Re: [PATCH] srcu: Remove dead code in srcu_gp_end()

From: Paul E. McKenney
Date: Wed Feb 14 2018 - 17:18:33 EST


On Wed, Feb 14, 2018 at 10:00:54AM -0500, Steven Rostedt wrote:
> On Wed, 14 Feb 2018 18:05:24 +0900
> Byungchul Park <byungchul.park@xxxxxxx> wrote:
>
> > Of course, compilers will optimize out a dead code. Anyway, remove
> > any dead code for better readibility.
> >
> > Signed-off-by: Byungchul Park <byungchul.park@xxxxxxx>
> > ---
> > kernel/rcu/srcutree.c | 2 --
> > 1 file changed, 2 deletions(-)
> >
> > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
> > index 44bc0fa..829453b 100644
> > --- a/kernel/rcu/srcutree.c
> > +++ b/kernel/rcu/srcutree.c
> > @@ -531,7 +531,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
> > unsigned long flags;
> > unsigned long gpseq;
> > int idx;
> > - int idxnext;
>
> Interesting. According to git history, idxnext was never actually used.

Which raises the question of what I intended to do with it. Reviewing
that function didn't activate any memories, though it did point out a
candidate simplification.

> Reviewed-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>

Applied, thank you both!

Thanx, Paul

> -- Steve
>
> > unsigned long mask;
> > struct srcu_data *sdp;
> > struct srcu_node *snp;
> > @@ -555,7 +554,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
> >
> > /* Initiate callback invocation as needed. */
> > idx = rcu_seq_ctr(gpseq) % ARRAY_SIZE(snp->srcu_have_cbs);
> > - idxnext = (idx + 1) % ARRAY_SIZE(snp->srcu_have_cbs);
> > rcu_for_each_node_breadth_first(sp, snp) {
> > spin_lock_irq_rcu_node(snp);
> > cbs = false;
>