throw("sysGrow bounds not aligned to pallocChunkBytes")
	}

	// addrRangeToSummaryRange converts a range of addresses into a range
	// of summary indices which must be mapped to support those addresses
	// in the summary range.
	addrRangeToSummaryRange := func(level int, r addrRange) (int, int) {
		sumIdxBase, sumIdxLimit := addrsToSummaryRange(level, r.base.addr(), r.limit.addr())