Re: [PATCH v8 1/8] mm/memfd: Introduce userspace inaccessible memfd

From: Sean Christopherson
Date: Fri Oct 21 2022 - 12:18:27 EST


On Fri, Oct 21, 2022, Chao Peng wrote:
> >
> > In the context of userspace inaccessible memfd, what would be a
> > suggested way to enforce NUMA memory policy for physical memory
> > allocation? mbind[1] won't work here in absence of virtual address
> > range.
>
> How about set_mempolicy():
> https://www.man7.org/linux/man-pages/man2/set_mempolicy.2.html

Andy Lutomirski brought this up in an off-list discussion way back when the whole
private-fd thing was first being proposed.

: The current Linux NUMA APIs (mbind, move_pages) work on virtual addresses. If
: we want to support them for TDX private memory, we either need TDX private
: memory to have an HVA or we need file-based equivalents. Arguably we should add
: fmove_pages and fbind syscalls anyway, since the current API is quite awkward
: even for tools like numactl.