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Commit 84c84ac7 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
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Revert "oom_kill.c: futex: delay the OOM reaper to allow time for proper futex cleanup" 



This reverts commit 0441d3e9.  It breaks
the abi and is not needed for Android devices.

Bug: 161946584
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@google.com>
Change-Id: I0d9f161b4250bb6ec960e2a5ee2f425f6f8dbf4e
parent 36dda914

include/linux/sched.h

+0 −1
Original line number Diff line number Diff line
@@ -1271,7 +1271,6 @@ struct task_struct { 
	int				pagefault_disabled;

#ifdef CONFIG_MMU

	struct task_struct		*oom_reaper_list;

	struct timer_list		oom_reaper_timer;

#endif

#ifdef CONFIG_VMAP_STACK

	struct vm_struct		*stack_vm_area;

mm/oom_kill.c

+14 −40
Original line number Diff line number Diff line
@@ -631,7 +631,7 @@ static void oom_reap_task(struct task_struct *tsk) 
	 */

	set_bit(MMF_OOM_SKIP, &mm->flags);



	/* Drop a reference taken by queue_oom_reaper */

	/* Drop a reference taken by wake_oom_reaper */

	put_task_struct(tsk);

}
@@ -641,12 +641,12 @@ static int oom_reaper(void *unused) 
		struct task_struct *tsk = NULL;



		wait_event_freezable(oom_reaper_wait, oom_reaper_list != NULL);

		spin_lock_irq(&oom_reaper_lock);

		spin_lock(&oom_reaper_lock);

		if (oom_reaper_list != NULL) {

			tsk = oom_reaper_list;

			oom_reaper_list = tsk->oom_reaper_list;

		}

		spin_unlock_irq(&oom_reaper_lock);

		spin_unlock(&oom_reaper_lock);



		if (tsk)

			oom_reap_task(tsk);
@@ -655,48 +655,22 @@ static int oom_reaper(void *unused) 
	return 0;

}



static void wake_oom_reaper(struct timer_list *timer)

static void wake_oom_reaper(struct task_struct *tsk)

{

	struct task_struct *tsk = container_of(timer, struct task_struct,

			oom_reaper_timer);

	struct mm_struct *mm = tsk->signal->oom_mm;

	unsigned long flags;



	/* The victim managed to terminate on its own - see exit_mmap */

	if (test_bit(MMF_OOM_SKIP, &mm->flags)) {

		put_task_struct(tsk);

	/* mm is already queued? */

	if (test_and_set_bit(MMF_OOM_REAP_QUEUED, &tsk->signal->oom_mm->flags))

		return;

	}



	spin_lock_irqsave(&oom_reaper_lock, flags);

	get_task_struct(tsk);



	spin_lock(&oom_reaper_lock);

	tsk->oom_reaper_list = oom_reaper_list;

	oom_reaper_list = tsk;

	spin_unlock_irqrestore(&oom_reaper_lock, flags);

	spin_unlock(&oom_reaper_lock);

	trace_wake_reaper(tsk->pid);

	wake_up(&oom_reaper_wait);

}



/*

 * Give the OOM victim time to exit naturally before invoking the oom_reaping.

 * The timers timeout is arbitrary... the longer it is, the longer the worst

 * case scenario for the OOM can take. If it is too small, the oom_reaper can

 * get in the way and release resources needed by the process exit path.

 * e.g. The futex robust list can sit in Anon|Private memory that gets reaped

 * before the exit path is able to wake the futex waiters.

 */

#define OOM_REAPER_DELAY (2*HZ)

static void queue_oom_reaper(struct task_struct *tsk)

{

	/* mm is already queued? */

	if (test_and_set_bit(MMF_OOM_REAP_QUEUED, &tsk->signal->oom_mm->flags))

		return;



	get_task_struct(tsk);

	timer_setup(&tsk->oom_reaper_timer, wake_oom_reaper, 0);

	tsk->oom_reaper_timer.expires = jiffies + OOM_REAPER_DELAY;

	add_timer(&tsk->oom_reaper_timer);

}



static int __init oom_init(void)

{

	oom_reaper_th = kthread_run(oom_reaper, NULL, "oom_reaper");
@@ -704,7 +678,7 @@ static int __init oom_init(void) 
}

subsys_initcall(oom_init)

#else

static inline void queue_oom_reaper(struct task_struct *tsk)

static inline void wake_oom_reaper(struct task_struct *tsk)

{

}

#endif /* CONFIG_MMU */
@@ -953,7 +927,7 @@ static void __oom_kill_process(struct task_struct *victim, const char *message) 
	rcu_read_unlock();



	if (can_oom_reap)

		queue_oom_reaper(victim);

		wake_oom_reaper(victim);



	mmdrop(mm);

	put_task_struct(victim);
@@ -989,7 +963,7 @@ static void oom_kill_process(struct oom_control *oc, const char *message) 
	task_lock(victim);

	if (task_will_free_mem(victim)) {

		mark_oom_victim(victim);

		queue_oom_reaper(victim);

		wake_oom_reaper(victim);

		task_unlock(victim);

		put_task_struct(victim);

		return;
@@ -1087,7 +1061,7 @@ bool out_of_memory(struct oom_control *oc) 
	 */

	if (task_will_free_mem(current)) {

		mark_oom_victim(current);

		queue_oom_reaper(current);

		wake_oom_reaper(current);

		return true;

	}