Teach usleep_range() to return how many usecs was actually spent in sleep. The rationale beyond this is to convert jiffies-based time-bound wait-for-hardware loops from using msleep() to usleep_range().
Signed-off-by: Dmitry Antipov dmitry.antipov@linaro.org --- fs/eventpoll.c | 2 +- fs/select.c | 2 +- include/linux/delay.h | 2 +- include/linux/hrtimer.h | 9 ++++++--- ipc/mqueue.c | 2 +- kernel/hrtimer.c | 28 ++++++++++++++++++++++++---- kernel/timer.c | 11 ++++++----- 7 files changed, 40 insertions(+), 16 deletions(-)
diff --git a/fs/eventpoll.c b/fs/eventpoll.c index aabdfc3..7a957fd 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1349,7 +1349,7 @@ fetch_events: }
spin_unlock_irqrestore(&ep->lock, flags); - if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS)) + if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS, NULL)) timed_out = 1;
spin_lock_irqsave(&ep->lock, flags); diff --git a/fs/select.c b/fs/select.c index d33418f..eceb573 100644 --- a/fs/select.c +++ b/fs/select.c @@ -236,7 +236,7 @@ int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
set_current_state(state); if (!pwq->triggered) - rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS); + rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS, NULL); __set_current_state(TASK_RUNNING);
/* diff --git a/include/linux/delay.h b/include/linux/delay.h index a6ecb34..e512a50 100644 --- a/include/linux/delay.h +++ b/include/linux/delay.h @@ -45,7 +45,7 @@ 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); +unsigned long usleep_range(unsigned long min, unsigned long max);
static inline void ssleep(unsigned int seconds) { diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index fd0dc30..661dd25 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -128,6 +128,7 @@ struct hrtimer { struct hrtimer_sleeper { struct hrtimer timer; struct task_struct *task; + ktime_t elapsed; };
/** @@ -429,9 +430,11 @@ extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *tsk);
extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta, - const enum hrtimer_mode mode); -extern int schedule_hrtimeout_range_clock(ktime_t *expires, - unsigned long delta, const enum hrtimer_mode mode, int clock); + const enum hrtimer_mode mode, + unsigned long *elapsed); +extern int schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta, + const enum hrtimer_mode mode, int clock, + unsigned long *elapsed); extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
/* Soft interrupt function to run the hrtimer queues: */ diff --git a/ipc/mqueue.c b/ipc/mqueue.c index 9b7c8ab..578cce7 100644 --- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -450,7 +450,7 @@ static int wq_sleep(struct mqueue_inode_info *info, int sr,
spin_unlock(&info->lock); time = schedule_hrtimeout_range_clock(timeout, 0, - HRTIMER_MODE_ABS, CLOCK_REALTIME); + HRTIMER_MODE_ABS, CLOCK_REALTIME, NULL);
while (ewp->state == STATE_PENDING) cpu_relax(); diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index ae34bf5..75c9c5c 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -1475,6 +1475,12 @@ static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer) struct hrtimer_sleeper *t = container_of(timer, struct hrtimer_sleeper, timer); struct task_struct *task = t->task; + struct hrtimer_clock_base *base; + unsigned long flags; + + base = lock_hrtimer_base(timer, &flags); + t->elapsed = ktime_sub(base->get_time(), t->elapsed); + unlock_hrtimer_base(timer, &flags);
t->task = NULL; if (task) @@ -1485,6 +1491,13 @@ static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task) { + struct hrtimer_clock_base *base; + unsigned long flags; + + base = lock_hrtimer_base(&sl->timer, &flags); + sl->elapsed = base->get_time(); + unlock_hrtimer_base(&sl->timer, &flags); + sl->timer.function = hrtimer_wakeup; sl->task = task; } @@ -1750,10 +1763,13 @@ void __init hrtimers_init(void) * @delta: slack in expires timeout (ktime_t) * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL * @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME + * @elapsed: pointer to unsigned long variable where to store + * the time actually slept in timeout (usecs) */ int __sched schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta, - const enum hrtimer_mode mode, int clock) + const enum hrtimer_mode mode, int clock, + unsigned long *elapsed) { struct hrtimer_sleeper t;
@@ -1787,6 +1803,8 @@ schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta, if (likely(t.task)) schedule();
+ if (elapsed) + *elapsed = ktime_to_us(t.elapsed); hrtimer_cancel(&t.timer); destroy_hrtimer_on_stack(&t.timer);
@@ -1800,6 +1818,8 @@ schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta, * @expires: timeout value (ktime_t) * @delta: slack in expires timeout (ktime_t) * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL + * @elapsed: pointer to unsigned long variable where to store + * the time actually slept in timeout (usecs) * * Make the current task sleep until the given expiry time has * elapsed. The routine will return immediately unless @@ -1824,10 +1844,10 @@ schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta, * 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) + const enum hrtimer_mode mode, unsigned long *elapsed) { return schedule_hrtimeout_range_clock(expires, delta, mode, - CLOCK_MONOTONIC); + CLOCK_MONOTONIC, elapsed); } EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
@@ -1856,6 +1876,6 @@ EXPORT_SYMBOL_GPL(schedule_hrtimeout_range); int __sched schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode) { - return schedule_hrtimeout_range(expires, 0, mode); + return schedule_hrtimeout_range(expires, 0, mode, NULL); } EXPORT_SYMBOL_GPL(schedule_hrtimeout); diff --git a/kernel/timer.c b/kernel/timer.c index a297ffc..2a52040 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -1819,14 +1819,15 @@ unsigned long msleep_interruptible(unsigned int msecs)
EXPORT_SYMBOL(msleep_interruptible);
-static int __sched do_usleep_range(unsigned long min, unsigned long max) +static unsigned long __sched do_usleep_range(unsigned long min, unsigned long max) { ktime_t kmin; - unsigned long delta; + unsigned long elapsed, delta;
kmin = ktime_set(0, min * NSEC_PER_USEC); delta = (max - min) * NSEC_PER_USEC; - return schedule_hrtimeout_range(&kmin, delta, HRTIMER_MODE_REL); + return schedule_hrtimeout_range(&kmin, delta, HRTIMER_MODE_REL, + &elapsed) ? 0 : elapsed; }
/** @@ -1834,9 +1835,9 @@ static int __sched do_usleep_range(unsigned long min, unsigned long max) * @min: Minimum time in usecs to sleep * @max: Maximum time in usecs to sleep */ -void usleep_range(unsigned long min, unsigned long max) +unsigned long usleep_range(unsigned long min, unsigned long max) { __set_current_state(TASK_UNINTERRUPTIBLE); - do_usleep_range(min, max); + return do_usleep_range(min, max); } EXPORT_SYMBOL(usleep_range);
-
Dmitry Antipov