diff options
| -rw-r--r-- | include/linux/migrate.h | 3 | ||||
| -rw-r--r-- | include/linux/mmu_notifier.h | 6 | ||||
| -rw-r--r-- | mm/migrate.c | 8 |
3 files changed, 16 insertions, 1 deletions
diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 16e03a51e5cf..540998d9810b 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -206,6 +206,9 @@ struct migrate_vma { * Set to the owner value also stored in page->pgmap->owner for * migrating out of device private memory. The flags also need to * be set to MIGRATE_VMA_SELECT_DEVICE_PRIVATE. + * The caller should always set this field when using mmu notifier + * callbacks to avoid device MMU invalidations for device private + * pages that are not being migrated. */ void *pgmap_owner; unsigned long flags; diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index fc68f3570e19..c6f0708195cd 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -38,6 +38,10 @@ struct mmu_interval_notifier; * * @MMU_NOTIFY_RELEASE: used during mmu_interval_notifier invalidate to signal * that the mm refcount is zero and the range is no longer accessible. + * + * @MMU_NOTIFY_MIGRATE: used during migrate_vma_collect() invalidate to signal + * a device driver to possibly ignore the invalidation if the + * migrate_pgmap_owner field matches the driver's device private pgmap owner. */ enum mmu_notifier_event { MMU_NOTIFY_UNMAP = 0, @@ -46,6 +50,7 @@ enum mmu_notifier_event { MMU_NOTIFY_PROTECTION_PAGE, MMU_NOTIFY_SOFT_DIRTY, MMU_NOTIFY_RELEASE, + MMU_NOTIFY_MIGRATE, }; #define MMU_NOTIFIER_RANGE_BLOCKABLE (1 << 0) @@ -264,6 +269,7 @@ struct mmu_notifier_range { unsigned long end; unsigned flags; enum mmu_notifier_event event; + void *migrate_pgmap_owner; }; static inline int mm_has_notifiers(struct mm_struct *mm) diff --git a/mm/migrate.c b/mm/migrate.c index e3ea68e3a08b..96e1f41a991e 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2392,8 +2392,14 @@ static void migrate_vma_collect(struct migrate_vma *migrate) { struct mmu_notifier_range range; - mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, + /* + * Note that the pgmap_owner is passed to the mmu notifier callback so + * that the registered device driver can skip invalidating device + * private page mappings that won't be migrated. + */ + mmu_notifier_range_init(&range, MMU_NOTIFY_MIGRATE, 0, migrate->vma, migrate->vma->vm_mm, migrate->start, migrate->end); + range.migrate_pgmap_owner = migrate->pgmap_owner; mmu_notifier_invalidate_range_start(&range); walk_page_range(migrate->vma->vm_mm, migrate->start, migrate->end, |