selftests/mm: add a GUP selftest

Add a new GUP selftest which uses kselftest_harness.h.  Cover 12 mapping
configurations: THP enabled, THP disabled and HugeTLB, each across
private/shared mappings and with/without FOLL_WRITE.  Run 5 test cases for
every variant: get_user_pages, get_user_pages_fast, pin_user_pages,
pin_user_pages_fast and pin_user_pages_longterm.

Use two default hugeTLB pages and derive the mapping size from their size.
This exercises GUP both within a single HugeTLB page and across a HugeTLB
boundary, without reserving an excessive number of pages.

Sweep four nr_pages_per_call values for each test: 1, 512, 123 and all
pages.  This preserves the coverage previously provided by
run_gup_matrix(): 12 mapping combinations x 5 GUP/PUP operations x 4 batch
sizes.  In total the selftest reports 60 TAP cases and issues 240 ioctls.

Do not carry DUMP_USER_PAGES_TEST into the new selftest because its output
is written to the kernel log and the selftest does not verify that output.

Add the new gup binary to the selftests/mm build, run_vmtests.sh and
MAINTAINERS.  Update mm/Kconfig to describe the benchmark and selftest
split.

Link: https://lore.kernel.org/20260918112234.195857-7-sarthak.sharma@arm.com
Signed-off-by: Sarthak Sharma <sarthak.sharma@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Suggested-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Tested-by: Muhammad Usama Anjum <usama.anjum@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Zi Yan <ziy@nvidia.com>

0 files changed, 0 insertions, 0 deletions