On Thu, Aug 18, 2022 at 08:00:41PM -0700, Hugh Dickins wrote: > tmpfs and hugetlbfs and page cache are designed around sharing memory: > TDX is designed around absolutely not sharing memory; and the further > uses which Sean foresees appear not to need it as page cache either. > > Except perhaps for page migration reasons. It's somewhat incidental, > but of course page migration knows how to migrate page cache, so > masquerading as page cache will give a short cut to page migration, > when page migration becomes at all possible. I haven't read the patch series, and I'm not taking a position one way or the other on whether this is better implemented as a shmem addition or a shim that asks shmem for memory. Page migration can be done for driver memory by using PageMovable. I just rewrote how it works, so the details are top of my mind at the moment if anyone wants something explained. Commit 68f2736a8583 is the key one to look at.
