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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