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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 A7C32C433DF for ; Fri, 15 May 2020 07:44:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8609F206F4 for ; Fri, 15 May 2020 07:44:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589528688; bh=4ulSJZHEbPwPApbgbMErWimKM8LRMGl1NjDhth/liIw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=hTydRLhkxldPrr1gY+pvLNO3ZTSFo8HCN6XUZU+89V2pH+ndzWD//bhX82V3bvnYn Pc1aRnfIibLqUj7Dv3AHgInLfIC3slQKzf/rDzO7Hn+jrc9hUkDzpPBwJrvcxNSP5G Y7qVXdLpK1vKwFgf2VqqGjtPU8EXzGQSv7NQ5HEc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726727AbgEOHor (ORCPT ); Fri, 15 May 2020 03:44:47 -0400 Received: from mail-wm1-f67.google.com ([209.85.128.67]:52439 "EHLO mail-wm1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726622AbgEOHor (ORCPT ); Fri, 15 May 2020 03:44:47 -0400 Received: by mail-wm1-f67.google.com with SMTP id z4so112980wmi.2 for ; Fri, 15 May 2020 00:44:45 -0700 (PDT) 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=vJVWJQVk8CciTsSCvsqJGG8XKk2NT2HP/Zje3wxePpk=; b=Nj54Wor2yF2UtoHvPKf8CCT6bpACcqk7Zc9DZRZFiMVBh270jguWqstgA689Gyxhh1 30bdBtppDtZAKJf09ZBGTPRUo4dahaRRBwkJmFNdXkJ5PdxJoB8amPmPYzehXYc9Xe+e 6NdCXuMRWSBWuScKYmy6BTKN0XvILbeB8y5adrRV3mzqi9cS+CLvBVwbJi0EVM1+Y0HW tTHVW0yviTzU6mApo9ijai5mqeBkTDciMFxZktFhRuPKHPwM2esAIJplSnU7RpcAvcV7 wLyhQTbm0eyUhPpIVsial2RHD0fnH6ewrMhacPoFyuuCRurK1eEn34gLuAANWUx54sQm /fWQ== X-Gm-Message-State: AOAM531s8LrP7kmtWUNlhhperFkAjdx4slDNlBqjTzQ6war7YMLbIfJG WbQahAbzoe4dk6cMsU66uUM= X-Google-Smtp-Source: ABdhPJzvvHdgX5ui4nSJTmyuDZ8V7G9BS6vKsmATdulV+5BVtxjVEsfdhBS0PT9CUX0cVS6RBi/lDg== X-Received: by 2002:a05:600c:1403:: with SMTP id g3mr2660839wmi.51.1589528685290; Fri, 15 May 2020 00:44:45 -0700 (PDT) Received: from localhost (ip-37-188-249-36.eurotel.cz. [37.188.249.36]) by smtp.gmail.com with ESMTPSA id p17sm5856361wmi.3.2020.05.15.00.44.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 May 2020 00:44:44 -0700 (PDT) Date: Fri, 15 May 2020 09:44:43 +0200 From: Michal Hocko To: Feng Tang Cc: Andrew Morton , Johannes Weiner , Matthew Wilcox , Mel Gorman , Kees Cook , Luis Chamberlain , Iurii Zaikin , andi.kleen@intel.com, tim.c.chen@intel.com, dave.hansen@intel.com, ying.huang@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] mm: adjust vm_committed_as_batch according to vm overcommit policy Message-ID: <20200515074443.GI29153@dhcp22.suse.cz> References: <1588922717-63697-1-git-send-email-feng.tang@intel.com> <1588922717-63697-4-git-send-email-feng.tang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1588922717-63697-4-git-send-email-feng.tang@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 08-05-20 15:25:17, Feng Tang wrote: > When checking a performance change for will-it-scale scalability > mmap test [1], we found very high lock contention for spinlock of > percpu counter 'vm_committed_as': Btw. you are focusing on a microbenchmark here but I believe that there are non-synthetic worklaods which would benefit from a larger batch. E.g. large in memory databases which do large mmaps during startups from multiple threads. -- Michal Hocko SUSE Labs