Re: [PATCH 1/1] mm/madvise: enhance lazyfreeing with mTHP in madvise_free

Barry Song
2024-02-27T02:12:56Z

On Tue, Feb 27, 2024 at 2:48 PM Lance Yang <ioworker0@gmail.com> wrote:
>
> On Tue, Feb 27, 2024 at 9:21 AM Barry Song <21cnbao@gmail.com> wrote:
> >
> > > Thanks for your suggestion. I'll use folio_pte_batch() in v2.
> >
> > Hi Lance,
> > Obviously, we both need this. While making large folio swap-in
> > v2, I am exporting folio_pte_batch() as below,
>
> Thanks, Barry.
>
> Could you separate the export of folio_pte_batch() from the large folio
> swap-in v2? Prioritizing the push for this specific change would aid in
> the development of the v2 based on it.

I agree we should make this one pulled in by Andrew early to avoid potential
dependencies and conflicts in two jobs.

>
> Best,
> Lance
>
> >
> > From: Barry Song <v-songbaohua@oppo.com>
> > Date: Tue, 27 Feb 2024 14:05:43 +1300
> > Subject: [PATCH] mm: export folio_pte_batch as a couple of modules need it
> >
> > MADV_FREE, MADV_PAGEOUT and some other modules might need folio_pte_batch
> > to check if a range of PTEs are completely mapped to a large folio with
> > contiguous physcial offset.
> >
> > Cc: Lance Yang <ioworker0@gmail.com>
> > Cc: Ryan Roberts <ryan.roberts@arm.com>
> > Cc: David Hildenbrand <david@redhat.com>
> > Signed-off-by: Barry Song <v-songbaohua@oppo.com>
> > ---
> > mm/internal.h | 13 +++++++++++++
> > mm/memory.c | 2 +-
> > 2 files changed, 14 insertions(+), 1 deletion(-)
> >
> > diff --git a/mm/internal.h b/mm/internal.h
> > index 36c11ea41f47..7e11aea3eda9 100644
> > --- a/mm/internal.h
> > +++ b/mm/internal.h
> > @@ -83,6 +83,19 @@ static inline void *folio_raw_mapping(struct folio *folio)
> > return (void *)(mapping & ~PAGE_MAPPING_FLAGS);
> > }
> >
> > +/* Flags for folio_pte_batch(). */
> > +typedef int __bitwise fpb_t;
> > +
> > +/* Compare PTEs after pte_mkclean(), ignoring the dirty bit. */
> > +#define FPB_IGNORE_DIRTY ((__force fpb_t)BIT(0))
> > +
> > +/* Compare PTEs after pte_clear_soft_dirty(), ignoring the soft-dirty bit. */
> > +#define FPB_IGNORE_SOFT_DIRTY ((__force fpb_t)BIT(1))
> > +
> > +extern int folio_pte_batch(struct folio *folio, unsigned long addr,
> > + pte_t *start_ptep, pte_t pte, int max_nr, fpb_t flags,
> > + bool *any_writable);
> > +
> > void __acct_reclaim_writeback(pg_data_t *pgdat, struct folio *folio,
> > int nr_throttled);
> > static inline void acct_reclaim_writeback(struct folio *folio)
> > diff --git a/mm/memory.c b/mm/memory.c
> > index 6378f6bc22c5..dd9bd67f037a 100644
> > --- a/mm/memory.c
> > +++ b/mm/memory.c
> > @@ -989,7 +989,7 @@ static inline pte_t __pte_batch_clear_ignored(pte_t pte, fpb_t flags)
> > * If "any_writable" is set, it will indicate if any other PTE besides the
> > * first (given) PTE is writable.
> > */
> > -static inline int folio_pte_batch(struct folio *folio, unsigned long addr,
> > +int folio_pte_batch(struct folio *folio, unsigned long addr,
> > pte_t *start_ptep, pte_t pte, int max_nr, fpb_t flags,
> > bool *any_writable)
> > {
> > --
> > 2.34.1
> >
> > > Best,
> > > Lance
> >
Thanks
Barry
> >