[RFC v6 0/3] Introduce KUnit tests for TTM subsystem

[Christian König]

Am 08.08.23 um 11:51 schrieb Karolina Stolarek:
> This series introduces KUnit[1] tests for TTM (Translation Table Manager)
> subsystem, a memory manager used by graphics drivers to create and manage
> memory buffers across different memory domains, such as system memory
> or VRAM.
>
> Unit tests implemented here cover two data structures:
>    - ttm_device -- referred as a buffer object device, which stores
>      resource managers and page pools
>    - ttm_pool -- a struct of pools (ttm_pool_type) of different page
>      orders and caching attributes, with pages that can be reused on
>      the next buffer allocation
>
> Use kunit_tool script to manually run the tests:
>
> $ ./tools/testing/kunit/kunit.py run --kunitconfig=drivers/gpu/drm/ttm/tests
>
> To build a kernel with TTM KUnit tests, first enable CONFIG_KUNIT, and then
> CONFIG_DRM_TTM_KUNIT_TEST.
>
> As for now, tests are architecture-agnostic (i.e. KUnit runner uses UML
> kernel), which means that we have limited coverage in some places. For
> example, we can't fully test the initialization of global page pools,
> such as global_write_combined. It is to be decided if we want to stick
> to UML or use CONFIG_X86 (at least to some extent).
>
> These patches are just a beginning of the work to improve the test
> coverage of TTM. Feel free to suggest changes, test cases or priorities.

Couldn't find time for further testing, so I just reviewed and pushed 
this to drm-misc-next.

Thanks,
Christian.

>
> Many thanks,
> Karolina
>
> v6:
>    - Rebase the series on the top of drm-misc-next (Christian)
>    - Remove drm_dev_put() call from ttm_test_devices_put, the drm device is
>      already freed in drm_kunit_helper_free_device()
>    - Remove an unnecessary priv assignment in ttm_test_devices_all()
>    - Delete ttm_bo_put() from ttm_pool_test_fini() (as for now, we don't count
>      krefs for dummy BOs)
>
> v5:
>    - Drop unnecessary brackets in 2/3
>    - Rebase KConfig file on the top of drm-tip
>
> v4:
>    - Test helpers have been changed to make the creation of init/fini
>      functions for each test suite easier:
>      + Decouple device creation from test initialization by adding
>        helpers that initialize ttm_test_devices, a struct which stores
>        DRM/TTM devices, and can be used in test-specific init/finis
>        (see ttm_pool_tests.c for an example)
>      + Introduce generic init/fini functions for tests that only need
>        devices
>      + Add ttm_device field to ttm_test_devices (previously
>        ttm_test_devices_priv)
>    - Make TTM buffer object outlive its TT (Christian)
>    - Add a dedicated struct for ttm_pool_test (struct ttm_pool_test_priv)
>    - Rename functions and structs:
>      + struct ttm_test_devices_priv   --> struct ttm_test_devices
>      + ttm_kunit_helper_init_device() --> ttm_device_kunit_init()
>      + ttm_kunit_helper_ttm_bo_init() --> ttm_bo_kunit_init()
>    - Split ttm_kunit_helper_init() into full config (with ttm_device
>      init) and basic (init only with device/drm_device) initialization
>      functions
>
> v3:
>    - Rename ttm_kunit_helper_alloc_device() to ttm_kunit_helper_init_device()
>      (Christian)
>    - Don't leak a full-blown drm_gem_object in ttm_kunit_helper_ttm_bo_init().
>      (Christian). Create a small mock object just to get ttm_tt_init_fields()
>      to init the right number of pages
>    - As a follow up to the change above, delete ttm_kunit_helper_ttm_bo_fini()
>      and just use ttm_bo_put()
>
> v2:
>    - Add missing symbol exports in ttm_kunit_helpers.c
>    - Update helpers include to fix compilation issues (didn't catch it as
>      KUnit tests weren't enabled in the kernel I tested, an oversight
>      on my part)
>    - Add checks for ttm_pool fields in ttm_pool_alloc_basic(), including the
>      one for NUMA node id
>    - Rebase the changes on the top of drm-tip
>
> --------------------------------
> [1] - https://www.kernel.org/doc/html/latest/dev-tools/kunit/index.html
>
> Karolina Stolarek (3):
>    drm/ttm: Introduce KUnit test
>    drm/ttm/tests: Add tests for ttm_device
>    drm/ttm/tests: Add tests for ttm_pool
>
>   drivers/gpu/drm/Kconfig                       |  15 +
>   drivers/gpu/drm/ttm/Makefile                  |   1 +
>   drivers/gpu/drm/ttm/tests/.kunitconfig        |   4 +
>   drivers/gpu/drm/ttm/tests/Makefile            |   6 +
>   drivers/gpu/drm/ttm/tests/ttm_device_test.c   | 212 +++++++++
>   drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c | 113 +++++
>   drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.h |  41 ++
>   drivers/gpu/drm/ttm/tests/ttm_pool_test.c     | 437 ++++++++++++++++++
>   8 files changed, 829 insertions(+)
>   create mode 100644 drivers/gpu/drm/ttm/tests/.kunitconfig
>   create mode 100644 drivers/gpu/drm/ttm/tests/Makefile
>   create mode 100644 drivers/gpu/drm/ttm/tests/ttm_device_test.c
>   create mode 100644 drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c
>   create mode 100644 drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.h
>   create mode 100644 drivers/gpu/drm/ttm/tests/ttm_pool_test.c
>