Re: [PATCH 1/6] iommu: Move IOVA power-of-2 roundup into allocator

John Garry
2021-03-22T15:04:07Z

On 19/03/2021 19:20, Robin Murphy wrote:

Hi Robin,

>> So then we have the issue of how to dynamically increase this rcache
>> threshold. The problem is that we may have many devices associated with
>> the same domain. So, in theory, we can't assume that when we increase
>> the threshold that some other device will try to fast free an IOVA which
>> was allocated prior to the increase and was not rounded up.
>>
>> I'm very open to better (or less bad) suggestions on how to do this ...
> ...but yes, regardless of exactly where it happens, rounding up or not
> is the problem for rcaches in general. I've said several times that my
> preferred approach is to not change it that dynamically at all, but
> instead treat it more like we treat the default domain type.
>

Can you remind me of that idea? I don't remember you mentioning using
default domain handling as a reference in any context.

Thanks,
John