Re: [Intel-IOMMU 02/10] Library routines for handling pre-allocated pool of objects

From: Keshavamurthy, Anil S
Date: Mon Jun 04 2007 - 19:54:56 EST


On Mon, Jun 04, 2007 at 07:43:54PM -0400, Jeff Garzik wrote:
> On Mon, Jun 04, 2007 at 04:06:49PM -0700, Keshavamurthy, Anil S wrote:
> > On Mon, Jun 04, 2007 at 06:57:14PM -0400, Jeff Garzik wrote:
> > > you should add logic to free resources here (or queue_work to free the
> > > resources), if the pool grows beyond a certain size.
>
> > Can be added as an add on, testing showed that pool
> > grows to a certain size and will not grow beyond that
> > as we tend to reuse the elements.
>
> Yes, but is it possible? If no, what part of the code guarantees the
> pool is limited?
>
> We should not merge code that allows the pool to grow without bound.
> In-house testing certainly never covers all the cases seen in the
> field, so I wouldn't make too many assumptions based on that. Some
> vendor will inevitably build a $BigNum system where the IOMMU is very
> heavily used.

No problem, I can add the code to free the pool element if
the curr_count ever goes greater than (min_count + 2 * grow_count)
then bring the curr_count to min_count + grow_count by freeing
some pool objects.

A patch which will apply to this current patch will follow soon.

Thanks Jeff for making your case stronger :)

-Anil


>
> Jeff
>
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