Thanks for fixing. I'm guessing Andrew will want you to resend this as part of
a new v6 series, but please add:
Reviewed-by: Alistair Popple <apopple@xxxxxxxxxx>
On Tuesday, 1 February 2022 6:48:13 AM AEDT Alex Sierra wrote:
> This case is used to migrate pages from device memory, back to system
> memory. Device coherent type memory is cache coherent from device and CPU
> point of view.
>
> Signed-off-by: Alex Sierra <alex.sierra@xxxxxxx>
> Acked-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
> ---
> v2:
> condition added when migrations from device coherent pages.
> ---
> include/linux/migrate.h | 1 +
> mm/migrate.c | 12 +++++++++---
> 2 files changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/migrate.h b/include/linux/migrate.h
> index db96e10eb8da..66a34eae8cb6 100644
> --- a/include/linux/migrate.h
> +++ b/include/linux/migrate.h
> @@ -130,6 +130,7 @@ static inline unsigned long migrate_pfn(unsigned long pfn)
> enum migrate_vma_direction {
> MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
> MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
> + MIGRATE_VMA_SELECT_DEVICE_COHERENT = 1 << 2,
> };
>
> struct migrate_vma {
> diff --git a/mm/migrate.c b/mm/migrate.c
> index cd137aedcfe5..69c6830c47c6 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -2264,15 +2264,21 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
> if (is_writable_device_private_entry(entry))
> mpfn |= MIGRATE_PFN_WRITE;
> } else {
> - if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
> - goto next;
> pfn = pte_pfn(pte);
> - if (is_zero_pfn(pfn)) {
> + if (is_zero_pfn(pfn) &&
> + (migrate->flags & MIGRATE_VMA_SELECT_SYSTEM)) {
> mpfn = MIGRATE_PFN_MIGRATE;
> migrate->cpages++;
> goto next;
> }
> page = vm_normal_page(migrate->vma, addr, pte);
> + if (page && !is_zone_device_page(page) &&
> + !(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
> + goto next;
> + else if (page && is_device_coherent_page(page) &&
> + (!(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_COHERENT) ||
> + page->pgmap->owner != migrate->pgmap_owner))
> + goto next;
> mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;
> mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0;
> }
>
