Commit 536bd00c authored May 06, 2016 by Rafael J. Wysocki Committed by Ingo Molnar May 07, 2016

sched/fair: Fix !CONFIG_SMP kernel cpufreq governor breakage



The following commit:

  34e2c555 ("cpufreq: Add mechanism for registering utilization update callbacks")

overlooked the fact that update_load_avg(), where CFS invokes cpufreq
utilization update callbacks, becomes an empty stub on UP kernels.

In consequence, if !CONFIG_SMP, cpufreq governors are never invoked
from CFS and they do not have a chance to evaluate CPU performace
levels and update them often enough.

Needless to say, things don't work as expected then.

Fix the problem by making the !CONFIG_SMP stub of update_load_avg()
invoke cpufreq update callbacks too.

Reported-by: Steve Muckle <steve.muckle@linaro.org>
Tested-by: Steve Muckle <steve.muckle@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Steve Muckle <steve.muckle@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux PM list <linux-pm@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Fixes: 34e2c555 (cpufreq: Add mechanism for registering utilization update callbacks)
Link: http://lkml.kernel.org/r/6282396.VVEdgVYxO3@vostro.rjw.lan


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 2548d546

kernel/sched/fair.c

+8 −1

Original line number	Diff line number	Diff line
		@@ -3030,7 +3030,14 @@ static int idle_balance(struct rq *this_rq);

		#else /* CONFIG_SMP */

		static inline void update_load_avg(struct sched_entity *se, int update_tg) {}
		static inline void update_load_avg(struct sched_entity *se, int not_used)
		{
		struct cfs_rq *cfs_rq = cfs_rq_of(se);
		struct rq *rq = rq_of(cfs_rq);

		cpufreq_trigger_update(rq_clock(rq));
		}

		static inline void
		enqueue_entity_load_avg(struct cfs_rq cfs_rq, struct sched_entity se) {}
		static inline void

Admin message