help me, what is this witchcraft

include/linux/ologk.h

@@ -0,0 +1,15 @@
+#ifndef _OLOG_KERNEL_H_
+#define _OLOG_KERNEL_H_
+
+#include <linux/unistd.h>
+#include "olog.pb.h"
+
+#define OLOG_CPU_FREQ_FILTER   1500000
+#define PERFLOG_MUTEX_THRESHOLD   20
+
+#define ologk(...) _perflog(PERFLOG_LOG, PERFLOG_UNKNOWN, __VA_ARGS__)
+#define perflog(...) _perflog(PERFLOG_LOG, __VA_ARGS__)
+extern void _perflog(int type, int logid, const char *fmt, ...);
+extern void perflog_evt(int logid, int arg1);
+
+#endif