tracing: Simplify test for function_graph tracing start point (ea2c68a0) · Commits · 戴 / test

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:

Lai 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:

Frederic Weisbecker <fweisbec@gmail.com>

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);
		}

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