Re: + mm-mark-idle-page-tracking-as-broken.patch added to -mm tree

[Rafael Aquini <aquini@redhat.com>]

On Thu, Jun 17, 2021 at 04:37:17PM +0100, Matthew Wilcox wrote:
> On Wed, Jun 16, 2021 at 06:29:19PM -0400, Rafael Aquini wrote:
> > > In discussion with other MM developers around how idle page tracking
> > > should be fixed for transparent huge pages, several expressed the opinion
> > > that it should be removed as it is inefficient at accomplishing the job
> > > that it is supposed to, and we have better mechanisms (eg uffd) for
> > > accomplishing the same goals these days.
> > 
> > I didn't follow the aforementioned discussion, so it would be nice to
> > have a little bit more detailed explanation on both points raised here
> > (issues with THP and innefficiency). There are some Red Hat customers
> > and partners that do rely on the feature, thus the interest. Thanks.
> 
> It would be nice if you asked this on the original thread (which you're
> cc'd on) instead of starting a new thread.

Sorry about that, but for some weird reason only Andrew's email made its way
into my inbox.



> > > Mark the feature as BROKEN for now and we can remove it entirely in a few
> > > months if nobody complains.  It is not enabled by Android, ChromeOS,
> > > Debian, Fedora or SUSE.  Red Hat enabled it with RHEL-8.1 and UEK followed
> > > suit, but I have been unable to find why RHEL enabled it.
> > 
> > minor nit on the RHEL mention: CONFIG_IDLE_PAGE_TRACKING is enabled since 8.0
> > for RHEL-8, and 7.7 for RHEL-7.
> 
> Red Hat makes it incredibly hard to find out what changed when.
> You can't then whine about us not understanding what you're doing,
> when you're going out of your way to obfuscate what you do.
>

Not whining about it, just pointing out the fixup. That's part
of the review process, isn't it? There's no need to whine back at it.