Re: [PATCH 2/2] mm/page_alloc: use a single function to free page

[Dave Hansen]

On 11/5/18 12:58 AM, Aaron Lu wrote:
> We have multiple places of freeing a page, most of them doing similar
> things and a common function can be used to reduce code duplicate.
> 
> It also avoids bug fixed in one function and left in another.

Haha, should have read the next patch. :)

> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 91a9a6af41a2..2b330296e92a 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -4425,9 +4425,17 @@ unsigned long get_zeroed_page(gfp_t gfp_mask)
>  }
>  EXPORT_SYMBOL(get_zeroed_page);
>  
> -void __free_pages(struct page *page, unsigned int order)
> +/*
> + * Free a page by reducing its ref count by @nr.
> + * If its refcount reaches 0, then according to its order:
> + * order0: send to PCP;
> + * high order: directly send to Buddy.
> + */

FWIW, I'm not a fan of comments on the function like this.  Please just
comment the *code* that's doing what you describe.  It's easier to read
and less likely to diverge from the code.

The rest of the patch looks great, though.