Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754867Ab3IKPYA (ORCPT ); Wed, 11 Sep 2013 11:24:00 -0400 Received: from e35.co.us.ibm.com ([32.97.110.153]:59042 "EHLO e35.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752981Ab3IKPX6 (ORCPT ); Wed, 11 Sep 2013 11:23:58 -0400 Date: Wed, 11 Sep 2013 08:23:31 -0700 From: "Paul E. McKenney" To: Steven Rostedt Cc: Mathieu Desnoyers , Frederic Weisbecker , Peter Zijlstra , Eric Dumazet , linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, dhowells@redhat.com, edumazet@google.com, darren@dvhart.com, sbw@mit.edu Subject: Re: [PATCH] rcu: Is it safe to enter an RCU read-side critical section? Message-ID: <20130911152331.GZ3966@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20130909161708.GX3966@linux.vnet.ibm.com> <20130909123422.7936e868@gandalf.local.home> <20130909165836.GB3966@linux.vnet.ibm.com> <20130909172908.GA31239@Krystal> <20130909175656.GF3966@linux.vnet.ibm.com> <20130909214026.GA8830@Krystal> <20130909175917.794b19bd@gandalf.local.home> <20130909223426.GM3966@linux.vnet.ibm.com> <20130911141302.GA11342@linux.vnet.ibm.com> <20130911102607.16a3da91@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130911102607.16a3da91@gandalf.local.home> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13091115-6688-0000-0000-0000019577E0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2281 Lines: 60 On Wed, Sep 11, 2013 at 10:26:07AM -0400, Steven Rostedt wrote: > On Wed, 11 Sep 2013 07:13:02 -0700 > "Paul E. McKenney" wrote: > > > On Mon, Sep 09, 2013 at 03:34:26PM -0700, Paul E. McKenney wrote: > > > On Mon, Sep 09, 2013 at 05:59:17PM -0400, Steven Rostedt wrote: > > > > On Mon, 9 Sep 2013 17:40:26 -0400 > > > > Mathieu Desnoyers wrote: > > > > > > > > > Agreed. So how about rcu_is_online() ? > > > > > > > > Nope, what about all_your_base_are_belong_to_rcu()? > > > > > > Let's see if I can remember the candidates... > > > > > > rcu_is_cpu_idle() # reversed sense from the others > > > rcu_is_ignored() # reversed sense from the others > > > rcu_is_not_active() # reversed sense from the others > > > rcu_is_watching_cpu() > > > rcu_read_check() > > > rcu_is_active() > > > rcu_is_active_local() > > > rcu_is_online() > > > rcu_is_watching_task() > > > rcu_is_watching_thread() > > > rcu_is_watching_you() > > > all_your_base_are_belong_to_rcu() > > > rcu_is_active_loco() > > > rcu_kilroy_was_here() > > > > > > Maybe I should just lock them all in a room overnight and see which > > > are still alive in the morning. > > > > And after treating injuries, the survivor is rcu_is_watching(). > > > > But, but, but... > > That wasn't one of the contenders! > > What happened? Did rcu_is_watching_cpu(), rcu_is_watching_task(), > rcu_is_watching_thread() and rcu_is_watching_you() all get together to > gang up on the others, and then combined to be one? > > It's another Iraq! Several segments joined together by an outside > force and they don't play well together. And like Iraq (and the US), > hidden inside of this "community" is "rcu_is_watching_you"! C'mon, Steven! I did say "after treating injuries"! In the opinion of the surgeon, the only option was to ampute what was left of either the _cpu(), _task(), _thread(), or _you(). Heck, the damage was so severe that we couldn't even tell which one it was! 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/