Re: [PATCH v3 1/3] mm/memory-failure: set has_hwpoisoned flags on HugeTLB folio

[Jiaqi Yan <jiaqiyan@google.com>]

On Sun, Jan 11, 2026 at 6:50 PM Zi Yan <ziy@nvidia.com> wrote:
>
> On 11 Jan 2026, at 19:49, Jiaqi Yan wrote:
>
> > When a free HWPoison HugeTLB folio is dissolved, it becomes
> > non-HugeTLB and is released to buddy allocator as a high-order
> > folio.
> >
> > Set has_hwpoisoned flags on the high-order folio so that buddy
> > allocator can tell that it contains certain HWPoison page(s).
> > This is a prepare change for buddy allocator to handle only the
> > high-order HWPoison folio differently.
> >
> > This cannot be done with hwpoison flag because users cannot tell
> > from the case that the page with hwpoison is hardware corrupted.
> >
> > Signed-off-by: Jiaqi Yan <jiaqiyan@google.com>
> > ---
> >  include/linux/page-flags.h | 2 +-
> >  mm/memory-failure.c        | 1 +
> >  2 files changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
> > index f7a0e4af0c734..d13835e265952 100644
> > --- a/include/linux/page-flags.h
> > +++ b/include/linux/page-flags.h
> > @@ -904,7 +904,7 @@ static inline int PageTransCompound(const struct page *page)
> >  TESTPAGEFLAG_FALSE(TransCompound, transcompound)
> >  #endif
> >
> > -#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
> > +#if defined(CONFIG_MEMORY_FAILURE) && (defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLB_PAGE))
> >  /*
> >   * PageHasHWPoisoned indicates that at least one subpage is hwpoisoned in the
> >   * compound page.
> > diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> > index fbc5a01260c89..d204de6c9792a 100644
> > --- a/mm/memory-failure.c
> > +++ b/mm/memory-failure.c
> > @@ -1952,6 +1952,7 @@ void folio_clear_hugetlb_hwpoison(struct folio *folio)
> >       if (folio_test_hugetlb_vmemmap_optimized(folio))
> >               return;
> >       folio_clear_hwpoison(folio);
> > +     folio_set_has_hwpoisoned(folio);
> >       folio_free_raw_hwp(folio, true);
> >  }
>
> Should this patch go after Patch 2 where has_hwpoisoned folio handling code
> is added?

Hi Zi, thanks for the comment. Will reorder this one.

I initially thought this patch was for preparation. However, if I look
at patch 2 differently: it enables page_alloc to handle
PG_has_hwpoisoned folios generally, not only for HugeTLB, but also for
split-failed THP compound pages. Then this one can be just to make
HugeTLB start to use patch 2.

>
> --
> Best Regards,
> Yan, Zi