Commit da7f84cd authored by Viktor Rosendahl's avatar Viktor Rosendahl Committed by Steven Rostedt (VMware)
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tracing: Use pause-on-trace with the latency tracers 

Eaerlier, tracing was disabled when reading the trace file. This behavior
was changed with:

commit 06e0a548 ("tracing: Do not disable tracing when reading the
trace file").

This doesn't seem to work with the latency tracers.

The above mentioned commit dit not only change the behavior but also added
an option to emulate the old behavior. The idea with this patch is to
enable this pause-on-trace option when the latency tracers are used.

Link: https://lkml.kernel.org/r/20210119164344.37500-2-Viktor.Rosendahl@bmw.de



Cc: stable@vger.kernel.org
Fixes: 06e0a548 ("tracing: Do not disable tracing when reading the trace file")
Signed-off-by: default avatarViktor Rosendahl <Viktor.Rosendahl@bmw.de>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 7e0a9220

kernel/trace/trace_irqsoff.c

+4 −0
Original line number Diff line number Diff line
@@ -562,6 +562,8 @@ static int __irqsoff_tracer_init(struct trace_array *tr) 
	/* non overwrite screws up the latency tracers */

	set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);

	set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);

	/* without pause, we will produce garbage if another latency occurs */

	set_tracer_flag(tr, TRACE_ITER_PAUSE_ON_TRACE, 1);



	tr->max_latency = 0;

	irqsoff_trace = tr;
@@ -583,11 +585,13 @@ static void __irqsoff_tracer_reset(struct trace_array *tr) 
{

	int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;

	int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;

	int pause_flag = save_flags & TRACE_ITER_PAUSE_ON_TRACE;



	stop_irqsoff_tracer(tr, is_graph(tr));



	set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);

	set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);

	set_tracer_flag(tr, TRACE_ITER_PAUSE_ON_TRACE, pause_flag);

	ftrace_reset_array_ops(tr);



	irqsoff_busy = false;