Re: [PATCH -mm] vmscan: make mapped executable pages the first class citizen

Peter Zijlstra
2009-05-07T14:38:57Z

On Thu, 2009-05-07 at 10:18 -0400, Christoph Lameter wrote:
> On Thu, 7 May 2009, Peter Zijlstra wrote:
>
> > It re-instates the young bit for PROT_EXEC pages, so that they will only
> > be paged when they are really cold, or there is severe pressure.
>
> But they are rescanned until then. Really cold means what exactly? I do a
> back up of a few hundred gigabytes and do not use firefox while the backup
> is ongoing. Will the firefox pages still be in memory or not?

Likely not.

What this patch does is check the young bit on active_file scan, if its
found to be set and the page is PROT_EXEC, put the page back on the
active_file list, otherwise drop it to the inactive_file list.

So if you haven't ran any firefox code, it should be gone from the
active list after 2 full cycles, and from the inactive list on the first
full inactive cycle after that.

If you don't understand the patch, what are you complaining about, whats
your point?