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/sched/coredump.h> /* MMF_* */
11#include <linux/mm.h> /* VM_FAULT* */
12
13struct zonelist;
14struct notifier_block;
15struct mem_cgroup;
16struct task_struct;
17
18/*
19 * Details of the page allocation that triggered the oom killer that are used to
20 * determine what should be killed.
21 */
22struct oom_control {
23 /* Used to determine cpuset */
24 struct zonelist *zonelist;
25
26 /* Used to determine mempolicy */
27 nodemask_t *nodemask;
28
29 /* Memory cgroup in which oom is invoked, or NULL for global oom */
30 struct mem_cgroup *memcg;
31
32 /* Used to determine cpuset and node locality requirement */
33 const gfp_t gfp_mask;
34
35 /*
36 * order == -1 means the oom kill is required by sysrq, otherwise only
37 * for display purposes.
38 */
39 const int order;
40
41 /* Used by oom implementation, do not set */
42 unsigned long totalpages;
43 struct task_struct *chosen;
44 unsigned long chosen_points;
45};
46
47extern struct mutex oom_lock;
48
49static inline void set_current_oom_origin(void)
50{
51 current->signal->oom_flag_origin = true;
52}
53
54static inline void clear_current_oom_origin(void)
55{
56 current->signal->oom_flag_origin = false;
57}
58
59static inline bool oom_task_origin(const struct task_struct *p)
60{
61 return p->signal->oom_flag_origin;
62}
63
64static inline bool tsk_is_oom_victim(struct task_struct * tsk)
65{
66 return tsk->signal->oom_mm;
67}
68
69/*
70 * Use this helper if tsk->mm != mm and the victim mm needs a special
71 * handling. This is guaranteed to stay true after once set.
72 */
73static inline bool mm_is_oom_victim(struct mm_struct *mm)
74{
75 return test_bit(MMF_OOM_VICTIM, &mm->flags);
76}
77
78/*
79 * Checks whether a page fault on the given mm is still reliable.
80 * This is no longer true if the oom reaper started to reap the
81 * address space which is reflected by MMF_UNSTABLE flag set in
82 * the mm. At that moment any !shared mapping would lose the content
83 * and could cause a memory corruption (zero pages instead of the
84 * original content).
85 *
86 * User should call this before establishing a page table entry for
87 * a !shared mapping and under the proper page table lock.
88 *
89 * Return 0 when the PF is safe VM_FAULT_SIGBUS otherwise.
90 */
91static inline int check_stable_address_space(struct mm_struct *mm)
92{
93 if (unlikely(test_bit(MMF_UNSTABLE, &mm->flags)))
94 return VM_FAULT_SIGBUS;
95 return 0;
96}
97
98void __oom_reap_task_mm(struct mm_struct *mm);
99
100extern unsigned long oom_badness(struct task_struct *p,
101 struct mem_cgroup *memcg, const nodemask_t *nodemask,
102 unsigned long totalpages);
103
104extern bool out_of_memory(struct oom_control *oc);
105
106extern void exit_oom_victim(void);
107
108extern int register_oom_notifier(struct notifier_block *nb);
109extern int unregister_oom_notifier(struct notifier_block *nb);
110
111extern bool oom_killer_disable(signed long timeout);
112extern void oom_killer_enable(void);
113
114extern struct task_struct *find_lock_task_mm(struct task_struct *p);
115
116/* sysctls */
117extern int sysctl_oom_dump_tasks;
118extern int sysctl_oom_kill_allocating_task;
119extern int sysctl_panic_on_oom;
120#endif /* _INCLUDE_LINUX_OOM_H */
121