irq: Add irq_tasks, move NVMe to it

sched/sched_dumb.c

@@ -84,6 +84,12 @@ void sched_init(struct scheduler* sched) {
 
 // Asks the CPU of `sched` to reschedule as soon as it has interrupts enabled.
 static void kick(struct scheduler* sched) {
+    if (sched == &percpu_get()->sched) {
+        sched->owe_preempt = true;
+        if (percpu_ref(irq_data)->depth == 0 && irq_get_state() && !sched->preempt_level && sched->current)
+            sched_reschedule(sched);
+        return;
+    }
     if (!atomic_exchange(&sched->kick_pending, true, ATOMIC_RELAXED))
         arch_sched_kick(cpu_of(sched));
 }
@@ -217,6 +223,7 @@ static void finish_switch(struct task* prev) {
 
 static void do_reschedule(struct scheduler* sched, uint64_t now) {
     atomic_store(&sched->kick_pending, false, ATOMIC_RELAXED);
+    sched->owe_preempt = false;
     struct task* from = sched->current;
     struct task* to = next_task(sched, now);