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Commit ea2c68a0 authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Frederic Weisbecker
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tracing: Simplify test for function_graph tracing start point 



In the function graph tracer, a calling function is to be traced
only when it is enabled through the set_graph_function file,
or when it is nested in an enabled function.

Current code uses TSK_TRACE_FL_GRAPH to test whether it is nested
or not. Looking at the code, we can get this:
(trace->depth > 0) <==> (TSK_TRACE_FL_GRAPH is set)

trace->depth is more explicit to tell that it is nested.
So we use trace->depth directly and simplify the code.

No functionality is changed.
TSK_TRACE_FL_GRAPH is not removed yet, it is left for future usage.

Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4B4DB0B6.7040607@cn.fujitsu.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent 24a53652

kernel/trace/trace.h

+1 −1
Original line number Diff line number Diff line
@@ -504,7 +504,7 @@ static inline int ftrace_graph_addr(unsigned long addr) 
{

	int i;



	if (!ftrace_graph_count || test_tsk_trace_graph(current))

	if (!ftrace_graph_count)

		return 1;



	for (i = 0; i < ftrace_graph_count; i++) {

kernel/trace/trace_functions_graph.c

+2 −6
Original line number Diff line number Diff line
@@ -215,7 +215,8 @@ int trace_graph_entry(struct ftrace_graph_ent *trace) 
	if (!ftrace_trace_task(current))

		return 0;



	if (!ftrace_graph_addr(trace->func))

	/* trace it when it is-nested-in or is a function enabled. */

	if (!(trace->depth || ftrace_graph_addr(trace->func)))

		return 0;



	local_irq_save(flags);
@@ -228,9 +229,6 @@ int trace_graph_entry(struct ftrace_graph_ent *trace) 
	} else {

		ret = 0;

	}

	/* Only do the atomic if it is not already set */

	if (!test_tsk_trace_graph(current))

		set_tsk_trace_graph(current);



	atomic_dec(&data->disabled);

	local_irq_restore(flags);
@@ -278,8 +276,6 @@ void trace_graph_return(struct ftrace_graph_ret *trace) 
		pc = preempt_count();

		__trace_graph_return(tr, trace, flags, pc);

	}

	if (!trace->depth)

		clear_tsk_trace_graph(current);

	atomic_dec(&data->disabled);

	local_irq_restore(flags);

}