[tip:perf/urgent] perf db-export: Move export__comm_thread into db_export__sample()

tip-bot for Adrian Hunter
2019-07-17T22:55:01Z

Commit-ID: 1ed119589834e25c130fdaa911ca8b0e3fd1cddf
Gitweb: https://git.kernel.org/tip/1ed119589834e25c130fdaa911ca8b0e3fd1cddf
Author: Adrian Hunter <adrian.hunter@intel.com>
AuthorDate: Wed, 10 Jul 2019 11:57:55 +0300
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 10 Jul 2019 12:12:45 -0300

perf db-export: Move export__comm_thread into db_export__sample()

Move call to db_export__comm_thread() from db_export__thread() into
db_export__sample() because it makes the code easier to understand, and
add explanatory comments.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20190710085810.1650-7-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/db-export.c | 35 +++++++++++++++++++++--------------
tools/perf/util/db-export.h | 3 +--
2 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/tools/perf/util/db-export.c b/tools/perf/util/db-export.c
index 99ad759561de..78f62a733b9d 100644
--- a/tools/perf/util/db-export.c
+++ b/tools/perf/util/db-export.c
@@ -59,25 +59,17 @@ int db_export__machine(struct db_export *dbe, struct machine *machine)
}

int db_export__thread(struct db_export *dbe, struct thread *thread,
- struct machine *machine, struct comm *comm,
- struct thread *main_thread)
+ struct machine *machine, struct thread *main_thread)
{
u64 main_thread_db_id = 0;
- int err;

if (thread->db_id)
return 0;

thread->db_id = ++dbe->thread_last_db_id;

- if (main_thread) {
- if (main_thread != thread && comm) {
- err = db_export__comm_thread(dbe, comm, thread);
- if (err)
- return err;
- }
+ if (main_thread)
main_thread_db_id = main_thread->db_id;
- }

if (dbe->export_thread)
return dbe->export_thread(dbe, thread, main_thread_db_id,
@@ -303,15 +295,19 @@ int db_export__sample(struct db_export *dbe, union perf_event *event,

main_thread = thread__main_thread(al->machine, thread);
if (main_thread) {
- comm = machine__thread_exec_comm(al->machine, main_thread);
/*
* A thread has a reference to the main thread, so export the
* main thread first.
*/
- err = db_export__thread(dbe, main_thread, al->machine, comm,
+ err = db_export__thread(dbe, main_thread, al->machine,
main_thread);
if (err)
goto out_put;
+ /*
+ * Export comm before exporting the non-main thread because
+ * db_export__comm_thread() can be called further below.
+ */
+ comm = machine__thread_exec_comm(al->machine, main_thread);
if (comm) {
err = db_export__exec_comm(dbe, comm, main_thread);
if (err)
@@ -321,10 +317,21 @@ int db_export__sample(struct db_export *dbe, union perf_event *event,
}

if (thread != main_thread) {
- err = db_export__thread(dbe, thread, al->machine, comm,
- main_thread);
+ /*
+ * For a non-main thread, db_export__comm_thread() must be
+ * called only if thread has not previously been exported.
+ */
+ bool export_comm_thread = comm && !thread->db_id;
+
+ err = db_export__thread(dbe, thread, al->machine, main_thread);
if (err)
goto out_put;
+
+ if (export_comm_thread) {
+ err = db_export__comm_thread(dbe, comm, thread);
+ if (err)
+ goto out_put;
+ }
}

es.db_id = ++dbe->sample_last_db_id;
diff --git a/tools/perf/util/db-export.h b/tools/perf/util/db-export.h
index 6e267321594c..811a678a910d 100644
--- a/tools/perf/util/db-export.h
+++ b/tools/perf/util/db-export.h
@@ -75,8 +75,7 @@ void db_export__exit(struct db_export *dbe);
int db_export__evsel(struct db_export *dbe, struct perf_evsel *evsel);
int db_export__machine(struct db_export *dbe, struct machine *machine);
int db_export__thread(struct db_export *dbe, struct thread *thread,
- struct machine *machine, struct comm *comm,
- struct thread *main_thread);
+ struct machine *machine, struct thread *main_thread);
int db_export__exec_comm(struct db_export *dbe, struct comm *comm,
struct thread *main_thread);
int db_export__comm_thread(struct db_export *dbe, struct comm *comm,