Merge tag 'pwm/for-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry...

[platform/kernel/linux-rpi.git] / kernel / trace / trace_benchmark.c

diff --git a/kernel/trace/trace_benchmark.c b/kernel/trace/trace_benchmark.c
index e49fbe9..16a8cf0 100644 (file)
--- a/kernel/trace/trace_benchmark.c
+++ b/kernel/trace/trace_benchmark.c
@@ -153,10 +153,18 @@ static int benchmark_event_kthread(void *arg)
                trace_do_benchmark();
 
                /*
-                * We don't go to sleep, but let others
-                * run as well.
+                * We don't go to sleep, but let others run as well.
+                * This is bascially a "yield()" to let any task that
+                * wants to run, schedule in, but if the CPU is idle,
+                * we'll keep burning cycles.
+                *
+                * Note the _rcu_qs() version of cond_resched() will
+                * notify synchronize_rcu_tasks() that this thread has
+                * passed a quiescent state for rcu_tasks. Otherwise
+                * this thread will never voluntarily schedule which would
+                * block synchronize_rcu_tasks() indefinitely.
                 */
-               cond_resched();
+               cond_resched_rcu_qs();
        }
 
        return 0;