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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 1D52AC433E0 for ; Fri, 15 May 2020 08:38:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EFDEC207D0 for ; Fri, 15 May 2020 08:38:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728010AbgEOIiU (ORCPT ); Fri, 15 May 2020 04:38:20 -0400 Received: from mga09.intel.com ([134.134.136.24]:20585 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726894AbgEOIiT (ORCPT ); Fri, 15 May 2020 04:38:19 -0400 IronPort-SDR: KRFIazBTHIqofEYfQHF0FO8IuhHW63A0sjuUtsWsOJ6OzEyZaNk6AsUCVGQ1hbyYMvSMx7If9/ vD0Xs2eh0W7A== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 May 2020 01:38:19 -0700 IronPort-SDR: ap3WmmjCJ0XbtaIaCaJF842iRRfzguCYuAbsDRQGIGn9+Qi4YB05k3DtnE0xXnRKEtBuXBkG+J ZZcHxIHmcvWg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,394,1583222400"; d="scan'208";a="438238552" Received: from shbuild999.sh.intel.com (HELO localhost) ([10.239.146.107]) by orsmga005.jf.intel.com with ESMTP; 15 May 2020 01:38:15 -0700 Date: Fri, 15 May 2020 16:38:14 +0800 From: Feng Tang To: Michal Hocko Cc: Andrew Morton , Johannes Weiner , Matthew Wilcox , Mel Gorman , Kees Cook , Luis Chamberlain , Iurii Zaikin , "Kleen, Andi" , "Chen, Tim C" , "Hansen, Dave" , "Huang, Ying" , "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: <20200515083814.GE69177@shbuild999.sh.intel.com> References: <1588922717-63697-1-git-send-email-feng.tang@intel.com> <1588922717-63697-4-git-send-email-feng.tang@intel.com> <20200515074443.GI29153@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200515074443.GI29153@dhcp22.suse.cz> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 15, 2020 at 03:44:43PM +0800, Michal Hocko wrote: > 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. I imagined cases like this too :) but was not sure there are such cases. So I only put down the the benchmark I've worked with in 0day. Thanks, Feng > -- > Michal Hocko > SUSE Labs