1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2 #ifndef __LIBPERF_BPF_PERF_H
3 #define __LIBPERF_BPF_PERF_H
4 
5 #include <linux/types.h>  /* for __u32 */
6 
7 /*
8  * bpf_perf uses a hashmap, the attr_map, to track all the leader programs.
9  * The hashmap is pinned in bpffs. flock() on this file is used to ensure
10  * no concurrent access to the attr_map.  The key of attr_map is struct
11  * perf_event_attr, and the value is struct perf_event_attr_map_entry.
12  *
13  * struct perf_event_attr_map_entry contains two __u32 IDs, bpf_link of the
14  * leader prog, and the diff_map. Each perf-stat session holds a reference
15  * to the bpf_link to make sure the leader prog is attached to sched_switch
16  * tracepoint.
17  *
18  * Since the hashmap only contains IDs of the bpf_link and diff_map, it
19  * does not hold any references to the leader program. Once all perf-stat
20  * sessions of these events exit, the leader prog, its maps, and the
21  * perf_events will be freed.
22  */
23 struct perf_event_attr_map_entry {
24 	__u32 link_id;
25 	__u32 diff_map_id;
26 };
27 
28 /* default attr_map name */
29 #define BPF_PERF_DEFAULT_ATTR_MAP_PATH "perf_attr_map"
30 
31 #endif /* __LIBPERF_BPF_PERF_H */
32