Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752572AbdHRQpI (ORCPT ); Fri, 18 Aug 2017 12:45:08 -0400 Received: from mga03.intel.com ([134.134.136.65]:61611 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751046AbdHRQpH (ORCPT ); Fri, 18 Aug 2017 12:45:07 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.41,393,1498546800"; d="scan'208";a="1207274593" Date: Fri, 18 Aug 2017 09:45:06 -0700 From: Andi Kleen To: Tim Chen Cc: Mel Gorman , "Liang, Kan" , Linus Torvalds , Mel Gorman , "Kirill A. Shutemov" , Peter Zijlstra , Ingo Molnar , Andrew Morton , Johannes Weiner , Jan Kara , linux-mm , Linux Kernel Mailing List Subject: Re: [PATCH 1/2] sched/wait: Break up long wake list walk Message-ID: <20170818164506.GO28715@tassilo.jf.intel.com> References: <84c7f26182b7f4723c0fe3b34ba912a9de92b8b7.1502758114.git.tim.c.chen@linux.intel.com> <37D7C6CF3E00A74B8858931C1DB2F07753786CE9@SHSMSX103.ccr.corp.intel.com> <37D7C6CF3E00A74B8858931C1DB2F0775378761B@SHSMSX103.ccr.corp.intel.com> <20170818122339.24grcbzyhnzmr4qw@techsingularity.net> <37D7C6CF3E00A74B8858931C1DB2F077537879BB@SHSMSX103.ccr.corp.intel.com> <20170818144622.oabozle26hasg5yo@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.8.3 (2017-05-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 405 Lines: 9 > Still, I don't think this problem is THP specific. If there is a hot > regular page getting migrated, we'll also see many threads get > queued up quickly. THP may have made the problem worse as migrating > it takes a longer time, meaning more threads could get queued up. Also THP probably makes more threads collide because the pages are larger. But still it can all happen even without THP. -Andi