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

From: Minchan Kim
Date: Mon Aug 08 2011 - 20:02:32 EST

On Mon, Aug 8, 2011 at 8:07 PM, Konstantin Khlebnikov
<khlebnikov@xxxxxxxxxx> 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.
> run some cool tests like in v2.6.30-5507-g8cab475 =)
> Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx>
> ---

It might be a very controversial topic.
AFAIR, at least, we did when vmscan: make mapped executable pages the
first class citizen was merged. :)

You try to change behavior.

Old : protect *working set* executable page
New: protect executable page *unconditionally*.

At least, old logic can ignore some executable pages which are not
accessed recently.

Wu had many testing to persuade others.
As you said, we need some number to change policy.

Kind regards,
Minchan Kim
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at