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

[prasanna wakhare <prasannawakhare@xxxxxxxxx>]

--- mandeep sandhu <msandhu_d@xxxxxxxxxxx> wrote:
> can another ISR preempt the current executing ISR!
> during execution of ISR's are'nt the interrupts
> disabled?
> 
> do ISR's also have priority associated with them???
> 
> i think b4 executing an ISR the kernel calls
> "preempt-disable"
> (not very sure though....)???
> 
> - /dev/mandeep
> 
> 
> 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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