// Free extra data structures.
	sysFreeOS(unsafe.Pointer(&p.scav.index.chunks[0]), uintptr(cap(p.scav.index.chunks))*unsafe.Sizeof(atomicScavChunkData{}))

	// Subtract back out whatever we mapped for the summaries.
	// sysUsed adds to p.sysStat and memstats.mappedReady no matter what
	// (and in anger should actually be accounted for), and there's no other
	// way to figure out how much we actually mapped.

	//
	// For most systems the cost of scavenging greatly outweighs the costs
	// associated with using scavenged memory, making this constant 0. On other systems
	// (especially ones where "sysUsed" is not just a no-op) this cost is non-trivial.
	//
	// This ratio is used as part of multiplicative factor to help the scavenger account
	// for the additional costs of using scavenged memory in its pacing.

	if pEnd := alignUp(l.next-1, physPageSize); pEnd > l.mapped {
		if l.mapMemory {
			// Transition from Reserved to Prepared to Ready.
			n := pEnd - l.mapped
			sysMap(unsafe.Pointer(l.mapped), n, sysStat)
			sysUsed(unsafe.Pointer(l.mapped), n, n)
		}
		l.mapped = pEnd
	}
	return unsafe.Pointer(p)
}

// notInHeap is off-heap memory allocated by a lower-level allocator
// like sysAlloc or persistentAlloc.