On Mon, Feb 17, 2014 at 01:50:53PM -0800, Josh Triplett wrote:
> On Mon, Feb 17, 2014 at 01:40:25PM -0800, Paul E. McKenney wrote:
> > From: "Paul E. McKenney" <paul...@linux.vnet.ibm.com>
> >
> > If CONFIG_RCU_NOCB_CPU_ALL=y, then rcu_is_nocb_cpu() will always
> > return true, however, the current version nevertheless checks
> > rcu_nocb_mask. This commit therefore creates a static inline
> > implementation of rcu_is_nocb_cpu() that unconditionally returns
> > true when CONFIG_RCU_NOCB_CPU_ALL=y.
> >
> > Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com>
>
> One suggestion below. With or without that change:
> Reviewed-by: Josh Triplett <j...@joshtriplett.org>
I like the change -- applied both it and your Reviewed-by.
Thanx, Paul
> > include/linux/rcupdate.h | 4 ++++
> > kernel/rcu/tree_plugin.h | 2 ++
> > 2 files changed, 6 insertions(+)
> >
> > diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
> > index 72bf3a01a4ee..92365b1fede4 100644
> > --- a/include/linux/rcupdate.h
> > +++ b/include/linux/rcupdate.h
> > @@ -1016,7 +1016,11 @@ static inline notrace void
> > rcu_read_unlock_sched_notrace(void)
> > __kfree_rcu(&((ptr)->rcu_head), offsetof(typeof(*(ptr)), rcu_head))
> >
> > #ifdef CONFIG_RCU_NOCB_CPU
> > +#ifdef CONFIG_RCU_NOCB_CPU_ALL
> > +static inline bool rcu_is_nocb_cpu(int cpu) { return true; }
> > +#else /* #ifdef CONFIG_RCU_NOCB_CPU_ALL */
> > bool rcu_is_nocb_cpu(int cpu);
> > +#endif /* #else #ifdef CONFIG_RCU_NOCB_CPU_ALL */
> > #else
> > static inline bool rcu_is_nocb_cpu(int cpu) { return false; }
> > #endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */
>
> This seem clearer if written without the nesting:
>
> #if defined(CONFIG_RCU_NOCB_CPU_ALL)
> static inline bool rcu_is_nocb_cpu(int cpu) { return true; }
> #elif defined(CONFIG_RCU_NOCB_CPU)
> bool rcu_is_nocb_cpu(int cpu);
> #else
> static inline bool rcu_is_nocb_cpu(int cpu) { return false; }
> #endif
>
> That clearly distinguishes the three cases: all, some, none.
>
> > diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
> > index 6e2ef4b2b920..39a50b918bff 100644
> > --- a/kernel/rcu/tree_plugin.h
> > +++ b/kernel/rcu/tree_plugin.h
> > @@ -2101,6 +2101,7 @@ static void rcu_init_one_nocb(struct rcu_node *rnp)
> > init_waitqueue_head(&rnp->nocb_gp_wq[1]);
> > }
> >
> > +#ifndef CONFIG_RCU_NOCB_CPU_ALL
> > /* Is the specified CPU a no-CPUs CPU? */
> > bool rcu_is_nocb_cpu(int cpu)
> > {
> > @@ -2108,6 +2109,7 @@ bool rcu_is_nocb_cpu(int cpu)
> > return cpumask_test_cpu(cpu, rcu_nocb_mask);
> > return false;
> > }
> > +#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
> >
> > /*
> > * Enqueue the specified string of rcu_head structures onto the specified
> > --
> > 1.8.1.5
> >
>
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