On 2026-02-10 at 01:47 +1100, Thomas Hellström
<[email protected]> wrote...
> @Alistair, any chance of an R-B for the below version?
For sure. Sorry I've been getting back to this but caught up with internal
stuff.
> > +static inline void softleaf_entry_wait_on_locked(softleaf_t entry,
> > spinlock_t *ptl)
> > + __releases(ptl)
> > +{
> > + spin_unlock(ptl);
> > +}
> > +
I noticed this just because we didn't have it previously, but I assume it's to
avoid compilation failures in do_swap_page(). This is definitely the better way
of dealing with the conditional compilation, though if I were to add a nit it
would be that a WARN_ON_ONCE() would be nice here.
But this is fine, and thanks for doing the rename. Feel free to add:
Reviewed-by: Alistair Popple <[email protected]>
> > #endif /* CONFIG_MIGRATION */
> >
> > #ifdef CONFIG_NUMA_BALANCING
> > diff --git a/mm/filemap.c b/mm/filemap.c
> > index ebd75684cb0a..d98e4883f13d 100644
> > --- a/mm/filemap.c
> > +++ b/mm/filemap.c
> > @@ -1379,14 +1379,16 @@ static inline int
> > folio_wait_bit_common(struct folio *folio, int bit_nr,
> >
> > #ifdef CONFIG_MIGRATION
> > /**
> > - * migration_entry_wait_on_locked - Wait for a migration entry to be
> > removed
> > - * @entry: migration swap entry.
> > + * softleaf_entry_wait_on_locked - Wait for a migration entry or
> > + * device_private entry to be removed.
> > + * @entry: migration or device_private swap entry.
> > * @ptl: already locked ptl. This function will drop the lock.
> > *
> > - * Wait for a migration entry referencing the given page to be
> > removed. This is
> > + * Wait for a migration entry referencing the given page, or
> > device_private
> > + * entry referencing a dvice_private page to be unlocked. This is
> > * equivalent to folio_put_wait_locked(folio, TASK_UNINTERRUPTIBLE)
> > except
> > * this can be called without taking a reference on the page.
> > Instead this
> > - * should be called while holding the ptl for the migration entry
> > referencing
> > + * should be called while holding the ptl for @entry referencing
> > * the page.
> > *
> > * Returns after unlocking the ptl.
> > @@ -1394,7 +1396,7 @@ static inline int folio_wait_bit_common(struct
> > folio *folio, int bit_nr,
> > * This follows the same logic as folio_wait_bit_common() so see the
> > comments
> > * there.
> > */
> > -void migration_entry_wait_on_locked(softleaf_t entry, spinlock_t
> > *ptl)
> > +void softleaf_entry_wait_on_locked(softleaf_t entry, spinlock_t
> > *ptl)
> > __releases(ptl)
> > {
> > struct wait_page_queue wait_page;
> > @@ -1428,6 +1430,9 @@ void migration_entry_wait_on_locked(softleaf_t
> > entry, spinlock_t *ptl)
> > * If a migration entry exists for the page the migration
> > path must hold
> > * a valid reference to the page, and it must take the ptl
> > to remove the
> > * migration entry. So the page is valid until the ptl is
> > dropped.
> > + * Similarly any path attempting to drop the last reference
> > to a
> > + * device-private page needs to grab the ptl to remove the
> > device-private
> > + * entry.
> > */
> > spin_unlock(ptl);
> >
> > diff --git a/mm/memory.c b/mm/memory.c
> > index da360a6eb8a4..20172476a57f 100644
> > --- a/mm/memory.c
> > +++ b/mm/memory.c
> > @@ -4684,7 +4684,8 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
> > unlock_page(vmf->page);
> > put_page(vmf->page);
> > } else {
> > - pte_unmap_unlock(vmf->pte, vmf-
> > >ptl);
> > + pte_unmap(vmf->pte);
> > + softleaf_entry_wait_on_locked(entry,
> > vmf->ptl);
> > }
> > } else if (softleaf_is_hwpoison(entry)) {
> > ret = VM_FAULT_HWPOISON;
> > diff --git a/mm/migrate.c b/mm/migrate.c
> > index 4688b9e38cd2..cf6449b4202e 100644
> > --- a/mm/migrate.c
> > +++ b/mm/migrate.c
> > @@ -499,7 +499,7 @@ void migration_entry_wait(struct mm_struct *mm,
> > pmd_t *pmd,
> > if (!softleaf_is_migration(entry))
> > goto out;
> >
> > - migration_entry_wait_on_locked(entry, ptl);
> > + softleaf_entry_wait_on_locked(entry, ptl);
> > return;
> > out:
> > spin_unlock(ptl);
> > @@ -531,10 +531,10 @@ void migration_entry_wait_huge(struct
> > vm_area_struct *vma, unsigned long addr, p
> > * If migration entry existed, safe to release vma
> > lock
> > * here because the pgtable page won't be freed
> > without the
> > * pgtable lock released. See comment right above
> > pgtable
> > - * lock release in migration_entry_wait_on_locked().
> > + * lock release in softleaf_entry_wait_on_locked().
> > */
> > hugetlb_vma_unlock_read(vma);
> > - migration_entry_wait_on_locked(entry, ptl);
> > + softleaf_entry_wait_on_locked(entry, ptl);
> > return;
> > }
> >
> > @@ -552,7 +552,7 @@ void pmd_migration_entry_wait(struct mm_struct
> > *mm, pmd_t *pmd)
> > ptl = pmd_lock(mm, pmd);
> > if (!pmd_is_migration_entry(*pmd))
> > goto unlock;
> > - migration_entry_wait_on_locked(softleaf_from_pmd(*pmd),
> > ptl);
> > + softleaf_entry_wait_on_locked(softleaf_from_pmd(*pmd), ptl);
> > return;
> > unlock:
> > spin_unlock(ptl);
> > diff --git a/mm/migrate_device.c b/mm/migrate_device.c
> > index 23379663b1e1..deab89fd4541 100644
> > --- a/mm/migrate_device.c
> > +++ b/mm/migrate_device.c
> > @@ -176,7 +176,7 @@ static int migrate_vma_collect_huge_pmd(pmd_t
> > *pmdp, unsigned long start,
> > }
> >
> > if (softleaf_is_migration(entry)) {
> > - migration_entry_wait_on_locked(entry, ptl);
> > + softleaf_entry_wait_on_locked(entry, ptl);
> > spin_unlock(ptl);
> > return -EAGAIN;
> > }
