1 files changed, 132 insertions, 0 deletions
diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c
new file mode 100644
index 000000000000..8eb33e6f5029
--- /dev/null
+++ b/tools/perf/util/bpf_lock_contention.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "util/debug.h"
+#include "util/machine.h"
+#include "util/map.h"
+#include "util/symbol.h"
+#include "util/lock-contention.h"
+#include <linux/zalloc.h>
+#include <bpf/bpf.h>
+
+#include "bpf_skel/lock_contention.skel.h"
+
+static struct lock_contention_bpf *skel;
+
+/* should be same as bpf_skel/lock_contention.bpf.c */
+struct lock_contention_key {
+	u32 stack_id;
+};
+
+struct lock_contention_data {
+	u64 total_time;
+	u64 min_time;
+	u64 max_time;
+	u32 count;
+	u32 flags;
+};
+
+int lock_contention_prepare(void)
+{
+	skel = lock_contention_bpf__open();
+	if (!skel) {
+		pr_err("Failed to open lock-contention BPF skeleton\n");
+		return -1;
+	}
+
+	if (lock_contention_bpf__load(skel) < 0) {
+		pr_err("Failed to load lock-contention BPF skeleton\n");
+		return -1;
+	}
+
+	lock_contention_bpf__attach(skel);
+	return 0;
+}
+
+int lock_contention_start(void)
+{
+	skel->bss->enabled = 1;
+	return 0;
+}
+
+int lock_contention_stop(void)
+{
+	skel->bss->enabled = 0;
+	return 0;
+}
+
+int lock_contention_read(struct machine *machine, struct hlist_head *head)
+{
+	int fd, stack;
+	u32 prev_key, key;
+	struct lock_contention_data data;
+	struct lock_stat *st;
+	u64 stack_trace[CONTENTION_STACK_DEPTH];
+
+	fd = bpf_map__fd(skel->maps.lock_stat);
+	stack = bpf_map__fd(skel->maps.stacks);
+
+	prev_key = 0;
+	while (!bpf_map_get_next_key(fd, &prev_key, &key)) {
+		struct map *kmap;
+		struct symbol *sym;
+		int idx;
+
+		bpf_map_lookup_elem(fd, &key, &data);
+		st = zalloc(sizeof(*st));
+		if (st == NULL)
+			return -1;
+
+		st->nr_contended = data.count;
+		st->wait_time_total = data.total_time;
+		st->wait_time_max = data.max_time;
+		st->wait_time_min = data.min_time;
+
+		if (data.count)
+			st->avg_wait_time = data.total_time / data.count;
+
+		st->flags = data.flags;
+
+		bpf_map_lookup_elem(stack, &key, stack_trace);
+
+		/* skip BPF + lock internal functions */
+		idx = CONTENTION_STACK_SKIP;
+		while (is_lock_function(machine, stack_trace[idx]) &&
+		       idx < CONTENTION_STACK_DEPTH - 1)
+			idx++;
+
+		st->addr = stack_trace[idx];
+		sym = machine__find_kernel_symbol(machine, st->addr, &kmap);
+
+		if (sym) {
+			unsigned long offset;
+			int ret = 0;
+
+			offset = kmap->map_ip(kmap, st->addr) - sym->start;
+
+			if (offset)
+				ret = asprintf(&st->name, "%s+%#lx", sym->name, offset);
+			else
+				st->name = strdup(sym->name);
+
+			if (ret < 0 || st->name == NULL)
+				return -1;
+		} else if (asprintf(&st->name, "%#lx", (unsigned long)st->addr) < 0) {
+			free(st);
+			return -1;
+		}
+
+		hlist_add_head(&st->hash_entry, head);
+		prev_key = key;
+	}
+
+	return 0;
+}
+
+int lock_contention_finish(void)
+{
+	if (skel) {
+		skel->bss->enabled = 0;
+		lock_contention_bpf__destroy(skel);
+	}
+
+	return 0;
+}