[Intel-gfx] [PATCH v6 00/20] drm/i915/vm_bind: Add VM_BIND functionality

Niranjana Vishwanathapura niranjana.vishwanathapura at intel.com
Thu Nov 10 05:49:13 UTC 2022


On Wed, Nov 09, 2022 at 04:16:25PM -0800, Zanoni, Paulo R wrote:
>On Mon, 2022-11-07 at 00:51 -0800, Niranjana Vishwanathapura wrote:
>> DRM_I915_GEM_VM_BIND/UNBIND ioctls allows UMD to bind/unbind GEM
>> buffer objects (BOs) or sections of a BOs at specified GPU virtual
>> addresses on a specified address space (VM). Multiple mappings can map
>> to the same physical pages of an object (aliasing). These mappings (also
>> referred to as persistent mappings) will be persistent across multiple
>> GPU submissions (execbuf calls) issued by the UMD, without user having
>> to provide a list of all required mappings during each submission (as
>> required by older execbuf mode).
>>
>> This patch series support VM_BIND version 1, as described by the param
>> I915_PARAM_VM_BIND_VERSION.
>>
>> Add new execbuf3 ioctl (I915_GEM_EXECBUFFER3) which only works in
>> vm_bind mode. The vm_bind mode only works with this new execbuf3 ioctl.
>> The new execbuf3 ioctl will not have any execlist support and all the
>> legacy support like relocations etc., are removed.
>>
>> NOTEs:
>> * It is based on below VM_BIND design+uapi rfc.
>>   Documentation/gpu/rfc/i915_vm_bind.rst
>
>Hi
>
>One difference for execbuf3 that I noticed that is not mentioned in the
>RFC document is that we now don't have a way to signal
>EXEC_OBJECT_WRITE. When looking at the Kernel code, some there are some
>pieces that check for this flag:
>
>- there's code that deals with frontbuffer rendering
>- there's code that deals with fences
>- there's code that prevents self-modifying batches
>- another that seems related to waiting for objects
>
>Are there any new rules regarding frontbuffer rendering when we use
>execbuf3? Any other behavior changes related to the other places that
>we should expect when using execbuf3?
>

Paulo,
Most of the EXEC_OBJECT_WRITE check in execbuf path is related to
implicit dependency tracker which execbuf3 does not support. The
frontbuffer related updated is the only exception and I don't
remember the rationale to not require this on execbuf3.

Matt, Tvrtko, Daniel, can you please comment here?

Thanks,
Niranjana

>Thanks,
>Paulo
>
>>
>> * The IGT RFC series is posted as,
>>   [PATCH i-g-t v5 0/12] vm_bind: Add VM_BIND validation support
>>
>> v2: Address various review comments
>> v3: Address review comments and other fixes
>> v4: Remove vm_unbind out fence uapi which is not supported yet,
>>     replace vm->vm_bind_mode check with i915_gem_vm_is_vm_bind_mode()
>> v5: Render kernel-doc, use PIN_NOEVICT, limit vm_bind support to
>>     non-recoverable faults
>> v6: Rebased, minor fixes, add reserved fields to drm_i915_gem_vm_bind,
>>     add new patch for async vm_unbind support
>>
>> Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura at intel.com>
>>
>> Niranjana Vishwanathapura (20):
>>   drm/i915/vm_bind: Expose vm lookup function
>>   drm/i915/vm_bind: Add __i915_sw_fence_await_reservation()
>>   drm/i915/vm_bind: Expose i915_gem_object_max_page_size()
>>   drm/i915/vm_bind: Add support to create persistent vma
>>   drm/i915/vm_bind: Implement bind and unbind of object
>>   drm/i915/vm_bind: Support for VM private BOs
>>   drm/i915/vm_bind: Add support to handle object evictions
>>   drm/i915/vm_bind: Support persistent vma activeness tracking
>>   drm/i915/vm_bind: Add out fence support
>>   drm/i915/vm_bind: Abstract out common execbuf functions
>>   drm/i915/vm_bind: Use common execbuf functions in execbuf path
>>   drm/i915/vm_bind: Implement I915_GEM_EXECBUFFER3 ioctl
>>   drm/i915/vm_bind: Update i915_vma_verify_bind_complete()
>>   drm/i915/vm_bind: Expose i915_request_await_bind()
>>   drm/i915/vm_bind: Handle persistent vmas in execbuf3
>>   drm/i915/vm_bind: userptr dma-resv changes
>>   drm/i915/vm_bind: Limit vm_bind mode to non-recoverable contexts
>>   drm/i915/vm_bind: Add uapi for user to enable vm_bind_mode
>>   drm/i915/vm_bind: Render VM_BIND documentation
>>   drm/i915/vm_bind: Async vm_unbind support
>>
>>  Documentation/gpu/i915.rst                    |  78 +-
>>  drivers/gpu/drm/i915/Makefile                 |   3 +
>>  drivers/gpu/drm/i915/gem/i915_gem_context.c   |  43 +-
>>  drivers/gpu/drm/i915/gem/i915_gem_context.h   |  17 +
>>  drivers/gpu/drm/i915/gem/i915_gem_create.c    |  72 +-
>>  drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c    |   6 +
>>  .../gpu/drm/i915/gem/i915_gem_execbuffer.c    | 516 +----------
>>  .../gpu/drm/i915/gem/i915_gem_execbuffer3.c   | 871 ++++++++++++++++++
>>  .../drm/i915/gem/i915_gem_execbuffer_common.c | 666 +++++++++++++
>>  .../drm/i915/gem/i915_gem_execbuffer_common.h |  74 ++
>>  drivers/gpu/drm/i915/gem/i915_gem_ioctls.h    |   2 +
>>  drivers/gpu/drm/i915/gem/i915_gem_object.c    |   3 +
>>  drivers/gpu/drm/i915/gem/i915_gem_object.h    |   2 +
>>  .../gpu/drm/i915/gem/i915_gem_object_types.h  |   6 +
>>  drivers/gpu/drm/i915/gem/i915_gem_userptr.c   |  19 +
>>  drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h   |  30 +
>>  .../drm/i915/gem/i915_gem_vm_bind_object.c    | 449 +++++++++
>>  drivers/gpu/drm/i915/gt/intel_gtt.c           |  17 +
>>  drivers/gpu/drm/i915/gt/intel_gtt.h           |  21 +
>>  drivers/gpu/drm/i915/i915_driver.c            |   4 +
>>  drivers/gpu/drm/i915/i915_drv.h               |   2 +
>>  drivers/gpu/drm/i915/i915_gem_gtt.c           |  39 +
>>  drivers/gpu/drm/i915/i915_gem_gtt.h           |   3 +
>>  drivers/gpu/drm/i915/i915_getparam.c          |   3 +
>>  drivers/gpu/drm/i915/i915_sw_fence.c          |  28 +-
>>  drivers/gpu/drm/i915/i915_sw_fence.h          |  23 +-
>>  drivers/gpu/drm/i915/i915_vma.c               | 186 +++-
>>  drivers/gpu/drm/i915/i915_vma.h               |  68 +-
>>  drivers/gpu/drm/i915/i915_vma_types.h         |  39 +
>>  include/uapi/drm/i915_drm.h                   | 264 +++++-
>>  30 files changed, 3008 insertions(+), 546 deletions(-)
>>  create mode 100644 drivers/gpu/drm/i915/gem/i915_gem_execbuffer3.c
>>  create mode 100644 drivers/gpu/drm/i915/gem/i915_gem_execbuffer_common.c
>>  create mode 100644 drivers/gpu/drm/i915/gem/i915_gem_execbuffer_common.h
>>  create mode 100644 drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h
>>  create mode 100644 drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>>
>


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