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 
12 struct zonelist;
13 struct notifier_block;
14 struct mem_cgroup;
15 struct task_struct;
16 
17 enum 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  */
28 struct 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 
56 extern struct mutex oom_lock;
57 extern struct mutex oom_adj_mutex;
58 
set_current_oom_origin(void)59 static inline void set_current_oom_origin(void)
60 {
61 	current->signal->oom_flag_origin = true;
62 }
63 
clear_current_oom_origin(void)64 static inline void clear_current_oom_origin(void)
65 {
66 	current->signal->oom_flag_origin = false;
67 }
68 
oom_task_origin(const struct task_struct * p)69 static inline bool oom_task_origin(const struct task_struct *p)
70 {
71 	return p->signal->oom_flag_origin;
72 }
73 
tsk_is_oom_victim(struct task_struct * tsk)74 static 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  */
check_stable_address_space(struct mm_struct * mm)92 static 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 
99 long oom_badness(struct task_struct *p,
100 		unsigned long totalpages);
101 
102 extern bool out_of_memory(struct oom_control *oc);
103 
104 extern void exit_oom_victim(void);
105 
106 extern int register_oom_notifier(struct notifier_block *nb);
107 extern int unregister_oom_notifier(struct notifier_block *nb);
108 
109 extern bool oom_killer_disable(signed long timeout);
110 extern void oom_killer_enable(void);
111 
112 extern struct task_struct *find_lock_task_mm(struct task_struct *p);
113 
114 #endif /* _INCLUDE_LINUX_OOM_H */
115