[tip:perf/core] ftrace/perf: Check sample types only for sampling events

tip-bot for Jiri Olsa
2016-03-31T09:26:51Z

Commit-ID: 0a74c5b3d20d2a8693848b6ae4f1a97624f5b781
Gitweb: http://git.kernel.org/tip/0a74c5b3d20d2a8693848b6ae4f1a97624f5b781
Author: Jiri Olsa <jolsa@kernel.org>
AuthorDate: Wed, 16 Mar 2016 15:34:29 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 31 Mar 2016 10:30:45 +0200

ftrace/perf: Check sample types only for sampling events

Currently we check sample type for ftrace:function events
even if it's not created as a sampling event. That prevents
creating ftrace_function event in counting mode.

Make sure we check sample types only for sampling events.

Before:
$ sudo perf stat -e ftrace:function ls
...

Performance counter stats for 'ls':

<not supported> ftrace:function

0.001983662 seconds time elapsed

After:
$ sudo perf stat -e ftrace:function ls
...

Performance counter stats for 'ls':

44,498 ftrace:function

0.037534722 seconds time elapsed

Suggested-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1458138873-1553-2-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/trace/trace_event_perf.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 00df25f..e11108f 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -47,6 +47,9 @@ static int perf_trace_event_perm(struct trace_event_call *tp_event,
if (perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN))
return -EPERM;

+ if (!is_sampling_event(p_event))
+ return 0;
+
/*
* We don't allow user space callchains for function trace
* event, due to issues with page faults while tracing page