for order := range stackpool {
		lock(&stackpool[order].item.mu)
		list := &stackpool[order].item.span
		for s := list.first; s != nil; {
			next := s.next
			if s.allocCount == 0 {
				list.remove(s)
				s.manualFreeList = 0
				osStackFree(s)
				mheap_.freeManual(s, spanAllocStack)
			}
			s = next
		}
		unlock(&stackpool[order].item.mu)
	}