}

// If useCheckmark is true, marking of an object uses the checkmark
// bits instead of the standard mark bits.
var useCheckmark = false

// startCheckmarks prepares for the checkmarks phase.
//
// The world must be stopped.
func startCheckmarks() {
	assertWorldStopped()

	// Clear all checkmarks.
	for _, ai := range mheap_.allArenas {
		arena := mheap_.arenas[ai.l1()][ai.l2()]
		bitmap := arena.checkmarks

		if debug.gccheckmark > 0 {
			// Run a full non-parallel, stop-the-world
			// mark using checkmark bits, to check that we
			// didn't forget to mark anything during the
			// concurrent mark process.
			startCheckmarks()
			gcResetMarkState()
			gcw := &getg().m.p.ptr().gcw
			gcDrain(gcw, 0)
			wbBufFlush1(getg().m.p.ptr())
			gcw.dispose()
			endCheckmarks()
		}