From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 2E3278D003B for ; Fri, 4 Feb 2011 18:40:37 -0500 (EST) Received: from hpaq7.eem.corp.google.com (hpaq7.eem.corp.google.com [172.25.149.7]) by smtp-out.google.com with ESMTP id p14NeQJ2023924 for ; Fri, 4 Feb 2011 15:40:26 -0800 Received: from qyk12 (qyk12.prod.google.com [10.241.83.140]) by hpaq7.eem.corp.google.com with ESMTP id p14Ncm4Q028777 (version=TLSv1/SSLv3 cipher=RC4-MD5 bits=128 verify=NOT) for ; Fri, 4 Feb 2011 15:40:25 -0800 Received: by qyk12 with SMTP id 12so2472344qyk.5 for ; Fri, 04 Feb 2011 15:40:24 -0800 (PST) MIME-Version: 1.0 Date: Fri, 4 Feb 2011 15:40:24 -0800 Message-ID: Subject: [LSF/MM TOPIC][ATTEND]cold page tracking / working set estimation From: Michel Lespinasse Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: lsf-pc@lists.linuxfoundation.org, linux-mm@kvack.org Cc: Hugh Dickins Google uses an automated system to assign compute jobs to individual machines within a cluster. In order to improve memory utilization in the cluster, this system collects memory utilization statistics for each cgroup on each machine. The following properties are desired for the working set estimation mechanism: - Low impact on the normal MM algorithms - we don't want to stress the VM just by enabling working set estimation; - Collected statistics should be comparable across multiple machines - we don't just want to know which cgroup to reclaim from on an individual machine, we also need to know which machine is best to target a job onto within a large cluster; - Low, predictable CPU usage; - Among cold pages, differentiate between these that are immediately reclaimable and these that would require a disk write. We use a very simple approach, scanning memory at a fixed rate and identifying pages that haven't been touched in a number of scans. We are currently switching from a fakenuma based implementation (which we don't think is very upstreamable) to a memcg based one. We think this could be of interest to the wider community & would like to discuss requirement with other interested folks. -- Michel "Walken" Lespinasse A program is never fully debugged until the last user dies. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org