Re: [PATCH 7/8] mm: remove the extra ZONE_DEVICE struct page refcount

From: Christoph Hellwig
Date: Wed Feb 09 2022 - 01:25:09 EST


On Tue, Feb 08, 2022 at 07:30:11PM -0800, Dan Williams wrote:
> Interesting. I had expected that to really fix the refcount problem
> that fs/dax.c would need to start taking real page references as pages
> were added to a mapping, just like page cache.

I think we should do that eventually. But I think this series that
just attacks the device private type and extends to the device coherent
and p2p enhacements is a good first step to stop the proliferation of
the one off refcount and to allow to deal with the fsdax pages in another
more focuessed series.