Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756248AbdCWPiq (ORCPT ); Thu, 23 Mar 2017 11:38:46 -0400 Received: from mga07.intel.com ([134.134.136.100]:35078 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753202AbdCWPip (ORCPT ); Thu, 23 Mar 2017 11:38:45 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.36,210,1486454400"; d="scan'208";a="78629971" Subject: Re: [PATCH v2 3/5] mm: use a dedicated workqueue for the free workers To: Aaron Lu , Minchan Kim References: <1489568404-7817-1-git-send-email-aaron.lu@intel.com> <1489568404-7817-4-git-send-email-aaron.lu@intel.com> <20170322063335.GF30149@bbox> <20170322084103.GC2360@aaronlu.sh.intel.com> Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Tim Chen , Andrew Morton , Ying Huang From: Dave Hansen Message-ID: <4549498a-befc-133d-b204-dd69b191e579@intel.com> Date: Thu, 23 Mar 2017 08:38:43 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <20170322084103.GC2360@aaronlu.sh.intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 856 Lines: 19 On 03/22/2017 01:41 AM, Aaron Lu wrote: > On Wed, Mar 22, 2017 at 03:33:35PM +0900, Minchan Kim wrote: >> On Wed, Mar 15, 2017 at 05:00:02PM +0800, Aaron Lu wrote: >>> Introduce a workqueue for all the free workers so that user can fine >>> tune how many workers can be active through sysfs interface: max_active. >>> More workers will normally lead to better performance, but too many can >>> cause severe lock contention. >> >> Let me ask a question. >> >> How well can workqueue distribute the jobs in multiple CPU? > > I would say it's good enough for my needs. > After all, it doesn't need many kworkers to achieve the 50% time > decrease: 2-4 kworkers for EP and 4-8 kworkers for EX are enough from > previous attched data. It's also worth noting that we'd like to *also* like to look into increasing how scalable freeing pages to a given zone is.