Commit adcc3bfa authored by Gabriele Monaco's avatar Gabriele Monaco Committed by Steven Rostedt (Google)
Browse files

sched: Adapt sched tracepoints for RV task model 

Add the following tracepoint:
* sched_set_need_resched(tsk, cpu, tif)
    Called when a task is set the need resched [lazy] flag

Remove the unused ip parameter from sched_entry and sched_exit and alter
sched_entry to have a value of preempt consistent with the one used in
sched_switch.

Also adapt all monitors using sched_{entry,exit} to avoid breaking build.

These tracepoints are useful to describe the Linux task model and are
adapted from the patches by Daniel Bristot de Oliveira
(https://bristot.me/linux-task-model/).

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Nam Cao <namcao@linutronix.de>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: Juri Lelli <jlelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Link: https://lore.kernel.org/20250728135022.255578-7-gmonaco@redhat.com


Signed-off-by: default avatarGabriele Monaco <gmonaco@redhat.com>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 9d475d80

include/linux/sched.h

+6 −1
Original line number Diff line number Diff line
@@ -339,9 +339,11 @@ extern void io_schedule_finish(int token); 
extern long io_schedule_timeout(long timeout);

extern void io_schedule(void);



/* wrapper function to trace from this header file */

/* wrapper functions to trace from this header file */

DECLARE_TRACEPOINT(sched_set_state_tp);

extern void __trace_set_current_state(int state_value);

DECLARE_TRACEPOINT(sched_set_need_resched_tp);

extern void __trace_set_need_resched(struct task_struct *curr, int tif);



/**

 * struct prev_cputime - snapshot of system and user cputime
@@ -2063,6 +2065,9 @@ static inline int test_tsk_thread_flag(struct task_struct *tsk, int flag) 


static inline void set_tsk_need_resched(struct task_struct *tsk)

{

	if (tracepoint_enabled(sched_set_need_resched_tp) &&

	    !test_tsk_thread_flag(tsk, TIF_NEED_RESCHED))

		__trace_set_need_resched(tsk, TIF_NEED_RESCHED);

	set_tsk_thread_flag(tsk,TIF_NEED_RESCHED);

}

include/trace/events/sched.h

+8 −4
Original line number Diff line number Diff line
@@ -882,18 +882,22 @@ DECLARE_TRACE(sched_compute_energy, 
	TP_ARGS(p, dst_cpu, energy, max_util, busy_time));



DECLARE_TRACE(sched_entry,

	TP_PROTO(bool preempt, unsigned long ip),

	TP_ARGS(preempt, ip));

	TP_PROTO(bool preempt),

	TP_ARGS(preempt));



DECLARE_TRACE(sched_exit,

	TP_PROTO(bool is_switch, unsigned long ip),

	TP_ARGS(is_switch, ip));

	TP_PROTO(bool is_switch),

	TP_ARGS(is_switch));



DECLARE_TRACE_CONDITION(sched_set_state,

	TP_PROTO(struct task_struct *tsk, int state),

	TP_ARGS(tsk, state),

	TP_CONDITION(!!(tsk->__state) != !!state));



DECLARE_TRACE(sched_set_need_resched,

	TP_PROTO(struct task_struct *tsk, int cpu, int tif),

	TP_ARGS(tsk, cpu, tif));



#endif /* _TRACE_SCHED_H */



/* This part must be outside protection */

kernel/sched/core.c

+10 −3
Original line number Diff line number Diff line
@@ -1110,6 +1110,7 @@ static void __resched_curr(struct rq *rq, int tif) 


	cpu = cpu_of(rq);



	trace_sched_set_need_resched_tp(curr, cpu, tif);

	if (cpu == smp_processor_id()) {

		set_ti_thread_flag(cti, tif);

		if (tif == TIF_NEED_RESCHED)
@@ -1125,6 +1126,11 @@ static void __resched_curr(struct rq *rq, int tif) 
	}

}



void __trace_set_need_resched(struct task_struct *curr, int tif)

{

	trace_sched_set_need_resched_tp(curr, smp_processor_id(), tif);

}



void resched_curr(struct rq *rq)

{

	__resched_curr(rq, TIF_NEED_RESCHED);
@@ -5329,7 +5335,7 @@ asmlinkage __visible void schedule_tail(struct task_struct *prev) 
	 * switched the context for the first time. It is returning from

	 * schedule for the first time in this path.

	 */

	trace_sched_exit_tp(true, CALLER_ADDR0);

	trace_sched_exit_tp(true);

	preempt_enable();



	if (current->set_child_tid)
@@ -6678,7 +6684,8 @@ static void __sched notrace __schedule(int sched_mode) 
	struct rq *rq;

	int cpu;



	trace_sched_entry_tp(preempt, CALLER_ADDR0);

	/* Trace preemptions consistently with task switches */

	trace_sched_entry_tp(sched_mode == SM_PREEMPT);



	cpu = smp_processor_id();

	rq = cpu_rq(cpu);
@@ -6793,7 +6800,7 @@ static void __sched notrace __schedule(int sched_mode) 
		__balance_callbacks(rq);

		raw_spin_rq_unlock_irq(rq);

	}

	trace_sched_exit_tp(is_switch, CALLER_ADDR0);

	trace_sched_exit_tp(is_switch);

}



void __noreturn do_task_dead(void)

kernel/trace/rv/monitors/sco/sco.c

+2 −2
Original line number Diff line number Diff line
@@ -24,12 +24,12 @@ static void handle_sched_set_state(void *data, struct task_struct *tsk, int stat 
	da_handle_start_event_sco(sched_set_state_sco);

}



static void handle_schedule_entry(void *data, bool preempt, unsigned long ip)

static void handle_schedule_entry(void *data, bool preempt)

{

	da_handle_event_sco(schedule_entry_sco);

}



static void handle_schedule_exit(void *data, bool is_switch, unsigned long ip)

static void handle_schedule_exit(void *data, bool is_switch)

{

	da_handle_start_event_sco(schedule_exit_sco);

}

kernel/trace/rv/monitors/scpd/scpd.c

+2 −2
Original line number Diff line number Diff line
@@ -30,12 +30,12 @@ static void handle_preempt_enable(void *data, unsigned long ip, unsigned long pa 
	da_handle_start_event_scpd(preempt_enable_scpd);

}



static void handle_schedule_entry(void *data, bool preempt, unsigned long ip)

static void handle_schedule_entry(void *data, bool preempt)

{

	da_handle_event_scpd(schedule_entry_scpd);

}



static void handle_schedule_exit(void *data, bool is_switch, unsigned long ip)

static void handle_schedule_exit(void *data, bool is_switch)

{

	da_handle_event_scpd(schedule_exit_scpd);

}