Re: [RFC v2 0/3] iommu/intel: Free empty page tables on unmaps

[David Hildenbrand]

On 26.04.24 05:43, Pasha Tatashin wrote:
> Changelog
> ================================================================
> v2: Use mapcount instead of refcount
>      Synchronized with IOMMU Observability changes.
> ================================================================
>
> This series frees empty page tables on unmaps. It intends to be a
> low overhead feature.
>
> The read-writer lock is used to synchronize page table, but most of
> time the lock is held is reader. It is held as a writer for short
> period of time when unmapping a page that is bigger than the current
> iova request. For all other cases this lock is read-only.
>
> page->mapcount is used in order to track number of entries at each page
> table.

I'm wondering if this will conflict with page_type at some point? We're 
already converting other page table users to ptdesc. CCing Willy.

--
Cheers,

David / dhildenb