[PATCH v7 15/20] perf session: Introduce reader objects in session object

[Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>]

Allow to allocate multiple reader objects, so we could load multiple
data files located in data directory at the same time.

Design and implementation are based on the prototype [1], [2].

[1] git clone https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git -b perf/record_threads
[2] https://lore.kernel.org/lkml/20180913125450.21342-1-jolsa@kernel.org/

Suggested-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
---
 tools/perf/util/session.c | 33 +++++++++++++++++++++------------
 tools/perf/util/session.h |  3 +++
 2 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index d9ba87a754be..335c073bae87 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -342,6 +342,10 @@ void perf_session__delete(struct perf_session *session)
 	auxtrace_index__free(&session->auxtrace_index);
 	perf_session__destroy_kernel_maps(session);
 	perf_session__delete_threads(session);
+	if (session->readers) {
+		zfree(&session->readers);
+		session->nr_readers = 0;
+	}
 	perf_session__release_decomp_events(session);
 	perf_env__exit(&session->header.env);
 	machines__exit(&session->machines);
@@ -2298,14 +2302,7 @@ static s64 process_simple(struct perf_session *session,
 
 static int __perf_session__process_events(struct perf_session *session)
 {
-	struct reader rd = {
-		.fd		= perf_data__fd(session->data),
-		.data_size	= session->header.data_size,
-		.data_offset	= session->header.data_offset,
-		.process	= process_simple,
-		.path		= session->data->file.path,
-		.in_place_update = session->data->in_place_update,
-	};
+	struct reader *rd;
 	struct ordered_events *oe = &session->ordered_events;
 	struct perf_tool *tool = session->tool;
 	struct ui_progress prog;
@@ -2313,12 +2310,24 @@ static int __perf_session__process_events(struct perf_session *session)
 
 	perf_tool__fill_defaults(tool);
 
-	if (rd.data_size == 0)
-		return -1;
+	rd = session->readers = zalloc(sizeof(struct reader));
+	if (!rd)
+		return -ENOMEM;
+
+	session->nr_readers = 1;
+
+	*rd = (struct reader) {
+		.fd		 = perf_data__fd(session->data),
+		.data_size	 = session->header.data_size,
+		.data_offset	 = session->header.data_offset,
+		.process	 = process_simple,
+		.path		 = session->data->file.path,
+		.in_place_update = session->data->in_place_update,
+	};
 
-	ui_progress__init_size(&prog, rd.data_size, "Processing events...");
+	ui_progress__init_size(&prog, rd->data_size, "Processing events...");
 
-	err = reader__process_events(&rd, session, &prog);
+	err = reader__process_events(rd, session, &prog);
 	if (err)
 		goto out_err;
 	/* do the final flush for ordered samples */
diff --git a/tools/perf/util/session.h b/tools/perf/util/session.h
index 6895a22ab5b7..2815d00b5467 100644
--- a/tools/perf/util/session.h
+++ b/tools/perf/util/session.h
@@ -19,6 +19,7 @@ struct thread;
 
 struct auxtrace;
 struct itrace_synth_opts;
+struct reader;
 
 struct perf_session {
 	struct perf_header	header;
@@ -41,6 +42,8 @@ struct perf_session {
 	struct zstd_data	zstd_data;
 	struct decomp		*decomp;
 	struct decomp		*decomp_last;
+	struct reader		*readers;
+	int			nr_readers;
 };
 
 struct decomp {
-- 
2.19.0