Re: [PATCH 2/3] vmscan: make mapped executable pages the first class citizen

[Wu Fengguang <fengguang.wu@intel.com>]

On Tue, May 19, 2009 at 04:05:51PM +0800, Pekka Enberg wrote:
> Hi Peter,
> 
> On Tue, 2009-05-19 at 09:44 +0200, Peter Zijlstra wrote:
> > Its a sekrit conspiracy against bloat by making JIT'd crap run
> > slower :-)
> > 
> > <rant>
> > Anyway, I just checked, we install tons of mono junk for _2_
> > applications, f-spot and tomboy, both are shite and both have
> > alternatives not requiring this disease.
> > </rant>
> 
> :-)
> 
> On Tue, 2009-05-19 at 09:44 +0200, Peter Zijlstra wrote:
> > But seriously, like Kosaka-san already said, anonymous pages are treated
> > differently from file pages and should not suffer the same problems.
> 
> OK, thanks for the explanation. The comment is a little bit misleading
> because I got the impression that we don't care about anon exec pages.

Ah yes!  Will this one dismiss the possible mis-interception?

                        /*
                         * Identify referenced, file-backed active pages and
                         * give them one more trip around the active list. So
                         * that executable code get better chances to stay in
                         * memory under moderate memory pressure.  Anon pages
modified ==>             * are not likely to be evicted by use-once streaming
modified ==>             * IO, plus JVM can create lots of anon VM_EXEC pages,
modified ==>             * so we ignore them here.
                         */
                        if ((vm_flags & VM_EXEC) && !PageAnon(page)) {
                                list_add(&page->lru, &l_active);
                                continue;
                        }