Re: sharing data (can ISR be pre-empted???)

[Tyler <tyler@xxxxxxxx>]

mandeep sandhu wrote:
> hi all,
> i've heard that the linux kernel is preemptive from 2.5 onwards....
> so can an ISR be preempted by the kernel. as i understand an ISR doest not
> have a process context, so then what can preempt it????

Yes you're right. An ISR has no process context. But an ISR can be 
interrupted by some code lika for example another ISR. Interrupts can be 
nested in Linux (even in 2.4).
And in 2.5 and 2.6, ISR can be preempted by a thread or anything else 
which has a higher priority.


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