// Update heapLive and heapScan.
	gcController.update(dHeapLive, scanAlloc)
}

// prepareForSweep flushes c if the system has entered a new sweep phase
// since c was populated. This must happen between the sweep phase
// starting and the first allocation from c.
func (c *mcache) prepareForSweep() {
	// Alternatively, instead of making sure we do this on every P