Kernel code interrupted by Timer

[anish kumar]

On Fri, 2013-02-08 at 18:08 +0100, Gaurav Jain wrote:
> What happens if the kernel executing in some process context (let's
> say executing a time-consuming syscall) gets interrupted by the Timer
> - which is apparently allowed in 2.6 onwards kernels.
> 
> 
> My understanding is that once the interrupt handler is done executing,
> we should switch back to where the kernel code was executing.
*Should* doesn't mean immediately.
>  Specifically, the interrupt handler for the Timer interrupt should
> not schedule some other task since that might leave kernel data in an
> inconsistent state - kernel didn't finish doing whatever it was doing
> when interrupted. 
Timer interrupts is supposed to cause scheduling and scheduler may or
may not pick up your last process(we always use the term "task" in
kernel space) after handling timer interrupt.
> 
> 
> So, does the Timer interrupt handler include such a policy for the
> above case?
what do you mean?
>  
> 
> 
> -- 
> Gaurav Jain
> 
> 
> 
> 
> 
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