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 /*
  19  * Details of the page allocation that triggered the oom killer that are used to
  20  * determine what should be killed.
  21  */
  22 struct 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
  47 extern struct mutex oom_lock;
  48
  49 static inline void set_current_oom_origin(void)
  50 {
  51         current->signal->oom_flag_origin = true;
  52 }
  53
  54 static inline void clear_current_oom_origin(void)
  55 {
  56         current->signal->oom_flag_origin = false;
  57 }
  58
  59 static inline bool oom_task_origin(const struct task_struct *p)
  60 {
  61         return p->signal->oom_flag_origin;
  62 }
  63
  64 static 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  */
  73 static 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  */
  91 static 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
  98 extern unsigned long oom_badness(struct task_struct *p,
  99                 struct mem_cgroup *memcg, const nodemask_t *nodemask,
 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 /* sysctls */
 115 extern int sysctl_oom_dump_tasks;
 116 extern int sysctl_oom_kill_allocating_task;
 117 extern int sysctl_panic_on_oom;
 118 #endif /* _INCLUDE_LINUX_OOM_H */