Re: [PATCH 0/2] mm: introduce per-order mTHP split counters

[David Hildenbrand]

On 24.04.24 17:20, Ryan Roberts wrote:
> On 24/04/2024 16:00, David Hildenbrand wrote:
> > On 24.04.24 15:51, Lance Yang wrote:
> > > Hi all,
> > >
> > > At present, the split counters in THP statistics no longer include
> > > PTE-mapped mTHP. Therefore, we want to introduce per-order mTHP split
> > > counters to monitor the frequency of mTHP splits. This will assist
> > > developers in better analyzing and optimizing system performance.
> > >
> > > /sys/kernel/mm/transparent_hugepage/hugepages-<size>/stats
> > >           split_page
> > >           split_page_failed
> > >           deferred_split_page
> > >
> > > Thanks,
> > > Lance
> > > ---
> > >
> > > Lance Yang (2):
> > >    mm: add per-order mTHP split counters
> > >    mm: add docs for per-order mTHP split counters
> > >
> > >    Documentation/admin-guide/mm/transhuge.rst | 16 ----------------
> >
> > We really have to start documenting these, and what the sementics are.
>
> I think the diffstat is backwards; the series definitely adds more lines than it
> removes. And patch 2 is adding 16 lines of docs, not removing them. How are you
> generating this? `git format-patch` should do it correctly for you.
>
> > E.g., is split_page_failed contained in split_page? Is deferred_split_page
> > contained in split_page?
> >
> > But also: just don't call it "split_page". Drop the "_page".
> >
> > split
> > split_failed
> > split_deferred
>
> I guess we are back in "should we be consistent with the existing vmstats"
> territory, which uses split_page/split_page_failed/deferred_split_page

Yeah, "thp_split_page" really is odd "transparent huge page split page".

> But here, I agree that dropping _page is nicer.
Right; we also shouldn't call it "thp_split_page" here :)

--
Cheers,

David / dhildenb