perf lock contention: Add lock_data.h for common data

Accessing BPF maps should use the same data types.  Add bpf_skel/lock_data.h
to define the common data structures.  No functional changes.

Committer notes:

Fixed contention_key.stack_id missing rename to contention_key.stack_or_task_id.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20221209190727.759804-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/bpf_lock_contention.c

@@ -12,17 +12,10 @@
 #include <bpf/bpf.h>
 
 #include "bpf_skel/lock_contention.skel.h"
+#include "bpf_skel/lock_data.h"
 
 static struct lock_contention_bpf *skel;
 
-struct lock_contention_data {
-	u64 total_time;
-	u64 min_time;
-	u64 max_time;
-	u32 count;
-	u32 flags;
-};
-
 int lock_contention_prepare(struct lock_contention *con)
 {
 	int i, fd;
@@ -110,8 +103,8 @@ int lock_contention_stop(void)
 int lock_contention_read(struct lock_contention *con)
 {
 	int fd, stack, err = 0;
-	s32 prev_key, key;
-	struct lock_contention_data data = {};
+	struct contention_key *prev_key, key;
+	struct contention_data data = {};
 	struct lock_stat *st = NULL;
 	struct machine *machine = con->machine;
 	u64 *stack_trace;
@@ -126,8 +119,8 @@ int lock_contention_read(struct lock_contention *con)
 	if (stack_trace == NULL)
 		return -1;
 
-	prev_key = 0;
-	while (!bpf_map_get_next_key(fd, &prev_key, &key)) {
+	prev_key = NULL;
+	while (!bpf_map_get_next_key(fd, prev_key, &key)) {
 		struct map *kmap;
 		struct symbol *sym;
 		int idx = 0;
@@ -184,7 +177,7 @@ int lock_contention_read(struct lock_contention *con)
 		}
 
 		hlist_add_head(&st->hash_entry, con->result);
-		prev_key = key;
+		prev_key = &key;
 
 		/* we're fine now, reset the values */
 		st = NULL;

tools/perf/util/bpf_skel/lock_contention.bpf.c

@@ -5,24 +5,11 @@
 #include <bpf/bpf_tracing.h>
 #include <bpf/bpf_core_read.h>
 
-/* maximum stack trace depth */
-#define MAX_STACKS   8
+#include "lock_data.h"
 
 /* default buffer size */
 #define MAX_ENTRIES  10240
 
-struct contention_key {
-	__s32 stack_id;
-};
-
-struct contention_data {
-	__u64 total_time;
-	__u64 min_time;
-	__u64 max_time;
-	__u32 count;
-	__u32 flags;
-};
-
 struct tstamp_data {
 	__u64 timestamp;
 	__u64 lock;
@@ -34,7 +21,7 @@ struct tstamp_data {
 struct {
 	__uint(type, BPF_MAP_TYPE_STACK_TRACE);
 	__uint(key_size, sizeof(__u32));
-	__uint(value_size, MAX_STACKS * sizeof(__u64));
+	__uint(value_size, sizeof(__u64));
 	__uint(max_entries, MAX_ENTRIES);
 } stacks SEC(".maps");
 
@@ -154,7 +141,7 @@ int contention_end(u64 *ctx)
 
 	duration = bpf_ktime_get_ns() - pelem->timestamp;
 
-	key.stack_id = pelem->stack_id;
+	key.stack_or_task_id = pelem->stack_id;
 	data = bpf_map_lookup_elem(&lock_stat, &key);
 	if (!data) {
 		struct contention_data first = {

tools/perf/util/bpf_skel/lock_data.h

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/* Data structures shared between BPF and tools. */
+#ifndef UTIL_BPF_SKEL_LOCK_DATA_H
+#define UTIL_BPF_SKEL_LOCK_DATA_H
+
+struct contention_key {
+	s32 stack_or_task_id;
+};
+
+#define TASK_COMM_LEN  16
+
+struct contention_task_data {
+	char comm[TASK_COMM_LEN];
+};
+
+struct contention_data {
+	u64 total_time;
+	u64 min_time;
+	u64 max_time;
+	u32 count;
+	u32 flags;
+};
+
+enum lock_aggr_mode {
+	LOCK_AGGR_ADDR = 0,
+	LOCK_AGGR_TASK,
+	LOCK_AGGR_CALLER,
+};
+
+#endif /* UTIL_BPF_SKEL_LOCK_DATA_H */