Re: [mm-unstable v7 13/18] proc/smaps: add PMDMappable field to smaps

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 12 Jul 2022 10:57:07 -0700 "Zach O'Keefe" <zokeefe@google.com> wrote:

> > I'm not sure what applications rely on this hint, but if they are just
> > some test scripts, I think it should be fine. I don't think we
> > guarantee the test scripts won't get broken. AFAIK some test scripts
> > rely on the kernel dmesg text, for example, OOMs. And the meaning of
> > the fields do change, for example, inactive anon of /proc/meminfo,
> > which was changed by the patchset which put anon pages on inactive
> > list first instead of active list. We already noticed the abnormal
> > value from our monitoring tool when we adopted 5.10+ kernel. And
> > /proc/vmstat also had some fields renamed, for example,
> > workingset_refault of /proc/vmstat, it was split to
> > workseting_refault_anon and workingset_refault_file, so we had to
> > update our monitoring scripts accordingly. I think /proc/meminfo and
> > /proc/vmstat are more heavily used than smaps.
> >
> 
> Thanks for the great context. My guess is, right now, THPelligible is more
> useful as-is than if we were to relax it to MADV_COLLAPSE eligibility. As such,
> I'm fine dropping this until a stronger and more immediate usecase presents
> itself. Thanks for checking my rationale here.

So... should I drop this patch?