Re: [rfc] no ZERO_PAGE?

Hugh Dickins
2007-04-04T13:32:03Z

On Wed, 4 Apr 2007, Andrea Arcangeli wrote:
> On Wed, Apr 04, 2007 at 01:45:06PM +0100, Hugh Dickins wrote:
> > I'm confused. CONFIG_ZERO_PAGE off is where we'd like to end up: how
> > would turning CONFIG_ZERO_PAGE on in -rc kernels help us to get there?
>
> He most certainly meant on by default.

Okay, I thought it more diplomatic to label myself as the confused one ;)

>
> I think if we do this, we also need a zeropage counter in the vm stats
> so that we'll get a measure of the waste and it'll be possible to
> identify apps to optimize/fix.

That's a little unfortunate, since we'd then have to lose the win from
this change, that we issue a writable zeroed page (when VM_WRITE) in
do_anonymous_page, even when it's a read fault, saving subsequent fault.

Wouldn't we? Or am I confused ;?

Hugh