Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965445AbZLQTdt (ORCPT ); Thu, 17 Dec 2009 14:33:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965428AbZLQTds (ORCPT ); Thu, 17 Dec 2009 14:33:48 -0500 Received: from nlpi129.sbcis.sbc.com ([207.115.36.143]:43523 "EHLO nlpi129.prodigy.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965425AbZLQTdr (ORCPT ); Thu, 17 Dec 2009 14:33:47 -0500 Date: Thu, 17 Dec 2009 13:33:01 -0600 (CST) From: Christoph Lameter X-X-Sender: cl@router.home To: Andi Kleen cc: Peter Zijlstra , KAMEZAWA Hiroyuki , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "akpm@linux-foundation.org" , "mingo@elte.hu" , minchan.kim@gmail.com Subject: Re: [mm][RFC][PATCH 0/11] mm accessor updates. In-Reply-To: <20091217084046.GA9804@basil.fritz.box> Message-ID: References: <20091216120011.3eecfe79.kamezawa.hiroyu@jp.fujitsu.com> <20091216101107.GA15031@basil.fritz.box> <20091216191312.f4655dac.kamezawa.hiroyu@jp.fujitsu.com> <20091216102806.GC15031@basil.fritz.box> <20091216193109.778b881b.kamezawa.hiroyu@jp.fujitsu.com> <1261004224.21028.500.camel@laptop> <20091217084046.GA9804@basil.fritz.box> User-Agent: Alpine 2.00 (DEB 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: 18 On Thu, 17 Dec 2009, Andi Kleen wrote: > > There are a few interesting cases like stack extention and hugetlbfs, > > but I think we could start by falling back to mmap_sem locked behaviour > > if the speculative thing fails. > > You mean fall back to mmap_sem if anything sleeps? Maybe. Would need > to check how many such points are really there. You always need some reference on the mm_struct (mm_read_lock) if you are going to sleep to ensure that mm_struct still exists after waking up (page fault, page allocation). RCU and other spin locks are not helping there. -- 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/