On 25.10.22 17:26, Gerald Schaefer wrote:
> hugepage-vmemmap test fails for s390 because it assumes a hugepagesize
> of 2 MB, while we have 1 MB on s390. This results in iterating over two
> hugepages. If they are consecutive in memory, check_page_flags() will
> stumble over the additional head page. Otherwise, it will stumble over
> non-huge pageflags, after crossing the first 1 MB hugepage.
>
> Fix this by using 1 MB MAP_LENGTH for s390.
>
> Signed-off-by: Gerald Schaefer <[email protected]>
> ---
> tools/testing/selftests/vm/hugepage-vmemmap.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/tools/testing/selftests/vm/hugepage-vmemmap.c b/tools/testing/selftests/vm/hugepage-vmemmap.c
> index 557bdbd4f87e..a4695f138cec 100644
> --- a/tools/testing/selftests/vm/hugepage-vmemmap.c
> +++ b/tools/testing/selftests/vm/hugepage-vmemmap.c
> @@ -11,7 +11,14 @@
> #include <sys/mman.h>
> #include <fcntl.h>
>
> +/*
> + * 1 MB hugepage size for s390
> + */
> +#if defined(__s390x__)
> +#define MAP_LENGTH (1UL * 1024 * 1024)
> +#else
> #define MAP_LENGTH (2UL * 1024 * 1024)
> +#endif
Why not detect it at runtime, so this works on any architecture (e.g.,
ppc64 with 16 MiB IIRC and arm64 with weird sizes)?
A patch that adds such detection code is currently on its way upstream:
https://lore.kernel.org/all/[email protected]/T/#u
We could factor that out into vm_utils.c
--
Thanks,
David / dhildenb
On Tue, 25 Oct 2022 17:34:52 +0200
David Hildenbrand <[email protected]> wrote:
> On 25.10.22 17:26, Gerald Schaefer wrote:
> > hugepage-vmemmap test fails for s390 because it assumes a hugepagesize
> > of 2 MB, while we have 1 MB on s390. This results in iterating over two
> > hugepages. If they are consecutive in memory, check_page_flags() will
> > stumble over the additional head page. Otherwise, it will stumble over
> > non-huge pageflags, after crossing the first 1 MB hugepage.
> >
> > Fix this by using 1 MB MAP_LENGTH for s390.
> >
> > Signed-off-by: Gerald Schaefer <[email protected]>
> > ---
> > tools/testing/selftests/vm/hugepage-vmemmap.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/tools/testing/selftests/vm/hugepage-vmemmap.c b/tools/testing/selftests/vm/hugepage-vmemmap.c
> > index 557bdbd4f87e..a4695f138cec 100644
> > --- a/tools/testing/selftests/vm/hugepage-vmemmap.c
> > +++ b/tools/testing/selftests/vm/hugepage-vmemmap.c
> > @@ -11,7 +11,14 @@
> > #include <sys/mman.h>
> > #include <fcntl.h>
> >
> > +/*
> > + * 1 MB hugepage size for s390
> > + */
> > +#if defined(__s390x__)
> > +#define MAP_LENGTH (1UL * 1024 * 1024)
> > +#else
> > #define MAP_LENGTH (2UL * 1024 * 1024)
> > +#endif
>
> Why not detect it at runtime, so this works on any architecture (e.g.,
> ppc64 with 16 MiB IIRC and arm64 with weird sizes)?
>
> A patch that adds such detection code is currently on its way upstream:
>
> https://lore.kernel.org/all/[email protected]/T/#u
>
> We could factor that out into vm_utils.c
>
Hello David, nice, I guess that would be much better than adding new #ifdefs,
and also allow to check all available hugepage sizes per arch.