ha := mheap_.arenas[ai.l1()][ai.l2()]
	atomic.Or8(&ha.pageSpecials[arenaPage/8], uint8(1)<<(arenaPage%8))
}

// spanHasNoSpecials marks a span as having no specials in the arena bitmap.
func spanHasNoSpecials(s *mspan) {
	arenaPage := (s.base() / pageSize) % pagesPerArena
	ai := arenaIndex(s.base())
	ha := mheap_.arenas[ai.l1()][ai.l2()]
	atomic.And8(&ha.pageSpecials[arenaPage/8], ^(uint8(1) << (arenaPage % 8)))
}

	ha := mheap_.arenas[ai.l1()][ai.l2()]
	arenaPage := uint(uintptr(shard) * pagesPerSpanRoot % pagesPerArena)

	// Construct slice of bitmap which we'll iterate over.
	specialsbits := ha.pageSpecials[arenaPage/8:]
	specialsbits = specialsbits[:pagesPerSpanRoot/8]
	for i := range specialsbits {
		// Find set bits, which correspond to spans with specials.
		specials := atomic.Load8(&specialsbits[i])