On Thu, 2025-02-06 at 09:19 +0100, Peter Zijlstra wrote:

On Thu, Feb 06, 2025 at 09:09:39AM +0100, Gabriele Monaco wrote:

quoted

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 9632e3318e0d6..af9fa18035c71 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h

@@ -226,12 +226,14 @@ struct user_event_mm;

 #define
__set_current_state(state_value)				\
 	do
{								\
 		debug_normal_state_change((state_value));	
	\
+		trace_set_current_state(state_value);		
	\
 		WRITE_ONCE(current->__state,
(state_value));		\
 	} while (0)
 
 #define
set_current_state(state_value)					\
 	do
{								\
 		debug_normal_state_change((state_value));	
	\
+		trace_set_current_state(state_value);		
	\
 		smp_store_mb(current->__state,
(state_value));		\
 	} while (0)
 

@@ -247,6 +249,7 @@ struct user_event_mm;

 								
	\
 		raw_spin_lock_irqsave(&current->pi_lock,
flags);	\
 		debug_special_state_change((state_value));	
	\
+		trace_set_current_state(state_value);		
	\
 		WRITE_ONCE(current->__state,
(state_value));		\
 		raw_spin_unlock_irqrestore(&current->pi_lock,
flags);	\
 	} while (0)

@@ -282,6 +285,7 @@ struct user_event_mm;

 		raw_spin_lock(&current-

quoted

pi_lock);			\

 		current->saved_state = current-

quoted

__state;		\

 		debug_rtlock_wait_set_state();			
	\
+		trace_set_current_state(TASK_RTLOCK_WAIT);	
	\
 		WRITE_ONCE(current->__state,
TASK_RTLOCK_WAIT);		\
 		raw_spin_unlock(&current-

quoted

pi_lock);			\

 	} while (0);

@@ -291,6 +295,7 @@ struct user_event_mm;

 		lockdep_assert_irqs_disabled();		
		\
 		raw_spin_lock(&current-

quoted

pi_lock);			\

 		debug_rtlock_wait_restore_state();		
	\
+		trace_set_current_state(TASK_RUNNING);		
	\
 		WRITE_ONCE(current->__state, current-

quoted

saved_state);	\

 		current->saved_state =
TASK_RUNNING;			\
 		raw_spin_unlock(&current-

quoted

pi_lock);			\

quoted

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 165c90ba64ea9..fb5f8aa61ef5d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c

@@ -491,6 +491,12 @@ sched_core_dequeue(struct rq *rq, struct

task_struct *p, int flags) { }
 
 #endif /* CONFIG_SCHED_CORE */
 
+void trace_set_current_state(int state_value)
+{
+	trace_sched_set_state_tp(current, current->__state,
state_value);
+}
+EXPORT_SYMBOL(trace_set_current_state);

Urgh, why !?!

Do you mean why exporting it?
At first I was puzzled too (this line is borrowed from Daniel), but the
thing is: set_current_state and friends are macros called by any sort
of code (e.g. modules), this seems the easiest way without messing up
with the current code.

I'm not sure if it would be cleaner to just drop this function and
define it directly in the header (including also trace/events/sched.h
there). It felt like files including sched shouldn't know about
tracepoints.

What do you think would be better?