Re: [PATCH -mm -v7 4/9] mm, THP, swap: Add get_huge_swap_page()

From: Johannes Weiner
Date: Wed Mar 29 2017 - 13:08:11 EST


On Tue, Mar 28, 2017 at 01:32:04PM +0800, Huang, Ying wrote:
> @@ -527,6 +527,23 @@ static inline swp_entry_t get_swap_page(void)
>
> #endif /* CONFIG_SWAP */
>
> +#ifdef CONFIG_THP_SWAP_CLUSTER
> +static inline swp_entry_t get_huge_swap_page(void)
> +{
> + swp_entry_t entry;
> +
> + if (get_swap_pages(1, &entry, true))
> + return entry;
> + else
> + return (swp_entry_t) {0};
> +}
> +#else
> +static inline swp_entry_t get_huge_swap_page(void)
> +{
> + return (swp_entry_t) {0};
> +}
> +#endif

Your introducing a function without a user, making it very hard to
judge whether the API is well-designed for the callers or not.

I pointed this out as a systemic problem with this patch series in v3,
along with other stuff, but with the way this series is structured I'm
having a hard time seeing whether you implemented my other feedback or
whether your counter arguments to them are justified.

I cannot review and ack these patches this way.