// Allocate pointer-less objects from the tail end of the chunk.
		v, ok := s.userArenaChunkFree.takeFromBack(size, typ.Align_)
		if ok {
			ptr = unsafe.Pointer(v)
		}
	} else {
		v, ok := s.userArenaChunkFree.takeFromFront(size, typ.Align_)
		if ok {
			ptr = unsafe.Pointer(v)
		}
	}
	if ptr == nil {
		// Failed to allocate.
		mp.mallocing = 0
		releasem(mp)
		return nil
	}
	if s.needzero != 0 {