func (b *pageBits) setBlock64(i uint, v uint64) {
	b[i/64] |= v
}

// clear clears bit i of pageBits.
func (b *pageBits) clear(i uint) {
	b[i/64] &^= 1 << (i % 64)
}

// clearRange clears bits in the range [i, i+n).
func (b *pageBits) clearRange(i, n uint) {
	_ = b[i/64]
	if n == 1 {
		// Fast path for the n == 1 case.
		b.clear(i)
		return
	}
	// Clear bits [i, j].
	j := i + n - 1
	if i/64 == j/64 {

		})

		// Initialize the bitmap and update pageAlloc metadata.
		ci := chunkIndex(addr)
		chunk := p.chunkOf(ci)

		// Clear all the scavenged bits which grow set.
		chunk.scavenged.clearRange(0, pallocChunkPages)

		// Simulate the allocation and subsequent free of all pages in
		// the chunk for the scavenge index. This sets the state equivalent
		// with all pages within the index being free.