From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id BA7AA6B0047 for ; Thu, 17 Dec 2009 14:33:40 -0500 (EST) Date: Thu, 17 Dec 2009 13:33:01 -0600 (CST) From: Christoph Lameter 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> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org 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 List-ID: 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org