Re: [PATCH] selftest/vm: Use correct PAGE_SHIFT value for ppc64

Shuah Khan [off-list ref] writes:

On 2/9/22 8:43 AM, Aneesh Kumar K.V wrote:

quoted

Keep it simple by using a #define and limiting hugepage size to 2M.
This keeps the test simpler instead of dynamically finding the page size
and huge page size.

Without this tests are broken w.r.t reading /proc/self/pagemap

	if (pread(pagemap_fd, ent, sizeof(ent),
			(uintptr_t)ptr >> (PAGE_SHIFT - 3)) != sizeof(ent))
		err(2, "read pagemap");

Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Aneesh Kumar K.V <redacted>
---
  tools/testing/selftests/vm/ksm_tests.c        | 8 ++++++++
  tools/testing/selftests/vm/transhuge-stress.c | 8 ++++++++
  2 files changed, 16 insertions(+)

diff --git a/tools/testing/selftests/vm/ksm_tests.c b/tools/testing/selftests/vm/ksm_tests.c
index 1436e1a9a3d3..8200328ff018 100644
--- a/tools/testing/selftests/vm/ksm_tests.c
+++ b/tools/testing/selftests/vm/ksm_tests.c

@@ -22,8 +22,16 @@
  #define KSM_MERGE_ACROSS_NODES_DEFAULT true
  #define MB (1ul << 20)
  
+#ifdef __powerpc64__
+#define PAGE_SHIFT	16
+/*
+ * This will only work with radix 2M hugepage size
+ */
+#define HPAGE_SHIFT 21
+#else
  #define PAGE_SHIFT 12
  #define HPAGE_SHIFT 21
+#endif
  
  #define PAGE_SIZE (1 << PAGE_SHIFT)
  #define HPAGE_SIZE (1 << HPAGE_SHIFT)

diff --git a/tools/testing/selftests/vm/transhuge-stress.c b/tools/testing/selftests/vm/transhuge-stress.c
index 5e4c036f6ad3..f04c8aa4bcf6 100644
--- a/tools/testing/selftests/vm/transhuge-stress.c
+++ b/tools/testing/selftests/vm/transhuge-stress.c

@@ -16,8 +16,16 @@
  #include <string.h>
  #include <sys/mman.h>
  
+#ifdef __powerpc64__
+#define PAGE_SHIFT	16
+/*
+ * This will only work with radix 2M hugepage size
+ */
+#define HPAGE_SHIFT 21

Why not have this is in common code?

Can you suggest where I can move that. We also have helper functions
like allocate_transhuge() duplicated between tests. I didn't find
libutil.a or anything similar supported by the selftets build. 

quoted

+#else
  #define PAGE_SHIFT 12
  #define HPAGE_SHIFT 21

Same here.

quoted

+#endif
  
  #define PAGE_SIZE (1 << PAGE_SHIFT)
  #define HPAGE_SIZE (1 << HPAGE_SHIFT)

Please cc linux-kselftest mailing list in the future.

With the above fixed.

Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah

-aneesh