code: public int minVMAllocation(int vmIdx, int v) {
          int vv = Math.max(v, vmAllocation.get(vmIdx));
          vmAllocation.set(vmIdx, vv);
          return vv;
      }
docs: Change the VM resource allocation.
  
  @param vmIdx the VM identifier
  @param v     the amount to ask.
  @return the retained value. May be bigger than {@code v} if a previous call asks for more