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Subject: Re: [PATCH] mm/mm_init: use helper macro BITS_PER_LONG
To:     Mike Rapoport <rppt@kernel.org>
CC:     <akpm@linux-foundation.org>, <linux-mm@kvack.org>,
        <linux-kernel@vger.kernel.org>
References: <20230803114051.637709-1-linmiaohe@huawei.com>
 <20230803133346.GH2607694@kernel.org>
From:   Miaohe Lin <linmiaohe@huawei.com>
Message-ID: <b1dd7fd9-3454-c6d7-2195-4dfbc295f56d@huawei.com>
Date:   Fri, 4 Aug 2023 09:53:17 +0800
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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 <linmiaohe@huawei.com>
>> ---
>>  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.