v4.19.13 snapshot.
diff --git a/tools/perf/util/namespaces.h b/tools/perf/util/namespaces.h
new file mode 100644
index 0000000..d5f46c0
--- /dev/null
+++ b/tools/perf/util/namespaces.h
@@ -0,0 +1,67 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * Copyright (C) 2017 Hari Bathini, IBM Corporation
+ */
+
+#ifndef __PERF_NAMESPACES_H
+#define __PERF_NAMESPACES_H
+
+#include <sys/types.h>
+#include <linux/stddef.h>
+#include <linux/perf_event.h>
+#include <linux/refcount.h>
+#include <linux/types.h>
+
+struct namespaces_event;
+
+struct namespaces {
+ struct list_head list;
+ u64 end_time;
+ struct perf_ns_link_info link_info[];
+};
+
+struct namespaces *namespaces__new(struct namespaces_event *event);
+void namespaces__free(struct namespaces *namespaces);
+
+struct nsinfo {
+ pid_t pid;
+ pid_t tgid;
+ pid_t nstgid;
+ bool need_setns;
+ char *mntns_path;
+ refcount_t refcnt;
+};
+
+struct nscookie {
+ int oldns;
+ int newns;
+ char *oldcwd;
+};
+
+int nsinfo__init(struct nsinfo *nsi);
+struct nsinfo *nsinfo__new(pid_t pid);
+struct nsinfo *nsinfo__copy(struct nsinfo *nsi);
+void nsinfo__delete(struct nsinfo *nsi);
+
+struct nsinfo *nsinfo__get(struct nsinfo *nsi);
+void nsinfo__put(struct nsinfo *nsi);
+
+void nsinfo__mountns_enter(struct nsinfo *nsi, struct nscookie *nc);
+void nsinfo__mountns_exit(struct nscookie *nc);
+
+char *nsinfo__realpath(const char *path, struct nsinfo *nsi);
+
+static inline void __nsinfo__zput(struct nsinfo **nsip)
+{
+ if (nsip) {
+ nsinfo__put(*nsip);
+ *nsip = NULL;
+ }
+}
+
+#define nsinfo__zput(nsi) __nsinfo__zput(&nsi)
+
+#endif /* __PERF_NAMESPACES_H */