[PATCH] timer: Added usleep[_range] timer
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From: Patrick Pannuto on 19 Jul 2010 18:20 > I like the general idea, but I kinda doubt the "interruptible" version > makes sense for this... > do you have any users for that in mind? if not... can we leave the > interruptible version out... makes it simpler by a lot. > Respun without interruptible... From 08b717cf4f76d7578cb20c1b1444d89a9331ce02 Mon Sep 17 00:00:00 2001 From: Patrick Pannuto <ppannuto(a)codeaurora.org> Date: Mon, 19 Jul 2010 15:09:26 -0700 Subject: [PATCH] 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> --- 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 ee305c8..4e6746f 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -1750,3 +1750,25 @@ 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); -- 1.7.1.1 -- 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/ |