From 844077762734c8bc620844ceb1f986006051f120 Mon Sep 17 00:00:00 2001 From: Con Kolivas Date: Tue, 1 Nov 2016 12:54:20 +1100 Subject: [PATCH 02/14] Implement min and msec hrtimeout un/interruptible schedule timeout variants with a lower resolution of 1ms to work around low Hz time resolutions. --- include/linux/sched.h | 6 +++++ kernel/time/hrtimer.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 68 insertions(+) diff --git a/include/linux/sched.h b/include/linux/sched.h index 7b9e719..62dd304 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -437,6 +437,12 @@ extern signed long schedule_timeout_interruptible(signed long timeout); extern signed long schedule_timeout_killable(signed long timeout); extern signed long schedule_timeout_uninterruptible(signed long timeout); extern signed long schedule_timeout_idle(signed long timeout); + +extern signed long schedule_msec_hrtimeout(signed long timeout); +extern signed long schedule_min_hrtimeout(void); +extern signed long schedule_msec_hrtimeout_interruptible(signed long timeout); +extern signed long schedule_msec_hrtimeout_uninterruptible(signed long timeout); + asmlinkage void schedule(void); extern void schedule_preempt_disabled(void); diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 9ba7c82..53291d7 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -1788,3 +1788,65 @@ int __sched schedule_hrtimeout(ktime_t *expires, return schedule_hrtimeout_range(expires, 0, mode); } EXPORT_SYMBOL_GPL(schedule_hrtimeout); + +/* + * As per schedule_hrtimeout but taskes a millisecond value and returns how + * many milliseconds are left. + */ +signed long __sched schedule_msec_hrtimeout(signed long timeout) +{ + struct hrtimer_sleeper t; + ktime_t expires; + int delta, secs; + + if (!timeout) { + __set_current_state(TASK_RUNNING); + return 0; + } + + secs = timeout / 1000; + delta = (timeout % 1000) * NSEC_PER_MSEC; + expires = ktime_set(secs, delta); + + hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + hrtimer_set_expires_range_ns(&t.timer, expires, delta); + + hrtimer_init_sleeper(&t, current); + + hrtimer_start_expires(&t.timer, HRTIMER_MODE_REL); + + if (likely(t.task)) + schedule(); + + hrtimer_cancel(&t.timer); + destroy_hrtimer_on_stack(&t.timer); + + __set_current_state(TASK_RUNNING); + + expires = hrtimer_expires_remaining(&t.timer); + timeout = ktime_to_ms(expires); + return timeout < 0 ? 0 : timeout; +} + +EXPORT_SYMBOL(schedule_msec_hrtimeout); + +signed long __sched schedule_min_hrtimeout(void) +{ + return schedule_msec_hrtimeout(1); +} + +EXPORT_SYMBOL(schedule_min_hrtimeout); + +signed long __sched schedule_msec_hrtimeout_interruptible(signed long timeout) +{ + __set_current_state(TASK_INTERRUPTIBLE); + return schedule_msec_hrtimeout(timeout); +} +EXPORT_SYMBOL(schedule_msec_hrtimeout_interruptible); + +signed long __sched schedule_msec_hrtimeout_uninterruptible(signed long timeout) +{ + __set_current_state(TASK_UNINTERRUPTIBLE); + return schedule_msec_hrtimeout(timeout); +} +EXPORT_SYMBOL(schedule_msec_hrtimeout_uninterruptible); -- 2.7.4