Re: [PATCH 2/5] mm, vmscan: Remove highmem_file_pages

[Minchan Kim]

On Thu, Jul 21, 2016 at 03:10:58PM +0100, Mel Gorman wrote:
> With the reintroduction of per-zone LRU stats, highmem_file_pages is
> redundant so remove it.
> 
> Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
> ---
>  include/linux/mm_inline.h | 17 -----------------
>  mm/page-writeback.c       | 12 ++++--------
>  2 files changed, 4 insertions(+), 25 deletions(-)
> 
> diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
> index 9cc130f5feb2..71613e8a720f 100644
> --- a/include/linux/mm_inline.h
> +++ b/include/linux/mm_inline.h
> @@ -4,22 +4,6 @@
>  #include <linux/huge_mm.h>
>  #include <linux/swap.h>
>  
> -#ifdef CONFIG_HIGHMEM
> -extern atomic_t highmem_file_pages;
> -
> -static inline void acct_highmem_file_pages(int zid, enum lru_list lru,
> -							int nr_pages)
> -{
> -	if (is_highmem_idx(zid) && is_file_lru(lru))
> -		atomic_add(nr_pages, &highmem_file_pages);
> -}
> -#else
> -static inline void acct_highmem_file_pages(int zid, enum lru_list lru,
> -							int nr_pages)
> -{
> -}
> -#endif
> -
>  /**
>   * page_is_file_cache - should the page be on a file LRU or anon LRU?
>   * @page: the page to test
> @@ -47,7 +31,6 @@ static __always_inline void __update_lru_size(struct lruvec *lruvec,
>  	__mod_node_page_state(pgdat, NR_LRU_BASE + lru, nr_pages);
>  	__mod_zone_page_state(&pgdat->node_zones[zid],
>  				NR_ZONE_LRU_BASE + lru, nr_pages);
> -	acct_highmem_file_pages(zid, lru, nr_pages);
>  }
>  
>  static __always_inline void update_lru_size(struct lruvec *lruvec,
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 573d138fa7a5..cfa78124c3c2 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -299,17 +299,13 @@ static unsigned long node_dirtyable_memory(struct pglist_data *pgdat)
>  
>  	return nr_pages;
>  }
> -#ifdef CONFIG_HIGHMEM
> -atomic_t highmem_file_pages;
> -#endif
>  
>  static unsigned long highmem_dirtyable_memory(unsigned long total)
>  {
>  #ifdef CONFIG_HIGHMEM
>  	int node;
> -	unsigned long x;
> +	unsigned long x = 0;
>  	int i;
> -	unsigned long dirtyable = 0;
>  
>  	for_each_node_state(node, N_HIGH_MEMORY) {
>  		for (i = ZONE_NORMAL + 1; i < MAX_NR_ZONES; i++) {
> @@ -326,12 +322,12 @@ static unsigned long highmem_dirtyable_memory(unsigned long total)
>  			nr_pages = zone_page_state(z, NR_FREE_PAGES);
>  			/* watch for underflows */
>  			nr_pages -= min(nr_pages, high_wmark_pages(z));
> -			dirtyable += nr_pages;
> +			nr_pages += zone_page_state(z, NR_INACTIVE_FILE);

                                                       NR_ZONE_INACTIVE_FILE

> +			nr_pages += zone_page_state(z, NR_ACTIVE_FILE);

                                                       NR_ZONE_ACTIVE_FILE

> +			x += nr_pages;