dynamic ftrace - graph

Michal Simek
2009-11-09T16:54:10Z

Hi Steve and others,

I have working dynamic ftrace function. :-)

I look at __ftrace_modify_code function and I have one question about.
Below are function which are called when I enable function_graph.

I personally think that make more sense to call
ftrace_enable_ftrace_graph_caller before ftrace_update_ftrace_func.
The reason for it is that graph_caller enable calling graph tracing
which should be setup before ftrace_update_ftrace_func which enable
whole tracing function.

# cd ; mkdir /debug; mount -t debugfs none /debug; cat
/debug/tracing/available_tracers; echo function_graph >
/debug/tracing/current_tracer;echo 0 > /debug/tra
cing/tracing_enabled;cat /debug/tracing/trace | head -n 10
function_graph function sched_switch nop

ftrace_update_ftrace_func 0xc0009100 0xc00091c4, 0xb000c000, 0x32809100
ftrace_enable_ftrace_graph_caller
# tracer: function_graph

For disabling graph trace is sequence ok I think.

# echo function > /debug/tracing/current_tracer
ftrace_disable_ftrace_graph_caller
ftrace_update_ftrace_func 0xc006afe4 0xc00091c4, 0xb000c006, 0x3280afe4

What do you think?

Thanks,