From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: linux-kernel@vger.kernel.org, vegard.nossum@gmail.com,
mingo@elte.hu, stable@kernel.org, akpm@linux-foundation.org,
npiggin@suse.de, penberg@cs.helsinki.fi
Subject: Re: [PATCH] v2 Teach RCU that idle task is not quiscent state at boot
Date: Mon, 23 Feb 2009 21:08:54 -0800 [thread overview]
Message-ID: <20090224050854.GD7173@linux.vnet.ibm.com> (raw)
In-Reply-To: <200902241502.57833.nickpiggin@yahoo.com.au>
On Tue, Feb 24, 2009 at 03:02:56PM +1100, Nick Piggin wrote:
> On Tuesday 24 February 2009 07:43:32 Paul E. McKenney wrote:
>
> > @@ -80,6 +81,10 @@ void wakeme_after_rcu(struct rcu_head *head)
> > void synchronize_rcu(void)
> > {
> > struct rcu_synchronize rcu;
> > +
> > + if (num_online_cpus() == 1)
> > + return; /* If UP, synchronize_rcu() is a grace period! */
> > +
>
> Nice patch... May I just suggest a comment to say that this is
> also a correctness requirement due to the grace period holdoff
> for early boot?
Excellent point! If Ingo reports that this actually fixes the hang that
he saw, I will add such a comment.
(And glad you like the patch!)
Thanx, Paul
next prev parent reply other threads:[~2009-02-24 5:09 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-23 16:16 [PATCH] Teach RCU that idle task is not quiscent state at boot Paul E. McKenney
2009-02-23 17:13 ` Ingo Molnar
2009-02-23 20:43 ` [PATCH] v2 " Paul E. McKenney
2009-02-24 4:02 ` Nick Piggin
2009-02-24 5:08 ` Paul E. McKenney [this message]
2009-02-24 14:50 ` Paul E. McKenney
2009-02-25 0:29 ` [PATCH] v3 " Paul E. McKenney
2009-02-25 4:12 ` Nick Piggin
2009-02-25 4:43 ` Paul E. McKenney
2009-02-25 14:19 ` [PATCH] v4 " Paul E. McKenney
2009-02-25 16:00 ` Ingo Molnar
2009-02-25 16:26 ` Nick Piggin
2009-02-25 17:12 ` Paul E. McKenney
2009-02-25 17:18 ` Nick Piggin
2009-02-25 17:36 ` Paul E. McKenney
2009-02-25 17:08 ` Paul E. McKenney
2009-02-26 3:09 ` Ingo Molnar
2009-02-25 18:38 ` Vegard Nossum
2009-02-25 19:01 ` Paul E. McKenney
2009-02-26 2:03 ` [PATCH] v5 " Paul E. McKenney
2009-02-26 3:08 ` Ingo Molnar
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