linux 内核回收

内核主要有4种LRU链表：

enum lru_list {

LRU_INACTIVE_ANON = LRU_BASE,

LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE,

LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE,

LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE,

LRU_UNEVICTABLE,

NR_LRU_LISTS

};

inactive_anon - # anonymous and swap cache memory on inactive LRU list.

active_anon - #anonymous and swap cache memory on active LRU list.

inactive_file - # file-backed memory on inactive LRU list.

active_file - # file-backed memory on active LRU list.

内核回收内存时，会在get_scan_out中计算每个链表中回收的page数量：