Hi Barry,
Thanks for taking time to review!
On Mon, Jun 3, 2024 at 12:14 PM Barry Song <21cnbao@xxxxxxxxx> wrote:
>
> On Mon, Jun 3, 2024 at 3:31 PM Lance Yang <ioworker0@xxxxxxxxx> wrote:
> >
> > Let's make folio_mlock_step() simply a wrapper around folio_pte_batch(),
> > which will greatly reduce the cost of ptep_get() when scanning a range of
> > contptes.
> >
> > Signed-off-by: Lance Yang <ioworker0@xxxxxxxxx>
> > ---
> > mm/mlock.c | 23 ++++++-----------------
> > 1 file changed, 6 insertions(+), 17 deletions(-)
> >
> > diff --git a/mm/mlock.c b/mm/mlock.c
> > index 30b51cdea89d..1ae6232d38cf 100644
> > --- a/mm/mlock.c
> > +++ b/mm/mlock.c
> > @@ -307,26 +307,15 @@ void munlock_folio(struct folio *folio)
> > static inline unsigned int folio_mlock_step(struct folio *folio,
> > pte_t *pte, unsigned long addr, unsigned long end)
> > {
> > - unsigned int count, i, nr = folio_nr_pages(folio);
> > - unsigned long pfn = folio_pfn(folio);
> > - pte_t ptent = ptep_get(pte);
> > -
> > - if (!folio_test_large(folio))
> > + if (likely(!folio_test_large(folio)))
> > return 1;
> >
> > - count = pfn + nr - pte_pfn(ptent);
> > - count = min_t(unsigned int, count, (end - addr) >> PAGE_SHIFT);
> > -
> > - for (i = 0; i < count; i++, pte++) {
> > - pte_t entry = ptep_get(pte);
> > -
> > - if (!pte_present(entry))
> > - break;
> > - if (pte_pfn(entry) - pfn >= nr)
> > - break;
> > - }
> > + const fpb_t fpb_flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY;
> > + int max_nr = (end - addr) / PAGE_SIZE;
> > + pte_t ptent = ptep_get(pte);
> >
> > - return i;
> > + return folio_pte_batch(folio, addr, pte, ptent, max_nr, fpb_flags, NULL,
> > + NULL, NULL);
> > }
>
> what about a minimum change as below?
Nice, that makes sense to me ;)
I'll adjust as you suggested.
Thanks again for your time!
Lance
> index 30b51cdea89d..e8b98f84fbd2 100644
> --- a/mm/mlock.c
> +++ b/mm/mlock.c
> @@ -307,26 +307,15 @@ void munlock_folio(struct folio *folio)
> static inline unsigned int folio_mlock_step(struct folio *folio,
> pte_t *pte, unsigned long addr, unsigned long end)
> {
> - unsigned int count, i, nr = folio_nr_pages(folio);
> - unsigned long pfn = folio_pfn(folio);
> + unsigned int count = (end - addr) >> PAGE_SHIFT;
> pte_t ptent = ptep_get(pte);
> + const fpb_t fpb_flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY;
>
> if (!folio_test_large(folio))
> return 1;
>
> - count = pfn + nr - pte_pfn(ptent);
> - count = min_t(unsigned int, count, (end - addr) >> PAGE_SHIFT);
> -
> - for (i = 0; i < count; i++, pte++) {
> - pte_t entry = ptep_get(pte);
> -
> - if (!pte_present(entry))
> - break;
> - if (pte_pfn(entry) - pfn >= nr)
> - break;
> - }
> -
> - return i;
> + return folio_pte_batch(folio, addr, pte, ptent, count, fpb_flags, NULL,
> + NULL, NULL);
> }
>
>
>
> >
> > static inline bool allow_mlock_munlock(struct folio *folio,
> > --
> > 2.33.1
> >
