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Subject[tip:perf/core] perf ftrace: Move setup_pager before opening trace_pipe
Commit-ID:  29681bc5bb4326c2f9eac5dc68d8fad3e88b4bb5
Gitweb: http://git.kernel.org/tip/29681bc5bb4326c2f9eac5dc68d8fad3e88b4bb5
Author: Namhyung Kim <namhyung@kernel.org>
AuthorDate: Sun, 18 Jun 2017 23:23:00 +0900
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 19 Jun 2017 22:05:52 -0300

perf ftrace: Move setup_pager before opening trace_pipe

The 'perf ftrace' command fails to reset tracer after finishing
recording like below:

$ sudo perf ftrace -v hello
write 'nop' to tracing/current_tracer failed: Device or resource busy
...

This is because the trace_pipe file is open in pager process. Move the
pager setup to before opening the file.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: kernel-team@lge.com
Fixes: 583359646fde ("perf ftrace: Use pager for displaying result")
Link: http://lkml.kernel.org/r/20170618142302.25390-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/builtin-ftrace.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 966a94f..982b98e 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -231,6 +231,8 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
goto out_reset;
}

+ setup_pager();
+
trace_file = get_tracing_file("trace_pipe");
if (!trace_file) {
pr_err("failed to open trace_pipe\n");
@@ -254,8 +256,6 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
goto out_close_fd;
}

- setup_pager();
-
perf_evlist__start_workload(ftrace->evlist);

while (!done) {
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