From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933353AbXCMVHY (ORCPT ); Tue, 13 Mar 2007 17:07:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933354AbXCMVHY (ORCPT ); Tue, 13 Mar 2007 17:07:24 -0400 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:58371 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S933353AbXCMVHX (ORCPT ); Tue, 13 Mar 2007 17:07:23 -0400 Date: Tue, 13 Mar 2007 14:07:22 -0700 (PDT) Message-Id: <20070313.140722.72711732.davem@davemloft.net> To: mpm@selenic.com Cc: jeremy@goop.org, nickpiggin@yahoo.com.au, akpm@linux-foundation.org, clameter@sgi.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [QUICKLIST 0/4] Arch independent quicklists V2 From: David Miller In-Reply-To: <20070313202125.GO10394@waste.org> References: <20070313200313.GG10459@waste.org> <45F706BC.7060407@goop.org> <20070313202125.GO10394@waste.org> X-Mailer: Mew version 5.1.52 on Emacs 21.4 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Matt Mackall Date: Tue, 13 Mar 2007 15:21:25 -0500 > Because the fan-out is large, the bulk of the work is bringing the last > layer of the tree into cache to find all the pages in the address > space. And there's really no way around that. That's right. And I will note that historically we used to be much worse in this area, as we used to walk the page table tree twice on address space teardown (once to hit the PTE entries, once to free the page tables). Happily it is a one-pass algorithm now. But, within active VMA ranges, we do have to walk all the bits at least one time.