oom.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef __INCLUDE_LINUX_OOM_H
  3#define __INCLUDE_LINUX_OOM_H
  4
  5
  6#include <linux/sched/signal.h>
  7#include <linux/types.h>
  8#include <linux/nodemask.h>
  9#include <uapi/linux/oom.h>
 10#include <linux/mm.h> /* VM_FAULT* */
 11
 12struct zonelist;
 13struct notifier_block;
 14struct mem_cgroup;
 15struct task_struct;
 16
 17enum oom_constraint {
 18	CONSTRAINT_NONE,
 19	CONSTRAINT_CPUSET,
 20	CONSTRAINT_MEMORY_POLICY,
 21	CONSTRAINT_MEMCG,
 22};
 23
 24/*
 25 * Details of the page allocation that triggered the oom killer that are used to
 26 * determine what should be killed.
 27 */
 28struct oom_control {
 29	/* Used to determine cpuset */
 30	struct zonelist *zonelist;
 31
 32	/* Used to determine mempolicy */
 33	nodemask_t *nodemask;
 34
 35	/* Memory cgroup in which oom is invoked, or NULL for global oom */
 36	struct mem_cgroup *memcg;
 37
 38	/* Used to determine cpuset and node locality requirement */
 39	const gfp_t gfp_mask;
 40
 41	/*
 42	 * order == -1 means the oom kill is required by sysrq, otherwise only
 43	 * for display purposes.
 44	 */
 45	const int order;
 46
 47	/* Used by oom implementation, do not set */
 48	unsigned long totalpages;
 49	struct task_struct *chosen;
 50	long chosen_points;
 51
 52	/* Used to print the constraint info. */
 53	enum oom_constraint constraint;
 54};
 55
 56extern struct mutex oom_lock;
 57extern struct mutex oom_adj_mutex;
 58
 59static inline void set_current_oom_origin(void)
 60{
 61	current->signal->oom_flag_origin = true;
 62}
 63
 64static inline void clear_current_oom_origin(void)
 65{
 66	current->signal->oom_flag_origin = false;
 67}
 68
 69static inline bool oom_task_origin(const struct task_struct *p)
 70{
 71	return p->signal->oom_flag_origin;
 72}
 73
 74static inline bool tsk_is_oom_victim(struct task_struct * tsk)
 75{
 76	return tsk->signal->oom_mm;
 77}
 78
 79/*
 80 * Checks whether a page fault on the given mm is still reliable.
 81 * This is no longer true if the oom reaper started to reap the
 82 * address space which is reflected by MMF_UNSTABLE flag set in
 83 * the mm. At that moment any !shared mapping would lose the content
 84 * and could cause a memory corruption (zero pages instead of the
 85 * original content).
 86 *
 87 * User should call this before establishing a page table entry for
 88 * a !shared mapping and under the proper page table lock.
 89 *
 90 * Return 0 when the PF is safe VM_FAULT_SIGBUS otherwise.
 91 */
 92static inline vm_fault_t check_stable_address_space(struct mm_struct *mm)
 93{
 94	if (unlikely(mm_flags_test(MMF_UNSTABLE, mm)))
 95		return VM_FAULT_SIGBUS;
 96	return 0;
 97}
 98
 99long oom_badness(struct task_struct *p,
100		unsigned long totalpages);
101
102extern bool out_of_memory(struct oom_control *oc);
103
104extern void exit_oom_victim(void);
105
106extern int register_oom_notifier(struct notifier_block *nb);
107extern int unregister_oom_notifier(struct notifier_block *nb);
108
109extern bool oom_killer_disable(signed long timeout);
110extern void oom_killer_enable(void);
111
112extern struct task_struct *find_lock_task_mm(struct task_struct *p);
113
114#endif /* _INCLUDE_LINUX_OOM_H */