Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754496AbYCIUVt (ORCPT ); Sun, 9 Mar 2008 16:21:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753193AbYCIUVm (ORCPT ); Sun, 9 Mar 2008 16:21:42 -0400 Received: from smtp-out02.alice-dsl.net ([88.44.60.12]:18811 "EHLO smtp-out02.alice-dsl.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751313AbYCIUVl (ORCPT ); Sun, 9 Mar 2008 16:21:41 -0400 To: Andrew Morton Cc: Ingo Molnar , KOSAKI Motohiro , Thomas Gleixner , LKML , Linus Torvalds , Christoph Lameter , Bart Van Assche Subject: Re: quicklists confuse meminfo References: <20080309111456.GA21690@elte.hu> <20080309210000.C6DE.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20080309120940.GA1695@elte.hu> <20080309123432.GA3267@elte.hu> <20080309114640.85c9c3eb.akpm@linux-foundation.org> From: Andi Kleen Date: 09 Mar 2008 21:21:38 +0100 In-Reply-To: <20080309114640.85c9c3eb.akpm@linux-foundation.org> Message-ID: <8763vv1wdp.fsf@basil.nowhere.org> User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-OriginalArrivalTime: 09 Mar 2008 20:15:07.0174 (UTC) FILETIME=[449DA460:01C88222] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1472 Lines: 31 Andrew Morton writes: > On Sun, 9 Mar 2008 13:34:32 +0100 Ingo Molnar wrote: > > > the right solution is to get rid of quicklists altogether > > Yes, I think so. > > - They are pretty marginal from a performance POV (iirc) One general issue -- as noted again by Christoph Lameter recently -- is that the order 0 fast path in page_alloc.c isn't actually very fast. That is why people keep inventing their own... > - As I said when we merged them (under protest): Private object caches > like this are just a bad idea - caches should be *shared*, because some > other code path which wants a zeroed page wants a cache-warm one, not a > cache-cold one from the allocator (iirc there was doubt over how > cache-warm these pages are, however). > > Making __GFP_ZERO smarter/more efficient would be a preferable way of > addressing any performance problems we have in there. To do the same as quicklists you would need a __free_pages_zeroed() and separate buddy lists I think. Later is probably somewhat ugly. Or perhaps do it only for order 0? Or perhaps idle time zeroing should be reinvestigated on modern CPUs, but I'm always a little sceptical of that. -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/