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Date: Fri, 18 Mar 2005 04:56:41 -0800
To: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: mingo@elte.hu, dipankar@in.ibm.com, shemminger@osdl.org, akpm@osdl.org,
       torvalds@osdl.org, rusty@au1.ibm.com, tgall@us.ibm.com,
       jim.houston@comcast.net, manfred@colorfullife.com, gh@us.ibm.com,
       linux-kernel@vger.kernel.org
Subject: Re: Real-Time Preemption and RCU
Message-ID: <20050318125641.GA5107@nietzsche.lynx.com>
References: <20050318002026.GA2693@us.ibm.com>
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From: Bill Huey (hui) <bhuey@lnxw.com>
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On Thu, Mar 17, 2005 at 04:20:26PM -0800, Paul E. McKenney wrote:
> 5. Scalability -and- Realtime Response.
...

> 	void
> 	rcu_read_lock(void)
> 	{
> 		preempt_disable();
> 		if (current->rcu_read_lock_nesting++ == 0) {
> 			current->rcu_read_lock_ptr =
> 				&__get_cpu_var(rcu_data).lock;
> 			read_lock(current->rcu_read_lock_ptr);
> 		}
> 		preempt_enable();
> 	}

Ok, here's a rather unsure question...

Uh, is that a sleep violation if that is exclusively held since it
can block within an atomic critical section (deadlock) ?

bill