text: #ifndef __INCLUDE_LINUX_OOM_H
  #define __INCLUDE_LINUX_OOM_H
  
  
  #include <linux/sched.h>
  #include <linux/types.h>
  #include <linux/nodemask.h>
  #include <uapi/linux/oom.h>
  
  struct zonelist;
  struct notifier_block;
  struct mem_cgroup;
  struct task_struct;
  
  /*
   * Types of limitations to the nodes from which allocations may occur
   */
  enum oom_constraint {
  	CONSTRAINT_NONE,
  	CONSTRAINT_CPUSET,
  	CONSTRAINT_MEMORY_POLICY,
  	CONSTRAINT_MEMCG,
  };
  
  enum oom_scan_t {
  	OOM_SCAN_OK,		/* scan thread and find its badness */
  	OOM_SCAN_CONTINUE,	/* do not consider thread for oom kill */
  	OOM_SCAN_ABORT,		/* abort the iteration and return */
  	OOM_SCAN_SELECT,	/* always select this thread first */
  };
  
  /* Thread is the potential origin of an oom condition; kill first on oom */
  #define OOM_FLAG_ORIGIN		((__force oom_flags_t)0x1)
  
  static inline void set_current_oom_origin(void)
  {
  	current->signal->oom_flags |= OOM_FLAG_ORIGIN;
  }
  
  static inline void clear_current_oom_origin(void)
  {
  	current->signal->oom_flags &= ~OOM_FLAG_ORIGIN;
  }
  
  static inline bool oom_task_origin(const struct task_struct *p)
  {
  	return !!(p->signal->oom_flags & OOM_FLAG_ORIGIN);
  }
  
  extern void mark_tsk_oom_victim(struct task_struct *tsk);
  
  extern void unmark_oom_victim(void);
  
  extern unsigned long oom_badness(struct task_struct *p,
  		struct mem_cgroup *memcg, const nodemask_t *nodemask,
  		unsigned long totalpages);
  
  extern int oom_kills_count(void);
  extern void note_oom_kill(void);
  extern void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
  			     unsigned int points, unsigned long totalpages,
  			     struct mem_cgroup *memcg, nodemask_t *nodemask,
  			     const char *message);
  
  extern bool oom_zonelist_trylock(struct zonelist *zonelist, gfp_t gfp_flags);
  extern void oom_zonelist_unlock(struct zonelist *zonelist, gfp_t gfp_flags);
  
  extern void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask,
  			       int order, const nodemask_t *nodemask,
  			       struct mem_cgroup *memcg);
  
  extern enum oom_scan_t oom_scan_process_thread(struct task_struct *task,
  		unsigned long totalpages, const nodemask_t *nodemask,
  		bool force_kill);
  
  extern bool out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
  		int order, nodemask_t *mask, bool force_kill);
  extern int register_oom_notifier(struct notifier_block *nb);
  extern int unregister_oom_notifier(struct notifier_block *nb);
  
  extern bool oom_killer_disabled;
  extern bool oom_killer_disable(void);
  extern void oom_killer_enable(void);
  
  extern struct task_struct *find_lock_task_mm(struct task_struct *p);
  
  static inline bool task_will_free_mem(struct task_struct *task)
  {
  	/*
  	 * A coredumping process may sleep for an extended period in exit_mm(),
  	 * so the oom killer cannot assume that the process will promptly exit
  	 * and release memory.
  	 */
  	return (task->flags & PF_EXITING) &&
  		!(task->signal->flags & SIGNAL_GROUP_COREDUMP);
  }
  
  /* sysctls */
  extern int sysctl_oom_dump_tasks;
  extern int sysctl_oom_kill_allocating_task;
  extern int sysctl_panic_on_oom;
  #endif /* _INCLUDE_LINUX_OOM_H */
  