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

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Thu, 10 Feb 2022 09:42:21 +0530

Shuah Khan <[email-masked]> writes:

> On 2/9/22 8:43 AM, Aneesh Kumar K.V wrote:
>> 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 <[email-masked]>
>> Signed-off-by: Aneesh Kumar K.V <[email-masked]>
>> ---
>>   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. 

>
>> +#else
>>   #define PAGE_SHIFT 12
>>   #define HPAGE_SHIFT 21
>
> Same here.
>
>> +#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 <[email-masked]>
>
> thanks,
> -- Shuah

-aneesh