ftrace: trace scheduler rbtree

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

kernel/trace/trace.c

@@ -129,6 +129,7 @@ static const char *trace_options[] = {
 	"bin",
 	"block",
 	"stacktrace",
+	"sched-tree",
 	NULL
 };
 

kernel/trace/trace.h

@@ -286,6 +286,7 @@ enum trace_iterator_flags {
 	TRACE_ITER_BIN			= 0x40,
 	TRACE_ITER_BLOCK		= 0x80,
 	TRACE_ITER_STACKTRACE		= 0x100,
+	TRACE_ITER_SCHED_TREE		= 0x200,
 };
 
 #endif /* _LINUX_KERNEL_TRACE_H */

kernel/trace/trace_sched_switch.c

@@ -36,7 +36,8 @@ ctx_switch_func(void *__rq, struct task_struct *prev, struct task_struct *next)
 
 	if (likely(disabled == 1)) {
 		tracing_sched_switch_trace(tr, data, prev, next, flags);
-		ftrace_all_fair_tasks(__rq, tr, data);
+		if (trace_flags & TRACE_ITER_SCHED_TREE)
+			ftrace_all_fair_tasks(__rq, tr, data);
 	}
 
 	atomic_dec(&data->disabled);
@@ -62,7 +63,8 @@ wakeup_func(void *__rq, struct task_struct *wakee, struct task_struct *curr)
 
 	if (likely(disabled == 1)) {
 		tracing_sched_wakeup_trace(tr, data, wakee, curr, flags);
-		ftrace_all_fair_tasks(__rq, tr, data);
+		if (trace_flags & TRACE_ITER_SCHED_TREE)
+			ftrace_all_fair_tasks(__rq, tr, data);
 	}
 
 	atomic_dec(&data->disabled);