Re: [PATCH v2 1/4] hugetlbfs: add arch_hugetlb_valid_size

[Mike Kravetz <mike.kravetz@oracle.com>]

On 4/10/20 12:16 PM, Peter Xu wrote:
> On Wed, Apr 01, 2020 at 11:38:16AM -0700, Mike Kravetz wrote:
>> diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h
>> index 2eb6c234d594..81606223494f 100644
>> --- a/arch/arm64/include/asm/hugetlb.h
>> +++ b/arch/arm64/include/asm/hugetlb.h
>> @@ -59,6 +59,8 @@ extern void huge_pte_clear(struct mm_struct *mm, unsigned long addr,
>>  extern void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr,
>>  				 pte_t *ptep, pte_t pte, unsigned long sz);
>>  #define set_huge_swap_pte_at set_huge_swap_pte_at
>> +bool __init arch_hugetlb_valid_size(unsigned long size);
>> +#define arch_hugetlb_valid_size arch_hugetlb_valid_size
> 
> Sorry for chimming in late.

Thank you for taking a look!

> Since we're working on removing arch-dependent codes after all.. I'm
> thinking whether we can define arch_hugetlb_valid_size() once in the
> common header (e.g. linux/hugetlb.h), then in mm/hugetlb.c:
> 
> bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size)
> {
> 	return size == HPAGE_SIZE;
> }
> 
> We can simply redefine arch_hugetlb_valid_size() in arch specific C
> files where we want to override the default.  Would that be slightly
> cleaner?

I think both the #define X X and weak attribute methods are acceptable.
I went with the #define method only because it was most familiar to me.
Using the weak attribute method does appear to be cleaner.  I'll code it up.

Anyone else have a preference?
-- 
Mike Kravetz