2021-03-23 14:06:39

by Andrew Jones

Subject: Re: [RFC PATCH v5 02/10] tools headers: Add a macro to get HUGETLB page sizes for mmap

$SUBJECT says "tools headers", but this is actually changing
a UAPI header and then copying the change to tools.

Thanks,
drew

On Tue, Mar 23, 2021 at 09:52:23PM +0800, Yanan Wang wrote:
> We know that if a system supports multiple hugetlb page sizes,
> the desired hugetlb page size can be specified in bits [26:31]
> of the flag arguments. The value in these 6 bits will be the
> shift of each hugetlb page size.
>
> So add a macro to get the page size shift and then calculate the
> corresponding hugetlb page size, using flag x.
>
> Cc: Ben Gardon <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Adrian Hunter <[email protected]>
> Cc: Jiri Olsa <[email protected]>
> Cc: Arnaldo Carvalho de Melo <[email protected]>
> Cc: Arnd Bergmann <[email protected]>
> Cc: Michael Kerrisk <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Suggested-by: Ben Gardon <[email protected]>
> Signed-off-by: Yanan Wang <[email protected]>
> Reviewed-by: Ben Gardon <[email protected]>
> ---
> include/uapi/linux/mman.h | 2 ++
> tools/include/uapi/linux/mman.h | 2 ++
> 2 files changed, 4 insertions(+)
>
> diff --git a/include/uapi/linux/mman.h b/include/uapi/linux/mman.h
> index f55bc680b5b0..d72df73b182d 100644
> --- a/include/uapi/linux/mman.h
> +++ b/include/uapi/linux/mman.h
> @@ -41,4 +41,6 @@
> #define MAP_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB
> #define MAP_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB
>
> +#define MAP_HUGE_PAGE_SIZE(x) (1ULL << ((x >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))
> +
> #endif /* _UAPI_LINUX_MMAN_H */
> diff --git a/tools/include/uapi/linux/mman.h b/tools/include/uapi/linux/mman.h
> index f55bc680b5b0..d72df73b182d 100644
> --- a/tools/include/uapi/linux/mman.h
> +++ b/tools/include/uapi/linux/mman.h
> @@ -41,4 +41,6 @@
> #define MAP_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB
> #define MAP_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB
>
> +#define MAP_HUGE_PAGE_SIZE(x) (1ULL << ((x >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))
> +
> #endif /* _UAPI_LINUX_MMAN_H */
> --
> 2.19.1
>

2021-03-24 21:46:59

by Yanan Wang

Subject: Re: [RFC PATCH v5 02/10] tools headers: Add a macro to get HUGETLB page sizes for mmap

On 2021/3/23 22:03, Andrew Jones wrote:
> $SUBJECT says "tools headers", but this is actually changing
> a UAPI header and then copying the change to tools.
Indeed. I think head of the subject should be "mm/hugetlb".
I will fix it.

Thanks,
Yanan
> Thanks,
> drew
>
> On Tue, Mar 23, 2021 at 09:52:23PM +0800, Yanan Wang wrote:
>> We know that if a system supports multiple hugetlb page sizes,
>> the desired hugetlb page size can be specified in bits [26:31]
>> of the flag arguments. The value in these 6 bits will be the
>> shift of each hugetlb page size.
>>
>> So add a macro to get the page size shift and then calculate the
>> corresponding hugetlb page size, using flag x.
>>
>> Cc: Ben Gardon <[email protected]>
>> Cc: Ingo Molnar <[email protected]>
>> Cc: Adrian Hunter <[email protected]>
>> Cc: Jiri Olsa <[email protected]>
>> Cc: Arnaldo Carvalho de Melo <[email protected]>
>> Cc: Arnd Bergmann <[email protected]>
>> Cc: Michael Kerrisk <[email protected]>
>> Cc: Thomas Gleixner <[email protected]>
>> Suggested-by: Ben Gardon <[email protected]>
>> Signed-off-by: Yanan Wang <[email protected]>
>> Reviewed-by: Ben Gardon <[email protected]>
>> ---
>> include/uapi/linux/mman.h | 2 ++
>> tools/include/uapi/linux/mman.h | 2 ++
>> 2 files changed, 4 insertions(+)
>>
>> diff --git a/include/uapi/linux/mman.h b/include/uapi/linux/mman.h
>> index f55bc680b5b0..d72df73b182d 100644
>> --- a/include/uapi/linux/mman.h
>> +++ b/include/uapi/linux/mman.h
>> @@ -41,4 +41,6 @@
>> #define MAP_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB
>> #define MAP_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB
>>
>> +#define MAP_HUGE_PAGE_SIZE(x) (1ULL << ((x >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))
>> +
>> #endif /* _UAPI_LINUX_MMAN_H */
>> diff --git a/tools/include/uapi/linux/mman.h b/tools/include/uapi/linux/mman.h
>> index f55bc680b5b0..d72df73b182d 100644
>> --- a/tools/include/uapi/linux/mman.h
>> +++ b/tools/include/uapi/linux/mman.h
>> @@ -41,4 +41,6 @@
>> #define MAP_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB
>> #define MAP_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB
>>
>> +#define MAP_HUGE_PAGE_SIZE(x) (1ULL << ((x >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))
>> +
>> #endif /* _UAPI_LINUX_MMAN_H */
>> --
>> 2.19.1
>>
> .