Re: Why can't we sleep in an ISR?

["pradeep singh" <2500.pradeep@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 1299 bytes --]

On 5/14/07, Bahadir Balban <bahadir.balban@gmail.com> wrote:
>
> On 5/14/07, Learning Linux <learninglinux4@gmail.com> wrote:
> > Ok, but how about an ISR, that does not take any locks? Why can't we
> > sleep in SUCH an ISR?
> > LL
> > -
>
> The killer reason why you can't sleep in an interrupt is because an
> interrupt is not associated with any context in the first place.


good enough, but i have a query regarding this then.
On a 8K kernel stack system, doesn't interrupts share the stack associated
with the current process which was interrupted?
Doesn't interrupt steals the CPU slice time allocated to the running process
to run?
Doesn't it run in current process's context ?

What am i missing here?

Thanks
~psr

What
> is a context, then? It is the state information for a process. This
> includes the kernel and userspace stack pointers, the register set,
> and the page tables for that process. The scheduler has access to all
> this information, to preempt one process and run another. Contrary to
> this, an interrupt, depending on the version of your kernel and arch,
> uses a separate irq stack or the kernel stack of the interrupted
> process. An irq is not a context but merely a temporary execution to
> be concluded asap.
>
> Hope this helps,
> Bahadir
>



-- 
play the game

[-- Attachment #2: Type: text/html, Size: 2156 bytes --]