[PATCH 00/35] Add HMM-based SVM memory manager to KFD

[Daniel Vetter]

On Wed, Jan 06, 2021 at 10:00:52PM -0500, Felix Kuehling wrote:
> This is the first version of our HMM based shared virtual memory manager
> for KFD. There are still a number of known issues that we're working through
> (see below). This will likely lead to some pretty significant changes in
> MMU notifier handling and locking on the migration code paths. So don't
> get hung up on those details yet.
> 
> But I think this is a good time to start getting feedback. We're pretty
> confident about the ioctl API, which is both simple and extensible for the
> future. (see patches 4,16) The user mode side of the API can be found here:
> https://github.com/RadeonOpenCompute/ROCT-Thunk-Interface/blob/fxkamd/hmm-wip/src/svm.c
> 
> I'd also like another pair of eyes on how we're interfacing with the GPU VM
> code in amdgpu_vm.c (see patches 12,13), retry page fault handling (24,25),
> and some retry IRQ handling changes (32).
> 
> 
> Known issues:
> * won't work with IOMMU enabled, we need to dma_map all pages properly
> * still working on some race conditions and random bugs
> * performance is not great yet

Still catching up, but I think there's another one for your list:

 * hmm gpu context preempt vs page fault handling. I've had a short
   discussion about this one with Christian before the holidays, and also
   some private chats with Jerome. It's nasty since no easy fix, much less
   a good idea what's the best approach here.

I'll try to look at this more in-depth when I'm catching up on mails.
-Daniel

> 
> Alex Sierra (12):
>   drm/amdgpu: replace per_device_list by array
>   drm/amdkfd: helper to convert gpu id and idx
>   drm/amdkfd: add xnack enabled flag to kfd_process
>   drm/amdkfd: add ioctl to configure and query xnack retries
>   drm/amdkfd: invalidate tables on page retry fault
>   drm/amdkfd: page table restore through svm API
>   drm/amdkfd: SVM API call to restore page tables
>   drm/amdkfd: add svm_bo reference for eviction fence
>   drm/amdgpu: add param bit flag to create SVM BOs
>   drm/amdkfd: add svm_bo eviction mechanism support
>   drm/amdgpu: svm bo enable_signal call condition
>   drm/amdgpu: add svm_bo eviction to enable_signal cb
> 
> Philip Yang (23):
>   drm/amdkfd: select kernel DEVICE_PRIVATE option
>   drm/amdkfd: add svm ioctl API
>   drm/amdkfd: Add SVM API support capability bits
>   drm/amdkfd: register svm range
>   drm/amdkfd: add svm ioctl GET_ATTR op
>   drm/amdgpu: add common HMM get pages function
>   drm/amdkfd: validate svm range system memory
>   drm/amdkfd: register overlap system memory range
>   drm/amdkfd: deregister svm range
>   drm/amdgpu: export vm update mapping interface
>   drm/amdkfd: map svm range to GPUs
>   drm/amdkfd: svm range eviction and restore
>   drm/amdkfd: register HMM device private zone
>   drm/amdkfd: validate vram svm range from TTM
>   drm/amdkfd: support xgmi same hive mapping
>   drm/amdkfd: copy memory through gart table
>   drm/amdkfd: HMM migrate ram to vram
>   drm/amdkfd: HMM migrate vram to ram
>   drm/amdgpu: reserve fence slot to update page table
>   drm/amdgpu: enable retry fault wptr overflow
>   drm/amdkfd: refine migration policy with xnack on
>   drm/amdkfd: add svm range validate timestamp
>   drm/amdkfd: multiple gpu migrate vram to vram
> 
>  drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c    |    3 +
>  drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h    |    4 +-
>  .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c  |   16 +-
>  .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  |   13 +-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c        |   83 +
>  drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h        |    7 +
>  drivers/gpu/drm/amd/amdgpu/amdgpu_object.h    |    5 +
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c       |   90 +-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c        |   47 +-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h        |   10 +
>  drivers/gpu/drm/amd/amdgpu/vega10_ih.c        |   32 +-
>  drivers/gpu/drm/amd/amdgpu/vega20_ih.c        |   32 +-
>  drivers/gpu/drm/amd/amdkfd/Kconfig            |    1 +
>  drivers/gpu/drm/amd/amdkfd/Makefile           |    4 +-
>  drivers/gpu/drm/amd/amdkfd/kfd_chardev.c      |  170 +-
>  drivers/gpu/drm/amd/amdkfd/kfd_iommu.c        |    8 +-
>  drivers/gpu/drm/amd/amdkfd/kfd_migrate.c      |  866 ++++++
>  drivers/gpu/drm/amd/amdkfd/kfd_migrate.h      |   59 +
>  drivers/gpu/drm/amd/amdkfd/kfd_priv.h         |   52 +-
>  drivers/gpu/drm/amd/amdkfd/kfd_process.c      |  200 +-
>  .../amd/amdkfd/kfd_process_queue_manager.c    |    6 +-
>  drivers/gpu/drm/amd/amdkfd/kfd_svm.c          | 2564 +++++++++++++++++
>  drivers/gpu/drm/amd/amdkfd/kfd_svm.h          |  135 +
>  drivers/gpu/drm/amd/amdkfd/kfd_topology.c     |    1 +
>  drivers/gpu/drm/amd/amdkfd/kfd_topology.h     |   10 +-
>  include/uapi/linux/kfd_ioctl.h                |  169 +-
>  26 files changed, 4296 insertions(+), 291 deletions(-)
>  create mode 100644 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
>  create mode 100644 drivers/gpu/drm/amd/amdkfd/kfd_migrate.h
>  create mode 100644 drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>  create mode 100644 drivers/gpu/drm/amd/amdkfd/kfd_svm.h
> 
> -- 
> 2.29.2
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch