25 Jul 2018 17:55:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=rynC+1+BbojgOz0vOxYXM2rzEbvJSFTQSc3rxp20pIk=; b=ABE80zD5AOk1b1yLewuC5OaxqhjJuHfLkhjWNqrX5NbxxfIZpWg/3tT7uJQP1Qga9H ZO34etH2eYxS3BD1DPAUITfulG73eZJFvkNyCoRkBaTFaNN1/2fyDzCmgIwZqzdhSwGV 17J9DuykOEMYuNTmv1rTvVtCS/60cpsH+In5G7v7pf2Jf0MgOjlRA0FBx9f7ywKMbeTS HDJOt5aonYDBLu4oAAPyq1EShglsEAg2aFfc8DA0MbzFJH4wC3ZUvINtjQTD/fpG2k5u mYBaufdPrHaS2cglUs0ZgsvGZII3iNwBTcxc1DSifdHSZOy1/yo0izXcQjNzYTIl6Dy5 JcxQ== 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=rynC+1+BbojgOz0vOxYXM2rzEbvJSFTQSc3rxp20pIk=; b=YV+NtnZNz0bV8ugqXWiVkhObw3J+uy56k89rTMp1ttISbEbOVXk47T2abu8FAmMNm9 238NvPI14JP3H2Ky6lWgh2w3sUWS/P+3ONtgsRQYBBEI/G7oOcuyfJgT+YgdQcVL0xpF us7TeqfuqRvuxg8zZKIstDVucUT3Tq5fyW+ZDexXVAHoEuAgm5IL6kMxHN3DyNBNBwwd 2K1IQ0dZ1e7XiSujVQu+x9UyX3fOAoFoGExisF5ti7WG3QsJSSbAtImYgBHnU9Ejnfk9 m2YWR5goK7WTpunJyJ1oPGZWTJzXZ25fMpMIIIAMLUb1D7l9TBUrluV0kd3ZmkX8vB3t 09Kw== X-Gm-Message-State: AOUpUlGNjSDJ8rf6SifdANvbjZZcBYHMViuq1eq8F68LnLeGBmxGCIKI HTgfP3IIjdNxhKEziLW5ffc= X-Google-Smtp-Source: AAOMgpcDjifLlXgS/mW0VnnaCQoa3mU5PdA8mS4V789k7PSm/vnov3t3KM1yWWzj6BsYYhU+8ZOQsA== X-Received: by 2002:a17:902:9a83:: with SMTP id w3-v6mr4452919plp.75.1532566516135; Wed, 25 Jul 2018 17:55:16 -0700 (PDT) Received: from 8c8590bceeee.ant.amazon.com ([54.240.193.1]) by smtp.gmail.com with ESMTPSA id s195-v6sm30930094pgs.76.2018.07.25.17.55.11 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 25 Jul 2018 17:55:14 -0700 (PDT) Subject: Re: Showing /sys/fs/cgroup/memory/memory.stat very slow on some machines To: Bruce Merry , Shakeel Butt Cc: Michal Hocko , Andrew Morton , LKML , Linux MM , Johannes Weiner , Vladimir Davydov References: <20180717212307.d6803a3b0bbfeb32479c1e26@linux-foundation.org> <20180718104230.GC1431@dhcp22.suse.cz> From: "Singh, Balbir" Message-ID: Date: Thu, 26 Jul 2018 10:55:08 +1000 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/19/18 3:40 AM, Bruce Merry wrote: > On 18 July 2018 at 17:49, Shakeel Butt wrote: >> On Wed, Jul 18, 2018 at 8:37 AM Bruce Merry wrote: >>> That sounds promising. Is there any way to tell how many zombies there >>> are, and is there any way to deliberately create zombies? If I can >>> produce zombies that might give me a reliable way to reproduce the >>> problem, which could then sensibly be tested against newer kernel >>> versions. >>> >> >> Yes, very easy to produce zombies, though I don't think kernel >> provides any way to tell how many zombies exist on the system. >> >> To create a zombie, first create a memcg node, enter that memcg, >> create a tmpfs file of few KiBs, exit the memcg and rmdir the memcg. >> That memcg will be a zombie until you delete that tmpfs file. > > Thanks, that makes sense. I'll see if I can reproduce the issue. Do > you expect the same thing to happen with normal (non-tmpfs) files that > are sitting in the page cache, and/or dentries? > Do you by any chance have use_hierarch=1? memcg_stat_show should just rely on counters inside the memory cgroup and the the LRU sizes for each node. Balbir Singh.