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authorRalph Campbell <rcampbell@nvidia.com>2020-07-24 00:30:01 +0200
committerJason Gunthorpe <jgg@nvidia.com>2020-07-28 21:20:33 +0200
commit998427b3ad2c769082853880cf353557ec0ec77d (patch)
tree05381a8bcb45c98431dff8f52d70d1cf87648ec9 /mm
parentmm/migrate: add a flags parameter to migrate_vma (diff)
downloadlinux-998427b3ad2c769082853880cf353557ec0ec77d.tar.xz
linux-998427b3ad2c769082853880cf353557ec0ec77d.zip
mm/notifier: add migration invalidation type
Currently migrate_vma_setup() calls mmu_notifier_invalidate_range_start() which flushes all device private page mappings whether or not a page is being migrated to/from device private memory. In order to not disrupt device mappings that are not being migrated, shift the responsibility for clearing device private mappings to the device driver and leave CPU page table unmapping handled by migrate_vma_setup(). To support this, the caller of migrate_vma_setup() should always set struct migrate_vma::pgmap_owner to a non NULL value that matches the device private page->pgmap->owner. This value is then passed to the struct mmu_notifier_range with a new event type which the driver's invalidation function can use to avoid device MMU invalidations. Link: https://lore.kernel.org/r/20200723223004.9586-4-rcampbell@nvidia.com Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'mm')
-rw-r--r--mm/migrate.c8
1 files changed, 7 insertions, 1 deletions
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,