[PATCH v3 1/4] perf util: move bpf_perf definitions to a libperf header

Song Liu
2021-04-16T22:13:52Z

By following the same protocol, other tools can share hardware PMCs with
perf. Move perf_event_attr_map_entry and BPF_PERF_DEFAULT_ATTR_MAP_PATH to
bpf_perf.h for other tools to use.

Signed-off-by: Song Liu <song@kernel.org>
---
tools/lib/perf/include/perf/bpf_perf.h | 31 ++++++++++++++++++++++++++
tools/perf/util/bpf_counter.c | 27 +++-------------------
2 files changed, 34 insertions(+), 24 deletions(-)
create mode 100644 tools/lib/perf/include/perf/bpf_perf.h

diff --git a/tools/lib/perf/include/perf/bpf_perf.h b/tools/lib/perf/include/perf/bpf_perf.h
new file mode 100644
index 0000000000000..e7cf6ba7b674b
--- /dev/null
+++ b/tools/lib/perf/include/perf/bpf_perf.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+#ifndef __LIBPERF_BPF_PERF_H
+#define __LIBPERF_BPF_PERF_H
+
+#include <linux/types.h> /* for __u32 */
+
+/*
+ * bpf_perf uses a hashmap, the attr_map, to track all the leader programs.
+ * The hashmap is pinned in bpffs. flock() on this file is used to ensure
+ * no concurrent access to the attr_map. The key of attr_map is struct
+ * perf_event_attr, and the value is struct perf_event_attr_map_entry.
+ *
+ * struct perf_event_attr_map_entry contains two __u32 IDs, bpf_link of the
+ * leader prog, and the diff_map. Each perf-stat session holds a reference
+ * to the bpf_link to make sure the leader prog is attached to sched_switch
+ * tracepoint.
+ *
+ * Since the hashmap only contains IDs of the bpf_link and diff_map, it
+ * does not hold any references to the leader program. Once all perf-stat
+ * sessions of these events exit, the leader prog, its maps, and the
+ * perf_events will be freed.
+ */
+struct perf_event_attr_map_entry {
+ __u32 link_id;
+ __u32 diff_map_id;
+};
+
+/* default attr_map name */
+#define BPF_PERF_DEFAULT_ATTR_MAP_PATH "perf_attr_map"
+
+#endif /* __LIBPERF_BPF_PERF_H */
diff --git a/tools/perf/util/bpf_counter.c b/tools/perf/util/bpf_counter.c
index 81d1df3c4ec0e..be484ddbbd5be 100644
--- a/tools/perf/util/bpf_counter.c
+++ b/tools/perf/util/bpf_counter.c
@@ -14,6 +14,7 @@
#include <bpf/btf.h>
#include <bpf/libbpf.h>
#include <api/fs/fs.h>
+#include <perf/bpf_perf.h>

#include "bpf_counter.h"
#include "counts.h"
@@ -29,28 +30,6 @@
#include "bpf_skel/bperf_leader.skel.h"
#include "bpf_skel/bperf_follower.skel.h"

-/*
- * bperf uses a hashmap, the attr_map, to track all the leader programs.
- * The hashmap is pinned in bpffs. flock() on this file is used to ensure
- * no concurrent access to the attr_map. The key of attr_map is struct
- * perf_event_attr, and the value is struct perf_event_attr_map_entry.
- *
- * struct perf_event_attr_map_entry contains two __u32 IDs, bpf_link of the
- * leader prog, and the diff_map. Each perf-stat session holds a reference
- * to the bpf_link to make sure the leader prog is attached to sched_switch
- * tracepoint.
- *
- * Since the hashmap only contains IDs of the bpf_link and diff_map, it
- * does not hold any references to the leader program. Once all perf-stat
- * sessions of these events exit, the leader prog, its maps, and the
- * perf_events will be freed.
- */
-struct perf_event_attr_map_entry {
- __u32 link_id;
- __u32 diff_map_id;
-};
-
-#define DEFAULT_ATTR_MAP_PATH "fs/bpf/perf_attr_map"
#define ATTR_MAP_SIZE 16

static inline void *u64_to_ptr(__u64 ptr)
@@ -341,8 +320,8 @@ static int bperf_lock_attr_map(struct target *target)
if (target->attr_map) {
scnprintf(path, PATH_MAX, "%s", target->attr_map);
} else {
- scnprintf(path, PATH_MAX, "%s/%s", sysfs__mountpoint(),
- DEFAULT_ATTR_MAP_PATH);
+ scnprintf(path, PATH_MAX, "%s/fs/bpf/%s", sysfs__mountpoint(),
+ BPF_PERF_DEFAULT_ATTR_MAP_PATH);
}

if (access(path, F_OK)) {
--
2.30.2