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fix scheduler bug

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This commit is contained in:
Christoph Urlacher
2022-07-04 21:24:18 +02:00
parent 4d5224ff38
commit 7ab5fdb361
1 changed files with 20 additions and 17 deletions
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37
c_os/kernel/threads/Scheduler.cc
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@ -21,16 +21,11 @@ void Scheduler::schedule() {
/* hier muss Code eingefuegt werden */
Thread* idle = new IdleThread();
// this->readyQueue.enqueue(idle);
this->ready(idle);
/* Bevor diese Methode anufgerufen wird, muss zumindest der Idle-Thread
* in der Queue eingefuegt worden sein.
*/
Thread& first = *(Thread*)this->readyQueue.dequeue();
this->start(first);
// We need to start the idle thread first as this one sets the scheduler to initialized
// Other wise preemption will be blocked and nothing will happen if the first threads
// ready() function is blocking
this->start(*(Thread*)new IdleThread()); // The idle thread set initialized to true, so preemption
// only starts after this
}
/*****************************************************************************
@ -115,9 +110,6 @@ void Scheduler::yield() {
/* hier muss Code eingefuegt werden */
// Thread-Wechsel durch PIT verhindern
// cpu.disable_int ();
// When only one thread exists (IdleThread) it can't yield as the readyqueue becomes empty
// and this is not handled anywhere else
if (this->readyQueue.isEmpty()) {
@ -125,12 +117,12 @@ void Scheduler::yield() {
return;
}
// Thread-Wechsel durch PIT verhindern
cpu.disable_int ();
Thread& next = *(Thread*)this->readyQueue.dequeue();
this->readyQueue.enqueue(this->get_active());
this->dispatch(next);
// Thread-Wechsel durch PIT jetzt wieder erlauben
// cpu.enable_int ();
}
/*****************************************************************************
@ -142,6 +134,17 @@ void Scheduler::yield() {
*****************************************************************************/
void Scheduler::preempt () {
/* Hier muss Code eingefuegt werden */
/* Hier muss Code eingefuegt werden */
if (this->readyQueue.isEmpty()) {
// Idle thread running
return;
}
// Thread-Wechsel durch PIT verhindern
cpu.disable_int ();
Thread& next = *(Thread*)this->readyQueue.dequeue();
this->readyQueue.enqueue(this->get_active());
this->dispatch(next);
}