if !isSweepDone() {
			h.reclaim(npages)
		}
		s = h.allocSpan(npages, spanAllocHeap, spanclass)
	})
	return s
}

// allocManual allocates a manually-managed span of npage pages.
// allocManual returns nil if allocation fails.
//
// allocManual adds the bytes used to *stat, which should be a
// memstats in-use field. Unlike allocations in the GC'd heap, the
// allocation does *not* count toward heapInUse.

			if s != nil {
				work.wbufSpans.free.remove(s)
				work.wbufSpans.busy.insert(s)
			}
			unlock(&work.wbufSpans.lock)
		}
		if s == nil {
			systemstack(func() {
				s = mheap_.allocManual(workbufAlloc/pageSize, spanAllocWorkBuf)
			})
			if s == nil {
				throw("out of memory")
			}
			// Record the new span in the busy list.
			lock(&work.wbufSpans.lock)
			work.wbufSpans.busy.insert(s)

	list := &stackpool[order].item.span
	s := list.first
	lockWithRankMayAcquire(&mheap_.lock, lockRankMheap)
	if s == nil {
		// no free stacks. Allocate another span worth.
		s = mheap_.allocManual(_StackCacheSize>>_PageShift, spanAllocStack)
		if s == nil {
			throw("out of memory")
		}
		if s.allocCount != 0 {
			throw("bad allocCount")
		}
		if s.manualFreeList.ptr() != nil {

			spaceNeeded += alignUp(typ.PtrBytes/goarch.PtrSize/8, goarch.PtrSize)
			npages := alignUp(spaceNeeded, pageSize) / pageSize
			var progSpan *mspan
			systemstack(func() {
				progSpan = mheap_.allocManual(npages, spanAllocPtrScalarBits)
				memclrNoHeapPointers(unsafe.Pointer(progSpan.base()), progSpan.npages*pageSize)
			})
			// Write a dummy _type in the new space.
			//