1. 根目录:
2. tools
3. perf
4. util
5. include
6. linux
7. compiler.h

#ifndef _PERF_LINUX_COMPILER_H_
#define _PERF_LINUX_COMPILER_H_

#ifndef __always_inline
#define __always_inline	inline
#endif
#define __user
#define __attribute_const__

#define __used		__attribute__((__unused__))

#endif