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