Re: [PATCH 2/2] vmscan: activate executable pages after first usage

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

On Mon, 8 Aug 2011 15:07:00 +0400
Konstantin Khlebnikov <khlebnikov@openvz.org> wrote:

> Logic added in commit v2.6.30-5507-g8cab475
> (vmscan: make mapped executable pages the first class citizen)
> was noticeably weakened in commit v2.6.33-5448-g6457474
> (vmscan: detect mapped file pages used only once)
> 
> Currently these pages can become "first class citizens" only after second usage.
> 
> After this patch page_check_references() will activate they after first usage,
> and executable code gets yet better chance to stay in memory.
> 
> TODO:
> run some cool tests like in v2.6.30-5507-g8cab475 =)
> 
> Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>

How effective does this work on your test ?



> ---
>  mm/vmscan.c |    6 ++++++
>  1 files changed, 6 insertions(+), 0 deletions(-)
> 
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 3cd766d..29b3612 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -727,6 +727,12 @@ static enum page_references page_check_references(struct page *page,
>  		if (referenced_page || referenced_ptes > 1)
>  			return PAGEREF_ACTIVATE;
>  
> +		/*
> +		 * Activate file-backed executable pages after first usage.
> +		 */
> +		if (vm_flags & VM_EXEC)
> +			return PAGEREF_ACTIVATE;
> +
>  		return PAGEREF_KEEP;
>  	}
>  
> 
> 

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>