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 32DDEC433DF for ; Fri, 15 May 2020 08:38:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E97DF205CB for ; Fri, 15 May 2020 08:38:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E97DF205CB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 945628E0008; Fri, 15 May 2020 04:38:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8F7048E0005; Fri, 15 May 2020 04:38:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 80C008E0008; Fri, 15 May 2020 04:38:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0109.hostedemail.com [216.40.44.109]) by kanga.kvack.org (Postfix) with ESMTP id 6D7F88E0005 for ; Fri, 15 May 2020 04:38:23 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 37BE28248047 for ; Fri, 15 May 2020 08:38:23 +0000 (UTC) X-FDA: 76818301686.05.root40_831103f3fb400 X-HE-Tag: root40_831103f3fb400 X-Filterd-Recvd-Size: 2770 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by imf48.hostedemail.com (Postfix) with ESMTP for ; Fri, 15 May 2020 08:38:20 +0000 (UTC) IronPort-SDR: xap5CY+GncsIbfhDSBOpf/t8XZq6xE1NW4sqRRZwp5/veqk0W9NXqKUWeFe+6YRUKNyMjiFd1K YLrKk78H8MJQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga104.fm.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) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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