Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752822Ab0AGSAt (ORCPT ); Thu, 7 Jan 2010 13:00:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752711Ab0AGSAs (ORCPT ); Thu, 7 Jan 2010 13:00:48 -0500 Received: from casper.infradead.org ([85.118.1.10]:43180 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752651Ab0AGSAs (ORCPT ); Thu, 7 Jan 2010 13:00:48 -0500 Subject: Re: [RFC][PATCH 6/8] mm: handle_speculative_fault() From: Peter Zijlstra To: Linus Torvalds 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 In-Reply-To: References: <20100104182429.833180340@chello.nl> <20100104182813.753545361@chello.nl> <20100105054536.44bf8002@infradead.org> <20100105192243.1d6b2213@infradead.org> <1262884960.4049.106.camel@laptop> Content-Type: text/plain; charset="UTF-8" Date: Thu, 07 Jan 2010 19:00:07 +0100 Message-ID: <1262887207.4049.127.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 864 Lines: 21 On Thu, 2010-01-07 at 09:49 -0800, Linus Torvalds wrote: > > The thing is, I can pretty much _guarantee_ that the speculative page > fault is going to end up doing a lot of nasty stuff that still needs > almost-global locking, and it's likely to be more complicated and slower > for the single-threaded case (you end up needing refcounts, a new "local" > lock or something). Well, with that sync_vma() thing I posted the other day all the speculative page fault needs is a write to current->fault_vma, the ptl and an O(nr_threads) loop on unmap() for file vmas -- aside from writing the pte itself of course. -- 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/