The goal for this series is to avoid device private memory TLB invalidations when migrating a range of addresses from system memory to device private memory and some of those pages have already been migrated. The approach taken is to introduce a new mmu notifier invalidation event type and use that in the device driver to skip invalidation callbacks from migrate_vma_setup(). The device driver is also then expected to handle device MMU invalidations as part of the migrate_vma_setup(), migrate_vma_pages(), migrate_vma_finalize() process. Note that this is opt-in. A device driver can simply invalidate its MMU in the mmu notifier callback and not handle MMU invalidations in the migration sequence.
This series is based on Jason Gunthorpe's HMM tree (linux-5.8.0-rc4).
Also, this replaces the need for the following two patches I sent: ("mm: fix migrate_vma_setup() src_owner and normal pages") https://lore.kernel.org/linux-mm/20200622222008.9971-1-rcampbell@nvidia.com ("nouveau: fix mixed normal and device private page migration") https://lore.kernel.org/lkml/20200622233854.10889-3-rcampbell@nvidia.com
Changes in v4: Added reviewed-by from Bharata B Rao. Removed dead code checking for source device private page in lib/test_hmm.c dmirror_migrate_alloc_and_copy() since the source filter flag guarantees that. Added patch 6 to remove a redundant invalidation in migrate_vma_pages().
Changes in v3: Changed the direction field "dir" to a "flags" field and renamed src_owner to pgmap_owner. Fixed a locking issue in nouveau for the migration invalidation. Added a HMM selftest test case to exercise the HMM test driver invalidation changes. Removed reviewed-by Bharata B Rao since this version is moderately changed.
Changes in v2: Rebase to Jason Gunthorpe's HMM tree. Added reviewed-by from Bharata B Rao. Rename the mmu_notifier_range::data field to migrate_pgmap_owner as suggested by Jason Gunthorpe.
Ralph Campbell (6): nouveau: fix storing invalid ptes mm/migrate: add a flags parameter to migrate_vma mm/notifier: add migration invalidation type nouveau/svm: use the new migration invalidation mm/hmm/test: use the new migration invalidation mm/migrate: remove range invalidation in migrate_vma_pages()
arch/powerpc/kvm/book3s_hv_uvmem.c | 4 +- drivers/gpu/drm/nouveau/nouveau_dmem.c | 19 ++++++-- drivers/gpu/drm/nouveau/nouveau_svm.c | 21 ++++----- drivers/gpu/drm/nouveau/nouveau_svm.h | 13 +++++- .../drm/nouveau/nvkm/subdev/mmu/vmmgp100.c | 13 ++++-- include/linux/migrate.h | 16 +++++-- include/linux/mmu_notifier.h | 7 +++ lib/test_hmm.c | 43 +++++++++---------- mm/migrate.c | 34 +++++---------- tools/testing/selftests/vm/hmm-tests.c | 18 ++++++-- 10 files changed, 112 insertions(+), 76 deletions(-)