Add preemption-and-migration overhead tracing supportwip-pm-ovd

Add per-task accounting (based on shared control page) of information
needed to trace preemption and migration overheads from userspace

1 files changed, 6 insertions, 0 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 1701eaebb79c..69fb86c87915 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -489,6 +489,9 @@ struct rt_rq {
 struct litmus_rq {
         unsigned long nr_running;
         struct task_struct *prev;
+#ifdef CONFIG_PREEMPT_MIGRAT_OVD
+        unsigned int last_rt_task;
+#endif
 };
 
 #ifdef CONFIG_SMP
@@ -2766,8 +2769,11 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
          */
         prev_state = prev->state;
         finish_arch_switch(prev);
+
         litmus->finish_switch(prev);
         prev->rt_param.stack_in_use = NO_CPU;
+        trace_preempt_migrat_ovd(prev, current, rq);
+
         perf_event_task_sched_in(current, cpu_of(rq));
         finish_lock_switch(rq, prev);