Re: [PATCH v14 11/22] selftests/vm: introduce two arch independent abstraction

[Dave Hansen <dave.hansen@intel.com>]

On 07/17/2018 06:49 AM, Ram Pai wrote:
> open_hugepage_file() <- opens the huge page file

Folks, a sentence here would be nice:

	Different architectures have different huge page sizes and thus
	have different sysfs filees to manipulate when allocating huge
	pages.

> get_start_key() <--  provides the first non-reserved key.

Does powerpc not start on key 0?  Why do you need this?

> cc: Dave Hansen <dave.hansen@intel.com>
> cc: Florian Weimer <fweimer@redhat.com>
> Signed-off-by: Ram Pai <linuxram@us.ibm.com>
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
> Reviewed-by: Dave Hansen <dave.hansen@intel.com>
> ---
>  tools/testing/selftests/vm/pkey-helpers.h    |   10 ++++++++++
>  tools/testing/selftests/vm/pkey-x86.h        |    1 +
>  tools/testing/selftests/vm/protection_keys.c |    6 +++---
>  3 files changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/testing/selftests/vm/pkey-helpers.h b/tools/testing/selftests/vm/pkey-helpers.h
> index ada0146..52a1152 100644
> --- a/tools/testing/selftests/vm/pkey-helpers.h
> +++ b/tools/testing/selftests/vm/pkey-helpers.h
> @@ -179,4 +179,14 @@ static inline void __pkey_write_allow(int pkey, int do_allow_write)
>  #define __stringify_1(x...)     #x
>  #define __stringify(x...)       __stringify_1(x)
>  
> +static inline int open_hugepage_file(int flag)
> +{
> +	return open(HUGEPAGE_FILE, flag);
> +}

open_nr_hugepages_file() if you revise this, please
> +
> +static inline int get_start_key(void)
> +{
> +	return 1;
> +}

get_first_user_pkey(), please.

>  #endif /* _PKEYS_HELPER_H */
> diff --git a/tools/testing/selftests/vm/pkey-x86.h b/tools/testing/selftests/vm/pkey-x86.h
> index 2b3780d..d5fa299 100644
> --- a/tools/testing/selftests/vm/pkey-x86.h
> +++ b/tools/testing/selftests/vm/pkey-x86.h
> @@ -48,6 +48,7 @@
>  #define MB			(1<<20)
>  #define pkey_reg_t		u32
>  #define PKEY_REG_FMT		"%016x"
> +#define HUGEPAGE_FILE		"/sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages"
>  
>  static inline u32 pkey_bit_position(int pkey)
>  {
> diff --git a/tools/testing/selftests/vm/protection_keys.c b/tools/testing/selftests/vm/protection_keys.c
> index 2565b4c..2e448e0 100644
> --- a/tools/testing/selftests/vm/protection_keys.c
> +++ b/tools/testing/selftests/vm/protection_keys.c
> @@ -788,7 +788,7 @@ void setup_hugetlbfs(void)
>  	 * Now go make sure that we got the pages and that they
>  	 * are 2M pages.  Someone might have made 1G the default.
>  	 */
> -	fd = open("/sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages", O_RDONLY);
> +	fd = open_hugepage_file(O_RDONLY);
>  	if (fd < 0) {
>  		perror("opening sysfs 2M hugetlb config");
>  		return;

This is fine, and obviously necessary.

> @@ -1075,10 +1075,10 @@ void test_kernel_gup_write_to_write_disabled_region(int *ptr, u16 pkey)
>  void test_pkey_syscalls_on_non_allocated_pkey(int *ptr, u16 pkey)
>  {
>  	int err;
> -	int i;
> +	int i = get_start_key();
>  
>  	/* Note: 0 is the default pkey, so don't mess with it */
> -	for (i = 1; i < NR_PKEYS; i++) {
> +	for (; i < NR_PKEYS; i++) {
>  		if (pkey == i)
>  			continue;

Grumble, grumble, you moved the code away from the comment connected to
it.