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.
--
Regards
Yafang
