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authorSteven Rostedt <srostedt@redhat.com>2008-12-03 07:50:05 +0300
committerIngo Molnar <mingo@elte.hu>2008-12-03 10:56:26 +0300
commite49dc19c6a19ea112fcb94b7c62ec62cdd5c08aa (patch)
tree851dcdfe321e16a327d656ecd7040ef6e8590bec /arch/x86/kernel/ftrace.c
parent7ee991fbc6f947e9b04f29c9c6c1d057d0671a16 (diff)
downloadlinux-e49dc19c6a19ea112fcb94b7c62ec62cdd5c08aa.tar.xz
ftrace: function graph return for function entry
Impact: feature, let entry function decide to trace or not This patch lets the graph tracer entry function decide if the tracing should be done at the end as well. This requires all function graph entry functions return 1 if it should trace, or 0 if the return should not be traced. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/ftrace.c')
-rw-r--r--arch/x86/kernel/ftrace.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index adba8e9a427c..d278ad2ebda2 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -425,6 +425,7 @@ static void pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
trace->calltime = current->ret_stack[index].calltime;
trace->overrun = atomic_read(&current->trace_overrun);
trace->depth = index;
+ barrier();
current->curr_ret_stack--;
}
@@ -506,7 +507,11 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
}
trace.func = self_addr;
- ftrace_graph_entry(&trace);
+ /* Only trace if the calling function expects to */
+ if (!ftrace_graph_entry(&trace)) {
+ current->curr_ret_stack--;
+ *parent = old;
+ }
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */