usleep[_range] are finer precision implementations of msleep and are designed to be drop-in replacements for udelay where a precise sleep / busy-wait is unnecessary. They also allow an easy interface to specify slack when a precise (ish) wakeup is unnecessary to help minimize wakeups
Showing the changes to kernel/timer.c (1 of 2 files). Show all
Unified · Split
| @@ -1755,3 +1755,25 @@ unsigned long msleep_interruptible(unsigned int msecs) · 1754 unmodified lines | |||
| 1755 | } | 1755 | } |
| 1756 | 1756 | ||
| 1757 | EXPORT_SYMBOL(msleep_interruptible); | 1757 | EXPORT_SYMBOL(msleep_interruptible); |
| 1758 | |||
| 1759 | static int __sched do_usleep_range(unsigned long min, unsigned long max) | ||
| 1760 | { | ||
| 1761 | ktime_t kmin; | ||
| 1762 | unsigned long delta; | ||
| 1763 | |||
| 1764 | kmin = ktime_set(0, min * NSEC_PER_USEC); | ||
| 1765 | delta = max - min; | ||
| 1766 | return schedule_hrtimeout_range(&kmin, delta, HRTIMER_MODE_REL); | ||
| 1767 | } | ||
| 1768 | |||
| 1769 | /** | ||
| 1770 | * usleep_range - Drop in replacement for udelay where wakeup is flexible | ||
| 1771 | * @min: Minimum time in usecs to sleep | ||
| 1772 | * @max: Maximum time in usecs to sleep | ||
| 1773 | */ | ||
| 1774 | void usleep_range(unsigned long min, unsigned long max) | ||
| 1775 | { | ||
| 1776 | __set_current_state(TASK_UNINTERRUPTIBLE); | ||
| 1777 | do_usleep_range(min, max); | ||
| 1778 | } | ||
| 1779 | EXPORT_SYMBOL(usleep_range); | ||