Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758856AbYHFStx (ORCPT ); Wed, 6 Aug 2008 14:49:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755708AbYHFStp (ORCPT ); Wed, 6 Aug 2008 14:49:45 -0400 Received: from one.firstfloor.org ([213.235.205.2]:52028 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754768AbYHFStp (ORCPT ); Wed, 6 Aug 2008 14:49:45 -0400 To: Andrew Morton Cc: Mel Gorman , linuxppc-dev@ozlabs.org, libhugetlbfs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC] [PATCH 0/5 V2] Huge page backed user-space stacks From: Andi Kleen References: <20080730014308.2a447e71.akpm@linux-foundation.org> <20080730172317.GA14138@csn.ul.ie> <20080730103407.b110afc2.akpm@linux-foundation.org> Date: Wed, 06 Aug 2008 20:49:40 +0200 In-Reply-To: <20080730103407.b110afc2.akpm@linux-foundation.org> (Andrew Morton's message of "Wed, 30 Jul 2008 10:34:07 -0700") Message-ID: <87fxpi567v.fsf@basil.nowhere.org> User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/21.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 652 Lines: 16 Andrew Morton writes: > Do we expect that this change will be replicated in other > memory-intensive apps? (I do). The catch with 2MB pages on x86 is that x86 CPUs generally have much less 2MB TLB entries than 4K entries. So if you're unlucky and access a lot of mappings you might actually thrash more with them. That is why they are not necessarily an universal win. -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/