From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757515AbdHYRqQ (ORCPT ); Fri, 25 Aug 2017 13:46:16 -0400 Received: from resqmta-ch2-08v.sys.comcast.net ([69.252.207.40]:35666 "EHLO resqmta-ch2-08v.sys.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756442AbdHYRqP (ORCPT ); Fri, 25 Aug 2017 13:46:15 -0400 Date: Fri, 25 Aug 2017 12:46:12 -0500 (CDT) From: Christopher Lameter X-X-Sender: cl@nuc-kabylake To: Tim Chen cc: Linus Torvalds , Mel Gorman , Peter Zijlstra , Ingo Molnar , Andi Kleen , Kan Liang , Andrew Morton , Johannes Weiner , Jan Kara , "Eric W . Biederman" , Davidlohr Bueso , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2 v2] sched/wait: Break up long wake list walk In-Reply-To: <83f675ad385d67760da4b99cd95ee912ca7c0b44.1503677178.git.tim.c.chen@linux.intel.com> Message-ID: References: <83f675ad385d67760da4b99cd95ee912ca7c0b44.1503677178.git.tim.c.chen@linux.intel.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-CMAE-Envelope: MS4wfPQ7z0xfwxlW2JBM9WRvAvVUutFh4wQo0lBVia0BvuegdhdR03V72MSRgzg/qU45HJ8QWIvThafQgKNaofskEV3KNIFHNGjOX8yKhdPRd9snWm50hoti YugKxfXboQdfLzne7Il8xBatzTJ13glTJ+mm36qTmHiwJgBi5SNWfzBtpA56Psciupqk8voUd1LTj6vdeAgeDGlHcQIbAbSNktCezyhPpjjtQvLsU1fqzfC/ W++TWqKCPhrD8/KpqSrNFX2izolgln+Rr/UZWJIm6KQstHaDnfD+8w1csaVU+K6iYATcq8q8YzFZgqpVWOKQnnVqkGk0nHRRmh+lE0NBITKvmpt0tXtbLaPx TBLfJaVyC9yuONF7IUbftYT6sDclaKyaTQ4LBU6vIsxYY1AJrU76OQESnP9Sf1aWLKWHp7y8T2XiLqjU+oFuL108b9zBpotUxW/ZmvBhK7DsZ+qspaMYIkMq Nn7h3BO3LggzNr7wyNSJY2d5+aV72u5yHuh0brELVbTiU/Ot9UfAs1SPdV2vdMzoJsjCpvUgC8E23AlrK8vs/Sv+0rWPf/0g1L8/LxxyfEk6qjZ/2ZqNPEtG klU= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 25 Aug 2017, Tim Chen wrote: > for a long time. It is a result of the numa balancing migration of hot > pages that are shared by many threads. I think that would also call for some work to limit numa balacing of hot shared pages. The cache lines of hot pages are likely in present the low level processor caches anyways so moving them would not cause a performance benefit. Limiting the migration there could stop wasting a lot of effort. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f69.google.com (mail-it0-f69.google.com [209.85.214.69]) by kanga.kvack.org (Postfix) with ESMTP id 1B4446810C8 for ; Fri, 25 Aug 2017 13:46:16 -0400 (EDT) Received: by mail-it0-f69.google.com with SMTP id b76so5238120itb.0 for ; Fri, 25 Aug 2017 10:46:16 -0700 (PDT) Received: from resqmta-ch2-11v.sys.comcast.net (resqmta-ch2-11v.sys.comcast.net. [2001:558:fe21:29:69:252:207:43]) by mx.google.com with ESMTPS id v66si6649384iov.15.2017.08.25.10.46.14 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 25 Aug 2017 10:46:14 -0700 (PDT) Date: Fri, 25 Aug 2017 12:46:12 -0500 (CDT) From: Christopher Lameter Subject: Re: [PATCH 1/2 v2] sched/wait: Break up long wake list walk In-Reply-To: <83f675ad385d67760da4b99cd95ee912ca7c0b44.1503677178.git.tim.c.chen@linux.intel.com> Message-ID: References: <83f675ad385d67760da4b99cd95ee912ca7c0b44.1503677178.git.tim.c.chen@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Tim Chen Cc: Linus Torvalds , Mel Gorman , Peter Zijlstra , Ingo Molnar , Andi Kleen , Kan Liang , Andrew Morton , Johannes Weiner , Jan Kara , "Eric W . Biederman" , Davidlohr Bueso , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Fri, 25 Aug 2017, Tim Chen wrote: > for a long time. It is a result of the numa balancing migration of hot > pages that are shared by many threads. I think that would also call for some work to limit numa balacing of hot shared pages. The cache lines of hot pages are likely in present the low level processor caches anyways so moving them would not cause a performance benefit. Limiting the migration there could stop wasting a lot of effort. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org