Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

Michal Suchánek
2019-03-06T11:44:59Z

On Wed, 06 Mar 2019 14:47:33 +0530
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> wrote:

> Dan Williams <dan.j.williams@intel.com> writes:
>
> > On Thu, Feb 28, 2019 at 1:40 AM Oliver <oohall@gmail.com> wrote:
> >>
> >> On Thu, Feb 28, 2019 at 7:35 PM Aneesh Kumar K.V
> >> <aneesh.kumar@linux.ibm.com> wrote:

> Also even if the user decided to not use THP, by
> echo "never" > transparent_hugepage/enabled , we should continue to map
> dax fault using huge page on platforms that can support huge pages.

Is this a good idea?

This knob is there for a reason. In some situations having huge pages
can severely impact performance of the system (due to host-guest
interaction or whatever) and the ability to really turn off all THP
would be important in those cases, right?

Thanks

Michal