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

From: Shaohua Li
Date: Mon Aug 08 2011 - 21:23:34 EST


On Mon, 2011-08-08 at 19:07 +0800, Konstantin Khlebnikov 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 =)
I used to post a similar patch here:
http://marc.info/?l=linux-mm&m=128572906801887&w=2
but running Fengguang's test doesn't show improvement. And actually the
VM_EXEC protect in shrink_active_list() doesn't show improvement too in
my run, I'm wondering if we should remove it. I guess the (vmscan:
detect mapped file pages used only once) patch makes VM_EXEC protect
lose its effect. It's great if you can show solid data.

Thanks,
Shaohua

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