linux-kernel - Re: [PATCH 4/5] sched/debug: remove several CONFIG

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Message-ID: <20160627163236.so6byunieylj5amx@treble>
Date:	Mon, 27 Jun 2016 11:32:36 -0500
From:	Josh Poimboeuf <jpoimboe@...hat.com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
	Mel Gorman <mgorman@...hsingularity.net>,
	Matt Fleming <matt@...eblueprint.co.uk>,
	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Subject: Re: [PATCH 4/5] sched/debug: remove several CONFIG_SCHEDSTATS guards

On Mon, Jun 27, 2016 at 06:21:11PM +0200, Peter Zijlstra wrote:
> On Fri, Jun 17, 2016 at 12:43:26PM -0500, Josh Poimboeuf wrote:
> > index 017a4f5..0aee5dd 100644
> > --- a/kernel/sched/core.c
> > +++ b/kernel/sched/core.c
> > @@ -1626,10 +1626,15 @@ static inline int __set_cpus_allowed_ptr(struct task_struct *p,
> >  static void
> >  ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
> >  {
> > -#ifdef CONFIG_SCHEDSTATS
> > -	struct rq *rq = this_rq();
> > +	struct rq *rq;
> > +
> > +	if (!schedstat_enabled())
> > +		return;
> > +
> > +	rq = this_rq();
> >  
> >  #ifdef CONFIG_SMP
> > +{
> >  	int this_cpu = smp_processor_id();
> >  
> >  	if (cpu == this_cpu) {
> > @@ -1651,7 +1656,7 @@ ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
> >  
> >  	if (wake_flags & WF_MIGRATED)
> >  		schedstat_inc(p->se.statistics.nr_wakeups_migrate);
> > -
> > +}
> >  #endif /* CONFIG_SMP */
> >  
> >  	schedstat_inc(rq->ttwu_count);
> 
> I did:
> 
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -1636,10 +1636,7 @@ ttwu_stat(struct task_struct *p, int cpu
>  	rq = this_rq();
>  
>  #ifdef CONFIG_SMP
> -{
> -	int this_cpu = smp_processor_id();
> -
> -	if (cpu == this_cpu) {
> +	if (cpu == rq->cpu) {
>  		schedstat_inc(rq->ttwu_local);
>  		schedstat_inc(p->se.statistics.nr_wakeups_local);
>  	} else {
> @@ -1647,7 +1644,7 @@ ttwu_stat(struct task_struct *p, int cpu
>  
>  		schedstat_inc(p->se.statistics.nr_wakeups_remote);
>  		rcu_read_lock();
> -		for_each_domain(this_cpu, sd) {
> +		for_each_domain(rq->cpu, sd) {
>  			if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
>  				schedstat_inc(sd->ttwu_wake_remote);
>  				break;
> @@ -1658,7 +1655,6 @@ ttwu_stat(struct task_struct *p, int cpu
>  
>  	if (wake_flags & WF_MIGRATED)
>  		schedstat_inc(p->se.statistics.nr_wakeups_migrate);
> -}
>  #endif /* CONFIG_SMP */
>  
>  	schedstat_inc(rq->ttwu_count);

Much better, thanks.

-- 
Josh