Re: [PATCH v17 00/10] mm: introduce memfd_secret system call to create "secret" memory areas

> Am 08.02.2021 um 22:13 schrieb Mike Rapoport <rppt(a)kernel.org&gt;: > > 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. That is not the point. Secretmem cannot go on CMA / ZONE_MOVABLE memory and behaves like long-term pinnings in that sense. This is a real issue when using a lot of sectremem.