From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265670AbTFNNgf (ORCPT ); Sat, 14 Jun 2003 09:36:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265663AbTFNNge (ORCPT ); Sat, 14 Jun 2003 09:36:34 -0400 Received: from holomorphy.com ([66.224.33.161]:34953 "EHLO holomorphy") by vger.kernel.org with ESMTP id S265670AbTFNNgS (ORCPT ); Sat, 14 Jun 2003 09:36:18 -0400 Date: Sat, 14 Jun 2003 06:49:27 -0700 From: William Lee Irwin III To: Oliver Neukum Cc: Dave Hansen , Linux Kernel Mailing List , linux-mm , "Martin J. Bligh" Subject: Re: [RFC] recursive pagetables for x86 PAE Message-ID: <20030614134927.GH26348@holomorphy.com> Mail-Followup-To: William Lee Irwin III , Oliver Neukum , Dave Hansen , Linux Kernel Mailing List , linux-mm , "Martin J. Bligh" References: <1055540875.3531.2581.camel@nighthawk> <200306141327.48649.oliver@neukum.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200306141327.48649.oliver@neukum.org> Organization: The Domain of Holomorphy User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Am Freitag, 13. Juni 2003 23:47 schrieb Dave Hansen: >> When you have lots of tasks, the pagetables start taking up lots of >> lowmem. We have the ability to push the PTE pages into highmem, but >> that exacts a penalty from the atomic kmaps which, depending on >> workload, can be a 10-15% performance hit. >> The following patches implement something which we like to call UKVA. >> It's a Kernel Virtual Area which is private to a process, just like >> Userspace. You can put any process-local data that you want in the >> area. But, for now, I just put PTE pages in there. On Sat, Jun 14, 2003 at 01:27:48PM +0200, Oliver Neukum wrote: > If you put only such pages there, do you really want that memory to > be per task? IMHO it should be per memory context to aid threading > performance. Per-process is essentially per-mm. On Sat, Jun 14, 2003 at 01:27:48PM +0200, Oliver Neukum wrote: > Secondly, doesn't this scream for using large pages? No, 2MB/4MB pages are not useful here. -- wli