Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752056Ab0AGRg4 (ORCPT ); Thu, 7 Jan 2010 12:36:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751916Ab0AGRgy (ORCPT ); Thu, 7 Jan 2010 12:36:54 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:44740 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751810Ab0AGRgx (ORCPT ); Thu, 7 Jan 2010 12:36:53 -0500 Date: Thu, 7 Jan 2010 09:36:17 -0800 (PST) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: Peter Zijlstra cc: Christoph Lameter , Arjan van de Ven , "Paul E. McKenney" , KAMEZAWA Hiroyuki , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "minchan.kim@gmail.com" , "hugh.dickins" , Nick Piggin , Ingo Molnar Subject: Re: [RFC][PATCH 6/8] mm: handle_speculative_fault() In-Reply-To: <1262884960.4049.106.camel@laptop> Message-ID: References: <20100104182429.833180340@chello.nl> <20100104182813.753545361@chello.nl> <20100105054536.44bf8002@infradead.org> <20100105192243.1d6b2213@infradead.org> <1262884960.4049.106.camel@laptop> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) 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: 818 Lines: 23 On Thu, 7 Jan 2010, Peter Zijlstra wrote: > > Right, supposing we can make this speculative fault stuff work, then we > can basically reduce the mmap_sem usage in fault to: > > - allocating new page tables > - extending the growable vmas > > And do everything else without holding it, including zeroing and IO. Well, I have yet to hear a realistic scenario of _how_ to do it all speculatively in the first place, at least not without horribly subtle complexity issues. So I'd really rather see how far we can possibly get by just improving mmap_sem. Linus -- 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/