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/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
  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  * 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  */
  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 */