[PATCH v8 RFC 1/3] sparc: Break up monolithic iommu table/lock into finer graularity pools and lock

[David Miller]

From: Sowmini Varadhan <sowmini.varadhan at oracle.com>
Date: Thu, 2 Apr 2015 17:54:53 -0400

> the other question that comes to my mind is: the whole lazy_flush
> optimization probably works best when there is exactly one pool,
> and no large pools. In most other cases, we'd end up doing a lazy_flush
> when we wrap within our pool itself, losing the benefit of that 
> optimization. 
> 
> Given that the lazy_flush is mostly there to avoid regressions for 
> the older sun4u architectures (which have other hardware bottlenecks 
> anyway), and this code is rapidly getting messy, does it make sense
> to constrain the lazy_flush check to only apply for the 1-pool, 
> no-large-pool case?

I think it's better to have the multiple pools with more often global
flushing.