Re: [PATCH tip/core/rcu 2/2] rcu: Apply review feedback from Josh Triplett, part 4

[Josh Triplett <josh@joshtriplett.org>]

On Sat, Sep 26, 2009 at 11:49:51PM -0700, Paul E. McKenney wrote:
> These issues identified during an old-fashioned face-to-face code
> review extending over many hours.  This group improves an existing
> abstraction and introduces two new ones.
> 
> o	Make RCU_INIT_FLAVOR() declare its own variables, removing
> 	the need to declare them at each call site.
> 
> o	Create an rcu_for_each_leaf() macro that scans the leaf nodes
> 	of the rcu_node tree.
> 
> o	Create an rcu_for_each_node_breadth_first() macro that does
> 	a breadth-first traversal of the rcu_node tree, AKA stepping
> 	through the array in index-number order.
> 
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

I noticed one bit of unrelated code in this patch, which the commit
message doesn't mention:

> --- a/kernel/rcutree.c
> +++ b/kernel/rcutree.c
[...]
> @@ -473,18 +471,24 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
>  		return;
>  	}
>  	rsp->jiffies_stall = jiffies + RCU_SECONDS_TILL_STALL_RECHECK;
> +
> +	/*
> +	 * Now rat on any tasks that got kicked up to the root rcu_node
> +	 * due to CPU offlining.
> +	 */
> +	rcu_print_task_stall(rnp);
>  	spin_unlock_irqrestore(&rnp->lock, flags);

- Josh Triplett