RFC Replace mmap_sem by a range lock
Get series with b4
b4 am [email protected]Versions newest first · linked by author and title
- v2 RFC Latest10 patches 3 repliesIn review
- v1 RFC4 patches 9 repliesSuperseded
Patches in v2 No applies recorded yet
| # | Subject and files | Size | Replies | Applied |
|---|---|---|---|---|
| 1/10 | mm: Deactivate mmap_sem assertarch/ arch/ fs/ +4 more | +27 | 1 reply | |
| 2/10 | mm: Remove nest locking operation with mmap_semmm/ | +8 | 1 reply | |
| 3/10 | mm: Add a range parameter to the vm_fault structureinclude/ | +3 | 0 replies | |
| 4/10 | mm: Handle range lock field when collapsing huge pagesmm/ | +33 | 0 replies | |
| 5/10 | mm: Add a range lock parameter to userfaultfd_remove()fs/ include/ mm/ +1 more | +78 | 0 replies | |
| 6/10 | mm: Add a range lock parameter to lock_page_or_retry()include/ mm/ mm/ | +26 | 0 replies | |
| 7/10 | mm: Add a range lock parameter to GUP() and handle_page_fault()arch/ arch/ arch/ +29 more | +202 | 0 replies | |
| 8/10 | mm: Define mem range lock operationsinclude/ include/ | +32 | 0 replies | |
| 9/10 | mm: Change mmap_sem to range lockarch/ arch/ arch/ +95 more | +667 | 0 replies | |
| 10/10 | mm: Introduce CONFIG_MEM_RANGE_LOCKmm/ | +12 | 1 reply |
Reviews trailers per patch
No Reviewed-by, Acked-by or Tested-by trailers for v2 yet.
Cover letter [RFC v2 00/10] Replace mmap_sem by a range lock
Following the series pushed by Davidlohr Bueso based on the Jan Kara's work [1] which introduces range locks, this series implements the first step of the attempt to replace the mmap_sem by a range lock.
While this series simply replaces the mmap_sem by a full range lock, the final goal is to introduce finer grain locking to allow better multi-thread performance in regards to the process's memory layout changes.
This series currently supports x86 and PowerPc architectures only. Some drivers are also impacted to allow build and basic test on few platforms but a lot of additional works is required to complete the job for all the supported architectures.
The goal of this series is to check that no major performance hit happens for mono threaded process, as we could hope major improvements in the multi-threaded case once the finer grain locking is implemented.
I didn't do massive performance checking yet, but building a full kernel on a 80 threaded Power node, doesn't show performance hits. The build time is 11m56.701s on a vanilla kernel and 12m4.679s when range lock is used.
The next steps will attempt to implement finer grain locking but specific locking would certainly be required to protect mm data like the VMA cache.
If this series is conform to the community expectation, I'll extend the other architectures, allowing the swith to a range lock to be turned on easily. This series will be a nightmare to maintain so it will be nice if it could merge as soon as possible.
This series applies on top of 4.12-rc2 with range lock series from Davidlohr [1] applies on top.
The first 2 patches temporary disable some assert which were based on lock service which are not provided by the range lock API. While some of these checks will not be valid with range locks, most of them will have to be reviewed later.
The next 5 patches add a new parameter to some memory service which need to release the lock, since range lock require the range to specify, caller has to know about it.
The last 2 patches are doing the job of replacing the mmap_sem by a range lock, and introduce a new config variable to enable that changes.
[1] "locking: Introduce range reader/writer lock"
https://lwn.net/Articles/722741/
Changes from v1 [https://lwn.net/Articles/720373/]:
- encapsulate change through #ifdef CONFIG_MEM_RANGE_LOCK
- introduce new mem range lock operations to move easily from a semaphore to a range lock.
- split the leading patches adding the range parameters to some services.
Laurent Dufour (10):
mm: Deactivate mmap_sem assert
mm: Remove nest locking operation with mmap_sem
mm: Add a range parameter to the vm_fault structure
mm: Handle range lock field when collapsing huge pages
mm: Add a range lock parameter to userfaultfd_remove()
mm: Add a range lock parameter to lock_page_or_retry()
mm: Add a range lock parameter to GUP() and handle_page_fault()
mm: Define mem range lock operations
mm: Change mmap_sem to range lock
mm: Introduce CONFIG_MEM_RANGE_LOCK
arch/powerpc/kernel/vdso.c | 7 +- arch/powerpc/kvm/book3s_64_mmu_hv.c | 5 +- arch/powerpc/kvm/book3s_64_mmu_radix.c | 5 +- arch/powerpc/kvm/book3s_64_vio.c | 5 +- arch/powerpc/kvm/book3s_hv.c | 7 +- arch/powerpc/kvm/e500_mmu_host.c | 6 +- arch/powerpc/mm/copro_fault.c | 7 +- arch/powerpc/mm/fault.c | 11 +- arch/powerpc/mm/mmu_context_iommu.c | 5 +- arch/powerpc/mm/subpage-prot.c | 14 ++- arch/powerpc/oprofile/cell/spu_task_sync.c | 7 +- arch/powerpc/platforms/cell/spufs/file.c | 4 +- arch/powerpc/platforms/powernv/npu-dma.c | 4 +- arch/x86/entry/vdso/vma.c | 12 +- arch/x86/events/core.c | 2 + arch/x86/kernel/tboot.c | 6 +- arch/x86/kernel/vm86_32.c | 5 +- arch/x86/mm/fault.c | 67 ++++++++--- arch/x86/mm/mpx.c | 17 +-- drivers/android/binder.c | 7 +- drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 5 +- drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 7 +- drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c | 7 +- drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 +- drivers/gpu/drm/amd/amdkfd/kfd_events.c | 5 +- drivers/gpu/drm/amd/amdkfd/kfd_process.c | 5 +- drivers/gpu/drm/etnaviv/etnaviv_gem.c | 8 +- drivers/gpu/drm/i915/i915_gem.c | 5 +- drivers/gpu/drm/i915/i915_gem_userptr.c | 12 +- drivers/gpu/drm/radeon/radeon_cs.c | 5 +- drivers/gpu/drm/radeon/radeon_gem.c | 8 +- drivers/gpu/drm/radeon/radeon_mn.c | 7 +- drivers/gpu/drm/radeon/radeon_ttm.c | 2 +- drivers/gpu/drm/ttm/ttm_bo_vm.c | 4 +- drivers/infiniband/core/umem.c | 19 +-- drivers/infiniband/core/umem_odp.c | 7 +- drivers/infiniband/hw/hfi1/user_pages.c | 16 ++- drivers/infiniband/hw/mlx4/main.c | 5 +- drivers/infiniband/hw/mlx5/main.c | 5 +- drivers/infiniband/hw/mthca/mthca_memfree.c | 3 +- drivers/infiniband/hw/qib/qib_user_pages.c | 13 +- drivers/infiniband/hw/usnic/usnic_uiom.c | 19 +-- drivers/iommu/amd_iommu_v2.c | 7 +- drivers/iommu/intel-svm.c | 7 +- drivers/media/v4l2-core/videobuf-core.c | 5 +- drivers/media/v4l2-core/videobuf-dma-contig.c | 5 +- drivers/media/v4l2-core/videobuf-dma-sg.c | 7 +- drivers/misc/cxl/fault.c | 5 +- drivers/misc/mic/scif/scif_rma.c | 18 +-- drivers/oprofile/buffer_sync.c | 12 +- drivers/staging/lustre/lustre/llite/llite_mmap.c | 3 +- drivers/staging/lustre/lustre/llite/vvp_io.c | 5 +- .../interface/vchiq_arm/vchiq_2835_arm.c | 6 +- .../vc04_services/interface/vchiq_arm/vchiq_arm.c | 5 +- drivers/vfio/vfio_iommu_spapr_tce.c | 11 +- drivers/vfio/vfio_iommu_type1.c | 16 +-- drivers/xen/gntdev.c | 5 +- drivers/xen/privcmd.c | 12 +- fs/aio.c | 5 +- fs/coredump.c | 5 +- fs/exec.c | 22 ++-- fs/proc/base.c | 32 +++-- fs/proc/internal.h | 3 + fs/proc/task_mmu.c | 24 ++-- fs/proc/task_nommu.c | 24 ++-- fs/userfaultfd.c | 35 ++++-- include/linux/huge_mm.h | 4 + include/linux/mm.h | 88 ++++++++++++-- include/linux/mm_types.h | 5 + include/linux/pagemap.h | 17 +++ include/linux/userfaultfd_k.h | 28 ++++- ipc/shm.c | 10 +- kernel/acct.c | 5 +- kernel/events/core.c | 5 +- kernel/events/uprobes.c | 24 ++-- kernel/exit.c | 9 +- kernel/fork.c | 20 +++- kernel/futex.c | 7 +- kernel/sched/fair.c | 6 +- kernel/sys.c | 22 ++-- kernel/trace/trace_output.c | 5 +- mm/Kconfig | 12 ++ mm/filemap.c | 13 +- mm/frame_vector.c | 8 +- mm/gup.c | 131 ++++++++++++++++----- mm/init-mm.c | 4 + mm/internal.h | 11 +- mm/khugepaged.c | 74 ++++++++---- mm/ksm.c | 39 +++--- mm/madvise.c | 57 ++++++--- mm/memcontrol.c | 12 +- mm/memory.c | 52 ++++++-- mm/mempolicy.c | 28 +++-- mm/migrate.c | 10 +- mm/mincore.c | 5 +- mm/mlock.c | 20 ++-- mm/mmap.c | 46 +++++--- mm/mmu_notifier.c | 5 +- mm/mprotect.c | 17 +-- mm/mremap.c | 5 +- mm/msync.c | 9 +- mm/nommu.c | 26 ++-- mm/oom_kill.c | 7 +- mm/pagewalk.c | 5 + mm/process_vm_access.c | 8 +- mm/shmem.c | 2 +- mm/swapfile.c | 7 +- mm/userfaultfd.c | 33 ++++-- mm/util.c | 11 +- security/tomoyo/domain.c | 2 +- virt/kvm/async_pf.c | 7 +- virt/kvm/kvm_main.c | 33 ++++-- 112 files changed, 1079 insertions(+), 526 deletions(-)
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