1 files changed, 183 insertions, 198 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index d53a9aa00977..ec9f11d4f094 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -132,6 +132,11 @@ static inline bool is_sysrq_oom(struct oom_control *oc)
 	return oc->order == -1;
 }
 
+static inline bool is_memcg_oom(struct oom_control *oc)
+{
+	return oc->memcg != NULL;
+}
+
 /* return true if the task is not adequate as candidate victim task. */
 static bool oom_unkillable_task(struct task_struct *p,
 		struct mem_cgroup *memcg, const nodemask_t *nodemask)
@@ -181,7 +186,7 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
 	 */
 	adj = (long)p->signal->oom_score_adj;
 	if (adj == OOM_SCORE_ADJ_MIN ||
-			test_bit(MMF_OOM_REAPED, &p->mm->flags) ||
+			test_bit(MMF_OOM_SKIP, &p->mm->flags) ||
 			in_vfork(p)) {
 		task_unlock(p);
 		return 0;
@@ -213,12 +218,17 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
 	return points > 0 ? points : 1;
 }
 
+enum oom_constraint {
+	CONSTRAINT_NONE,
+	CONSTRAINT_CPUSET,
+	CONSTRAINT_MEMORY_POLICY,
+	CONSTRAINT_MEMCG,
+};
+
 /*
  * Determine the type of allocation constraint.
  */
-#ifdef CONFIG_NUMA
-static enum oom_constraint constrained_alloc(struct oom_control *oc,
-					     unsigned long *totalpages)
+static enum oom_constraint constrained_alloc(struct oom_control *oc)
 {
 	struct zone *zone;
 	struct zoneref *z;
@@ -226,8 +236,16 @@ static enum oom_constraint constrained_alloc(struct oom_control *oc,
 	bool cpuset_limited = false;
 	int nid;
 
+	if (is_memcg_oom(oc)) {
+		oc->totalpages = mem_cgroup_get_limit(oc->memcg) ?: 1;
+		return CONSTRAINT_MEMCG;
+	}
+
 	/* Default to all available memory */
-	*totalpages = totalram_pages + total_swap_pages;
+	oc->totalpages = totalram_pages + total_swap_pages;
+
+	if (!IS_ENABLED(CONFIG_NUMA))
+		return CONSTRAINT_NONE;
 
 	if (!oc->zonelist)
 		return CONSTRAINT_NONE;
@@ -246,9 +264,9 @@ static enum oom_constraint constrained_alloc(struct oom_control *oc,
 	 */
 	if (oc->nodemask &&
 	    !nodes_subset(node_states[N_MEMORY], *oc->nodemask)) {
-		*totalpages = total_swap_pages;
+		oc->totalpages = total_swap_pages;
 		for_each_node_mask(nid, *oc->nodemask)
-			*totalpages += node_spanned_pages(nid);
+			oc->totalpages += node_spanned_pages(nid);
 		return CONSTRAINT_MEMORY_POLICY;
 	}
 
@@ -259,98 +277,84 @@ static enum oom_constraint constrained_alloc(struct oom_control *oc,
 			cpuset_limited = true;
 
 	if (cpuset_limited) {
-		*totalpages = total_swap_pages;
+		oc->totalpages = total_swap_pages;
 		for_each_node_mask(nid, cpuset_current_mems_allowed)
-			*totalpages += node_spanned_pages(nid);
+			oc->totalpages += node_spanned_pages(nid);
 		return CONSTRAINT_CPUSET;
 	}
 	return CONSTRAINT_NONE;
 }
-#else
-static enum oom_constraint constrained_alloc(struct oom_control *oc,
-					     unsigned long *totalpages)
-{
-	*totalpages = totalram_pages + total_swap_pages;
-	return CONSTRAINT_NONE;
-}
-#endif
 
-enum oom_scan_t oom_scan_process_thread(struct oom_control *oc,
-					struct task_struct *task)
+static int oom_evaluate_task(struct task_struct *task, void *arg)
 {
+	struct oom_control *oc = arg;
+	unsigned long points;
+
 	if (oom_unkillable_task(task, NULL, oc->nodemask))
-		return OOM_SCAN_CONTINUE;
+		goto next;
 
 	/*
 	 * This task already has access to memory reserves and is being killed.
 	 * Don't allow any other task to have access to the reserves unless
-	 * the task has MMF_OOM_REAPED because chances that it would release
+	 * the task has MMF_OOM_SKIP because chances that it would release
 	 * any memory is quite low.
 	 */
-	if (!is_sysrq_oom(oc) && atomic_read(&task->signal->oom_victims)) {
-		struct task_struct *p = find_lock_task_mm(task);
-		enum oom_scan_t ret = OOM_SCAN_ABORT;
-
-		if (p) {
-			if (test_bit(MMF_OOM_REAPED, &p->mm->flags))
-				ret = OOM_SCAN_CONTINUE;
-			task_unlock(p);
-		}
-
-		return ret;
+	if (!is_sysrq_oom(oc) && tsk_is_oom_victim(task)) {
+		if (test_bit(MMF_OOM_SKIP, &task->signal->oom_mm->flags))
+			goto next;
+		goto abort;
 	}
 
 	/*
 	 * If task is allocating a lot of memory and has been marked to be
 	 * killed first if it triggers an oom, then select it.
 	 */
-	if (oom_task_origin(task))
-		return OOM_SCAN_SELECT;
+	if (oom_task_origin(task)) {
+		points = ULONG_MAX;
+		goto select;
+	}
 
-	return OOM_SCAN_OK;
+	points = oom_badness(task, NULL, oc->nodemask, oc->totalpages);
+	if (!points || points < oc->chosen_points)
+		goto next;
+
+	/* Prefer thread group leaders for display purposes */
+	if (points == oc->chosen_points && thread_group_leader(oc->chosen))
+		goto next;
+select:
+	if (oc->chosen)
+		put_task_struct(oc->chosen);
+	get_task_struct(task);
+	oc->chosen = task;
+	oc->chosen_points = points;
+next:
+	return 0;
+abort:
+	if (oc->chosen)
+		put_task_struct(oc->chosen);
+	oc->chosen = (void *)-1UL;
+	return 1;
 }
 
 /*
- * Simple selection loop. We chose the process with the highest
- * number of 'points'.  Returns -1 on scan abort.
+ * Simple selection loop. We choose the process with the highest number of
+ * 'points'. In case scan was aborted, oc->chosen is set to -1.
  */
-static struct task_struct *select_bad_process(struct oom_control *oc,
-		unsigned int *ppoints, unsigned long totalpages)
+static void select_bad_process(struct oom_control *oc)
 {
-	struct task_struct *p;
-	struct task_struct *chosen = NULL;
-	unsigned long chosen_points = 0;
-
-	rcu_read_lock();
-	for_each_process(p) {
-		unsigned int points;
-
-		switch (oom_scan_process_thread(oc, p)) {
-		case OOM_SCAN_SELECT:
-			chosen = p;
-			chosen_points = ULONG_MAX;
-			/* fall through */
-		case OOM_SCAN_CONTINUE:
-			continue;
-		case OOM_SCAN_ABORT:
-			rcu_read_unlock();
-			return (struct task_struct *)(-1UL);
-		case OOM_SCAN_OK:
-			break;
-		};
-		points = oom_badness(p, NULL, oc->nodemask, totalpages);
-		if (!points || points < chosen_points)
-			continue;
+	if (is_memcg_oom(oc))
+		mem_cgroup_scan_tasks(oc->memcg, oom_evaluate_task, oc);
+	else {
+		struct task_struct *p;
 
-		chosen = p;
-		chosen_points = points;
+		rcu_read_lock();
+		for_each_process(p)
+			if (oom_evaluate_task(p, oc))
+				break;
+		rcu_read_unlock();
 	}
-	if (chosen)
-		get_task_struct(chosen);
-	rcu_read_unlock();
 
-	*ppoints = chosen_points * 1000 / totalpages;
-	return chosen;
+	oc->chosen_points = oc->chosen_points * 1000 / oc->totalpages;
 }
 
 /**
@@ -399,9 +403,14 @@ static void dump_tasks(struct mem_cgroup *memcg, const nodemask_t *nodemask)
 
 static void dump_header(struct oom_control *oc, struct task_struct *p)
 {
-	pr_warn("%s invoked oom-killer: gfp_mask=%#x(%pGg), order=%d, oom_score_adj=%hd\n",
-		current->comm, oc->gfp_mask, &oc->gfp_mask, oc->order,
+	nodemask_t *nm = (oc->nodemask) ? oc->nodemask : &cpuset_current_mems_allowed;
+
+	pr_warn("%s invoked oom-killer: gfp_mask=%#x(%pGg), nodemask=%*pbl, order=%d, oom_score_adj=%hd\n",
+		current->comm, oc->gfp_mask, &oc->gfp_mask,
+		nodemask_pr_args(nm), oc->order,
 		current->signal->oom_score_adj);
+	if (!IS_ENABLED(CONFIG_COMPACTION) && oc->order)
+		pr_warn("COMPACTION is disabled!!!\n");
 
 	cpuset_print_current_mems_allowed();
 	dump_stack();
@@ -419,7 +428,7 @@ static void dump_header(struct oom_control *oc, struct task_struct *p)
 static atomic_t oom_victims = ATOMIC_INIT(0);
 static DECLARE_WAIT_QUEUE_HEAD(oom_victims_wait);
 
-bool oom_killer_disabled __read_mostly;
+static bool oom_killer_disabled __read_mostly;
 
 #define K(x) ((x) << (PAGE_SHIFT-10))
 
@@ -452,12 +461,10 @@ static DECLARE_WAIT_QUEUE_HEAD(oom_reaper_wait);
 static struct task_struct *oom_reaper_list;
 static DEFINE_SPINLOCK(oom_reaper_lock);
 
-static bool __oom_reap_task(struct task_struct *tsk)
+static bool __oom_reap_task_mm(struct task_struct *tsk, struct mm_struct *mm)
 {
 	struct mmu_gather tlb;
 	struct vm_area_struct *vma;
-	struct mm_struct *mm = NULL;
-	struct task_struct *p;
 	struct zap_details details = {.check_swap_entries = true,
 				      .ignore_dirty = true};
 	bool ret = true;
@@ -465,7 +472,7 @@ static bool __oom_reap_task(struct task_struct *tsk)
 	/*
 	 * We have to make sure to not race with the victim exit path
 	 * and cause premature new oom victim selection:
-	 * __oom_reap_task		exit_mm
+	 * __oom_reap_task_mm		exit_mm
 	 *   mmget_not_zero
 	 *				  mmput
 	 *				    atomic_dec_and_test
@@ -478,22 +485,9 @@ static bool __oom_reap_task(struct task_struct *tsk)
 	 */
 	mutex_lock(&oom_lock);
 
-	/*
-	 * Make sure we find the associated mm_struct even when the particular
-	 * thread has already terminated and cleared its mm.
-	 * We might have race with exit path so consider our work done if there
-	 * is no mm.
-	 */
-	p = find_lock_task_mm(tsk);
-	if (!p)
-		goto unlock_oom;
-	mm = p->mm;
-	atomic_inc(&mm->mm_count);
-	task_unlock(p);
-
 	if (!down_read_trylock(&mm->mmap_sem)) {
 		ret = false;
-		goto mm_drop;
+		goto unlock_oom;
 	}
 
 	/*
@@ -503,9 +497,17 @@ static bool __oom_reap_task(struct task_struct *tsk)
 	 */
 	if (!mmget_not_zero(mm)) {
 		up_read(&mm->mmap_sem);
-		goto mm_drop;
+		goto unlock_oom;
 	}
 
+	/*
+	 * Tell all users of get_user/copy_from_user etc... that the content
+	 * is no longer stable. No barriers really needed because unmapping
+	 * should imply barriers already and the reader would hit a page fault
+	 * if it stumbled over a reaped memory.
+	 */
+	set_bit(MMF_UNSTABLE, &mm->flags);
+
 	tlb_gather_mmu(&tlb, mm, 0, -1);
 	for (vma = mm->mmap ; vma; vma = vma->vm_next) {
 		if (is_vm_hugetlb_page(vma))
@@ -541,18 +543,11 @@ static bool __oom_reap_task(struct task_struct *tsk)
 	up_read(&mm->mmap_sem);
 
 	/*
-	 * This task can be safely ignored because we cannot do much more
-	 * to release its memory.
-	 */
-	set_bit(MMF_OOM_REAPED, &mm->flags);
-	/*
 	 * Drop our reference but make sure the mmput slow path is called from a
 	 * different context because we shouldn't risk we get stuck there and
 	 * put the oom_reaper out of the way.
 	 */
 	mmput_async(mm);
-mm_drop:
-	mmdrop(mm);
 unlock_oom:
 	mutex_unlock(&oom_lock);
 	return ret;
@@ -562,44 +557,28 @@ unlock_oom:
 static void oom_reap_task(struct task_struct *tsk)
 {
 	int attempts = 0;
+	struct mm_struct *mm = tsk->signal->oom_mm;
 
 	/* Retry the down_read_trylock(mmap_sem) a few times */
-	while (attempts++ < MAX_OOM_REAP_RETRIES && !__oom_reap_task(tsk))
+	while (attempts++ < MAX_OOM_REAP_RETRIES && !__oom_reap_task_mm(tsk, mm))
 		schedule_timeout_idle(HZ/10);
 
-	if (attempts > MAX_OOM_REAP_RETRIES) {
-		struct task_struct *p;
+	if (attempts <= MAX_OOM_REAP_RETRIES)
+		goto done;
 
-		pr_info("oom_reaper: unable to reap pid:%d (%s)\n",
-				task_pid_nr(tsk), tsk->comm);
 
-		/*
-		 * If we've already tried to reap this task in the past and
-		 * failed it probably doesn't make much sense to try yet again
-		 * so hide the mm from the oom killer so that it can move on
-		 * to another task with a different mm struct.
-		 */
-		p = find_lock_task_mm(tsk);
-		if (p) {
-			if (test_and_set_bit(MMF_OOM_NOT_REAPABLE, &p->mm->flags)) {
-				pr_info("oom_reaper: giving up pid:%d (%s)\n",
-						task_pid_nr(tsk), tsk->comm);
-				set_bit(MMF_OOM_REAPED, &p->mm->flags);
-			}
-			task_unlock(p);
-		}
+	pr_info("oom_reaper: unable to reap pid:%d (%s)\n",
+		task_pid_nr(tsk), tsk->comm);
+	debug_show_all_locks();
 
-		debug_show_all_locks();
-	}
+done:
+	tsk->oom_reaper_list = NULL;
 
 	/*
-	 * Clear TIF_MEMDIE because the task shouldn't be sitting on a
-	 * reasonably reclaimable memory anymore or it is not a good candidate
-	 * for the oom victim right now because it cannot release its memory
-	 * itself nor by the oom reaper.
+	 * Hide this mm from OOM killer because it has been either reaped or
+	 * somebody can't call up_write(mmap_sem).
 	 */
-	tsk->oom_reaper_list = NULL;
-	exit_oom_victim(tsk);
+	set_bit(MMF_OOM_SKIP, &mm->flags);
 
 	/* Drop a reference taken by wake_oom_reaper */
 	put_task_struct(tsk);
@@ -607,8 +586,6 @@ static void oom_reap_task(struct task_struct *tsk)
 
 static int oom_reaper(void *unused)
 {
-	set_freezable();
-
 	while (true) {
 		struct task_struct *tsk = NULL;
 
@@ -627,7 +604,7 @@ static int oom_reaper(void *unused)
 	return 0;
 }
 
-void wake_oom_reaper(struct task_struct *tsk)
+static void wake_oom_reaper(struct task_struct *tsk)
 {
 	if (!oom_reaper_th)
 		return;
@@ -656,7 +633,11 @@ static int __init oom_init(void)
 	return 0;
 }
 subsys_initcall(oom_init)
-#endif
+#else
+static inline void wake_oom_reaper(struct task_struct *tsk)
+{
+}
+#endif /* CONFIG_MMU */
 
 /**
  * mark_oom_victim - mark the given task as OOM victim
@@ -664,14 +645,23 @@ subsys_initcall(oom_init)
  *
  * Has to be called with oom_lock held and never after
  * oom has been disabled already.
+ *
+ * tsk->mm has to be non NULL and caller has to guarantee it is stable (either
+ * under task_lock or operate on the current).
  */
-void mark_oom_victim(struct task_struct *tsk)
+static void mark_oom_victim(struct task_struct *tsk)
 {
+	struct mm_struct *mm = tsk->mm;
+
 	WARN_ON(oom_killer_disabled);
 	/* OOM killer might race with memcg OOM */
 	if (test_and_set_tsk_thread_flag(tsk, TIF_MEMDIE))
 		return;
-	atomic_inc(&tsk->signal->oom_victims);
+
+	/* oom_mm is bound to the signal struct life time. */
+	if (!cmpxchg(&tsk->signal->oom_mm, NULL, mm))
+		atomic_inc(&tsk->signal->oom_mm->mm_count);
+
 	/*
 	 * Make sure that the task is woken up from uninterruptible sleep
 	 * if it is frozen because OOM killer wouldn't be able to free
@@ -685,21 +675,29 @@ void mark_oom_victim(struct task_struct *tsk)
 /**
  * exit_oom_victim - note the exit of an OOM victim
  */
-void exit_oom_victim(struct task_struct *tsk)
+void exit_oom_victim(void)
 {
-	if (!test_and_clear_tsk_thread_flag(tsk, TIF_MEMDIE))
-		return;
-	atomic_dec(&tsk->signal->oom_victims);
+	clear_thread_flag(TIF_MEMDIE);
 
 	if (!atomic_dec_return(&oom_victims))
 		wake_up_all(&oom_victims_wait);
 }
 
 /**
+ * oom_killer_enable - enable OOM killer
+ */
+void oom_killer_enable(void)
+{
+	oom_killer_disabled = false;
+}
+
+/**
  * oom_killer_disable - disable OOM killer
+ * @timeout: maximum timeout to wait for oom victims in jiffies
  *
  * Forces all page allocations to fail rather than trigger OOM killer.
- * Will block and wait until all OOM victims are killed.
+ * Will block and wait until all OOM victims are killed or the given
+ * timeout expires.
  *
  * The function cannot be called when there are runnable user tasks because
  * the userspace would see unexpected allocation failures as a result. Any
@@ -708,8 +706,10 @@ void exit_oom_victim(struct task_struct *tsk)
  * Returns true if successful and false if the OOM killer cannot be
  * disabled.
  */
-bool oom_killer_disable(void)
+bool oom_killer_disable(signed long timeout)
 {
+	signed long ret;
+
 	/*
 	 * Make sure to not race with an ongoing OOM killer. Check that the
 	 * current is not killed (possibly due to sharing the victim's memory).
@@ -719,19 +719,16 @@ bool oom_killer_disable(void)
 	oom_killer_disabled = true;
 	mutex_unlock(&oom_lock);
 
-	wait_event(oom_victims_wait, !atomic_read(&oom_victims));
+	ret = wait_event_interruptible_timeout(oom_victims_wait,
+			!atomic_read(&oom_victims), timeout);
+	if (ret <= 0) {
+		oom_killer_enable();
+		return false;
+	}
 
 	return true;
 }
 
-/**
- * oom_killer_enable - enable OOM killer
- */
-void oom_killer_enable(void)
-{
-	oom_killer_disabled = false;
-}
-
 static inline bool __task_will_free_mem(struct task_struct *task)
 {
 	struct signal_struct *sig = task->signal;
@@ -760,7 +757,7 @@ static inline bool __task_will_free_mem(struct task_struct *task)
  * Caller has to make sure that task->mm is stable (hold task_lock or
  * it operates on the current).
  */
-bool task_will_free_mem(struct task_struct *task)
+static bool task_will_free_mem(struct task_struct *task)
 {
 	struct mm_struct *mm = task->mm;
 	struct task_struct *p;
@@ -781,15 +778,16 @@ bool task_will_free_mem(struct task_struct *task)
 	 * This task has already been drained by the oom reaper so there are
 	 * only small chances it will free some more
 	 */
-	if (test_bit(MMF_OOM_REAPED, &mm->flags))
+	if (test_bit(MMF_OOM_SKIP, &mm->flags))
 		return false;
 
 	if (atomic_read(&mm->mm_users) <= 1)
 		return true;
 
 	/*
-	 * This is really pessimistic but we do not have any reliable way
-	 * to check that external processes share with our mm
+	 * Make sure that all tasks which share the mm with the given tasks
+	 * are dying as well to make sure that a) nobody pins its mm and
+	 * b) the task is also reapable by the oom reaper.
 	 */
 	rcu_read_lock();
 	for_each_process(p) {
@@ -806,14 +804,10 @@ bool task_will_free_mem(struct task_struct *task)
 	return ret;
 }
 
-/*
- * Must be called while holding a reference to p, which will be released upon
- * returning.
- */
-void oom_kill_process(struct oom_control *oc, struct task_struct *p,
-		      unsigned int points, unsigned long totalpages,
-		      const char *message)
+static void oom_kill_process(struct oom_control *oc, const char *message)
 {
+	struct task_struct *p = oc->chosen;
+	unsigned int points = oc->chosen_points;
 	struct task_struct *victim = p;
 	struct task_struct *child;
 	struct task_struct *t;
@@ -860,7 +854,7 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
 			 * oom_badness() returns 0 if the thread is unkillable
 			 */
 			child_points = oom_badness(child,
-					oc->memcg, oc->nodemask, totalpages);
+				oc->memcg, oc->nodemask, oc->totalpages);
 			if (child_points > victim_points) {
 				put_task_struct(victim);
 				victim = child;
@@ -913,20 +907,20 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
 			continue;
 		if (same_thread_group(p, victim))
 			continue;
-		if (unlikely(p->flags & PF_KTHREAD) || is_global_init(p)) {
-			/*
-			 * We cannot use oom_reaper for the mm shared by this
-			 * process because it wouldn't get killed and so the
-			 * memory might be still used. Hide the mm from the oom
-			 * killer to guarantee OOM forward progress.
-			 */
+		if (is_global_init(p)) {
 			can_oom_reap = false;
-			set_bit(MMF_OOM_REAPED, &mm->flags);
+			set_bit(MMF_OOM_SKIP, &mm->flags);
 			pr_info("oom killer %d (%s) has mm pinned by %d (%s)\n",
 					task_pid_nr(victim), victim->comm,
 					task_pid_nr(p), p->comm);
 			continue;
 		}
+		/*
+		 * No use_mm() user needs to read from the userspace so we are
+		 * ok to reap it.
+		 */
+		if (unlikely(p->flags & PF_KTHREAD))
+			continue;
 		do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
 	}
 	rcu_read_unlock();
@@ -942,7 +936,8 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
 /*
  * Determines whether the kernel must panic because of the panic_on_oom sysctl.
  */
-void check_panic_on_oom(struct oom_control *oc, enum oom_constraint constraint)
+static void check_panic_on_oom(struct oom_control *oc,
+			       enum oom_constraint constraint)
 {
 	if (likely(!sysctl_panic_on_oom))
 		return;
@@ -988,19 +983,18 @@ EXPORT_SYMBOL_GPL(unregister_oom_notifier);
  */
 bool out_of_memory(struct oom_control *oc)
 {
-	struct task_struct *p;
-	unsigned long totalpages;
 	unsigned long freed = 0;
-	unsigned int uninitialized_var(points);
 	enum oom_constraint constraint = CONSTRAINT_NONE;
 
 	if (oom_killer_disabled)
 		return false;
 
-	blocking_notifier_call_chain(&oom_notify_list, 0, &freed);
-	if (freed > 0)
-		/* Got some memory back in the last second. */
-		return true;
+	if (!is_memcg_oom(oc)) {
+		blocking_notifier_call_chain(&oom_notify_list, 0, &freed);
+		if (freed > 0)
+			/* Got some memory back in the last second. */
+			return true;
+	}
 
 	/*
 	 * If current has a pending SIGKILL or is exiting, then automatically
@@ -1024,37 +1018,38 @@ bool out_of_memory(struct oom_control *oc)
 
 	/*
 	 * Check if there were limitations on the allocation (only relevant for
-	 * NUMA) that may require different handling.
+	 * NUMA and memcg) that may require different handling.
 	 */
-	constraint = constrained_alloc(oc, &totalpages);
+	constraint = constrained_alloc(oc);
 	if (constraint != CONSTRAINT_MEMORY_POLICY)
 		oc->nodemask = NULL;
 	check_panic_on_oom(oc, constraint);
 
-	if (sysctl_oom_kill_allocating_task && current->mm &&
-	    !oom_unkillable_task(current, NULL, oc->nodemask) &&
+	if (!is_memcg_oom(oc) && sysctl_oom_kill_allocating_task &&
+	    current->mm && !oom_unkillable_task(current, NULL, oc->nodemask) &&
 	    current->signal->oom_score_adj != OOM_SCORE_ADJ_MIN) {
 		get_task_struct(current);
-		oom_kill_process(oc, current, 0, totalpages,
-				 "Out of memory (oom_kill_allocating_task)");
+		oc->chosen = current;
+		oom_kill_process(oc, "Out of memory (oom_kill_allocating_task)");
 		return true;
 	}
 
-	p = select_bad_process(oc, &points, totalpages);
+	select_bad_process(oc);
 	/* Found nothing?!?! Either we hang forever, or we panic. */
-	if (!p && !is_sysrq_oom(oc)) {
+	if (!oc->chosen && !is_sysrq_oom(oc) && !is_memcg_oom(oc)) {
 		dump_header(oc, NULL);
 		panic("Out of memory and no killable processes...\n");
 	}
-	if (p && p != (void *)-1UL) {
-		oom_kill_process(oc, p, points, totalpages, "Out of memory");
+	if (oc->chosen && oc->chosen != (void *)-1UL) {
+		oom_kill_process(oc, !is_memcg_oom(oc) ? "Out of memory" :
+				 "Memory cgroup out of memory");
 		/*
 		 * Give the killed process a good chance to exit before trying
 		 * to allocate memory again.
 		 */
 		schedule_timeout_killable(1);
 	}
-	return true;
+	return !!oc->chosen;
 }
 
 /*
@@ -1077,16 +1072,6 @@ void pagefault_out_of_memory(void)
 
 	if (!mutex_trylock(&oom_lock))
 		return;
-
-	if (!out_of_memory(&oc)) {
-		/*
-		 * There shouldn't be any user tasks runnable while the
-		 * OOM killer is disabled, so the current task has to
-		 * be a racing OOM victim for which oom_killer_disable()
-		 * is waiting for.
-		 */
-		WARN_ON(test_thread_flag(TIF_MEMDIE));
-	}
-
+	out_of_memory(&oc);
 	mutex_unlock(&oom_lock);
 }