From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx130.postini.com [74.125.245.130]) by kanga.kvack.org (Postfix) with SMTP id E5BC86B004D for ; Fri, 16 Nov 2012 13:06:25 -0500 (EST) Message-ID: <50A68096.1050208@redhat.com> Date: Fri, 16 Nov 2012 13:06:14 -0500 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 5/8] sched, numa, mm: Add adaptive NUMA affinity support References: <20121112160451.189715188@chello.nl> <20121112161215.782018877@chello.nl> In-Reply-To: <20121112161215.782018877@chello.nl> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Paul Turner , Lee Schermerhorn , Christoph Lameter , Mel Gorman , Andrew Morton , Andrea Arcangeli , Linus Torvalds , Ingo Molnar , Thomas Gleixner On 11/12/2012 11:04 AM, Peter Zijlstra wrote: > We change the load-balancer to prefer moving tasks in order of: > > 1) !numa tasks and numa tasks in the direction of more faults > 2) allow !ideal tasks getting worse in the direction of faults > 3) allow private tasks to get worse > 4) allow shared tasks to get worse > > This order ensures we prefer increasing memory locality but when > we do have to make hard decisions we prefer spreading private > over shared, because spreading shared tasks significantly > increases the interconnect bandwidth since not all memory can > follow. Combined with the fact that we only turn a certain amount of memory into NUMA ptes each second, could this result in a program being classified as a private task one second, and a shared task a few seconds later? What does the code do to prevent such an oscillating of task classification? (which would have consequences for the way the task's NUMA placement is handled, and might result in the task moving from node to node needlessly) -- All rights reversed -- 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