On Wed, Oct 24, 2012 at 01:25:52PM -0700, Andrew Morton wrote:

On Wed, 24 Oct 2012 22:45:52 +0300
"Kirill A. Shutemov" [off-list ref] wrote:

quoted

On Wed, Oct 24, 2012 at 12:22:53PM -0700, Andrew Morton wrote:

quoted

I'm thinking that such a workload would be the above dd in parallel
with a small app which touches the huge page and then exits, then gets
executed again.  That "small app" sounds realistic to me.  Obviously
one could exercise the zero page's refcount at higher frequency with a
tight map/touch/unmap loop, but that sounds less realistic.  It's worth
trying that exercise as well though.

Or do something else.  But we should try to probe this code's
worst-case behaviour, get an understanding of its effects and then
decide whether any such workload is realisic enough to worry about.

Okay, I'll try few memory pressure scenarios.

Thanks.

quoted

Meanwhile, could you take patches 01-09? Patch 09 implements simpler
allocation scheme. It would be nice to get all other code tested.
Or do you see any other blocker?

I think I would take them all, to get them tested while we're still
poking at the code.  It's a matter of getting my lazy ass onto reviewing
the patches.

The patches have a disturbing lack of reviewed-by's, acked-by's and
tested-by's on them.  Have any other of the MM lazy asses actually
spent some time with them yet?

Andrea Revieved-by previous version of the patchset, but I've dropped the
tag after rebase to v3.7-rc1 due not-so-trivial conflicts. Patches 2, 3,
4, 7, 10 had conflicts. Mostly due new MMU notifiers interface.

I mentioned that in cover letter.

-- 
 Kirill A. Shutemov