what to use (sem/spinlock/etc)....

what to use (sem/spinlock/etc)....

[RANDAZZO]

I have a register on my hardware that I write to to increment a counter....
..all I want to do is make sure that only one "task" writes at a time, 
thus to not corrupt the value......

=EXAMPLE

Task A
- Write new Value to hardware
- Increment Hardware counter
- DONE

Task B
- Write new Value to hardware
- Increment Hardware counter
- DONE

..This will most likely not occur in a inthandler, but may....

...I have to make sure that Task A is "done" before "Task B" or any others
can do their writing....

...any opinion of what I should use....

 
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Re: what to use (sem/spinlock/etc)....

[Paulo Marques]

RANDAZZO@ddc-web.com wrote:

> I have a register on my hardware that I write to to increment a counter....
> ..all I want to do is make sure that only one "task" writes at a time, 
> thus to not corrupt the value......
> 
> =EXAMPLE
> 
> Task A
> - Write new Value to hardware
> - Increment Hardware counter
> - DONE
> 
> Task B
> - Write new Value to hardware
> - Increment Hardware counter
> - DONE
> 
> ..This will most likely not occur in a inthandler, but may....
> 
> ...I have to make sure that Task A is "done" before "Task B" or any others
> can do their writing....
> 
> ...any opinion of what I should use....

You can read the "Unreliable Guide To Locking" from Rusty Russell at:

http://www.kernel.org/pub/linux/kernel/people/rusty/kernel-locking/

I hope this helps,

-- 
Paulo Marques - www.grupopie.com

"In a world without walls and fences who needs windows and gates?"

Re: what to use (sem/spinlock/etc)....

[Davide Libenzi]

On Mon, 16 Feb 2004 RANDAZZO@ddc-web.com wrote:

> ...any opinion of what I should use....

I'd say a spindoc:

http://www.kernel.org/pub/linux/kernel/people/rusty/kernel-locking/



- Davide