Re: [PATCH 2/2] Filter unevictable page out in deactivate_page

KOSAKI Motohiro
2011-05-02T10:37:36Z

> It's pointless that deactive_page's pagevec operation about
> unevictable page as it's nop.
> This patch removes unnecessary overhead which might be a bit problem
> in case that there are many unevictable page in system(ex, mprotect workload)
>
> Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
> ---
> mm/swap.c | 9 +++++++++
> 1 files changed, 9 insertions(+), 0 deletions(-)
>
> diff --git a/mm/swap.c b/mm/swap.c
> index 2e9656d..b707694 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -511,6 +511,15 @@ static void drain_cpu_pagevecs(int cpu)
> */
> void deactivate_page(struct page *page)
> {
> +
> + /*
> + * In workload which system has many unevictable page(ex, mprotect),
> + * unevictalge page deactivation for accelerating reclaim
> + * is pointless.
> + */
> + if (PageUnevictable(page))
> + return;
> +

Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>

btw, I think we should check PageLRU too.