Re: [PATCH] rcu: make rcu_*_data variables static

From: Paul E. McKenney
Date: Wed May 06 2015 - 02:09:27 EST


On Tue, May 05, 2015 at 04:25:58PM -0700, josh@xxxxxxxxxxxxxxxx wrote:
> On Tue, May 05, 2015 at 09:57:06PM +0800, Nicolas Iooss wrote:
> > rcu_bh_data, rcu_sched_data and rcu_preempt_data are never used outside
> > kernel/rcu/tree.c and thus can be made static.
> >
> > Doing so fixes a section mismatch warning reported by clang when
> > building LLVMLinux with -Wsection, because these variables were declared
> > in .data..percpu and defined in .data..percpu..shared_aligned since
> > commit 11bbb235c26f ("rcu: Use DEFINE_PER_CPU_SHARED_ALIGNED for
> > rcu_data").
> >
> > Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@xxxxxxx>
>
> Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>

Applied, thank you both!

> Nice improvement.
>
> Minor nit: since these are only one line each now, they don't really
> need a blank line between them, but *shrug*.

I don't mind the grouping implied by the blank lines, but I agree that
it is close to the edge.

Thanx, Paul

> > ---
> > kernel/rcu/tree.c | 2 +-
> > kernel/rcu/tree.h | 3 ---
> > 2 files changed, 1 insertion(+), 4 deletions(-)
> >
> > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > index 233165da782f..e4a607fc5ad0 100644
> > --- a/kernel/rcu/tree.c
> > +++ b/kernel/rcu/tree.c
> > @@ -91,7 +91,7 @@ static const char *tp_##sname##_varname __used __tracepoint_string = sname##_var
> >
> > #define RCU_STATE_INITIALIZER(sname, sabbr, cr) \
> > DEFINE_RCU_TPS(sname) \
> > -DEFINE_PER_CPU_SHARED_ALIGNED(struct rcu_data, sname##_data); \
> > +static DEFINE_PER_CPU_SHARED_ALIGNED(struct rcu_data, sname##_data); \
> > struct rcu_state sname##_state = { \
> > .level = { &sname##_state.node[0] }, \
> > .rda = &sname##_data, \
> > diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
> > index a69d3dab2ec4..0c32f730d033 100644
> > --- a/kernel/rcu/tree.h
> > +++ b/kernel/rcu/tree.h
> > @@ -519,14 +519,11 @@ extern struct list_head rcu_struct_flavors;
> > * RCU implementation internal declarations:
> > */
> > extern struct rcu_state rcu_sched_state;
> > -DECLARE_PER_CPU(struct rcu_data, rcu_sched_data);
> >
> > extern struct rcu_state rcu_bh_state;
> > -DECLARE_PER_CPU(struct rcu_data, rcu_bh_data);
> >
> > #ifdef CONFIG_PREEMPT_RCU
> > extern struct rcu_state rcu_preempt_state;
> > -DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data);
> > #endif /* #ifdef CONFIG_PREEMPT_RCU */
> >
> > #ifdef CONFIG_RCU_BOOST
> > --
> > 2.3.6
> >
>

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