2023-08-03 12:04:58

by Miaohe Lin

Subject: [PATCH] mm/mm_init: use helper macro BITS_PER_LONG

It's more readable to use helper macro BITS_PER_LONG. No functional
change intended.

Signed-off-by: Miaohe Lin <[email protected]>
---
mm/mm_init.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/mm_init.c b/mm/mm_init.c
index 66aca3f6accd..2f37dbb5ff9a 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -79,7 +79,7 @@ void __init mminit_verify_pageflags_layout(void)
int shift, width;
unsigned long or_mask, add_mask;

- shift = 8 * sizeof(unsigned long);
+ shift = BITS_PER_LONG;
width = shift - SECTIONS_WIDTH - NODES_WIDTH - ZONES_WIDTH
- LAST_CPUPID_SHIFT - KASAN_TAG_WIDTH - LRU_GEN_WIDTH - LRU_REFS_WIDTH;
mminit_dprintk(MMINIT_TRACE, "pageflags_layout_widths",
@@ -1431,7 +1431,7 @@ static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned l
usemapsize = roundup(zonesize, pageblock_nr_pages);
usemapsize = usemapsize >> pageblock_order;
usemapsize *= NR_PAGEBLOCK_BITS;
- usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
+ usemapsize = roundup(usemapsize, BITS_PER_LONG);

return usemapsize / 8;
}
--
2.33.0

2023-08-03 14:02:55

by Mike Rapoport

Subject: Re: [PATCH] mm/mm_init: use helper macro BITS_PER_LONG

On Thu, Aug 03, 2023 at 07:40:51PM +0800, Miaohe Lin wrote:
> It's more readable to use helper macro BITS_PER_LONG. No functional
> change intended.
>
> Signed-off-by: Miaohe Lin <[email protected]>
> ---
> mm/mm_init.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/mm_init.c b/mm/mm_init.c
> index 66aca3f6accd..2f37dbb5ff9a 100644
> --- a/mm/mm_init.c
> +++ b/mm/mm_init.c
> @@ -79,7 +79,7 @@ void __init mminit_verify_pageflags_layout(void)
> int shift, width;
> unsigned long or_mask, add_mask;
>
> - shift = 8 * sizeof(unsigned long);
> + shift = BITS_PER_LONG;
> width = shift - SECTIONS_WIDTH - NODES_WIDTH - ZONES_WIDTH
> - LAST_CPUPID_SHIFT - KASAN_TAG_WIDTH - LRU_GEN_WIDTH - LRU_REFS_WIDTH;
> mminit_dprintk(MMINIT_TRACE, "pageflags_layout_widths",
> @@ -1431,7 +1431,7 @@ static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned l
> usemapsize = roundup(zonesize, pageblock_nr_pages);
> usemapsize = usemapsize >> pageblock_order;
> usemapsize *= NR_PAGEBLOCK_BITS;
> - usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
> + usemapsize = roundup(usemapsize, BITS_PER_LONG);
>
> return usemapsize / 8;

BITS_PER_BYTE instead of 8 here?

> }

--
Sincerely yours,
Mike.

2023-08-03 15:46:44

by David Hildenbrand

Subject: Re: [PATCH] mm/mm_init: use helper macro BITS_PER_LONG

On 03.08.23 13:40, Miaohe Lin wrote:
> It's more readable to use helper macro BITS_PER_LONG. No functional
> change intended.
>
> Signed-off-by: Miaohe Lin <[email protected]>
> ---
> mm/mm_init.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/mm_init.c b/mm/mm_init.c
> index 66aca3f6accd..2f37dbb5ff9a 100644
> --- a/mm/mm_init.c
> +++ b/mm/mm_init.c
> @@ -79,7 +79,7 @@ void __init mminit_verify_pageflags_layout(void)
> int shift, width;
> unsigned long or_mask, add_mask;
>
> - shift = 8 * sizeof(unsigned long);
> + shift = BITS_PER_LONG;
> width = shift - SECTIONS_WIDTH - NODES_WIDTH - ZONES_WIDTH
> - LAST_CPUPID_SHIFT - KASAN_TAG_WIDTH - LRU_GEN_WIDTH - LRU_REFS_WIDTH;
> mminit_dprintk(MMINIT_TRACE, "pageflags_layout_widths",
> @@ -1431,7 +1431,7 @@ static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned l
> usemapsize = roundup(zonesize, pageblock_nr_pages);
> usemapsize = usemapsize >> pageblock_order;
> usemapsize *= NR_PAGEBLOCK_BITS;
> - usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
> + usemapsize = roundup(usemapsize, BITS_PER_LONG);
>
> return usemapsize / 8;
> }

Reviewed-by: David Hildenbrand <[email protected]>

--
Cheers,

David / dhildenb

2023-08-04 02:34:45

by Miaohe Lin

Subject: Re: [PATCH] mm/mm_init: use helper macro BITS_PER_LONG

On 2023/8/3 21:33, Mike Rapoport wrote:
> On Thu, Aug 03, 2023 at 07:40:51PM +0800, Miaohe Lin wrote:
>> It's more readable to use helper macro BITS_PER_LONG. No functional
>> change intended.
>>
>> Signed-off-by: Miaohe Lin <[email protected]>
>> ---
>> mm/mm_init.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/mm_init.c b/mm/mm_init.c
>> index 66aca3f6accd..2f37dbb5ff9a 100644
>> --- a/mm/mm_init.c
>> +++ b/mm/mm_init.c
>> @@ -79,7 +79,7 @@ void __init mminit_verify_pageflags_layout(void)
>> int shift, width;
>> unsigned long or_mask, add_mask;
>>
>> - shift = 8 * sizeof(unsigned long);
>> + shift = BITS_PER_LONG;
>> width = shift - SECTIONS_WIDTH - NODES_WIDTH - ZONES_WIDTH
>> - LAST_CPUPID_SHIFT - KASAN_TAG_WIDTH - LRU_GEN_WIDTH - LRU_REFS_WIDTH;
>> mminit_dprintk(MMINIT_TRACE, "pageflags_layout_widths",
>> @@ -1431,7 +1431,7 @@ static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned l
>> usemapsize = roundup(zonesize, pageblock_nr_pages);
>> usemapsize = usemapsize >> pageblock_order;
>> usemapsize *= NR_PAGEBLOCK_BITS;
>> - usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
>> + usemapsize = roundup(usemapsize, BITS_PER_LONG);
>>
>> return usemapsize / 8;
>
> BITS_PER_BYTE instead of 8 here?

Sure, this is even better. Will do.

Thanks.