This code is currently setting the schedule for an xv6 practice operating system

Question

This code is currently setting the schedule for an xv6 practice operating system and I was wondering how to modify this code from it's current state, Round Robin, to MLFQ?

scheduler(void)
{
struct proc *p;

for(;;){
// Enable interrupts on this processor.
sti();

// Loop over process table looking for process to run.
acquire(&ptable.lock);
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
if(p->state != RUNNABLE)
continue;

// Switch to chosen process. It is the process's job
// to release ptable.lock and then reacquire it
// before jumping back to us.
proc = p;
switchuvm(p);
p->state = RUNNING;
swtch(&cpu->scheduler, proc->context);
switchkvm();

// Process is done running for now.
// It should have changed its p->state before coming back.
proc = 0;
}
release(&ptable.lock);

}
}

Explanation / Answer

scheduler(void)
{
struct proc *p;

for(;;){
// Enable interrupts on this processor.
sti();

// Loop over process table looking for process to run.
acquire(&ptable.lock);
for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
if(p->state != RUNNABLE)
continue;

// Switch to chosen process. It is the process's job
// to release ptable.lock and then reacquire it
// before jumping back to us.
proc = p;
switchuvm(p);
p->state = RUNNING;
swtch(&cpu->scheduler, proc->context);
switchkvm();

// Process is done running for now.
// It should have changed its p->state before coming back.
proc = 0;
}
release(&ptable.lock);

}
}

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