From: "Paul E. McKenney" <paulmck@us.ibm.com>
To: Bill Huey <bhuey@lnxw.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
Date: Fri, 18 Mar 2005 07:54:18 -0800 [thread overview]
Message-ID: <20050318155418.GC1299@us.ibm.com> (raw)
In-Reply-To: <20050318125641.GA5107@nietzsche.lynx.com>
On Fri, Mar 18, 2005 at 04:56:41AM -0800, Bill Huey wrote:
> 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) ?
Hey, I wasn't joking when I said that I probably got something wrong! ;-)
My current thought is that the preempt_disable()/preempt_enable() can
be dropped entirely. Messes up any tool that browses through
->rcu_read_lock_nesting, but don't see any other problem. Yet, anyway!
Thanx, Paul
next prev parent reply other threads:[~2005-03-18 15:54 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-18 0:20 Real-Time Preemption and RCU Paul E. McKenney
2005-03-18 7:49 ` Ingo Molnar
2005-03-18 16:43 ` Paul E. McKenney
2005-03-18 17:11 ` Ingo Molnar
2005-03-18 17:29 ` Paul E. McKenney
2005-03-18 20:35 ` Paul E. McKenney
2005-03-18 22:22 ` Paul E. McKenney
2005-03-19 0:48 ` Paul E. McKenney
2005-03-18 8:44 ` Ingo Molnar
2005-03-18 9:04 ` Ingo Molnar
2005-03-18 9:38 ` Ingo Molnar
2005-03-18 9:13 ` Ingo Molnar
2005-03-18 9:28 ` Ingo Molnar
2005-03-18 9:53 ` Ingo Molnar
2005-03-18 15:33 ` Paul E. McKenney
2005-03-19 5:03 ` Manfred Spraul
2005-03-19 16:26 ` Ingo Molnar
2005-03-20 6:36 ` Manfred Spraul
2005-03-20 9:25 ` Thomas Gleixner
2005-03-20 16:57 ` Manfred Spraul
2005-03-20 21:38 ` Bill Huey
2005-03-20 21:59 ` Bill Huey
2005-03-18 10:03 ` Ingo Molnar
2005-03-18 11:30 ` Ingo Molnar
2005-03-18 16:48 ` Esben Nielsen
2005-03-18 17:19 ` Ingo Molnar
2005-03-20 13:29 ` Esben Nielsen
2005-03-20 22:38 ` Paul E. McKenney
2005-03-20 23:23 ` Esben Nielsen
2005-03-22 5:53 ` Paul E. McKenney
2005-03-22 8:55 ` Esben Nielsen
2005-03-22 9:20 ` Ingo Molnar
2005-03-22 10:19 ` Esben Nielsen
2005-03-23 5:40 ` Paul E. McKenney
2005-03-23 11:44 ` Esben Nielsen
2005-03-24 7:02 ` Paul E. McKenney
2005-03-22 10:56 ` Ingo Molnar
2005-03-22 11:39 ` Esben Nielsen
2005-03-22 13:10 ` Ingo Molnar
2005-03-22 15:08 ` Esben Nielsen
2005-03-18 15:48 ` Paul E. McKenney
2005-03-18 11:38 ` Ingo Molnar
2005-03-18 12:56 ` Bill Huey
2005-03-18 13:17 ` Bill Huey
2005-03-18 15:57 ` Paul E. McKenney
2005-03-18 16:02 ` Ingo Molnar
2005-03-18 16:55 ` Esben Nielsen
2005-03-22 10:04 ` Bill Huey
2005-03-22 10:17 ` Bill Huey
2005-03-22 10:34 ` Bill Huey
2005-03-22 10:38 ` Esben Nielsen
2005-03-18 22:26 ` Herbert Xu
2005-03-19 16:31 ` Ingo Molnar
2005-03-20 8:01 ` Kyle Moffett
2005-03-22 8:08 ` Ingo Molnar
2005-03-18 15:54 ` Paul E. McKenney [this message]
2005-03-18 15:58 ` Ingo Molnar
2009-06-11 22:57 real-time preemption " James Huang
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