Re: [PATCH v4 1/4] mm: add NR_SECONDARY_PAGETABLE to count secondary page table uses.

Shakeel Butt
2022-05-12T20:37:01Z

On Mon, May 9, 2022 at 9:38 AM Yosry Ahmed <yosryahmed@google.com> wrote:
>
[...]
> > >
> > > What do you plan to do for IOMMU page tables? After all, they serve
> > > the exact same purpose, and I'd expect these to be handled the same
> > > way (i.e. why is this KVM specific?).
> >
> > The reason this was named NR_SECONDARY_PAGTABLE instead of
> > NR_KVM_PAGETABLE is exactly that. To leave room to incrementally
> > account other types of secondary page tables to this stat. It is just
> > that we are currently interested in the KVM MMU usage.
> >
>
>
> Any thoughts on this? Do you think MEMCG_SECONDARY_PAGETABLE would be
> more appropriate here?

I think NR_SECONDARY_PAGTABLE is good. Later it can include pagetables
from other subsystems. The only nit (which you can ignore) I have is
the very long memcg stat and vmstat names. Other than that the patch
looks good to me.