diff options
Diffstat (limited to 'kern/thread.c')
| -rw-r--r-- | kern/thread.c | 26 |
1 files changed, 20 insertions, 6 deletions
diff --git a/kern/thread.c b/kern/thread.c index aae8dfbe..418da9b6 100644 --- a/kern/thread.c +++ b/kern/thread.c @@ -497,6 +497,12 @@ thread_runq_wakeup_balancer(struct thread_runq *runq) thread_runq_wakeup(runq, runq->balancer); } +static void +thread_runq_schedule_prepare(struct thread *thread) +{ + pmap_load(thread->task->map->pmap); +} + static struct thread_runq * thread_runq_schedule(struct thread_runq *runq) { @@ -523,10 +529,9 @@ thread_runq_schedule(struct thread_runq *runq) next = thread_runq_get_next(runq); assert((next != runq->idler) || (runq->nr_threads == 0)); + assert(next->preempt == THREAD_SUSPEND_PREEMPT_LEVEL); if (likely(prev != next)) { - pmap_load(next->task->map->pmap); - /* * That's where the true context switch occurs. The next thread must * unlock the run queue and reenable preemption. Note that unlocking @@ -536,10 +541,18 @@ thread_runq_schedule(struct thread_runq *runq) tcb_switch(&prev->tcb, &next->tcb); /* - * When dispatched again, the thread might have been moved to another - * processor. + * The thread is dispatched on a processor once again. + * + * Keep in mind the system state may have changed a lot since this + * function was called. In particular, the next thread may have been + * destroyed, and must not be referenced any more. */ + barrier(); + + /* The thread might have been moved to another processor */ runq = thread_runq_local(); + + thread_runq_schedule_prepare(prev); } assert(prev->preempt == THREAD_SUSPEND_PREEMPT_LEVEL); @@ -1485,11 +1498,13 @@ thread_main(void) assert(!cpu_intr_enabled()); assert(!thread_preempt_enabled()); + thread = thread_self(); + thread_runq_schedule_prepare(thread); + spinlock_unlock(&thread_runq_local()->lock); cpu_intr_enable(); thread_preempt_enable(); - thread = thread_self(); thread->fn(thread->arg); thread_exit(); } @@ -2095,7 +2110,6 @@ thread_run_scheduler(void) spinlock_lock(&runq->lock); thread = thread_runq_get_next(thread_runq_local()); - pmap_load(thread->task->map->pmap); tcb_load(&thread->tcb); } |