RE: Interrupt Handling and Scheduler

["Sonawane, Rahul (Rahul)" <sonawane@avaya.com>]

When an interrupt happens say timer interrupt now the ISR will execute in the context of the current process. It will decrement the current process counter by the

number of clock ticks. If the counter is zero then resched_flag = 1. Now when returning from the  interrupt in ret_from_int()  the resched_flag is checked .

 If the resched_flag = 1 , then a call is made to the schedule()  which will do a context switch.

Have a made myself understood.

 

Regards,

Rahul

 

 

 -----Original Message-----
From: Anjaneyulu [mailto:anjaneyulu@mistralsoftware.com]
Sent: Thursday, October 24, 2002 9:55 AM
To: kernelnewbies@nl.linux.org
Subject: Interrupt Handling and Scheduler

Hi,

I have a doubt about the interrupt handling and the scheduling.

When an ISR is being executed, that particular interrupt is disable.

Suppose the ISR is waking up a process using wake_up_process().

Before that particular process is able to execute any statement, if another interrupt comes and hence ISR will again execute.

 

My question is if the interrupts are coming at very high frequency, the process will never get the chance to execute. Is it right???

 

Please tell me the scheduler reaction to an interrupt. What happens to the current process????

 

Thanks in advance.

 

Regards,

Anj