Messages in this thread | | | Date | Thu, 18 May 2017 11:01:20 +0900 | From | Byungchul Park <> | Subject | Re: [RESEND PATCH v3] sched/rt: Remove unnecessary condition in push_rt_task() |
| |
On Fri, May 12, 2017 at 10:05:43AM +0900, Byungchul Park wrote: > pick_next_pushable_task(rq) has BUG_ON(rq_cpu != task_cpu(task)) when > it returns a task other than NULL, which means that task_cpu(task) must > be rq->cpu. So if task == next_task, then task_cpu(next_task) must be > rq->cpu as well. Remove the redundant condition and make code simpler. > > By this patch, unnecessary one branch and two LOAD operations in 'if' > statement can be avoided.
+cc rostedt@goodmis.org +cc juri.lelli@arm.com +cc bristot@redhat.com
> > Signed-off-by: Byungchul Park <byungchul.park@lge.com> > Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> > Reviewed-by: Juri Lelli <juri.lelli@arm.com> > Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> > --- > kernel/sched/rt.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c > index 4101f9d..5abd9a52 100644 > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -1820,7 +1820,7 @@ static int push_rt_task(struct rq *rq) > * pushing. > */ > task = pick_next_pushable_task(rq); > - if (task_cpu(next_task) == rq->cpu && task == next_task) { > + if (task == next_task) { > /* > * The task hasn't migrated, and is still the next > * eligible task, but we failed to find a run-queue > -- > 1.9.1
| |