public Process getLowestProcess(){
        Process process = this.currentProcess;
        int cnt =0;
        while(this.priorityQueue.iterator().hasNext() && cnt++ < processNumber){
            Process tmp = this.priorityQueue.iterator().next();
            if(tmp == process)
                break;
            if(process==null && tmp.getInMemoryWorkingSet() > 0)
                process = this.priorityQueue.iterator().next();
            else{
                if(tmp.getInMemoryWorkingSet()>0 && process.getInMemoryWorkingSet() > tmp.getInMemoryWorkingSet()){
                    process = tmp;
                }
            }
        }
        logger.trace("return process "+process.getPid());
        return process;
    }