Re: [PATCH v5 10/12] mm/gup: /proc/vmstat: pin_user_pages (FOLL_PIN) reporting

[Jan Kara]

On Thu 06-02-20 19:37:33, John Hubbard wrote:
> @@ -2258,6 +2268,8 @@ static int record_subpages(struct page *page, unsigned long addr,
>  
>  static void put_compound_head(struct page *page, int refs, unsigned int flags)
>  {
> +	int orig_refs = refs;
> +
>  	if (flags & FOLL_PIN) {
>  		if (hpage_pincount_available(page))
>  			hpage_pincount_sub(page, refs);
> @@ -2273,6 +2285,8 @@ static void put_compound_head(struct page *page, int refs, unsigned int flags)
>  	if (refs > 1)
>  		page_ref_sub(page, refs - 1);
>  	put_page(page);
> +
> +	mod_node_page_state(page_pgdat(page), NR_FOLL_PIN_RELEASED, orig_refs);
>  }

Still not quite happy about this :) Now you update NR_FOLL_PIN_RELEASED
even if 'flags' don't have FOLL_PIN set. You need to have the
mod_node_page_state() inside the "if (flags & FOLL_PIN)" branch above...

									Honza
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR