Re: [PATCH 6/7] rcu: rename some CONFIG_PREEMPTION to CONFIG_PREEMPT_RCU

[Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>]

On 2019/10/16 11:54 上午, Paul E. McKenney wrote:
> On Tue, Oct 15, 2019 at 10:28:48AM +0000, Lai Jiangshan wrote:
> > CONFIG_PREEMPTION and CONFIG_PREEMPT_RCU are always identical,
> > but some code depends on CONFIG_PREEMPTION to access to
> > rcu_preempt functionalitis. This patch changes CONFIG_PREEMPTION
> > to CONFIG_PREEMPT_RCU in these cases.
> >
> > Signed-off-by: Lai Jiangshan <jiangshanlai@xxxxxxxxx>
> > Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>
>
> I believe that this does not cause problems with Sebastian's patch
> "[PATCH 27/34] rcu: Use CONFIG_PREEMPTION where appropriate", but could
> you please check?

I don't know for which commit the patch "[PATCH 27/34] rcu: Use
CONFIG_PREEMPTION where appropriate" should be applied against
after several tries. But I don't think there will be any conflicts
which this patch by "eye" applying.

Thanks,
Lai



> 							Thanx, Paul
>
> > ---
> >   kernel/rcu/tree.c       | 4 ++--
> >   kernel/rcu/tree_stall.h | 6 +++---
> >   2 files changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > index 7db5ea06a9ed..81eb64fcf5ab 100644
> > --- a/kernel/rcu/tree.c
> > +++ b/kernel/rcu/tree.c
> > @@ -1926,7 +1926,7 @@ rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags)
> >   	struct rcu_node *rnp_p;
> >   
> >   	raw_lockdep_assert_held_rcu_node(rnp);
> > -	if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPTION)) ||
> > +	if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT_RCU)) ||
> >   	    WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)) ||
> >   	    rnp->qsmask != 0) {
> >   		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
> > @@ -2294,7 +2294,7 @@ static void force_qs_rnp(int (*f)(struct rcu_data *rdp))
> >   		mask = 0;
> >   		raw_spin_lock_irqsave_rcu_node(rnp, flags);
> >   		if (rnp->qsmask == 0) {
> > -			if (!IS_ENABLED(CONFIG_PREEMPTION) ||
> > +			if (!IS_ENABLED(CONFIG_PREEMPT_RCU) ||
> >   			    rcu_preempt_blocked_readers_cgp(rnp)) {
> >   				/*
> >   				 * No point in scanning bits because they
> > diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
> > index 0b75426ebb3e..55f9b84790d3 100644
> > --- a/kernel/rcu/tree_stall.h
> > +++ b/kernel/rcu/tree_stall.h
> > @@ -163,7 +163,7 @@ static void rcu_iw_handler(struct irq_work *iwp)
> >   //
> >   // Printing RCU CPU stall warnings
> >   
> > -#ifdef CONFIG_PREEMPTION
> > +#ifdef CONFIG_PREEMPT_RCU
> >   
> >   /*
> >    * Dump detailed information for all tasks blocking the current RCU
> > @@ -215,7 +215,7 @@ static int rcu_print_task_stall(struct rcu_node *rnp)
> >   	return ndetected;
> >   }
> >   
> > -#else /* #ifdef CONFIG_PREEMPTION */
> > +#else /* #ifdef CONFIG_PREEMPT_RCU */
> >   
> >   /*
> >    * Because preemptible RCU does not exist, we never have to check for
> > @@ -233,7 +233,7 @@ static int rcu_print_task_stall(struct rcu_node *rnp)
> >   {
> >   	return 0;
> >   }
> > -#endif /* #else #ifdef CONFIG_PREEMPTION */
> > +#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
> >   
> >   /*
> >    * Dump stacks of all tasks running on stalled CPUs.  First try using
> > --
> > 2.20.1