linux-2.6.33/schedule_hrtimeout_range() の履歴(No.1)

• 履歴一覧
• 差分 を表示
• 現在との差分 を表示
• ソース を表示
• linux-2.6.33/schedule_hrtimeout_range() へ行く。
  • 1 (2013-06-26 (水) 23:49:00)

---

参照元†

• linux-2.6.33/schedule_hrtimeout()

説明†

• パス: linux-2.6.33/kernel/hrtimer.c

• FIXME: これは何？
  • 説明

引数†

• ktime_t *expires
  • linux-2.6.33/ktime_t
• unsigned long delta
• const enum hrtimer_mode mode
  • linux-2.6.33/hrtimer_mode

返り値†

• int

参考†

実装†

/**
 * schedule_hrtimeout_range - sleep until timeout
 * @expires:	timeout value (ktime_t)
 * @delta:	slack in expires timeout (ktime_t)
 * @mode:	timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
 *
 * Make the current task sleep until the given expiry time has
 * elapsed. The routine will return immediately unless
 * the current task state has been set (see set_current_state()).
 *
 * The @delta argument gives the kernel the freedom to schedule the
 * actual wakeup to a time that is both power and performance friendly.
 * The kernel give the normal best effort behavior for "@expires+@delta",
 * but may decide to fire the timer earlier, but no earlier than @expires.
 *
 * You can set the task state as follows -
 *
 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
 * pass before the routine returns.
 *
 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
 * delivered to the current task.
 *
 * The current task state is guaranteed to be TASK_RUNNING when this
 * routine returns.
 *
 * Returns 0 when the timer has expired otherwise -EINTR
 */
int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
			       const enum hrtimer_mode mode)
{
	struct hrtimer_sleeper t;

• • linux-2.6.33/hrtimer_sleeper

	/*
	 * Optimize when a zero timeout value is given. It does not
	 * matter whether this is an absolute or a relative time.
	 */
	if (expires && !expires->tv64) {
		__set_current_state(TASK_RUNNING);
		return 0;
	}

• • linux-2.6.33/__set_current_state()

• linux-2.6.33/TASK_RUNNING

	/*
	 * A NULL parameter means "inifinte"
	 */
	if (!expires) {
		schedule();
		__set_current_state(TASK_RUNNING);
		return -EINTR;
	}

• • linux-2.6.33/schedule()

	hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC, mode);
	hrtimer_set_expires_range_ns(&t.timer, *expires, delta);

• • linux-2.6.33/hrtimer_init_on_stack()

• linux-2.6.33/CLOCK_MONOTONIC

	hrtimer_init_sleeper(&t, current);

• • linux-2.6.33/hrtimer_init_sleeper()

• linux-2.6.33/current(global)

	hrtimer_start_expires(&t.timer, mode);
	if (!hrtimer_active(&t.timer))
		t.task = NULL;

• • linux-2.6.33/hrtimer_start_expires()

• linux-2.6.33/hrtimer_active()

	if (likely(t.task))
		schedule();

• • linux-2.6.33/likely()

	hrtimer_cancel(&t.timer);
	destroy_hrtimer_on_stack(&t.timer);

• • linux-2.6.33/hrtimer_cancel()

• linux-2.6.33/destroy_hrtimer_on_stack()

	__set_current_state(TASK_RUNNING);

	return !t.task ? 0 : -EINTR;
}
EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);

• GPL ライセンスのモジュールにのみシンボルを公開する。
  • linux-2.6.33/EXPORT_SYMBOL_GPL()

コメント†