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Commit b5130b1e authored by Carsten Emde's avatar Carsten Emde Committed by Steven Rostedt
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tracing: do not update tracing_max_latency when tracer is stopped 



The state of the function pair tracing_stop()/tracing_start() is
correctly considered when tracer data are updated. However, the global
and externally accessible variable tracing_max_latency is always updated
- even when tracing is stopped.

The update should only occur, if tracing was not stopped.

Signed-off-by: default avatarCarsten Emde <C.Emde@osadl.org>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 41dfba43

kernel/trace/trace.c

+5 −0
Original line number Original line Diff line number Diff line
@@ -825,6 +825,11 @@ static void trace_init_cmdlines(void) 
	cmdline_idx = 0;

	cmdline_idx = 0;

}

}





int is_tracing_stopped(void)

{

	return trace_stop_count;

}



/**

/**

 * ftrace_off_permanent - disable all ftrace code permanently

 * ftrace_off_permanent - disable all ftrace code permanently

 *

 *

kernel/trace/trace.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -461,6 +461,7 @@ void tracing_stop_sched_switch_record(void); 
void tracing_start_sched_switch_record(void);

void tracing_start_sched_switch_record(void);

int register_tracer(struct tracer *type);

int register_tracer(struct tracer *type);

void unregister_tracer(struct tracer *type);

void unregister_tracer(struct tracer *type);

int is_tracing_stopped(void);





extern unsigned long nsecs_to_usecs(unsigned long nsecs);

extern unsigned long nsecs_to_usecs(unsigned long nsecs);

kernel/trace/trace_irqsoff.c

+4 −2
Original line number Original line Diff line number Diff line
@@ -157,8 +157,10 @@ check_critical_timing(struct trace_array *tr, 




	data->critical_end = parent_ip;

	data->critical_end = parent_ip;





	if (likely(!is_tracing_stopped())) {

		tracing_max_latency = delta;

		tracing_max_latency = delta;

		update_max_tr_single(tr, current, cpu);

		update_max_tr_single(tr, current, cpu);

	}





	max_sequence++;

	max_sequence++;

kernel/trace/trace_sched_wakeup.c

+4 −2
Original line number Original line Diff line number Diff line
@@ -162,8 +162,10 @@ probe_wakeup_sched_switch(struct rq *rq, struct task_struct *prev, 
	if (!report_latency(delta))

	if (!report_latency(delta))

		goto out_unlock;

		goto out_unlock;





	if (likely(!is_tracing_stopped())) {

		tracing_max_latency = delta;

		tracing_max_latency = delta;

		update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu);

		update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu);

	}





out_unlock:

out_unlock:

	__wakeup_reset(wakeup_trace);

	__wakeup_reset(wakeup_trace);