1. 根目录:
2. include
3. linux
4. swap_cgroup.h

#ifndef __LINUX_SWAP_CGROUP_H
#define __LINUX_SWAP_CGROUP_H

#include <linux/swap.h>

#ifdef CONFIG_MEMCG_SWAP

extern unsigned short swap_cgroup_cmpxchg(swp_entry_t ent,
					unsigned short old, unsigned short new);
extern unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id);
extern unsigned short lookup_swap_cgroup_id(swp_entry_t ent);
extern int swap_cgroup_swapon(int type, unsigned long max_pages);
extern void swap_cgroup_swapoff(int type);

#else

static inline
unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)
{
	return 0;
}

static inline
unsigned short lookup_swap_cgroup_id(swp_entry_t ent)
{
	return 0;
}

static inline int
swap_cgroup_swapon(int type, unsigned long max_pages)
{
	return 0;
}

static inline void swap_cgroup_swapoff(int type)
{
	return;
}

#endif /* CONFIG_MEMCG_SWAP */

#endif /* __LINUX_SWAP_CGROUP_H */