From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268944AbUHMCGV (ORCPT ); Thu, 12 Aug 2004 22:06:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268945AbUHMCGV (ORCPT ); Thu, 12 Aug 2004 22:06:21 -0400 Received: from e5.ny.us.ibm.com ([32.97.182.105]:61588 "EHLO e5.ny.us.ibm.com") by vger.kernel.org with ESMTP id S268944AbUHMCGS (ORCPT ); Thu, 12 Aug 2004 22:06:18 -0400 Subject: Re: [PATCH] allocate page caches pages in round robin fasion From: Dave Hansen To: Jesse Barnes Cc: Andrew Morton , Linux Kernel Mailing List , steiner@sgi.com In-Reply-To: <200408121638.37416.jbarnes@engr.sgi.com> References: <200408121638.37416.jbarnes@engr.sgi.com> Content-Type: text/plain Message-Id: <1092360960.15667.26.camel@nighthawk> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Thu, 12 Aug 2004 18:36:00 -0700 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2004-08-12 at 16:38, Jesse Barnes wrote: > On a NUMA machine, page cache pages should be spread out across the system > since they're generally global in nature and can eat up whole nodes worth of > memory otherwise. This can end up hurting performance since jobs will have > to make off node references for much or all of their non-file data. Wouldn't this be painful for any workload that accesses a unique set of files on each node? If an application knows that it is touching truly shared data which every node could possibly access, then they can use the NUMA API to cause round-robin allocations to occur. Maybe a per-node watermark on page cache usage would be more useful. Once a node starts to get full, and it's past the watermark, we can go and shoot down some of the node's page cache. If the data access is truly global, then it has a good chance of being brought in on a different node. -- Dave