[tip:timers/core] timer: Added usleep[_range] timer
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From: tip-bot for Patrick Pannuto on 23 Jul 2010 09:20 Commit-ID: 22b8f15c2f7130bb0386f548428df2ffd4e81903 Gitweb: http://git.kernel.org/tip/22b8f15c2f7130bb0386f548428df2ffd4e81903 Author: Patrick Pannuto <ppannuto(a)codeaurora.org> AuthorDate: Mon, 19 Jul 2010 15:09:26 -0700 Committer: Thomas Gleixner <tglx(a)linutronix.de> CommitDate: Fri, 23 Jul 2010 15:08:12 +0200 timer: Added usleep[_range] timer 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 Signed-off-by: Patrick Pannuto <ppannuto(a)codeaurora.org> Cc: akinobu.mita(a)gmail.com Cc: sboyd(a)codeaurora.org Acked-by: Arjan van de Ven <arjan(a)linux.intel.com> LKML-Reference: <4C44CDD2.1070708(a)codeaurora.org> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> --- include/linux/delay.h | 6 ++++++ kernel/timer.c | 22 ++++++++++++++++++++++ 2 files changed, 28 insertions(+), 0 deletions(-) diff --git a/include/linux/delay.h b/include/linux/delay.h index fd832c6..0e303d1 100644 --- a/include/linux/delay.h +++ b/include/linux/delay.h @@ -45,6 +45,12 @@ extern unsigned long lpj_fine; void calibrate_delay(void); void msleep(unsigned int msecs); unsigned long msleep_interruptible(unsigned int msecs); +void usleep_range(unsigned long min, unsigned long max); + +static inline void usleep(unsigned long usecs) +{ + usleep_range(usecs, usecs); +} static inline void ssleep(unsigned int seconds) { diff --git a/kernel/timer.c b/kernel/timer.c index ce98685..f110f24 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -1755,3 +1755,25 @@ unsigned long msleep_interruptible(unsigned int msecs) } EXPORT_SYMBOL(msleep_interruptible); + +static int __sched do_usleep_range(unsigned long min, unsigned long max) +{ + ktime_t kmin; + unsigned long delta; + + kmin = ktime_set(0, min * NSEC_PER_USEC); + delta = max - min; + return schedule_hrtimeout_range(&kmin, delta, HRTIMER_MODE_REL); +} + +/** + * usleep_range - Drop in replacement for udelay where wakeup is flexible + * @min: Minimum time in usecs to sleep + * @max: Maximum time in usecs to sleep + */ +void usleep_range(unsigned long min, unsigned long max) +{ + __set_current_state(TASK_UNINTERRUPTIBLE); + do_usleep_range(min, max); +} +EXPORT_SYMBOL(usleep_range); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |