Messages in this thread | | | From | SeongJae Park <> | Subject | Re: [PATCH] damon: Use pmdp_get instead of drect dereferencing pmd. | Date | Thu, 27 Jul 2023 19:54:53 +0000 |
| |
Hi Levi,
Thank you for this patch.
Nit for the subject, what about s/drect/directly/? Also, let's remove the period at the end.
On Fri, 28 Jul 2023 03:37:45 +0900 Levi Yun <ppbuk5246@gmail.com> wrote:
> As ptep_get, Use the pmdp_get wrapper when we accessing pmdval > instead of direct dereferencing pmd.
Nit: s/Use/use/ and s/direct/directly
> > Signed-off-by: Levi Yun <ppbuk5246@gmail.com> > --- > mm/damon/ops-common.c | 2 +- > mm/damon/paddr.c | 2 +- > mm/damon/vaddr.c | 22 ++++++++++++++-------- > 3 files changed, 16 insertions(+), 10 deletions(-) > > diff --git a/mm/damon/ops-common.c b/mm/damon/ops-common.c > index e940802a15a4..ac1c3fa80f98 100644 > --- a/mm/damon/ops-common.c > +++ b/mm/damon/ops-common.c > @@ -54,7 +54,7 @@ void damon_ptep_mkold(pte_t *pte, struct vm_area_struct *vma, unsigned long addr > void damon_pmdp_mkold(pmd_t *pmd, struct vm_area_struct *vma, unsigned long addr) > { > #ifdef CONFIG_TRANSPARENT_HUGEPAGE > - struct folio *folio = damon_get_folio(pmd_pfn(*pmd)); > + struct folio *folio = damon_get_folio(pmd_pfn(pmdp_get(pmd))); > > if (!folio) > return; > diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c > index 40801e38fcf0..909db25efb35 100644 > --- a/mm/damon/paddr.c > +++ b/mm/damon/paddr.c > @@ -94,7 +94,7 @@ static bool __damon_pa_young(struct folio *folio, struct vm_area_struct *vma, > mmu_notifier_test_young(vma->vm_mm, addr); > } else { > #ifdef CONFIG_TRANSPARENT_HUGEPAGE > - *accessed = pmd_young(*pvmw.pmd) || > + *accessed = pmd_young(pmdp_get(pvmw.pmd)) || > !folio_test_idle(folio) || > mmu_notifier_test_young(vma->vm_mm, addr); > #else > diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c > index 2fcc9731528a..82f7865719fe 100644 > --- a/mm/damon/vaddr.c > +++ b/mm/damon/vaddr.c > @@ -301,16 +301,19 @@ static int damon_mkold_pmd_entry(pmd_t *pmd, unsigned long addr, > unsigned long next, struct mm_walk *walk) > { > pte_t *pte; > + pmd_t pmde; > spinlock_t *ptl; > > - if (pmd_trans_huge(*pmd)) { > + if (pmd_trans_huge(pmdp_get_lockless(pmd))) {
I don't think we really need to use pmdp_get_lockless() here, since we will do this check again with the lock, and we have the fallback for the intermediate changes.
> ptl = pmd_lock(walk->mm, pmd); > - if (!pmd_present(*pmd)) { > + pmde = pmdp_get(pmd); > + > + if (!pmd_present(pmde)) { > spin_unlock(ptl); > return 0; > } > > - if (pmd_trans_huge(*pmd)) { > + if (pmd_trans_huge(pmde)) { > damon_pmdp_mkold(pmd, walk->vma, addr); > spin_unlock(ptl); > return 0; > @@ -434,26 +437,29 @@ static int damon_young_pmd_entry(pmd_t *pmd, unsigned long addr, > { > pte_t *pte; > pte_t ptent; > + pmd_t pmde;
This would cause below build warning if CONFIG_TRANSPARENT_HUGEPAGE is not defined.
.../mm/damon/vaddr.c:440:8: warning: unused variable 'pmde' [-Wunused-variable] 440 | pmd_t pmde; | ^~~~
> spinlock_t *ptl; > struct folio *folio; > struct damon_young_walk_private *priv = walk->private; > > #ifdef CONFIG_TRANSPARENT_HUGEPAGE > - if (pmd_trans_huge(*pmd)) { > + if (pmd_trans_huge(pmdp_get_lockless(pmd))) {
Again, pmdp_get() might be enough?
> ptl = pmd_lock(walk->mm, pmd); > - if (!pmd_present(*pmd)) { > + pmde = pmdp_get(pmd); > + > + if (!pmd_present(pmde)) { > spin_unlock(ptl); > return 0; > } > > - if (!pmd_trans_huge(*pmd)) { > + if (!pmd_trans_huge(pmde)) { > spin_unlock(ptl); > goto regular_page; > } > - folio = damon_get_folio(pmd_pfn(*pmd)); > + folio = damon_get_folio(pmd_pfn(pmde)); > if (!folio) > goto huge_out; > - if (pmd_young(*pmd) || !folio_test_idle(folio) || > + if (pmd_young(pmde) || !folio_test_idle(folio) || > mmu_notifier_test_young(walk->mm, > addr)) > priv->young = true; > -- > 2.37.2 >
Thanks, SJ
| |