4 * Copyright (C) 1998,2000 Rik van Riel
5 * Thanks go out to Claus Fischer for some serious inspiration and
6 * for goading me into coding this file...
7 * Copyright (C) 2010 Google, Inc.
8 * Rewritten by David Rientjes
10 * The routines in this file are used to kill a process when
11 * we're seriously out of memory. This gets called from __alloc_pages()
12 * in mm/page_alloc.c when we really run out of memory.
14 * Since we won't call these routines often (on a well-configured
15 * machine) this file will double as a 'coding guide' and a signpost
16 * for newbie kernel hackers. It features several pointers to major
17 * kernel subsystems and hints as to where to find out what things do.
20 #include <linux/oom.h>
22 #include <linux/err.h>
23 #include <linux/gfp.h>
24 #include <linux/sched.h>
25 #include <linux/swap.h>
26 #include <linux/timex.h>
27 #include <linux/jiffies.h>
28 #include <linux/cpuset.h>
29 #include <linux/export.h>
30 #include <linux/notifier.h>
31 #include <linux/memcontrol.h>
32 #include <linux/mempolicy.h>
33 #include <linux/security.h>
34 #include <linux/ptrace.h>
35 #include <linux/freezer.h>
36 #include <linux/ftrace.h>
37 #include <linux/ratelimit.h>
38 #include <linux/kthread.h>
39 #include <linux/init.h>
44 #define CREATE_TRACE_POINTS
45 #include <trace/events/oom.h>
47 int sysctl_panic_on_oom;
48 int sysctl_oom_kill_allocating_task;
49 int sysctl_oom_dump_tasks = 1;
51 DEFINE_MUTEX(oom_lock);
55 * has_intersects_mems_allowed() - check task eligiblity for kill
56 * @start: task struct of which task to consider
57 * @mask: nodemask passed to page allocator for mempolicy ooms
59 * Task eligibility is determined by whether or not a candidate task, @tsk,
60 * shares the same mempolicy nodes as current if it is bound by such a policy
61 * and whether or not it has the same set of allowed cpuset nodes.
63 static bool has_intersects_mems_allowed(struct task_struct *start,
64 const nodemask_t *mask)
66 struct task_struct *tsk;
70 for_each_thread(start, tsk) {
73 * If this is a mempolicy constrained oom, tsk's
74 * cpuset is irrelevant. Only return true if its
75 * mempolicy intersects current, otherwise it may be
78 ret = mempolicy_nodemask_intersects(tsk, mask);
81 * This is not a mempolicy constrained oom, so only
82 * check the mems of tsk's cpuset.
84 ret = cpuset_mems_allowed_intersects(current, tsk);
94 static bool has_intersects_mems_allowed(struct task_struct *tsk,
95 const nodemask_t *mask)
99 #endif /* CONFIG_NUMA */
102 * The process p may have detached its own ->mm while exiting or through
103 * use_mm(), but one or more of its subthreads may still have a valid
104 * pointer. Return p, or any of its subthreads with a valid ->mm, with
107 struct task_struct *find_lock_task_mm(struct task_struct *p)
109 struct task_struct *t;
113 for_each_thread(p, t) {
127 * order == -1 means the oom kill is required by sysrq, otherwise only
128 * for display purposes.
130 static inline bool is_sysrq_oom(struct oom_control *oc)
132 return oc->order == -1;
135 /* return true if the task is not adequate as candidate victim task. */
136 static bool oom_unkillable_task(struct task_struct *p,
137 struct mem_cgroup *memcg, const nodemask_t *nodemask)
139 if (is_global_init(p))
141 if (p->flags & PF_KTHREAD)
144 /* When mem_cgroup_out_of_memory() and p is not member of the group */
145 if (memcg && !task_in_mem_cgroup(p, memcg))
148 /* p may not have freeable memory in nodemask */
149 if (!has_intersects_mems_allowed(p, nodemask))
156 * oom_badness - heuristic function to determine which candidate task to kill
157 * @p: task struct of which task we should calculate
158 * @totalpages: total present RAM allowed for page allocation
160 * The heuristic for determining which task to kill is made to be as simple and
161 * predictable as possible. The goal is to return the highest value for the
162 * task consuming the most memory to avoid subsequent oom failures.
164 unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
165 const nodemask_t *nodemask, unsigned long totalpages)
170 if (oom_unkillable_task(p, memcg, nodemask))
173 p = find_lock_task_mm(p);
177 adj = (long)p->signal->oom_score_adj;
178 if (adj == OOM_SCORE_ADJ_MIN) {
184 * The baseline for the badness score is the proportion of RAM that each
185 * task's rss, pagetable and swap space use.
187 points = get_mm_rss(p->mm) + get_mm_counter(p->mm, MM_SWAPENTS) +
188 atomic_long_read(&p->mm->nr_ptes) + mm_nr_pmds(p->mm);
192 * Root processes get 3% bonus, just like the __vm_enough_memory()
193 * implementation used by LSMs.
195 if (has_capability_noaudit(p, CAP_SYS_ADMIN))
196 points -= (points * 3) / 100;
198 /* Normalize to oom_score_adj units */
199 adj *= totalpages / 1000;
203 * Never return 0 for an eligible task regardless of the root bonus and
204 * oom_score_adj (oom_score_adj can't be OOM_SCORE_ADJ_MIN here).
206 return points > 0 ? points : 1;
210 * Determine the type of allocation constraint.
213 static enum oom_constraint constrained_alloc(struct oom_control *oc,
214 unsigned long *totalpages)
218 enum zone_type high_zoneidx = gfp_zone(oc->gfp_mask);
219 bool cpuset_limited = false;
222 /* Default to all available memory */
223 *totalpages = totalram_pages + total_swap_pages;
226 return CONSTRAINT_NONE;
228 * Reach here only when __GFP_NOFAIL is used. So, we should avoid
229 * to kill current.We have to random task kill in this case.
230 * Hopefully, CONSTRAINT_THISNODE...but no way to handle it, now.
232 if (oc->gfp_mask & __GFP_THISNODE)
233 return CONSTRAINT_NONE;
236 * This is not a __GFP_THISNODE allocation, so a truncated nodemask in
237 * the page allocator means a mempolicy is in effect. Cpuset policy
238 * is enforced in get_page_from_freelist().
241 !nodes_subset(node_states[N_MEMORY], *oc->nodemask)) {
242 *totalpages = total_swap_pages;
243 for_each_node_mask(nid, *oc->nodemask)
244 *totalpages += node_spanned_pages(nid);
245 return CONSTRAINT_MEMORY_POLICY;
248 /* Check this allocation failure is caused by cpuset's wall function */
249 for_each_zone_zonelist_nodemask(zone, z, oc->zonelist,
250 high_zoneidx, oc->nodemask)
251 if (!cpuset_zone_allowed(zone, oc->gfp_mask))
252 cpuset_limited = true;
254 if (cpuset_limited) {
255 *totalpages = total_swap_pages;
256 for_each_node_mask(nid, cpuset_current_mems_allowed)
257 *totalpages += node_spanned_pages(nid);
258 return CONSTRAINT_CPUSET;
260 return CONSTRAINT_NONE;
263 static enum oom_constraint constrained_alloc(struct oom_control *oc,
264 unsigned long *totalpages)
266 *totalpages = totalram_pages + total_swap_pages;
267 return CONSTRAINT_NONE;
271 enum oom_scan_t oom_scan_process_thread(struct oom_control *oc,
272 struct task_struct *task, unsigned long totalpages)
274 if (oom_unkillable_task(task, NULL, oc->nodemask))
275 return OOM_SCAN_CONTINUE;
278 * This task already has access to memory reserves and is being killed.
279 * Don't allow any other task to have access to the reserves.
281 if (test_tsk_thread_flag(task, TIF_MEMDIE)) {
282 if (!is_sysrq_oom(oc))
283 return OOM_SCAN_ABORT;
286 return OOM_SCAN_CONTINUE;
289 * If task is allocating a lot of memory and has been marked to be
290 * killed first if it triggers an oom, then select it.
292 if (oom_task_origin(task))
293 return OOM_SCAN_SELECT;
295 if (task_will_free_mem(task) && !is_sysrq_oom(oc))
296 return OOM_SCAN_ABORT;
302 * Simple selection loop. We chose the process with the highest
303 * number of 'points'. Returns -1 on scan abort.
305 static struct task_struct *select_bad_process(struct oom_control *oc,
306 unsigned int *ppoints, unsigned long totalpages)
308 struct task_struct *g, *p;
309 struct task_struct *chosen = NULL;
310 unsigned long chosen_points = 0;
313 for_each_process_thread(g, p) {
316 switch (oom_scan_process_thread(oc, p, totalpages)) {
317 case OOM_SCAN_SELECT:
319 chosen_points = ULONG_MAX;
321 case OOM_SCAN_CONTINUE:
325 return (struct task_struct *)(-1UL);
329 points = oom_badness(p, NULL, oc->nodemask, totalpages);
330 if (!points || points < chosen_points)
332 /* Prefer thread group leaders for display purposes */
333 if (points == chosen_points && thread_group_leader(chosen))
337 chosen_points = points;
340 get_task_struct(chosen);
343 *ppoints = chosen_points * 1000 / totalpages;
348 * dump_tasks - dump current memory state of all system tasks
349 * @memcg: current's memory controller, if constrained
350 * @nodemask: nodemask passed to page allocator for mempolicy ooms
352 * Dumps the current memory state of all eligible tasks. Tasks not in the same
353 * memcg, not in the same cpuset, or bound to a disjoint set of mempolicy nodes
355 * State information includes task's pid, uid, tgid, vm size, rss, nr_ptes,
356 * swapents, oom_score_adj value, and name.
358 static void dump_tasks(struct mem_cgroup *memcg, const nodemask_t *nodemask)
360 struct task_struct *p;
361 struct task_struct *task;
363 pr_info("[ pid ] uid tgid total_vm rss nr_ptes nr_pmds swapents oom_score_adj name\n");
365 for_each_process(p) {
366 if (oom_unkillable_task(p, memcg, nodemask))
369 task = find_lock_task_mm(p);
372 * This is a kthread or all of p's threads have already
373 * detached their mm's. There's no need to report
374 * them; they can't be oom killed anyway.
379 pr_info("[%5d] %5d %5d %8lu %8lu %7ld %7ld %8lu %5hd %s\n",
380 task->pid, from_kuid(&init_user_ns, task_uid(task)),
381 task->tgid, task->mm->total_vm, get_mm_rss(task->mm),
382 atomic_long_read(&task->mm->nr_ptes),
383 mm_nr_pmds(task->mm),
384 get_mm_counter(task->mm, MM_SWAPENTS),
385 task->signal->oom_score_adj, task->comm);
391 static void dump_header(struct oom_control *oc, struct task_struct *p,
392 struct mem_cgroup *memcg)
394 pr_warn("%s invoked oom-killer: gfp_mask=%#x(%pGg), order=%d, "
395 "oom_score_adj=%hd\n",
396 current->comm, oc->gfp_mask, &oc->gfp_mask, oc->order,
397 current->signal->oom_score_adj);
399 cpuset_print_current_mems_allowed();
402 mem_cgroup_print_oom_info(memcg, p);
404 show_mem(SHOW_MEM_FILTER_NODES);
405 if (sysctl_oom_dump_tasks)
406 dump_tasks(memcg, oc->nodemask);
410 * Number of OOM victims in flight
412 static atomic_t oom_victims = ATOMIC_INIT(0);
413 static DECLARE_WAIT_QUEUE_HEAD(oom_victims_wait);
415 bool oom_killer_disabled __read_mostly;
417 #define K(x) ((x) << (PAGE_SHIFT-10))
421 * OOM Reaper kernel thread which tries to reap the memory used by the OOM
422 * victim (if that is possible) to help the OOM killer to move on.
424 static struct task_struct *oom_reaper_th;
425 static struct task_struct *task_to_reap;
426 static DECLARE_WAIT_QUEUE_HEAD(oom_reaper_wait);
428 static bool __oom_reap_task(struct task_struct *tsk)
430 struct mmu_gather tlb;
431 struct vm_area_struct *vma;
432 struct mm_struct *mm;
433 struct task_struct *p;
434 struct zap_details details = {.check_swap_entries = true,
435 .ignore_dirty = true};
439 * Make sure we find the associated mm_struct even when the particular
440 * thread has already terminated and cleared its mm.
441 * We might have race with exit path so consider our work done if there
444 p = find_lock_task_mm(tsk);
449 if (!atomic_inc_not_zero(&mm->mm_users)) {
456 if (!down_read_trylock(&mm->mmap_sem)) {
461 tlb_gather_mmu(&tlb, mm, 0, -1);
462 for (vma = mm->mmap ; vma; vma = vma->vm_next) {
463 if (is_vm_hugetlb_page(vma))
467 * Only anonymous pages have a good chance to be dropped
468 * without additional steps which we cannot afford as we
471 * We do not even care about fs backed pages because all
472 * which are reclaimable have already been reclaimed and
473 * we do not want to block exit_mmap by keeping mm ref
474 * count elevated without a good reason.
476 if (vma_is_anonymous(vma) || !(vma->vm_flags & VM_SHARED)) {
477 if (vma->vm_flags & VM_LOCKED)
478 munlock_vma_pages_all(vma);
479 unmap_page_range(&tlb, vma, vma->vm_start, vma->vm_end,
483 tlb_finish_mmu(&tlb, 0, -1);
484 pr_info("oom_reaper: reaped process :%d (%s) anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lulB\n",
485 task_pid_nr(tsk), tsk->comm,
486 K(get_mm_counter(mm, MM_ANONPAGES)),
487 K(get_mm_counter(mm, MM_FILEPAGES)),
488 K(get_mm_counter(mm, MM_SHMEMPAGES)));
489 up_read(&mm->mmap_sem);
492 * Clear TIF_MEMDIE because the task shouldn't be sitting on a
493 * reasonably reclaimable memory anymore. OOM killer can continue
494 * by selecting other victim if unmapping hasn't led to any
495 * improvements. This also means that selecting this task doesn't
498 tsk->signal->oom_score_adj = OOM_SCORE_ADJ_MIN;
499 exit_oom_victim(tsk);
505 #define MAX_OOM_REAP_RETRIES 10
506 static void oom_reap_task(struct task_struct *tsk)
510 /* Retry the down_read_trylock(mmap_sem) a few times */
511 while (attempts++ < MAX_OOM_REAP_RETRIES && !__oom_reap_task(tsk))
512 schedule_timeout_idle(HZ/10);
514 if (attempts > MAX_OOM_REAP_RETRIES) {
515 pr_info("oom_reaper: unable to reap pid:%d (%s)\n",
516 task_pid_nr(tsk), tsk->comm);
517 debug_show_all_locks();
520 /* Drop a reference taken by wake_oom_reaper */
521 put_task_struct(tsk);
524 static int oom_reaper(void *unused)
527 struct task_struct *tsk;
529 wait_event_freezable(oom_reaper_wait,
530 (tsk = READ_ONCE(task_to_reap)));
532 WRITE_ONCE(task_to_reap, NULL);
538 static void wake_oom_reaper(struct task_struct *tsk)
540 struct task_struct *old_tsk;
545 get_task_struct(tsk);
548 * Make sure that only a single mm is ever queued for the reaper
549 * because multiple are not necessary and the operation might be
550 * disruptive so better reduce it to the bare minimum.
552 old_tsk = cmpxchg(&task_to_reap, NULL, tsk);
554 wake_up(&oom_reaper_wait);
556 put_task_struct(tsk);
559 static int __init oom_init(void)
561 oom_reaper_th = kthread_run(oom_reaper, NULL, "oom_reaper");
562 if (IS_ERR(oom_reaper_th)) {
563 pr_err("Unable to start OOM reaper %ld. Continuing regardless\n",
564 PTR_ERR(oom_reaper_th));
565 oom_reaper_th = NULL;
569 subsys_initcall(oom_init)
571 static void wake_oom_reaper(struct task_struct *mm)
577 * mark_oom_victim - mark the given task as OOM victim
580 * Has to be called with oom_lock held and never after
581 * oom has been disabled already.
583 void mark_oom_victim(struct task_struct *tsk)
585 WARN_ON(oom_killer_disabled);
586 /* OOM killer might race with memcg OOM */
587 if (test_and_set_tsk_thread_flag(tsk, TIF_MEMDIE))
590 * Make sure that the task is woken up from uninterruptible sleep
591 * if it is frozen because OOM killer wouldn't be able to free
592 * any memory and livelock. freezing_slow_path will tell the freezer
593 * that TIF_MEMDIE tasks should be ignored.
596 atomic_inc(&oom_victims);
600 * exit_oom_victim - note the exit of an OOM victim
602 void exit_oom_victim(struct task_struct *tsk)
604 if (!test_and_clear_tsk_thread_flag(tsk, TIF_MEMDIE))
607 if (!atomic_dec_return(&oom_victims))
608 wake_up_all(&oom_victims_wait);
612 * oom_killer_disable - disable OOM killer
614 * Forces all page allocations to fail rather than trigger OOM killer.
615 * Will block and wait until all OOM victims are killed.
617 * The function cannot be called when there are runnable user tasks because
618 * the userspace would see unexpected allocation failures as a result. Any
619 * new usage of this function should be consulted with MM people.
621 * Returns true if successful and false if the OOM killer cannot be
624 bool oom_killer_disable(void)
627 * Make sure to not race with an ongoing OOM killer
628 * and that the current is not the victim.
630 mutex_lock(&oom_lock);
631 if (test_thread_flag(TIF_MEMDIE)) {
632 mutex_unlock(&oom_lock);
636 oom_killer_disabled = true;
637 mutex_unlock(&oom_lock);
639 wait_event(oom_victims_wait, !atomic_read(&oom_victims));
645 * oom_killer_enable - enable OOM killer
647 void oom_killer_enable(void)
649 oom_killer_disabled = false;
653 * task->mm can be NULL if the task is the exited group leader. So to
654 * determine whether the task is using a particular mm, we examine all the
655 * task's threads: if one of those is using this mm then this task was also
658 static bool process_shares_mm(struct task_struct *p, struct mm_struct *mm)
660 struct task_struct *t;
662 for_each_thread(p, t) {
663 struct mm_struct *t_mm = READ_ONCE(t->mm);
671 * Must be called while holding a reference to p, which will be released upon
674 void oom_kill_process(struct oom_control *oc, struct task_struct *p,
675 unsigned int points, unsigned long totalpages,
676 struct mem_cgroup *memcg, const char *message)
678 struct task_struct *victim = p;
679 struct task_struct *child;
680 struct task_struct *t;
681 struct mm_struct *mm;
682 unsigned int victim_points = 0;
683 static DEFINE_RATELIMIT_STATE(oom_rs, DEFAULT_RATELIMIT_INTERVAL,
684 DEFAULT_RATELIMIT_BURST);
685 bool can_oom_reap = true;
688 * If the task is already exiting, don't alarm the sysadmin or kill
689 * its children or threads, just set TIF_MEMDIE so it can die quickly
692 if (p->mm && task_will_free_mem(p)) {
700 if (__ratelimit(&oom_rs))
701 dump_header(oc, p, memcg);
703 pr_err("%s: Kill process %d (%s) score %u or sacrifice child\n",
704 message, task_pid_nr(p), p->comm, points);
707 * If any of p's children has a different mm and is eligible for kill,
708 * the one with the highest oom_badness() score is sacrificed for its
709 * parent. This attempts to lose the minimal amount of work done while
710 * still freeing memory.
712 read_lock(&tasklist_lock);
713 for_each_thread(p, t) {
714 list_for_each_entry(child, &t->children, sibling) {
715 unsigned int child_points;
717 if (process_shares_mm(child, p->mm))
720 * oom_badness() returns 0 if the thread is unkillable
722 child_points = oom_badness(child, memcg, oc->nodemask,
724 if (child_points > victim_points) {
725 put_task_struct(victim);
727 victim_points = child_points;
728 get_task_struct(victim);
732 read_unlock(&tasklist_lock);
734 p = find_lock_task_mm(victim);
736 put_task_struct(victim);
738 } else if (victim != p) {
740 put_task_struct(victim);
744 /* Get a reference to safely compare mm after task_unlock(victim) */
746 atomic_inc(&mm->mm_count);
748 * We should send SIGKILL before setting TIF_MEMDIE in order to prevent
749 * the OOM victim from depleting the memory reserves from the user
750 * space under its control.
752 do_send_sig_info(SIGKILL, SEND_SIG_FORCED, victim, true);
753 mark_oom_victim(victim);
754 pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB\n",
755 task_pid_nr(victim), victim->comm, K(victim->mm->total_vm),
756 K(get_mm_counter(victim->mm, MM_ANONPAGES)),
757 K(get_mm_counter(victim->mm, MM_FILEPAGES)),
758 K(get_mm_counter(victim->mm, MM_SHMEMPAGES)));
762 * Kill all user processes sharing victim->mm in other thread groups, if
763 * any. They don't get access to memory reserves, though, to avoid
764 * depletion of all memory. This prevents mm->mmap_sem livelock when an
765 * oom killed thread cannot exit because it requires the semaphore and
766 * its contended by another thread trying to allocate memory itself.
767 * That thread will now get access to memory reserves since it has a
768 * pending fatal signal.
771 for_each_process(p) {
772 if (!process_shares_mm(p, mm))
774 if (same_thread_group(p, victim))
776 if (unlikely(p->flags & PF_KTHREAD) || is_global_init(p) ||
777 p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) {
779 * We cannot use oom_reaper for the mm shared by this
780 * process because it wouldn't get killed and so the
781 * memory might be still used.
783 can_oom_reap = false;
786 do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
791 wake_oom_reaper(victim);
794 put_task_struct(victim);
799 * Determines whether the kernel must panic because of the panic_on_oom sysctl.
801 void check_panic_on_oom(struct oom_control *oc, enum oom_constraint constraint,
802 struct mem_cgroup *memcg)
804 if (likely(!sysctl_panic_on_oom))
806 if (sysctl_panic_on_oom != 2) {
808 * panic_on_oom == 1 only affects CONSTRAINT_NONE, the kernel
809 * does not panic for cpuset, mempolicy, or memcg allocation
812 if (constraint != CONSTRAINT_NONE)
815 /* Do not panic for oom kills triggered by sysrq */
816 if (is_sysrq_oom(oc))
818 dump_header(oc, NULL, memcg);
819 panic("Out of memory: %s panic_on_oom is enabled\n",
820 sysctl_panic_on_oom == 2 ? "compulsory" : "system-wide");
823 static BLOCKING_NOTIFIER_HEAD(oom_notify_list);
825 int register_oom_notifier(struct notifier_block *nb)
827 return blocking_notifier_chain_register(&oom_notify_list, nb);
829 EXPORT_SYMBOL_GPL(register_oom_notifier);
831 int unregister_oom_notifier(struct notifier_block *nb)
833 return blocking_notifier_chain_unregister(&oom_notify_list, nb);
835 EXPORT_SYMBOL_GPL(unregister_oom_notifier);
838 * out_of_memory - kill the "best" process when we run out of memory
839 * @oc: pointer to struct oom_control
841 * If we run out of memory, we have the choice between either
842 * killing a random task (bad), letting the system crash (worse)
843 * OR try to be smart about which process to kill. Note that we
844 * don't have to be perfect here, we just have to be good.
846 bool out_of_memory(struct oom_control *oc)
848 struct task_struct *p;
849 unsigned long totalpages;
850 unsigned long freed = 0;
851 unsigned int uninitialized_var(points);
852 enum oom_constraint constraint = CONSTRAINT_NONE;
854 if (oom_killer_disabled)
857 blocking_notifier_call_chain(&oom_notify_list, 0, &freed);
859 /* Got some memory back in the last second. */
863 * If current has a pending SIGKILL or is exiting, then automatically
864 * select it. The goal is to allow it to allocate so that it may
865 * quickly exit and free its memory.
867 * But don't select if current has already released its mm and cleared
868 * TIF_MEMDIE flag at exit_mm(), otherwise an OOM livelock may occur.
871 (fatal_signal_pending(current) || task_will_free_mem(current))) {
872 mark_oom_victim(current);
877 * Check if there were limitations on the allocation (only relevant for
878 * NUMA) that may require different handling.
880 constraint = constrained_alloc(oc, &totalpages);
881 if (constraint != CONSTRAINT_MEMORY_POLICY)
883 check_panic_on_oom(oc, constraint, NULL);
885 if (sysctl_oom_kill_allocating_task && current->mm &&
886 !oom_unkillable_task(current, NULL, oc->nodemask) &&
887 current->signal->oom_score_adj != OOM_SCORE_ADJ_MIN) {
888 get_task_struct(current);
889 oom_kill_process(oc, current, 0, totalpages, NULL,
890 "Out of memory (oom_kill_allocating_task)");
894 p = select_bad_process(oc, &points, totalpages);
895 /* Found nothing?!?! Either we hang forever, or we panic. */
896 if (!p && !is_sysrq_oom(oc)) {
897 dump_header(oc, NULL, NULL);
898 panic("Out of memory and no killable processes...\n");
900 if (p && p != (void *)-1UL) {
901 oom_kill_process(oc, p, points, totalpages, NULL,
904 * Give the killed process a good chance to exit before trying
905 * to allocate memory again.
907 schedule_timeout_killable(1);
913 * The pagefault handler calls here because it is out of memory, so kill a
914 * memory-hogging task. If any populated zone has ZONE_OOM_LOCKED set, a
915 * parallel oom killing is already in progress so do nothing.
917 void pagefault_out_of_memory(void)
919 struct oom_control oc = {
926 if (mem_cgroup_oom_synchronize(true))
929 if (!mutex_trylock(&oom_lock))
932 if (!out_of_memory(&oc)) {
934 * There shouldn't be any user tasks runnable while the
935 * OOM killer is disabled, so the current task has to
936 * be a racing OOM victim for which oom_killer_disable()
939 WARN_ON(test_thread_flag(TIF_MEMDIE));
942 mutex_unlock(&oom_lock);