On Fri, Sep 12, 2025 at 03:20:38PM +0800, Yafang Shao wrote:
> On Thu, Sep 11, 2025 at 10:56 PM Lorenzo Stoakes
> <lorenzo.stoakes@xxxxxxxxxx> wrote:
> >
> > On Wed, Sep 10, 2025 at 10:44:40AM +0800, Yafang Shao wrote:
> > > The new BPF capability enables finer-grained THP policy decisions by
> > > introducing separate handling for swap faults versus normal page faults.
> > >
> > > As highlighted by Barry:
> > >
> > > We’ve observed that swapping in large folios can lead to more
> > > swap thrashing for some workloads- e.g. kernel build. Consequently,
> > > some workloads might prefer swapping in smaller folios than those
> > > allocated by alloc_anon_folio().
> > >
> > > While prtcl() could potentially be extended to leverage this new policy,
> > > doing so would require modifications to the uAPI.
> > >
> > > Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> >
> > Other than nits, these seems fine, so:
> >
> > Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
> >
> > > Cc: Barry Song <21cnbao@xxxxxxxxx>
> > > ---
> > > include/linux/huge_mm.h | 3 ++-
> > > mm/huge_memory.c | 2 +-
> > > mm/memory.c | 2 +-
> > > 3 files changed, 4 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> > > index f72a5fd04e4f..b9742453806f 100644
> > > --- a/include/linux/huge_mm.h
> > > +++ b/include/linux/huge_mm.h
> > > @@ -97,9 +97,10 @@ extern struct kobj_attribute thpsize_shmem_enabled_attr;
> > >
> > > enum tva_type {
> > > TVA_SMAPS, /* Exposing "THPeligible:" in smaps. */
> > > - TVA_PAGEFAULT, /* Serving a page fault. */
> > > + TVA_PAGEFAULT, /* Serving a non-swap page fault. */
> > > TVA_KHUGEPAGED, /* Khugepaged collapse. */
> > > TVA_FORCED_COLLAPSE, /* Forced collapse (e.g. MADV_COLLAPSE). */
> > > + TVA_SWAP, /* Serving a swap */
> >
> > Serving a swap what? :) I think TVA_SWAP_PAGEFAULT would be better here right?
> > And 'serving a swap page fault'.
>
> will change it. Thanks for your suggestion.
Thanks!
>
> --
> Regards
> Yafang
Cheers, Lorenzo
