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

On 4/10/20 12:16 PM, Peter Xu wrote:

On Wed, Apr 01, 2020 at 11:38:16AM -0700, Mike Kravetz wrote:

quoted

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