| Message ID | 1526494719-23361-1-git-send-email-vincent.guittot@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | sched/rt: fix call to cpufreq_update_util | expand |
On 16-05-18, 20:18, Vincent Guittot wrote: > With commit 8f111bc357aa ("cpufreq/schedutil: Rewrite CPUFREQ_RT support") > schedutil governor uses rq->rt.rt_nr_running to detect whether a RT task is > currently running on the CPU and to set frequency to max if necessary. > cpufreq_update_util() is called in enqueue/dequeue_top_rt_rq() but > rq->rt.rt_nr_running as not been updated yet when dequeue_top_rt_rq() is > called so schedutil still considers that a RT task is running when the > last task is dequeued. The update of rq->rt.rt_nr_running happens later > in dequeue_rt_stack() > > Fixes: 8f111bc357aa ('cpufreq/schedutil: Rewrite CPUFREQ_RT support') > Cc: <stable@vger.kernel.org> # v4.16+ > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> > --- > kernel/sched/rt.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c > index 7aef6b4..6e74d3d 100644 > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -1001,8 +1001,6 @@ dequeue_top_rt_rq(struct rt_rq *rt_rq) > sub_nr_running(rq, rt_rq->rt_nr_running); > rt_rq->rt_queued = 0; > Remove this blank line as well ? > - /* Kick cpufreq (see the comment in kernel/sched/sched.h). */ > - cpufreq_update_util(rq, 0); > } > > static void > @@ -1288,6 +1286,9 @@ static void dequeue_rt_stack(struct sched_rt_entity *rt_se, unsigned int flags) > if (on_rt_rq(rt_se)) > __dequeue_rt_entity(rt_se, flags); > } > + > + /* Kick cpufreq (see the comment in kernel/sched/sched.h). */ > + cpufreq_update_util(rq_of_rt_rq(rt_rq_of_se(back)), 0); > } > > static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags) > -- > 2.7.4 -- viresh
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 7aef6b4..6e74d3d 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1001,8 +1001,6 @@ dequeue_top_rt_rq(struct rt_rq *rt_rq) sub_nr_running(rq, rt_rq->rt_nr_running); rt_rq->rt_queued = 0; - /* Kick cpufreq (see the comment in kernel/sched/sched.h). */ - cpufreq_update_util(rq, 0); } static void @@ -1288,6 +1286,9 @@ static void dequeue_rt_stack(struct sched_rt_entity *rt_se, unsigned int flags) if (on_rt_rq(rt_se)) __dequeue_rt_entity(rt_se, flags); } + + /* Kick cpufreq (see the comment in kernel/sched/sched.h). */ + cpufreq_update_util(rq_of_rt_rq(rt_rq_of_se(back)), 0); } static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
With commit 8f111bc357aa ("cpufreq/schedutil: Rewrite CPUFREQ_RT support") schedutil governor uses rq->rt.rt_nr_running to detect whether a RT task is currently running on the CPU and to set frequency to max if necessary. cpufreq_update_util() is called in enqueue/dequeue_top_rt_rq() but rq->rt.rt_nr_running as not been updated yet when dequeue_top_rt_rq() is called so schedutil still considers that a RT task is running when the last task is dequeued. The update of rq->rt.rt_nr_running happens later in dequeue_rt_stack() Fixes: 8f111bc357aa ('cpufreq/schedutil: Rewrite CPUFREQ_RT support') Cc: <stable@vger.kernel.org> # v4.16+ Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> --- kernel/sched/rt.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) -- 2.7.4