Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757630AbXIRS3g (ORCPT ); Tue, 18 Sep 2007 14:29:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754336AbXIRS33 (ORCPT ); Tue, 18 Sep 2007 14:29:29 -0400 Received: from e3.ny.us.ibm.com ([32.97.182.143]:56534 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754334AbXIRS32 (ORCPT ); Tue, 18 Sep 2007 14:29:28 -0400 Date: Tue, 18 Sep 2007 11:29:24 -0700 From: "Paul E. McKenney" To: Andrew Morton Cc: Peter Zijlstra , Nadia Derbey , Alexey Dobriyan , linux-kernel@vger.kernel.org, Ingo Molnar Subject: Re: 2.6.23-rc6-mm1: IPC: sleeping function called ... Message-ID: <20070918182924.GF8665@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20070918091728.GA6766@localhost.sw.ru> <20070918031723.05689e92.akpm@linux-foundation.org> <46EFA8DC.2020909@bull.net> <20070918033400.495b02dd.akpm@linux-foundation.org> <20070918142451.418b3b51@twins> <20070918161337.GC8665@linux.vnet.ibm.com> <20070918095715.05899d12.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070918095715.05899d12.akpm@linux-foundation.org> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1289 Lines: 33 On Tue, Sep 18, 2007 at 09:57:15AM -0700, Andrew Morton wrote: > On Tue, 18 Sep 2007 09:13:37 -0700 "Paul E. McKenney" wrote: > > > On Tue, Sep 18, 2007 at 02:24:51PM +0200, Peter Zijlstra wrote: > > > On Tue, 18 Sep 2007 03:34:00 -0700 Andrew Morton > > > wrote: > > > > > > > Well, it was an optimisation. spin_lock() implies rcu_read_lock(). That's > > > > a bit dirty and we might choose to not do that. > > > > > > Not true for the preemptible-rcu work. All such sites should be fixed, > > > or at the very least heavily annotated. > > > > What he said!!! > > > > What he said! > > How are you going to find all such sites? A first step would be to look for patches in -rt that add rcu_read_lock() or friends. A second step would be to look for rcu_dereference() without an enclosing rcu_read_lock(), rcu_read_lock_bh(), or preempt_disable(). Beyond a certain point, this reduces to the problem of finding places where spin_lock() was omitted, right? Thanx, Paul - 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/