This is the eighth version of a series to add support to Nouveau for atomic memory operations on OpenCL shared virtual memory (SVM) regions. The main change for this version is a simplification of device exclusive entry handling. Instead of copying entries for copy-on-write mappings during fork they are removed instead. This is safer because there could be unique corner cases when copying, particularly for pinned pages which should follow the same logic as copy_present_page(). Removing entries avoids this possiblity by treating them as normal ptes. Exclusive device access is implemented by adding a new swap entry type (SWAP_DEVICE_EXCLUSIVE) which is similar to a migration entry. The main difference is that on fault the original entry is immediately restored by the fault handler instead of waiting. Restoring the entry triggers calls to MMU notifers which allows a device driver to revoke the atomic access permission from the GPU prior to the CPU finalising the entry. Patches 1 & 2 refactor existing migration and device private entry functions. Patches 3 & 4 rework try_to_unmap_one() by splitting out unrelated functionality into separate functions - try_to_migrate_one() and try_to_munlock_one(). These should not change any functionality, but any help testing would be much appreciated as I have not been able to test every usage of try_to_unmap_one(). Patch 5 contains the bulk of the implementation for device exclusive memory. Patch 6 contains some additions to the HMM selftests to ensure everything works as expected. Patch 7 is a cleanup for the Nouveau SVM implementation. Patch 8 contains the implementation of atomic access for the Nouveau driver. This has been tested using the latest upstream Mesa userspace with a simple OpenCL test program which checks the results of atomic GPU operations on a SVM buffer whilst also writing to the same buffer from the CPU. Alistair Popple (8): mm: Remove special swap entry functions mm/swapops: Rework swap entry manipulation code mm/rmap: Split try_to_munlock from try_to_unmap mm/rmap: Split migration into its own function mm: Device exclusive memory access mm: Selftests for exclusive device memory nouveau/svm: Refactor nouveau_range_fault nouveau/svm: Implement atomic SVM access Documentation/vm/hmm.rst | 19 +- Documentation/vm/unevictable-lru.rst | 33 +- arch/s390/mm/pgtable.c | 2 +- drivers/gpu/drm/nouveau/include/nvif/if000c.h | 1 + drivers/gpu/drm/nouveau/nouveau_svm.c | 156 ++++- drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.h | 1 + .../drm/nouveau/nvkm/subdev/mmu/vmmgp100.c | 6 + fs/proc/task_mmu.c | 23 +- include/linux/mmu_notifier.h | 26 +- include/linux/rmap.h | 11 +- include/linux/swap.h | 8 +- include/linux/swapops.h | 123 ++-- lib/test_hmm.c | 126 +++- lib/test_hmm_uapi.h | 2 + mm/debug_vm_pgtable.c | 12 +- mm/hmm.c | 12 +- mm/huge_memory.c | 45 +- mm/hugetlb.c | 10 +- mm/memcontrol.c | 2 +- mm/memory.c | 196 +++++- mm/migrate.c | 51 +- mm/mlock.c | 10 +- mm/mprotect.c | 18 +- mm/page_vma_mapped.c | 15 +- mm/rmap.c | 612 +++++++++++++++--- tools/testing/selftests/vm/hmm-tests.c | 158 +++++ 26 files changed, 1366 insertions(+), 312 deletions(-) -- 2.20.1
