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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: 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>
This commit is contained in:
Lai Jiangshan 2010-01-13 19:38:30 +08:00 committed by Frederic Weisbecker
parent 24a53652e3
commit ea2c68a08f
2 changed files with 3 additions and 7 deletions
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2
kernel/trace/trace.h
View File

@ -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++) {

8
kernel/trace/trace_functions_graph.c
View File

@ -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);
}