func (b *workbuf) checknonempty() {
    if b.nobj == 0 {
        throw("workbuf is empty")
    }
}

func (b *workbuf) checkempty() {
    if b.nobj != 0 {
        throw("workbuf is not empty")
    }
}

    nfreed := s.allocCount - nalloc
    if nalloc > s.allocCount {
        print("runtime: nelems=", s.nelems, " nalloc=", nalloc, " previous allocCount=", s.allocCount, " nfreed=", nfreed, "\n")
        throw("sweep increased allocation count")
    }

func (head *lfstack) push(node *lfnode) {
   ...
    for {
        old := atomic.Load64((*uint64)(head))
        node.next = old
        atomic.Mfence()  // mfence instruction
        if atomic.Cas64((*uint64)(head), old, new) {
            break
        }
    }
}
func (head *lfstack) pop() unsafe.Pointer {
    for {
        old := atomic.Load64((*uint64)(head))
        if old == 0 {
            return nil
        }
        node := lfstackUnpack(old)
        atomic.Mfence()  // mfence instruction
        next := atomic.Load64(&node.next)
        if atomic.Cas64((*uint64)(head), old, next) {
            return unsafe.Pointer(node)
        }
    }
}