Tracing In Brief

cd /sys/kernel/debug/tracing

# viewing functions
functions are listed in available_filter_function
grep shrink available_filter_function

# viewing tracers
cat available_tracers
function_graph, function are important

# setting function and graph
root@musfiq-Dell-DM051:/sys/kernel/debug/tracing# echo shrink_zone > set_ftrace_filter
root@musfiq-Dell-DM051:/sys/kernel/debug/tracing# echo shrink_zone > set_graph_function

# set tracer
root@musfiq-Dell-DM051:/sys/kernel/debug/tracing# echo function_graph > current_tracer
root@musfiq-Dell-DM051:/sys/kernel/debug/tracing# echo 1 > tracing_on

root@musfiq-Dell-DM051:/sys/kernel/debug/tracing# echo 0 > tracing_on