Starvation/ Aging

✅ Starvation

resource management problem

• process priority is low

• process is never allocated resource

• priority is low: came late, takes long time… 💡 How to prioritize process https://soheeparklee.github.io/posts/OS-8CPUscheduling/

• 프로세스가 원하는 자원을 계속 할당받지 못하는 상태
• several process compete for one resource, never gets it
• always lose in competition

🆚 Deadlock

process cannot get next resource, wait

• 프로세스가 자원을 얻지 못해 다음 처리를 못하는
• several process want one resource
• cannot go onto next step, locked

💊 Aging

to prevent starvation

• If certain process waits for a long time bc has low priority
• let it go first
• or take waiting time into account, make priority level higher

• allow process to be allocated resource

• SJF(Shortest Job First), process with longer time can never get resource

• HRN(Highest Response-ratio Next) take waiting time into account

• MLQ(MultiLevelQueue)
• MLFQ: take aging into account