LXR linux/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
  13struct zonelist;
  14struct notifier_block;
  15struct mem_cgroup;
  16struct task_struct;
  17
  18enum 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 */
  29struct 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
  57extern struct mutex oom_lock;
  58
  59static inline void set_current_oom_origin(void)
  60{
  61        current->signal->oom_flag_origin = true;
  62}
  63
  64static inline void clear_current_oom_origin(void)
  65{
  66        current->signal->oom_flag_origin = false;
  67}
  68
  69static inline bool oom_task_origin(const struct task_struct *p)
  70{
  71        return p->signal->oom_flag_origin;
  72}
  73
  74static 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 */
  83static 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 */
 101static 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
 108bool __oom_reap_task_mm(struct mm_struct *mm);
 109
 110extern unsigned long oom_badness(struct task_struct *p,
 111                struct mem_cgroup *memcg, const nodemask_t *nodemask,
 112                unsigned long totalpages);
 113
 114extern bool out_of_memory(struct oom_control *oc);
 115
 116extern void exit_oom_victim(void);
 117
 118extern int register_oom_notifier(struct notifier_block *nb);
 119extern int unregister_oom_notifier(struct notifier_block *nb);
 120
 121extern bool oom_killer_disable(signed long timeout);
 122extern void oom_killer_enable(void);
 123
 124extern struct task_struct *find_lock_task_mm(struct task_struct *p);
 125
 126/* sysctls */
 127extern int sysctl_oom_dump_tasks;
 128extern int sysctl_oom_kill_allocating_task;
 129extern int sysctl_panic_on_oom;
 130#endif /* _INCLUDE_LINUX_OOM_H */
 131