Re: [PATCH v17 00/10] mm: introduce memfd_secret system call to create "secret" memory areas
On Mon, Feb 08, 2021 at 10:27:18AM +0100, David Hildenbrand wrote:
On 08.02.21 09:49, Mike Rapoport wrote:
Some questions (and request to document the answers) as we now allow to have
unmovable allocations all over the place and I don't see a single comment
regarding that in the cover letter:
1. How will the issue of plenty of unmovable allocations for user space be
tackled in the future?
2. How has this issue been documented? E.g., interaction with ZONE_MOVABLE
and CMA, alloc_conig_range()/alloc_contig_pages?.
Secretmem sets the mappings gfp mask to GFP_HIGHUSER, so it does not
allocate movable pages at the first place.
3. How are the plans to support migration in the future and which
interface
changes will be required? (Michal mentioned some good points to make this
configurable via the interface, we should plan ahead and document)
The only interface change required is an addition of bit value for syscall
flags, I really think it can be documented with the addition of migration
or any other feature for that sake.
--
Sincerely yours,
Mike.