const runtime.arenaBits

5 uses

	runtime (current package)
		malloc.go#L297: 	arenaBits = arenaL1Bits + arenaL2Bits
		malloc.go#L575: 		const arenaMetaSize = (1 << arenaBits) * unsafe.Sizeof(heapArena{})
		malloc.go#L658: 		} else if arenaIndex(p+n-1) >= 1<<arenaBits {
		malloc.go#L718: 		} else if arenaIndex(p) >= 1<<arenaBits {
		malloc.go#L720: 		} else if arenaIndex(p+size-1) >= 1<<arenaBits {