tracing/function: Avoid perf_trace_buf_*() if event_function.perf_events is empty
authorOleg Nesterov <oleg@redhat.com>
Mon, 17 Jun 2013 17:02:04 +0000 (19:02 +0200)
committerSteven Rostedt <rostedt@goodmis.org>
Fri, 19 Jul 2013 01:31:27 +0000 (21:31 -0400)
commitb8ebfd3f7113b63dda93d76bfec638c00e6bd514
tree5a72a20c5fa86fe1c284308111132345f249c671
parentd611851b421731e2afd9cb956daae001af57a423
tracing/function: Avoid perf_trace_buf_*() if event_function.perf_events is empty

perf_trace_buf_prepare() + perf_trace_buf_submit(head, task => NULL)
make no sense if hlist_empty(head). Change perf_ftrace_function_call()
to check event_function.perf_events beforehand.

Link: http://lkml.kernel.org/r/20130617170204.GA19803@redhat.com
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
kernel/trace/trace_event_perf.c