From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932619AbXC1Vi5 (ORCPT ); Wed, 28 Mar 2007 17:38:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753159AbXC1Vi5 (ORCPT ); Wed, 28 Mar 2007 17:38:57 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:53582 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753156AbXC1Vi4 (ORCPT ); Wed, 28 Mar 2007 17:38:56 -0400 Date: Wed, 28 Mar 2007 14:38:55 -0700 (PDT) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: William Lee Irwin III cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org Subject: Re: [RFC] i386: Remove page sized slabs for pgds and pmds In-Reply-To: <20070328212459.GY8915@holomorphy.com> Message-ID: References: <20070328205055.GX8915@holomorphy.com> <20070328212459.GY8915@holomorphy.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 28 Mar 2007, William Lee Irwin III wrote: > I'd also appreciate if it were mentioned who actually wrote this, given > that the patch posted was what I sent you verbatim (and actually > requested you not post for good reasons, some centering around pageattr.c). Ughhh. Sorry I had this in there in early editions but removed the paragraph later. > The salient point from the above, which was conveniently omitted, was > "it's all dominated by PTE caching." However, even this needs some > qualification having to do with the VSZ of the parent process in fork(). > For very small processes, such as cannot be constructed with glibc due > to its massive bloat and cannot be constructed with the standard process > address space layouts due to stacks being too distant from text and > heap, PTE's actually don't substantially outnumber PMD's et al, so > there is more to this story. No that was described in the patch. Quote: "i386 only provides support for caching constructed pgd and pmds. These are comparatively rare to ptes so it is no surprise that the current approach has only minimal effect. ...."