// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/mm/oom_kill.c
 *
 *  Copyright (C)  1998,2000  Rik van Riel
 *	Thanks go out to Claus Fischer for some serious inspiration and
 *	for goading me into coding this file...
 *  Copyright (C)  2010  Google, Inc.
 *	Rewritten by David Rientjes
 *
 *  The routines in this file are used to kill a process when
 *  we're seriously out of memory. This gets called from __alloc_pages()
 *  in mm/page_alloc.c when we really run out of memory.
 *
 *  Since we won't call these routines often (on a well-configured
 *  machine) this file will double as a 'coding guide' and a signpost
 *  for newbie kernel hackers. It features several pointers to major
 *  kernel subsystems and hints as to where to find out what things do.
 */

/*
 * Official Linux v6.18: mm/oom_kill.c
 * https://github.com/torvalds/linux/blob/v6.18/mm/oom_kill.c#L671
 * Complete upstream scope, not an elided book-code reconstruction.
 * See GPL-2.0.txt. Not a standalone translation unit.
 */

static void wake_oom_reaper(struct timer_list *timer)
{
	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 (mm_flags_test(MMF_OOM_SKIP, mm)) {
		put_task_struct(tsk);
		return;
	}

	spin_lock_irqsave(&oom_reaper_lock, flags);
	tsk->oom_reaper_list = oom_reaper_list;
	oom_reaper_list = tsk;
	spin_unlock_irqrestore(&oom_reaper_lock, flags);
	trace_wake_reaper(tsk->pid);
	wake_up(&oom_reaper_wait);
}