metal-cos/sys/kern/ktimer.c

120 lines
2.3 KiB
C

#include <stddef.h>
#include <stdbool.h>
#include <stdint.h>
#include <sys/kassert.h>
#include <sys/queue.h>
#include <sys/spinlock.h>
#include <sys/kmem.h>
#include <sys/mp.h>
#include <sys/ktime.h>
#include <sys/ktimer.h>
#define TIMER_WHEEL_LENGTH 256
static int timerHead = 0;
static uint64_t timerNow = 0;
static LIST_HEAD(TimerWheelHead, KTimerEvent) timerSlot[TIMER_WHEEL_LENGTH];
static Spinlock timerLock;
static Slab timerSlab;
DEFINE_SLAB(KTimerEvent, &timerSlab);
void
KTimer_Init()
{
int i;
Spinlock_Init(&timerLock, "KTimer Lock", SPINLOCK_TYPE_NORMAL);
Slab_Init(&timerSlab, "KTimerEvent Slab", sizeof(KTimerEvent), 16);
// Initialize wheel
timerHead = 0;
timerNow = KTime_GetEpoch();
for (i = 0; i < TIMER_WHEEL_LENGTH; i++) {
LIST_INIT(&timerSlot[i]);
}
}
KTimerEvent *
KTimer_Create(uint64_t timeout, KTimerCB cb, void *arg)
{
int slot;
KTimerEvent *evt = KTimerEvent_Alloc();
evt->refCount = 2; // One for the wheel and one for the callee
evt->timeout = timerNow + timeout;
evt->cb = cb;
evt->arg = arg;
Spinlock_Lock(&timerLock);
slot = (timerHead + timeout + TIMER_WHEEL_LENGTH - 1) % TIMER_WHEEL_LENGTH;
// XXX: should insert into tail
LIST_INSERT_HEAD(&timerSlot[slot], evt, timerQueue);
Spinlock_Unlock(&timerLock);
return evt;
}
void
KTimer_Retain(KTimerEvent *evt)
{
ASSERT(evt->refCount != 0);
__sync_fetch_and_add(&evt->refCount, 1);
}
void
KTimer_Release(KTimerEvent *evt)
{
ASSERT(evt->refCount != 0);
if (__sync_fetch_and_sub(&evt->refCount, 1) == 1) {
KTimerEvent_Free(evt);
}
}
void
KTimer_Cancel(KTimerEvent *evt)
{
Spinlock_Lock(&timerLock);
LIST_REMOVE(evt, timerQueue);
KTimer_Release(evt);
Spinlock_Unlock(&timerLock);
}
void
KTimer_Process()
{
uint64_t now;
if (CPU() != 0) {
return;
}
now = KTime_GetEpoch();
Spinlock_Lock(&timerLock);
while (now > timerNow) {
KTimerEvent *it, *tmp;
// Dispatch pending timer events
LIST_FOREACH_SAFE(it, &timerSlot[timerHead], timerQueue, tmp) {
if (it->timeout <= now) {
(it->cb)(it->arg);
LIST_REMOVE(it, timerQueue);
KTimer_Release(it);
}
}
// Rotate wheel forward
timerNow = timerNow + 1;
timerHead = (timerHead + 1) % TIMER_WHEEL_LENGTH;
}
Spinlock_Unlock(&timerLock);
}