Messages in this thread | | | Date | Thu, 22 Jul 2010 16:16:54 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] timer: Added usleep[_range] timer |
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On Mon, 19 Jul 2010 15:12:34 -0700 Patrick Pannuto <ppannuto@codeaurora.org> wrote:
> Respun without interruptible... >
And without all the nice changelog info. Oh well.
> 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@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);
Fair enough, I guess. People can go over and look at the schedule_hrtimeout_range() documentation to work out why on earth they should specify a "range".
Of course, nobody will actually think to _use_ this thing. Someone owes me a "usleep_range is preferred over usleep" checkpatch rule!
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