Re: [PATCH v2 1/5] hugetlb: use page.private for hugetlb specific page flags

Oscar Salvador
2021-01-20T10:25:44Z

On Tue, Jan 19, 2021 at 05:30:45PM -0800, Mike Kravetz wrote:
> + * Macros to create test, set and clear function definitions for
> + * hugetlb specific page flags.
> + */
> +#ifdef CONFIG_HUGETLB_PAGE
> +#define TESTHPAGEFLAG(uname, flname) \
> +static inline int HPage##uname(struct page *page) \
> + { BUILD_BUG_ON(sizeof_field(struct page, private) * \
> + BITS_PER_BYTE < __NR_HPAGEFLAGS); \
> + return test_bit(HPG_##flname, &(page->private)); }
> +
> +#define SETHPAGEFLAG(uname, flname) \
> +static inline void SetHPage##uname(struct page *page) \
> + { set_bit(HPG_##flname, &(page->private)); }
> +
> +#define CLEARHPAGEFLAG(uname, flname) \
> +static inline void ClearHPage##uname(struct page *page) \
> + { clear_bit(HPG_##flname, &(page->private)); }
> +#else
> +#define TESTHPAGEFLAG(uname, flname) \
> +static inline int HPage##uname(struct page *page) \
> + { BUILD_BUG_ON(sizeof_field(struct page, private) * \
> + BITS_PER_BYTE < __NR_HPAGEFLAGS); \
> + return 0 }

You missed a ";" right there.

I might be missing something, but I do not think we need a BUILD_BUG_ON there
when CONFIG_HUGETLB_PAGE is not set?
Actually, would make more sense to move the BUILD_BUG_ON from above to
hugetlb_init?

Other than that, looks good to me, and I think it is a great improvment
towards readability and maintability.

--
Oscar Salvador
SUSE L3