Re: [PATCH tip/core/rcu 36/55] rcu: Prevent early bootset_need_resched() from __rcu_pending()

[Josh Triplett]

On Tue, Sep 06, 2011 at 11:00:30AM -0700, Paul E. McKenney wrote:
> From: Paul E. McKenney <paul.mckenney@xxxxxxxxxx>
> 
> There isn't a whole lot of point in poking the scheduler before there
> are other tasks to switch to.  This commit therefore adds a check
> for rcu_scheduler_fully_active in __rcu_pending() to suppress any
> pre-scheduler calls to set_need_resched().  The downside of this approach
> is additional runtime overhead in a reasonably hot code path.

If you're concerned about the runtime overhead, this does seem like a
perfect candidate for jump labels.

- Josh Triplett
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