[tip:perf/urgent] perf evlist: Fix side band thread draining

tip-bot for Jiri Olsa
2019-04-19T19:06:02Z

Commit-ID: adc6257c4a6f23ff97dca8314fcd33828e2d8db5
Gitweb: https://git.kernel.org/tip/adc6257c4a6f23ff97dca8314fcd33828e2d8db5
Author: Jiri Olsa <jolsa@kernel.org>
AuthorDate: Tue, 16 Apr 2019 18:01:23 +0200
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 17 Apr 2019 14:30:11 -0300

perf evlist: Fix side band thread draining

Current perf_evlist__poll_thread() code could finish without draining
the data. Adding the logic that makes sure we won't finish before the
drain.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Fixes: 657ee5531903 ("perf evlist: Introduce side band thread")
Link: http://lkml.kernel.org/r/20190416160127.30203-9-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/evlist.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 6689378ee577..51ead577533f 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1868,12 +1868,12 @@ static void *perf_evlist__poll_thread(void *arg)
{
struct perf_evlist *evlist = arg;
bool draining = false;
- int i;
+ int i, done = 0;
+
+ while (!done) {
+ bool got_data = false;

- while (draining || !(evlist->thread.done)) {
- if (draining)
- draining = false;
- else if (evlist->thread.done)
+ if (evlist->thread.done)
draining = true;

if (!draining)
@@ -1894,9 +1894,13 @@ static void *perf_evlist__poll_thread(void *arg)
pr_warning("cannot locate proper evsel for the side band event\n");

perf_mmap__consume(map);
+ got_data = true;
}
perf_mmap__read_done(map);
}
+
+ if (draining && !got_data)
+ break;
}
return NULL;
}