Re: [PATCH v11 01/12] iova: Export alloc_iova_fast() and free_iova_fast()

[John Garry]

On 25/08/2021 13:17, Yongji Xie wrote:
> > JFYI, There was a preliminary discussion to move the iova rcache code
> > (which the iova fast alloc and free functions are based on) out of the
> > iova code and maybe into dma-iommu (being the only user). There was
> > other motivation.
> Would it be better to move the code into ./lib as a general library?

For a start we/I think that the rcache could be removed from the IOVA 
code, but prob should stay in drivers/iommu. I had another IOVA issue to 
solve, which complicates things. No solid plans. Need to talk to Robin more.

> > https://lore.kernel.org/linux-iommu/83de3911-145d-77c8-17c1-981e4ff825d3@xxxxxxx/
> >
> > Having more users complicates that...
> Do we have some plan for this work? From our test [1],
> iova_alloc_fast() is much better than iova_alloc(). So I'd like to use
> it as much as possible
>
> [1]https://lore.kernel.org/kvm/CACycT3steXFeg7NRbWpo2J59dpYcumzcvM2zcPJAVe40-EvvEg@xxxxxxxxxxxxxx/

Well if you're alloc'ing and free'ing IOVAs a lot then I can imagine it is.

Thanks,
John