selftests/mm: hmm-tests: don't hardcode THP size to 2MB

Several HMM tests hardcode TWOMEG as the THP size. This is wrong on
architectures where the PMD size is not 2MB such as arm64 with 64K base
pages where THP is 512MB. Fix this by using read_pmd_pagesize() from
vm_util instead.

While here also replace the custom file_read_ulong() helper used to
parse the default hugetlbfs page size from /proc/meminfo with the
existing default_huge_page_size() from vm_util.

Link: https://lore.kernel.org/20260331063445.3551404-3-apopple@nvidia.com
Link: https://lore.kernel.org/linux-mm/8bd0396a-8997-4d2e-a13f-5aac033083d7@linux.dev/
Fixes: fee9f6d1b8df ("mm/hmm/test: add selftests for HMM")
Fixes: 519071529d2a ("selftests/mm/hmm-tests: new tests for zone device THP migration")
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reported-by: Zenghui Yu <zenghui.yu@linux.dev>
Closes: https://lore.kernel.org/linux-mm/8bd0396a-8997-4d2e-a13f-5aac033083d7@linux.dev/
Reviewed-by: Balbir Singh <balbirs@nvidia.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger,kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

0 files changed, 0 insertions, 0 deletions