Method SetCPUMask

pkg/sentry/kernel/task_sched.go:392–419

SetCPUMask sets t's allowed CPU mask based on mask. It takes ownership of mask. Preconditions: mask.Size() == sched.CPUSetSize(t.Kernel().ApplicationCores()).

(mask sched.CPUSet)

// Preconditions: mask.Size() ==
// sched.CPUSetSize(t.Kernel().ApplicationCores()).
func (t *Task) SetCPUMask(mask sched.CPUSet) error {
	if want := sched.CPUSetSize(t.k.applicationCores); mask.Size() != want {
		panic(fmt.Sprintf("Invalid CPUSet %v (expected %d bytes)", mask, want))
	}

	// Remove CPUs in mask above Kernel.applicationCores.
	mask.ClearAbove(t.k.applicationCores)

	// Ensure that at least 1 CPU is still allowed.
	if mask.NumCPUs() == 0 {
		return linuxerr.EINVAL
	}

	if t.k.useHostCores || t.k.Platform.HasCPUNumbers() {
		// No-op; pretend the mask was immediately changed back.
		return nil
	}

	t.tg.pidns.owner.mu.RLock()
	rootTID := t.tg.pidns.owner.Root.tids[t]
	t.tg.pidns.owner.mu.RUnlock()

	t.mu.Lock()
	defer t.mu.Unlock()
	t.allowedCPUMask = mask
	t.cpu.Store(assignCPU(mask, rootTID))
	return nil
}

// CPU returns the cpu id for a given task.
func (t *Task) CPU() int32 {