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72 lines
2.2 KiB
72 lines
2.2 KiB
#include <stdio.h>
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#include <monitor.h>
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#include <kmalloc.h>
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#include <assert.h>
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// Initialize monitor.
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void
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monitor_init (monitor_t * mtp, size_t num_cv) {
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int i;
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assert(num_cv>0);
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mtp->next_count = 0;
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mtp->cv = NULL;
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sem_init(&(mtp->mutex), 1); //unlocked
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sem_init(&(mtp->next), 0);
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mtp->cv =(condvar_t *) kmalloc(sizeof(condvar_t)*num_cv);
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assert(mtp->cv!=NULL);
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for(i=0; i<num_cv; i++){
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mtp->cv[i].count=0;
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sem_init(&(mtp->cv[i].sem),0);
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mtp->cv[i].owner=mtp;
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}
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}
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// Unlock one of threads waiting on the condition variable.
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void
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cond_signal (condvar_t *cvp) {
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//LAB7 EXERCISE1: YOUR CODE
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cprintf("cond_signal begin: cvp %x, cvp->count %d, cvp->owner->next_count %d\n", cvp, cvp->count, cvp->owner->next_count);
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/*
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* cond_signal(cv) {
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* if(cv.count>0) {
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* mt.next_count ++;
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* signal(cv.sem);
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* wait(mt.next);
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* mt.next_count--;
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* }
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* }
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*/
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if(cvp->count>0) {
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cvp->owner->next_count ++;
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up(&(cvp->sem));
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down(&(cvp->owner->next));
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cvp->owner->next_count --;
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}
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cprintf("cond_signal end: cvp %x, cvp->count %d, cvp->owner->next_count %d\n", cvp, cvp->count, cvp->owner->next_count);
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}
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// Suspend calling thread on a condition variable waiting for condition Atomically unlocks
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// mutex and suspends calling thread on conditional variable after waking up locks mutex. Notice: mp is mutex semaphore for monitor's procedures
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void
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cond_wait (condvar_t *cvp) {
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//LAB7 EXERCISE1: YOUR CODE
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cprintf("cond_wait begin: cvp %x, cvp->count %d, cvp->owner->next_count %d\n", cvp, cvp->count, cvp->owner->next_count);
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/*
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* cv.count ++;
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* if(mt.next_count>0)
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* signal(mt.next)
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* else
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* signal(mt.mutex);
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* wait(cv.sem);
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* cv.count --;
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*/
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cvp->count++;
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if(cvp->owner->next_count > 0)
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up(&(cvp->owner->next));
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else
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up(&(cvp->owner->mutex));
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down(&(cvp->sem));
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cvp->count --;
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cprintf("cond_wait end: cvp %x, cvp->count %d, cvp->owner->next_count %d\n", cvp, cvp->count, cvp->owner->next_count);
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}
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