for l := 0; l < summaryLevels; l++ {
			sysFreeOS(unsafe.Pointer(&p.summary[l][0]), uintptr(cap(p.summary[l]))*pallocSumBytes)
		}
	} else {
		resSize := uintptr(0)
		for _, s := range p.summary {
			resSize += uintptr(cap(s)) * pallocSumBytes
		}
		sysFreeOS(unsafe.Pointer(&p.summary[0][0]), alignUp(resSize, physPageSize))
	}

	// Free extra data structures.

		// re-reserve the aligned sub-region. This may race,
		// so we may have to try again.
		sysFreeOS(unsafe.Pointer(p), size+align)
		p = alignUp(p, align)
		p2 := sysReserve(unsafe.Pointer(p), size)
		if p != uintptr(p2) {
			// Must have raced. Try again.
			sysFreeOS(p2, size)
			if retries++; retries == 100 {
				throw("failed to allocate aligned heap memory; too many retries")
			}