Re: [PATCH] mm/mm_init.c: use round_up() to align movable range

[Wei Yang <richard.weiyang@gmail.com>]

On Tue, Feb 11, 2025 at 11:43:52PM +0530, Shivank Garg wrote:
>
>
>On 2/7/2025 3:34 PM, Wei Yang wrote:
>> Since MAX_ORDER_NR_PAGES is power of 2, let's use a faster version.
>
>Makes sense to me.
>
>Reviewed-by: Shivank Garg <shivankg@amd.com>
>

Thanks for taking a look.

>
>I noticed two similar instances in the same file
>where round_up() might also be applicable:
>
>  mm_init.c (usemap_size):
>    usemapsize = roundup(zonesize, pageblock_nr_pages);
>    usemapsize = roundup(usemapsize, BITS_PER_LONG);
>
>Since both pageblock_nr_pages (1UL << pageblock_order) and BITS_PER_LONG (32 or 64)
>are powers of 2, these could potentially use round_up() as well. Perhaps 
>worth considering in a follow-up patch?

It looks reasonable to me. I would prepare one.

Thanks.

>
>Thanks,
>Shivank
>
>
>
>> 
>> Signed-off-by: Wei Yang <richard.weiyang@gmail.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 dec4084fe15a..99ef70a8b63c 100644
>> --- a/mm/mm_init.c
>> +++ b/mm/mm_init.c
>> @@ -438,7 +438,7 @@ static void __init find_zone_movable_pfns_for_nodes(void)
>>  		 * was requested by the user
>>  		 */
>>  		required_movablecore =
>> -			roundup(required_movablecore, MAX_ORDER_NR_PAGES);
>> +			round_up(required_movablecore, MAX_ORDER_NR_PAGES);
>>  		required_movablecore = min(totalpages, required_movablecore);
>>  		corepages = totalpages - required_movablecore;
>>  
>> @@ -549,7 +549,7 @@ static void __init find_zone_movable_pfns_for_nodes(void)
>>  		unsigned long start_pfn, end_pfn;
>>  
>>  		zone_movable_pfn[nid] =
>> -			roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
>> +			round_up(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
>>  
>>  		get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
>>  		if (zone_movable_pfn[nid] >= end_pfn)

-- 
Wei Yang
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