linux-kernel - Re: [PATCHv2] rcu: tree: correctly handle sparse possible CPUs

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Date:	Wed, 18 May 2016 19:15:09 +0100
From:	Mark Rutland <mark.rutland@....com>
To:	Arnd Bergmann <arnd@...db.de>
Cc:	paulmck@...ux.vnet.ibm.com, catalin.marinas@....com,
	dennis.chen@....com, jiangshanlai@...il.com, josh@...htriplett.org,
	linux-kernel@...r.kernel.org, mathieu.desnoyers@...icios.com,
	rostedt@...dmis.org, steve.capper@....com, will.deacon@....com
Subject: Re: [PATCHv2] rcu: tree: correctly handle sparse possible CPUs

On Wed, May 18, 2016 at 02:02:36PM +0200, Arnd Bergmann wrote:
> It's the missing "possible_" that Mark mentioned in his reply on Friday.

Actually, that was this morning. My VM on my laptop had a stale date due to
suspend/resume of the host. :/

I should be back at a real computer by Friday, and can respin the patch to fix
the issue Andrey pointed out.

Thanks for the fixup, and sorry for the confusion!

Mark.

> Please fold the fixup below into the patch if you want to get it to build.
> 
> Signed-off-by: Arnd Bergmann <arnd@...db.de
> 
> diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
> index fd6b0f701bed..bb137b0ef6f3 100644
> --- a/kernel/rcu/tree_plugin.h
> +++ b/kernel/rcu/tree_plugin.h
> @@ -1165,7 +1165,7 @@ static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu)
>  		return;
>  	if (!zalloc_cpumask_var(&cm, GFP_KERNEL))
>  		return;
> -	for_each_leaf_node_cpu_bit(rnp, cpu, bit)
> +	for_each_leaf_node_possible_cpu_bit(rnp, cpu, bit)
>  		if ((mask & bit) && cpu != outgoingcpu)
>  			cpumask_set_cpu(cpu, cm);
>  	if (cpumask_weight(cm) == 0)
>