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From: Andrew Morton <akpm@osdl.org>
To: dipankar@in.ibm.com
Cc: Ingo Molnar <mingo@elte.hu>,
	Paul E McKenney <paulmck@linux.vnet.ibm.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [mm PATCH 4/6] RCU: preemptible RCU
Date: Tue, 23 Jan 2007 16:38:26 -0800	[thread overview]
Message-ID: <20070123163826.d4ba703a.akpm@osdl.org> (raw)
In-Reply-To: <20070115192858.GE32238@in.ibm.com>

On Tue, 16 Jan 2007 00:58:58 +0530
Dipankar Sarma <dipankar@in.ibm.com> wrote:

> +/*
> + * Wait for CPUs to acknowledge the flip.
> + */
> +static int rcu_try_flip_waitack(int flipctr)
> +{
> +	int cpu;
> +
> +	for_each_possible_cpu(cpu)
> +		if (per_cpu(rcu_flip_flag, cpu) != RCU_FLIP_SEEN) 
> +			return 1;
> +
> +	/*
> +	 * Make sure our checks above don't bleed into subsequent
> +	 * waiting for the sum of the counters to reach zero.
> +	 */
> +	smp_mb();
> +	return 0;
> +}

Confused.  If some of the possible cpus aren't online, doesn't the 
state machine get stuck??

  parent reply	other threads:[~2007-01-24  0:39 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-15 19:19 [mm PATCH] RCU: various patches Dipankar Sarma
2007-01-15 19:21 ` [mm PATCH 1/6] RCU: split classic rcu Dipankar Sarma
2007-01-16 17:49   ` Paul E. McKenney
2007-01-15 19:22 ` [mm PATCH 2/6] RCU: softirq for RCU Dipankar Sarma
2007-01-16 17:49   ` Paul E. McKenney
2007-01-15 19:24 ` [mm PATCH 3/6] RCU: Fix barriers Dipankar Sarma
2007-01-16 17:53   ` Paul E. McKenney
2007-01-15 19:28 ` [mm PATCH 4/6] RCU: preemptible RCU Dipankar Sarma
2007-01-24  0:32   ` Andrew Morton
2007-01-26 21:00     ` Dipankar Sarma
2007-01-26 21:25       ` Andrew Morton
2007-01-24  0:38   ` Andrew Morton [this message]
2007-01-15 19:30 ` [mm PATCH 5/6] RCU: debug trace for RCU Dipankar Sarma
2007-01-15 19:31 ` [mm PATCH 6/6] RCU: trivial fixes Dipankar Sarma
2007-01-16 17:56   ` Paul E. McKenney

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