3D-printing/klipper
1
0
Fork 0
mirror of https://github.com/Klipper3d/klipper.git synced 2025-07-10 08:17:52 -06:00
Code Issues Projects Releases Packages Wiki Activity Actions 3

sched: Avoid rescheduling the currently active timer

Browse source 
It's tricky to reschedule the timer irq correctly (due to race
conditions with the irq) and in practice it's very rarely needed.
Handle the special cases in the generic sched.c code so that the board
code doesn't have to handle it.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor 2017-03-10 20:03:56 -05:00
parent cb286ede9d
commit 0a3c23bcf6
5 changed files with 53 additions and 90 deletions
Download patch file Download diff file Expand all files Collapse all files

51
src/sched.c
View file

@ -101,33 +101,39 @@ sched_timer(struct timer *add)
{
uint32_t waketime = add->waketime;
irqstatus_t flag = irq_save();
if (sched_is_before(waketime, timer_list->waketime)) {
// This timer is the next - insert at front of list and reschedule
add->next = timer_list;
timer_list = add;
uint8_t ret = timer_set_next(waketime);
if (ret)
shutdown("Timer too close");
} else {
// Find position in list and insert
struct timer *pos = timer_list;
while (!sched_is_before(waketime, pos->next->waketime))
pos = pos->next;
add->next = pos->next;
pos->next = add;
}
if (sched_is_before(waketime, timer_list->waketime))
// Timer in past (or very near future)
shutdown("Timer too close");
// Find position in list and insert
struct timer *pos = timer_list;
while (!sched_is_before(waketime, pos->next->waketime))
pos = pos->next;
add->next = pos->next;
pos->next = add;
irq_restore(flag);
}
// The deleted timer is used when deleting an active timer.
static uint_fast8_t
deleted_event(struct timer *t)
{
return SF_DONE;
}
static struct timer deleted_timer = {
.func = deleted_event,
};
// Remove a timer that may be live.
void
sched_del_timer(struct timer *del)
{
irqstatus_t flag = irq_save();
if (timer_list == del) {
// Deleting the next active timer - delete and reschedule
timer_list = del->next;
timer_set_next(timer_list->waketime);
// Deleting the next active timer - replace with deleted_timer
deleted_timer.waketime = del->waketime;
deleted_timer.next = del->next;
timer_list = &deleted_timer;
} else {
// Find and remove from timer list (if present)
struct timer *pos;
@ -197,13 +203,14 @@ sched_timer_kick(void)
// Shutdown all user timers on an emergency stop.
static void
timer_shutdown(void)
sched_timer_shutdown(void)
{
timer_list = &ms_timer;
timer_list = &deleted_timer;
deleted_timer.waketime = ms_timer.waketime;
deleted_timer.next = &ms_timer;
ms_timer.next = &sentinel_timer;
timer_set_next(timer_list->waketime);
}
DECL_SHUTDOWN(timer_shutdown);
DECL_SHUTDOWN(sched_timer_shutdown);
/****************************************************************