From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755046Ab3F1JhA (ORCPT ); Fri, 28 Jun 2013 05:37:00 -0400 Received: from merlin.infradead.org ([205.233.59.134]:46604 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754643Ab3F1Jg6 (ORCPT ); Fri, 28 Jun 2013 05:36:58 -0400 Date: Fri, 28 Jun 2013 11:36:25 +0200 From: Peter Zijlstra To: Srikar Dronamraju Cc: Mel Gorman , Ingo Molnar , Andrea Arcangeli , Johannes Weiner , Linux-MM , LKML Subject: Re: [PATCH 7/8] sched: Split accounting of NUMA hinting faults that pass two-stage filter Message-ID: <20130628093625.GF29209@dyad.programming.kicks-ass.net> References: <1372257487-9749-1-git-send-email-mgorman@suse.de> <1372257487-9749-8-git-send-email-mgorman@suse.de> <20130628070027.GD17195@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130628070027.GD17195@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 28, 2013 at 12:30:27PM +0530, Srikar Dronamraju wrote: > * Mel Gorman [2013-06-26 15:38:06]: > > > Ideally it would be possible to distinguish between NUMA hinting faults > > that are private to a task and those that are shared. This would require > > that the last task that accessed a page for a hinting fault would be > > recorded which would increase the size of struct page. Instead this patch > > approximates private pages by assuming that faults that pass the two-stage > > filter are private pages and all others are shared. The preferred NUMA > > node is then selected based on where the maximum number of approximately > > private faults were measured. > > Should we consider only private faults for preferred node? I don't think so; its optimal for the task to be nearest most of its pages; irrespective of whether they be private or shared. > I would think if tasks have shared pages then moving all tasks that share > the same pages to a node where the share pages are around would be > preferred. No? Well no; not if there's only 5 shared pages but 1024 private pages. > If yes, how does the preferred node logic help to achieve > the above? There's no packing logic yet... From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx178.postini.com [74.125.245.178]) by kanga.kvack.org (Postfix) with SMTP id AE9516B0032 for ; Fri, 28 Jun 2013 05:36:55 -0400 (EDT) Date: Fri, 28 Jun 2013 11:36:25 +0200 From: Peter Zijlstra Subject: Re: [PATCH 7/8] sched: Split accounting of NUMA hinting faults that pass two-stage filter Message-ID: <20130628093625.GF29209@dyad.programming.kicks-ass.net> References: <1372257487-9749-1-git-send-email-mgorman@suse.de> <1372257487-9749-8-git-send-email-mgorman@suse.de> <20130628070027.GD17195@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130628070027.GD17195@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Srikar Dronamraju Cc: Mel Gorman , Ingo Molnar , Andrea Arcangeli , Johannes Weiner , Linux-MM , LKML On Fri, Jun 28, 2013 at 12:30:27PM +0530, Srikar Dronamraju wrote: > * Mel Gorman [2013-06-26 15:38:06]: > > > Ideally it would be possible to distinguish between NUMA hinting faults > > that are private to a task and those that are shared. This would require > > that the last task that accessed a page for a hinting fault would be > > recorded which would increase the size of struct page. Instead this patch > > approximates private pages by assuming that faults that pass the two-stage > > filter are private pages and all others are shared. The preferred NUMA > > node is then selected based on where the maximum number of approximately > > private faults were measured. > > Should we consider only private faults for preferred node? I don't think so; its optimal for the task to be nearest most of its pages; irrespective of whether they be private or shared. > I would think if tasks have shared pages then moving all tasks that share > the same pages to a node where the share pages are around would be > preferred. No? Well no; not if there's only 5 shared pages but 1024 private pages. > If yes, how does the preferred node logic help to achieve > the above? There's no packing logic yet... -- 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