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=-9.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 A36B3C433DB for ; Tue, 16 Mar 2021 00:53:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 77A0C64F6D for ; Tue, 16 Mar 2021 00:53:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233305AbhCPAwc (ORCPT ); Mon, 15 Mar 2021 20:52:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44982 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232118AbhCPAwa (ORCPT ); Mon, 15 Mar 2021 20:52:30 -0400 Received: from mail-pf1-x434.google.com (mail-pf1-x434.google.com [IPv6:2607:f8b0:4864:20::434]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01C01C06174A; Mon, 15 Mar 2021 17:52:29 -0700 (PDT) Received: by mail-pf1-x434.google.com with SMTP id o3so3018231pfh.11; Mon, 15 Mar 2021 17:52:29 -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=xZoZuWb2tBzrGLpbmU0QlJ3nLJM79Q95ZotWRYdo/dU=; b=udPVwzShPfqLnJku3Fi+dpSMekaBCR/1LK2aWf1PcUDLZZrudJibDmi0qfrv/bqFQi 2H93ctwVoCfgOr2SN8hWgsDeHQvcBvP8XiGlBtPsy1YjVOKrLNSDioU8RZp8zwqXc3A6 oJI2UWvwmwVvKThzHVEDxhD1X5nOp/VOJj4PbXs+hR49oilZocWDgVy25YKK8EOHXYdm qYcsl+P22j8n75mkw0RH4x+LoJ8q9WWI19/8ttIpLAb5Tp5h50c6BXldIRsMApX7ghT4 eTArYFObAgWoCrP6O+yFbQ/MxkIiKeK6kzPC9Og6q+TOirm7W6j9lHvVgDGzbYPmZY3q 8c5Q== 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=xZoZuWb2tBzrGLpbmU0QlJ3nLJM79Q95ZotWRYdo/dU=; b=JeikaMJHsgccufQd+KwsVzgCKNDx18kzGUW+c/CrDecwCCZ4Km78qjmoMck8hpUDyO jNCi9RgaJ6NPM3QsPSq3vorycY3Wam5BRGTeafANy8YC11sSJVoilFq9uYmlurgz1YAN R8RpYCKrj+l4VzrK1+8vaOv+8W/otCUJX+z3kMiRAp7UZ2rb6Zb3UOFi8AhqpQUyvttW xIuZRMWjEh8yBWKkwIf/rT0KE4JhEfGH+jBbV4OSD+Yyjg0u6eTt+dJ/96N6Ixa4SZ9T /KiU6LG8b9v+ezrveVPKyGWJVJKtZCVGfSpX1jD+g/TueH1HnJTXGGWXExmmdy2aTAR+ g2Vw== X-Gm-Message-State: AOAM533uzKO1zw7Fkb9x3mtMQt5+A85y2qraBb1cihclsdO/1ZntwIWm YfZ/6zckNtOkIdYv8UUIuH5lWbvuZt4= X-Google-Smtp-Source: ABdhPJxtgToEh90OsCzFZ8X/0t8eT0FJAw1LQkF78w9cJu/2scgskfJvfnWyygm0lV6xkfQGigLdTA== X-Received: by 2002:a63:1026:: with SMTP id f38mr1582605pgl.142.1615855949298; Mon, 15 Mar 2021 17:52:29 -0700 (PDT) Received: from f8ffc2228008.ant.amazon.com ([54.240.193.129]) by smtp.gmail.com with ESMTPSA id gz12sm759496pjb.33.2021.03.15.17.52.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 15 Mar 2021 17:52:28 -0700 (PDT) Subject: Re: [PATCH] mm: memcontrol: switch to rstat fix To: Johannes Weiner , Andrew Morton Cc: Michal Hocko , Roman Gushchin , Shakeel Butt , Tejun Heo , =?UTF-8?Q?Michal_Koutn=c3=bd?= , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@fb.com References: <20210315234100.64307-1-hannes@cmpxchg.org> From: "Singh, Balbir" Message-ID: <494a5169-7e18-804b-3975-3a6442aff601@gmail.com> Date: Tue, 16 Mar 2021 11:52:22 +1100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20210315234100.64307-1-hannes@cmpxchg.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 16/3/21 10:41 am, Johannes Weiner wrote: > Fix a sleep in atomic section problem: wb_writeback() takes a spinlock > and calls wb_over_bg_thresh() -> mem_cgroup_wb_stats, but the regular > rstat flushing function called from in there does lockbreaking and may > sleep. Switch to the atomic variant, cgroup_rstat_irqsafe(). > > To be consistent with other memcg flush calls, but without adding > another memcg wrapper, inline and drop memcg_flush_vmstats() instead. > > Signed-off-by: Johannes Weiner > --- The patch make sense, but it does break any notion of abstraction we had about controllers have some independence in their strategy to maintain their own counters and stats. It now couples writeback with rstat instead of just memcg. Acked-by: Balbir Singh From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Singh, Balbir" Subject: Re: [PATCH] mm: memcontrol: switch to rstat fix Date: Tue, 16 Mar 2021 11:52:22 +1100 Message-ID: <494a5169-7e18-804b-3975-3a6442aff601@gmail.com> References: <20210315234100.64307-1-hannes@cmpxchg.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: 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=xZoZuWb2tBzrGLpbmU0QlJ3nLJM79Q95ZotWRYdo/dU=; b=udPVwzShPfqLnJku3Fi+dpSMekaBCR/1LK2aWf1PcUDLZZrudJibDmi0qfrv/bqFQi 2H93ctwVoCfgOr2SN8hWgsDeHQvcBvP8XiGlBtPsy1YjVOKrLNSDioU8RZp8zwqXc3A6 oJI2UWvwmwVvKThzHVEDxhD1X5nOp/VOJj4PbXs+hR49oilZocWDgVy25YKK8EOHXYdm qYcsl+P22j8n75mkw0RH4x+LoJ8q9WWI19/8ttIpLAb5Tp5h50c6BXldIRsMApX7ghT4 eTArYFObAgWoCrP6O+yFbQ/MxkIiKeK6kzPC9Og6q+TOirm7W6j9lHvVgDGzbYPmZY3q 8c5Q== In-Reply-To: <20210315234100.64307-1-hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org> Content-Language: en-GB List-ID: Content-Type: text/plain; charset="us-ascii" To: Johannes Weiner , Andrew Morton Cc: Michal Hocko , Roman Gushchin , Shakeel Butt , Tejun Heo , =?UTF-8?Q?Michal_Koutn=c3=bd?= , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-team-b10kYP2dOMg@public.gmane.org On 16/3/21 10:41 am, Johannes Weiner wrote: > Fix a sleep in atomic section problem: wb_writeback() takes a spinlock > and calls wb_over_bg_thresh() -> mem_cgroup_wb_stats, but the regular > rstat flushing function called from in there does lockbreaking and may > sleep. Switch to the atomic variant, cgroup_rstat_irqsafe(). > > To be consistent with other memcg flush calls, but without adding > another memcg wrapper, inline and drop memcg_flush_vmstats() instead. > > Signed-off-by: Johannes Weiner > --- The patch make sense, but it does break any notion of abstraction we had about controllers have some independence in their strategy to maintain their own counters and stats. It now couples writeback with rstat instead of just memcg. Acked-by: Balbir Singh