include/linux/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/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         unsigned 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
  59 static inline void set_current_oom_origin(void)
  60 {
  61         current->signal->oom_flag_origin = true;
  62 }
  63
  64 static inline void clear_current_oom_origin(void)
  65 {
  66         current->signal->oom_flag_origin = false;
  67 }
  68
  69 static inline bool oom_task_origin(const struct task_struct *p)
  70 {
  71         return p->signal->oom_flag_origin;
  72 }
  73
  74 static inline bool tsk_is_oom_victim(struct task_struct * tsk)
  75 {
  76         return tsk->signal->oom_mm;
  77 }
  78
  79 /*
  80  * Use this helper if tsk->mm != mm and the victim mm needs a special
  81  * handling. This is guaranteed to stay true after once set.
  82  */
  83 static inline bool mm_is_oom_victim(struct mm_struct *mm)
  84 {
  85         return test_bit(MMF_OOM_VICTIM, &mm->flags);
  86 }
  87
  88 /*
  89  * Checks whether a page fault on the given mm is still reliable.
  90  * This is no longer true if the oom reaper started to reap the
  91  * address space which is reflected by MMF_UNSTABLE flag set in
  92  * the mm. At that moment any !shared mapping would lose the content
  93  * and could cause a memory corruption (zero pages instead of the
  94  * original content).
  95  *
  96  * User should call this before establishing a page table entry for
  97  * a !shared mapping and under the proper page table lock.
  98  *
  99  * Return 0 when the PF is safe VM_FAULT_SIGBUS otherwise.
 100  */
 101 static inline vm_fault_t check_stable_address_space(struct mm_struct *mm)
 102 {
 103         if (unlikely(test_bit(MMF_UNSTABLE, &mm->flags)))
 104                 return VM_FAULT_SIGBUS;
 105         return 0;
 106 }
 107
 108 bool __oom_reap_task_mm(struct mm_struct *mm);
 109
 110 extern unsigned long oom_badness(struct task_struct *p,
 111                 unsigned long totalpages);
 112
 113 extern bool out_of_memory(struct oom_control *oc);
 114
 115 extern void exit_oom_victim(void);
 116
 117 extern int register_oom_notifier(struct notifier_block *nb);
 118 extern int unregister_oom_notifier(struct notifier_block *nb);
 119
 120 extern bool oom_killer_disable(signed long timeout);
 121 extern void oom_killer_enable(void);
 122
 123 extern struct task_struct *find_lock_task_mm(struct task_struct *p);
 124
 125 /* sysctls */
 126 extern int sysctl_oom_dump_tasks;
 127 extern int sysctl_oom_kill_allocating_task;
 128 extern int sysctl_panic_on_oom;
 129 #endif /* _INCLUDE_LINUX_OOM_H */