Re: [PATCH 2/5] Fix mismatched variable in rcutree_trace.c

From: Paul E. McKenney
Date: Tue Jun 07 2011 - 19:13:17 EST


On Wed, Jun 08, 2011 at 12:42:17AM +0200, Thomas Gleixner wrote:
>
>
> On Tue, 7 Jun 2011, Andi Kleen wrote:
>
> > From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> >
> > rcutree.c defines rcu_cpu_kthread_cpu as int, not unsigned int,
> > so the extern has to follow that.
> >
> > Cc: paulmck@xxxxxxxxxxxxxxxxxx
> > Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> > ---
> > kernel/rcutree_trace.c | 2 +-
> > 1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c
> > index 9678cc3..91c56e5 100644
> > --- a/kernel/rcutree_trace.c
> > +++ b/kernel/rcutree_trace.c
> > @@ -47,7 +47,7 @@
> > #include "rcutree.h"
> >
> > DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
> > -DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_cpu);
> > +DECLARE_PER_CPU(int, rcu_cpu_kthread_cpu);
>
> Can we rather fix the DEFINE to use unsigned int. Signed cpu numbers
> are pointless in that context, right ?

Hmmm... Some arches have signed CPU numbers while others have unsigned
CPU numbers. I do use "-1" to mean "no CPU" in some cases (for example,
in rcu_node_kthread_setaffinity()), so I guess for consistency I should
be using "int" everywhere.

So, any plans for systems with 2,147,483,648 CPUs? ;-)

Thanx, Paul

> > DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);
> > DECLARE_PER_CPU(char, rcu_cpu_has_work);
> >
> > --
> > 1.7.4.4
> >
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