Messages in this thread | | | Date | Tue, 25 Oct 2022 17:34:52 +0200 | Subject | Re: [PATCH] selftests: vm: use 1 MB hugepage size for s390 | From | David Hildenbrand <> |
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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 <gerald.schaefer@linux.ibm.com> > --- > 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/20220927110120.106906-5-david@redhat.com/T/#u
We could factor that out into vm_utils.c
-- Thanks,
David / dhildenb
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