| Message ID | 20221025152610.3439102-1-gerald.schaefer@linux.ibm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | selftests: vm: use 1 MB hugepage size for s390 | expand |
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
On Tue, 25 Oct 2022 17:34:52 +0200 David Hildenbrand <david@redhat.com> 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 <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 > 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.
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 #ifndef MAP_HUGETLB #define MAP_HUGETLB 0x40000 /* arch specific */
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(+)