Linux kernel mirror (for testing)
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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(test_bit(MMF_UNSTABLE, &mm->flags)))
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 */