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

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Date:	Tue, 09 Aug 2011 09:23:29 +0800
From:	Shaohua Li <shaohua.li@...el.com>
To:	Konstantin Khlebnikov <khlebnikov@...nvz.org>
Cc:	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Wu, Fengguang" <fengguang.wu@...el.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Johannes Weiner <hannes@...xchg.org>
Subject: Re: [PATCH 2/2] vmscan: activate executable pages after first usage

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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