AppMaster will not retry to request resource if AppMaster happens to decide to not use the resource

I am viewing code in RMContainerAllocator.java. I want to do some improvement so that the AppMaster could give up some containers that may not be optimal when it receives new assigned containers. But I found that if AppMaster give up the containers, it will not retry to request the resource again.

int RMContainerRequestor.java, Set<ResourceRequest> ask is used to ask resource from ResourceManager. I found each container could only be requested once. It mean ask can be filled by addResourceRequestToAsk(ResourceRequest remoteRequest[]), but it can only added for once for each container. If we give up one assigned container, It will never request again