diff --git a/kernel-src/arch/x86-64/apic.c b/kernel-src/arch/x86-64/apic.c index e4dd9771..8ce93224 100644 --- a/kernel-src/arch/x86-64/apic.c +++ b/kernel-src/arch/x86-64/apic.c @@ -237,7 +237,7 @@ void arch_apic_timerinit() { writelapic(APIC_LVT_TIMER, vec); - current_cpu()->timer = timer_new(ticksperus, armtimer, stoptimer); + current_cpu()->timer = timer_new(ticksperus, armtimer, stoptimer, 0xffffffff); __assert(current_cpu()->timer); } diff --git a/kernel-src/include/kernel/timer.h b/kernel-src/include/kernel/timer.h index b77d25d7..e42ee7ed 100644 --- a/kernel-src/include/kernel/timer.h +++ b/kernel-src/include/kernel/timer.h @@ -19,8 +19,10 @@ typedef struct timerentry_t { typedef struct { spinlock_t lock; + time_t tick_limit; time_t ticksperus; time_t tickcurrent; + time_t current_target; bool running; void (*arm)(time_t); time_t (*stop)(); @@ -32,6 +34,6 @@ void timer_stop(timer_t *timer); void timer_isr(timer_t *timer, context_t *context); void timer_insert(timer_t *timer, timerentry_t *entry, dpcfn_t fn, dpcarg_t arg, time_t us, bool repeating); uintmax_t timer_remove(timer_t *timer, timerentry_t *entry); -timer_t *timer_new(time_t ticksperus, void (*arm)(time_t), time_t (*stop)()); +timer_t *timer_new(time_t ticksperus, void (*arm)(time_t), time_t (*stop)(), time_t tick_limit); #endif diff --git a/kernel-src/sys/timer.c b/kernel-src/sys/timer.c index acc4f977..e9789113 100644 --- a/kernel-src/sys/timer.c +++ b/kernel-src/sys/timer.c @@ -36,6 +36,18 @@ static void insert(timer_t *timer, timerentry_t *entry, time_t us) { } } +// expects IPL to be at least IPL_TIMER +static inline void arm_for_next_target(timer_t *timer) { + time_t target; + if (timer->queue) + target = min(timer->queue->absolutetick - timer->tickcurrent, timer->tick_limit); + else + target = timer->tick_limit; + + timer->current_target = timer->tickcurrent + target; + timer->arm(target); +} + // expects IPL to be at least IPL_TIMER static void timercheck(timer_t *timer) { while (timer->queue && timer->queue->absolutetick == timer->tickcurrent) { @@ -52,14 +64,12 @@ static void timercheck(timer_t *timer) { } } -// TODO if an entry is removed and the timer still fires, -// it will skip forwards in time which is bad BAD void timer_isr(timer_t *timer, context_t *context) { spinlock_acquire(&timer->lock); __assert(timer->queue); - timer->tickcurrent = timer->queue->absolutetick; + timer->tickcurrent = timer->current_target; timerentry_t *oldentry = timer->queue; timer->queue = timer->queue->next; oldentry->next = NULL; @@ -71,10 +81,8 @@ void timer_isr(timer_t *timer, context_t *context) { dpc_enqueue(&oldentry->dpc, oldentry->fn, oldentry->arg); - if (timer->queue) { - timercheck(timer); - timer->arm(timer->queue->absolutetick - timer->tickcurrent); - } + timercheck(timer); + arm_for_next_target(timer); spinlock_release(&timer->lock); } @@ -89,7 +97,7 @@ void timer_resume(timer_t *timer) { goto leave; timercheck(timer); - timer->arm(timer->queue->absolutetick - timer->tickcurrent); + arm_for_next_target(timer); leave: spinlock_release(&timer->lock); @@ -123,7 +131,7 @@ void timer_insert(timer_t *timer, timerentry_t *entry, dpcfn_t fn, dpcarg_t arg, if (timer->running) { timercheck(timer); - timer->arm(timer->queue->absolutetick - timer->tickcurrent); + arm_for_next_target(timer); } spinlock_release(&timer->lock); @@ -165,7 +173,7 @@ uintmax_t timer_remove(timer_t *timer, timerentry_t *entry) { if (timer->queue) { timercheck(timer); - timer->arm(timer->queue->absolutetick - timer->tickcurrent); + arm_for_next_target(timer); } cleanup: @@ -174,13 +182,14 @@ uintmax_t timer_remove(timer_t *timer, timerentry_t *entry) { return timeremaining; } -timer_t *timer_new(time_t ticksperus, void (*arm)(time_t), time_t (*stop)()) { +timer_t *timer_new(time_t ticksperus, void (*arm)(time_t), time_t (*stop)(), time_t tick_limit) { timer_t *timer = alloc(sizeof(timer_t)); if (timer == NULL) return NULL; timer->ticksperus = ticksperus; timer->running = false; + timer->tick_limit = tick_limit; timer->arm = arm; timer->stop = stop; SPINLOCK_INIT(timer->lock);