Linux 内核源码分析-理解 cgroup 内存资源控制

/*
 * The memory controller data structure. The memory controller controls both
 * page cache and RSS per cgroup. We would eventually like to provide
 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
 * to help the administrator determine what knobs to tune.
 */
struct mem_cgroup {
	struct cgroup_subsys_state css;

	/* Private memcg ID. Used to ID objects that outlive the cgroup */
	struct mem_cgroup_id id;

	/* Accounted resources */
	struct page_counter memory;  /* 内存计数器 */
	struct page_counter swap;    /* 交换区计数器 */

	/* Legacy consumer-oriented counters */
	struct page_counter memsw;
	struct page_counter kmem;     /* 内核内存限制计数器 */
	struct page_counter tcpmem;   /* TCP的socket缓冲区计数器 */

	/* Upper bound of normal memory consumption range */
	unsigned long high;   /* 限制使用的内存上限 */

	/* Range enforcement for interrupt charges */
	struct work_struct high_work;

	unsigned long soft_limit;

	/* vmpressure notifications */
	struct vmpressure vmpressure;

	/*
	 * Should the accounting and control be hierarchical, per subtree?
	 */
	bool use_hierarchy;			/* 是否启用分层计数 */

	/*
	 * Should the OOM killer kill all belonging tasks, had it kill one?
	 */
	bool oom_group;

	/* protected by memcg_oom_lock */
	bool		oom_lock;
	int		under_oom;

	int	swappiness;
	/* OOM-Killer disable */
	int		oom_kill_disable;    /* 是否打开OOM的killer, 即kill超出限制的内存容量的进程 */

	/* ... */
};

struct page_counter {
        atomic_long_t usage;   /* 已使用的Page数量 */
        unsigned long min;     
        unsigned long low;
        unsigned long max;
        struct page_counter *parent;

        /* effective memory.min and memory.min usage tracking */
        unsigned long emin;
        atomic_long_t min_usage;
        atomic_long_t children_min_usage;

        /* effective memory.low and memory.low usage tracking */
        unsigned long elow;
        atomic_long_t low_usage;
        atomic_long_t children_low_usage;

        /* legacy */
        unsigned long watermark;
        unsigned long failcnt;
};