Messages in this thread | | | Date | Tue, 9 Aug 2011 09:04:55 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [PATCH 2/2] vmscan: activate executable pages after first usage |
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On Tue, 9 Aug 2011 09:02:28 +0900 Minchan Kim <minchan.kim@gmail.com> wrote:
> On Mon, Aug 8, 2011 at 8:07 PM, 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> > > --- > > 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*. >
Hmm ? I thought Old: protect pages if referenced twice New: protect executable page if referenced once.
IIUC, ANON is proteced if it's referenced once.
So, this patch changes EXECUTABLE file to the same class as ANON pages.
Anyway, I agree test/measurement is required.
Thanks, -Kame
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