sched: add latency tracer callbacks to the scheduler

add 3 lightweight callbacks to the tracer backend.

zero impact if tracing is turned off.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 26 insertions, 0 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 5395a6176f4b..717cab8a0c83 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2117,6 +2117,32 @@ static inline void arch_pick_mmap_layout(struct mm_struct *mm)
 }
 #endif
 
+#ifdef CONFIG_CONTEXT_SWITCH_TRACER
+extern void
+ftrace_ctx_switch(struct task_struct *prev, struct task_struct *next);
+#else
+static inline void
+ftrace_ctx_switch(struct task_struct *prev, struct task_struct *next)
+{
+}
+#endif
+
+#ifdef CONFIG_SCHED_TRACER
+extern void
+ftrace_wake_up_task(struct task_struct *wakee, struct task_struct *curr);
+extern void
+ftrace_wake_up_new_task(struct task_struct *wakee, struct task_struct *curr);
+#else
+static inline void
+ftrace_wake_up_task(struct task_struct *wakee, struct task_struct *curr)
+{
+}
+static inline void
+ftrace_wake_up_new_task(struct task_struct *wakee, struct task_struct *curr)
+{
+}
+#endif
+
 extern long sched_setaffinity(pid_t pid, const cpumask_t *new_mask);
 extern long sched_getaffinity(pid_t pid, cpumask_t *mask);