From mboxrd@z Thu Jan  1 00:00:00 1970
From: paulmck@linux.vnet.ibm.com (Paul E. McKenney)
Date: Thu, 2 Feb 2012 15:51:28 -0800
Subject: [PATCH RFC idle 2/3] arm: Avoid invoking RCU when CPU is idle
In-Reply-To: <20120202232736.GL2518@linux.vnet.ibm.com>
References: <alpine.LFD.2.02.1202012234050.2759@xanadu.home>
 <20120202044439.GD2435@linux.vnet.ibm.com>
 <alpine.LFD.2.02.1202021159560.2759@xanadu.home>
 <20120202174337.GS2518@linux.vnet.ibm.com>
 <alpine.LFD.2.02.1202021257340.2759@xanadu.home>
 <20120202190708.GE2518@linux.vnet.ibm.com> <87obtgc1xx.fsf@ti.com>
 <4F2B1307.5010207@gmail.com>
 <1328223819.5882.133.camel@gandalf.stny.rr.com>
 <20120202232736.GL2518@linux.vnet.ibm.com>
Message-ID: <20120202235128.GA21031@linux.vnet.ibm.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Thu, Feb 02, 2012 at 03:27:36PM -0800, Paul E. McKenney wrote:
> On Thu, Feb 02, 2012 at 06:03:39PM -0500, Steven Rostedt wrote:
> 
> [ . . . ]
> 
> > Anyway, one answer is (and I was talking with Paul about this on IRC) is
> > that we can create a special "TRACE_EVENT_IDLE()" that will explicitly
> > call "rcu_idle_exit/enter()" as it expects to be called with it off.
> > 
> > This should solve most issues I believe.
> 
> You OK with something like RCU_NONIDLE() rather than RCU_EVENT_IDLE()?
> I have this funny feeling that tracing won't be the only thing using
> RCU from idle.  :-/
> 
> Something like this, perhaps?

Or perhaps with the trailing "while (0)" included:

	#define RCU_NONIDLE(a) \
		do { \
			rcu_idle_exit(); \
			do { a; } while (0); \
			rcu_idle_enter(); \
		} while (0)

							Thanx, Paul