critical sections การใช้

• TNSDL explicitly supports critical sections to be marked in the code.
• The process then returns to its non-critical section.
• Other users posted critical sections to the article, which were removed.
• Longer critical sections should be divided into small pieces.
• These schemes also require clever programming to keep the critical sections very brief.
• This allows critical sections to be entered and exited at almost zero cost.
• Critical sections should not be used as a long-lasting locking primitive.
• If process P1 wants to enter its critical section it has to wait.
• On acquiring the lock the thread enters the critical section of the code.
• Processes with priority will break from the while loop and enter their critical section.
• A process at is in the critical section, and by assumption will exit it.
• As a result, two processes can enter the critical section at the same time.
• Before entering the critical section, every new reader must go through the entry section.
• #Every process maintains a queue of pending requests for entering critical section in order.
• It signals after executing its critical section.
• The process holding the token is the only process able to enter its critical section.
• The acquire operation is a load / read that is performed to access the critical section.
• P2 and P3 now spin while P1 is in the critical section ( Time 2 ).
• Prior to kernel version 2.6, Linux disabled interrupt to implement short critical sections.
• In other words, we need a way to execute a critical section with mutual exclusion.