Re: [PATCH v1 3/4] mm: account nr_isolated_xxx in [isolate|putback]_lru_page

[Hillf Danton <hdanton@sina.com>]

Hi Minchan

On Mon, 3 Jun 2019 13:37:27 +0800 Minchan Kim wrote:
> @@ -1181,10 +1179,17 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page,
>  		return -ENOMEM;
> 
>  	if (page_count(page) == 1) {
> +		bool is_lru = !__PageMovable(page);
> +
>  		/* page was freed from under us. So we are done. */
>  		ClearPageActive(page);
>  		ClearPageUnevictable(page);
> -		if (unlikely(__PageMovable(page))) {
> +		if (likely(is_lru))
> +			mod_node_page_state(page_pgdat(page),
> +						NR_ISOLATED_ANON +
> +						page_is_file_cache(page),
> +						hpage_nr_pages(page));
> +		else {
>  			lock_page(page);
>  			if (!PageMovable(page))
>  				__ClearPageIsolated(page);

As this page will go down the path only through the MIGRATEPAGE_SUCCESS branches,
with no putback ahead, the current code is, I think, doing right things for this
work to keep isolated stat balanced.

> @@ -1210,15 +1215,6 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page,
>  		 * restored.
>  		 */
>  		list_del(&page->lru);
> -
> -		/*
> -		 * Compaction can migrate also non-LRU pages which are
> -		 * not accounted to NR_ISOLATED_*. They can be recognized
> -		 * as __PageMovable
> -		 */
> -		if (likely(!__PageMovable(page)))
> -			mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON +
> -					page_is_file_cache(page), -hpage_nr_pages(page));
>  	}
> 

BR
Hillf