On Tue 31-05-22 16:47:49, Yang Shi wrote:
> On Fri, May 27, 2022 at 2:46 AM Michal Hocko <mhocko@xxxxxxxx> wrote:
[...]
> > I really do not see any good reason to tightly couple kernel and user
> > policies. Hints like MADV_{NO}HUGEPAGE are one thing and both kernel
> > and userspace might decide to interpret them. But binding MADV_COLLAPSE
> > to in kernel THP tunables just seems like pushing ourselves into the
> > corner.
>
> I don't mean we should tightly couple kernel and user policies. I
> think it is about how "never" is treated. AFAICT, typically sys admins
> tend to expect "never" as a global switch and they don't expect any
> THP allocation should happen in "never" mode even though it is
> requested by the users. Maybe they should not expect so in the first
> place.
But this is not how the knob works, right? At least shmem has its own
thing. So we do not have any global kill switch for transparent huge
pages.
--
Michal Hocko
SUSE Labs
