聊聊Linux内核的内存回收上篇

struct zone {
	// 用于空闲页帧管理的buddy系统
	struct free_area	free_area[MAX_ORDER];
	
	// 已经在使用的LRU链表管理
	struct pglist_data	*zone_pgdat;
	
	atomic_long_t		vm_stat[NR_VM_ZONE_STAT_ITEMS];
}

// 用于管理已经在使用的内存页帧
typedef struct pglist_data {
	spinlock_t		lru_lock;
	// LRU 链表
	struct lruvec		lruvec;

	atomic_long_t		vm_stat[NR_VM_NODE_STAT_ITEMS];
} pg_data_t;

// LRU链表
struct lruvec {
	struct list_head		lists[NR_LRU_LISTS];
	struct zone_reclaim_stat	reclaim_stat;
	/* Evictions & activations on the inactive file list */
	atomic_long_t			inactive_age;
	/* Refaults at the time of last reclaim cycle */
	unsigned long			refaults;
#ifdef CONFIG_MEMCG
	struct pglist_data *pgdat;
#endif
};


enum lru_list {
	// 不活跃的匿名页帧
	LRU_INACTIVE_ANON = LRU_BASE,
	// 活跃的匿名页帧
	LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE,
	// 不活跃的文件页帧
	LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE,
	// 活跃的文件页帧
	LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE,
	// 不可换出的页帧
	LRU_UNEVICTABLE,
	NR_LRU_LISTS
};