diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/proc.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/kernel/proc.c b/kernel/proc.c index b5d929d..71d4146 100644 --- a/kernel/proc.c +++ b/kernel/proc.c @@ -372,12 +372,14 @@ wait(void) } // Loop over process table looking for process to run. -struct proc *find_runnable() { +struct proc *find_runnable(int start) { struct proc *p; acquire(&ptable.lock); - for(p = ptable.proc; p < &ptable.proc[NPROC]; p++) { + for(int i = start; i < start+NPROC; i++) { + p = &ptable.proc[i % NPROC]; acquire(&p->lock); if(p->state == RUNNABLE) { + p->state = RUNNING; release(&ptable.lock); return p; } @@ -400,19 +402,19 @@ scheduler(void) { struct proc *p; struct cpu *c = mycpu(); - + int next; + c->proc = 0; for(;;){ // Enable interrupts on this processor. intr_on(); - if((p = find_runnable()) != 0){ + if((p = find_runnable(next)) != 0) { + next = (next + 1) & NPROC; // Switch to chosen process. It is the process's job // to release its lock and then reacquire it // before jumping back to us. c->proc = p; - p->state = RUNNING; - swtch(&c->scheduler, &p->context); // Process is done running for now. |