87 lines
2.9 KiB
C++
87 lines
2.9 KiB
C++
/*****************************************************************************
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* *
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* S C H E D U L E R *
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* *
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*---------------------------------------------------------------------------*
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* Beschreibung: Implementierung eines einfachen Zeitscheiben-Schedulers. *
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* Rechenbereite Threads werden in 'readQueue' verwaltet. *
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* *
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* Autor: Michael, Schoettner, HHU, 22.8.2016 *
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*****************************************************************************/
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#ifndef __Scheduler_include__
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#define __Scheduler_include__
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#include "devices/CGA_Stream.h"
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#include "kernel/threads/Thread.h"
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#include "lib/Queue.h"
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#include "lib/SpinLock.h"
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#include "user/lib/ArrayList.h"
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#include "user/lib/Logger.h"
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class Scheduler {
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private:
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Scheduler(const Scheduler& copy) = delete; // Verhindere Kopieren
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// Queue readyQueue; // auf die CPU wartende Threads
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// Scheduler wird evt. von einer Unterbrechung vom Zeitgeber gerufen,
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// bevor er initialisiert wurde
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Thread* active;
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bool has_idle_thread;
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Logger log;
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// NOTE: I would have to release the lock when switching threads but I don't know exactly how to do this
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// in the assembly function
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// SpinLock lock; // Use spinlock instead of cpu.disable_int() because it still allows preemption
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// // for threads that don't use the scheduler
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// NOTE: Using this instead of the Queue is a side effect, I added the ArrayList for different reasons
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// but my Queue was shit so I replaced it (and didn't fix the Queue)
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ArrayList<Thread*> ready_queue;
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ArrayList<Thread*> block_queue;
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void start(Thread& first);
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void dispatch(Thread& next);
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public:
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Scheduler() : has_idle_thread(false), log("SCHED") {}
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Thread* get_active() const {
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return this->active;
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}
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// Scheduler initialisiert?
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// Zeitgeber-Unterbrechung kommt evt. bevor der Scheduler fertig
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// intiialisiert wurde!
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bool preemption_enabled() const { return has_idle_thread; }
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// ruft nur der Idle-Thread (erster Thread der vom Scheduler gestartet wird)
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void enable_preemption() { has_idle_thread = true; }
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// Scheduler starten
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void schedule();
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// Thread in readyQueue eintragen
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void ready(Thread* that);
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// Thread terminiert sich selbst
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void exit();
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// Thread mit 'Gewalt' terminieren
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void kill(Thread* that);
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void kill(unsigned int id);
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// CPU freiwillig abgeben und Auswahl des naechsten Threads
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void yield();
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// Thread umschalten; wird aus der ISR des PITs gerufen
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void preempt();
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void block();
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void deblock(Thread* that);
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};
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#endif
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