[PATCH] selftests: mm: fix map_hugetlb failure on 64K page size systems

[PATCH] selftests: mm: fix map_hugetlb failure on 64K page size systems

[Nico Pache]

On systems with 64k page size and 512M huge page sizes, the allocation
and test succeeds but errors out at the munmap. As the comment states,
munmap will failure if its not HUGEPAGE aligned. This is due to the
length of the mapping being 1/2 the size of the hugepage causing the
munmap to not be hugepage aligned. Fix this by making the mapping length
the full hugepage if the hugepage is larger than the length of the
mapping.

Signed-off-by: Nico Pache <npache@redhat.com>
---
 tools/testing/selftests/mm/map_hugetlb.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/testing/selftests/mm/map_hugetlb.c b/tools/testing/selftests/mm/map_hugetlb.c
index 193281560b61..dcb8095fcd45 100644
--- a/tools/testing/selftests/mm/map_hugetlb.c
+++ b/tools/testing/selftests/mm/map_hugetlb.c
@@ -58,10 +58,16 @@ int main(int argc, char **argv)
 {
 	void *addr;
 	int ret;
+	size_t maplength;
 	size_t length = LENGTH;
 	int flags = FLAGS;
 	int shift = 0;
 
+	maplength = default_huge_page_size();
+	/* mmap with fail if the length is not page */
+	if (maplength > length)
+		length = maplength;
+
 	if (argc > 1)
 		length = atol(argv[1]) << 20;
 	if (argc > 2) {
-- 
2.43.0

Re: [PATCH] selftests: mm: fix map_hugetlb failure on 64K page size systems

[Nico Pache]

NACK.

I accidentally sent an older version of this patch. Following up with V2.

On Fri, Jan 19, 2024 at 5:58 AM Nico Pache <npache@redhat.com> wrote:
>
> On systems with 64k page size and 512M huge page sizes, the allocation
> and test succeeds but errors out at the munmap. As the comment states,
> munmap will failure if its not HUGEPAGE aligned. This is due to the
> length of the mapping being 1/2 the size of the hugepage causing the
> munmap to not be hugepage aligned. Fix this by making the mapping length
> the full hugepage if the hugepage is larger than the length of the
> mapping.
>
> Signed-off-by: Nico Pache <npache@redhat.com>
> ---
>  tools/testing/selftests/mm/map_hugetlb.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/tools/testing/selftests/mm/map_hugetlb.c b/tools/testing/selftests/mm/map_hugetlb.c
> index 193281560b61..dcb8095fcd45 100644
> --- a/tools/testing/selftests/mm/map_hugetlb.c
> +++ b/tools/testing/selftests/mm/map_hugetlb.c
> @@ -58,10 +58,16 @@ int main(int argc, char **argv)
>  {
>         void *addr;
>         int ret;
> +       size_t maplength;
>         size_t length = LENGTH;
>         int flags = FLAGS;
>         int shift = 0;
>
> +       maplength = default_huge_page_size();
> +       /* mmap with fail if the length is not page */
> +       if (maplength > length)
> +               length = maplength;
> +
>         if (argc > 1)
>                 length = atol(argv[1]) << 20;
>         if (argc > 2) {
> --
> 2.43.0
>