diff options
| -rw-r--r-- | sys/kern/kern_sched.c | 38 |
1 files changed, 13 insertions, 25 deletions
diff --git a/sys/kern/kern_sched.c b/sys/kern/kern_sched.c index 01f2efe..b964fc5 100644 --- a/sys/kern/kern_sched.c +++ b/sys/kern/kern_sched.c @@ -115,17 +115,8 @@ done: __noreturn static void sched_enter(void) { - struct proc *td; - struct cpu_info *ci = this_cpu(); - struct sched_state *state = &ci->sched_state; - + sched_oneshot(); for (;;) { - if ((td = sched_dequeue_td()) != NULL) { - state->td = td; - sched_oneshot(); - __sched_switch_to(td->tf); - } - hint_spinwait(); } } @@ -179,36 +170,33 @@ sched_context_switch(struct trapframe *tf) struct sched_state *state = &ci->sched_state; struct proc *td, *next_td; - spinlock_acquire(&tdq_lock); - td = state->td; - /* - * If we have no current thread or the queue is empty, - * preempting would be bad because there is nothing to - * switch to. And if we only have one thread, there is + * If we only have one thread or even no threads, there is * no point in preempting. */ - if (td == NULL || TAILQ_NELEM(&td_queue) == 1) { + if (nthread == 1 || nthread == 0) { goto done; } else if ((next_td = sched_dequeue_td()) == NULL) { /* Empty */ goto done; } - - /* Save our trapframe */ - memcpy(td->tf, tf, sizeof(struct trapframe)); - - if ((next_td = TAILQ_NEXT(td, link)) == NULL) { - /* We need to wrap to the first thread */ - next_td = TAILQ_FIRST(&td_queue); + if (state->td != NULL) { + /* Save our trapframe */ + td = state->td; + memcpy(td->tf, tf, sizeof(struct trapframe)); } /* Copy to stack */ memcpy(tf, next_td->tf, sizeof(struct trapframe)); + + td = state->td; state->td = next_td; + + if (td != NULL) { + sched_enqueue_td(td); + } done: - spinlock_release(&tdq_lock); sched_oneshot(); } |