[PATCH v15 0/9] TTM shrinker helpers and xe buffer object shrinker

Fri Jan 10 09:47:33 UTC 2025

Any objections that I push patch #1 and #3 to drm-misc-next?

They are general cleanups anyway and this way we have them out of the way.

Regards,
Christian.

Am 17.12.24 um 15:58 schrieb Thomas Hellström:
> This series implements TTM shrinker / eviction helpers and an xe bo
> shrinker. It builds on a previous series, *and obsoletes that one*.
>
> https://lore.kernel.org/linux-mm/b7491378-defd-4f1c-31e2-29e4c77e2d67@amd.com/T/
>
> Where the comment about layering
> https://lore.kernel.org/linux-mm/b7491378-defd-4f1c-31e2-29e4c77e2d67@amd.com/T/#ma918844aa8a6efe8768fdcda0c6590d5c93850c9
>
> now addressed, and this version also implements shmem objects for backup
> rather than direct swap-cache insertions, which was used in the previuos
> series. It turns out that with per-page backup / shrinking, shmem objects
> appears to work just as well as direct swap-cache insertions with the
> added benefit that was introduced in the previous TTM shrinker series to
> avoid running out of swap entries isn't really needed.
>
> The series earlier consisted of a LRU traversal part and the current part.
> The LRU traversal part is merged, but is still mentioned in the history
> below.
>
> Patch 1 balances ttm_resource_cursor_fini() with an init function. It
> makes patch 5 more straightforward.
>
> Patch 2 introduces a backup implemententaion.
>
> Patch 3 reworks the structure of ttm_pool_alloc in preparation for patch 4.
>
> Patch 4 introduces functionality in the ttm_pool code for page-by-page shrinking
> and recovery. It avoids having to temporarily allocate a huge amount of
> memory to be able to shrink a buffer object. It also introduces the
> possibility to immediately write-back pages if needed.
>
> Patch 5 Adds a simple error injection to the above code to help increase
> test coverage.
>
> Patch 6 Implements a macro for LRU iteration.
>
> Patch 7 Introduces driver-facing helpers for shrinking.
>
> Patch 8 Implements the xe bo shrinker.
>
> Patch 9 Increases (removes) the XE_PL_TT watermark.
>
> v2:
> - Squash obsolete revision history in the patch commit messages.
> - Fix a couple of review comments by Christian
> - Don't store the mem_type in the TTM managers but in the
>    resource cursor.
> - Rename introduced TTM *back_up* function names to *backup*
> - Add ttm pool recovery fault injection.
> - Shrinker xe kunit test
> - Various bugfixes
>
> v3:
> - Address some review comments from Matthew Brost and Christian König.
> - Use the restartable LRU walk for TTM swapping and eviction.
> - Provide a POC drm_exec locking implementation for exhaustive
>    eviction. (Christian König).
>
> v4:
> - Remove the RFC exhaustive eviction part. While the path to exhaustive
>    eviction is pretty clear and demonstrated in v3, there is still some
>    drm_exec work that needs to be agreed and implemented.
> - Add shrinker power management. On some hw we need to wake when shrinking.
> - Fix the lru walker helper for -EALREADY errors.
> - Add drm/xe: Increase the XE_PL_TT watermark.
>
> v5:
> - Update also TTM kunit tests
> - Handle ghost- and zombie objects in the shrinker.
> - A couple of compile- and UAF fixes reported by Kernel Build Robot and
>    Dan Carpenter.
>
> v6:
> - Address review comments from Matthew Brost on the
>    restartable LRU traversal path.
>
> v7:
> - Split out TTM restartable LRU traversal path and merge that.
> - Adapt the review comments on that series.
>
> v8:
> - Address review comments from Matthew Brost as detailed in the
>    respective patches.
>
> v9:
> - Rebase and fix compilation errors
>
> v10:
> - Use a LRU iteration macro rather than a function with a callback.
> - Rebasing and cleanups
> - Address some additional review comments from Matt Brost.
> - Drop the shrinker selftest. It was already merged as a swapout
>    self-test.
>
> v11:
> - Move more core interaction to additional TTM helpers.
> - Don't back up without __GFP_FS, and don't start writeback without __GFP_IO.
> - Rebase.
>
> v12:
> - Fix an indentation flaw.
> - Rebase
>
> v13:
> - Remove the backup base-class, and use direct calls for ttm_backup
>    (Christian König).
> - Rebase on the ttm_backup changes.
> - Move shrunken bos from the LRU list to the unevictable list.
> - Provide an accessor function with sanity checks to set the
> - ttm_tt::backup field.
> - Update documentation.
>
> v14:
> - Update documentation of ttm_backup_bytes_avail().
> - Work around converting between struct file * and struct ttm-backup *.
> - Don't set up backup for imported buffers.
>
> v15:
> - ttm_backup return value change. (Christian König)
> - ttm_pool restore/alloc implementation rework (Christian König)
> - Documentation update.
> - Remove cond_resched (Christian König)
>
> Cc: Somalapuram Amaranath <Amaranath.Somalapuram at amd.com>
> Cc: Christian König <christian.koenig at amd.com>
> Cc: Matthew Brost <matthew.brost at intel.com>
> Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
> Cc: <dri-devel at lists.freedesktop.org>
>
> Thomas Hellström (9):
>    drm/ttm: Balance ttm_resource_cursor_init() and
>      ttm_resource_cursor_fini()
>    drm/ttm: Provide a shmem backup implementation
>    drm/ttm/pool: Restructure the pool allocation code
>    drm/ttm/pool, drm/ttm/tt: Provide a helper to shrink pages
>    drm/ttm: Use fault-injection to test error paths
>    drm/ttm: Add a macro to perform LRU iteration
>    drm/ttm: Add helpers for shrinking
>    drm/xe: Add a shrinker for xe bos
>    drm/xe: Increase the XE_PL_TT watermark
>
>   drivers/gpu/drm/ttm/Makefile         |   2 +-
>   drivers/gpu/drm/ttm/ttm_backup.c     | 207 ++++++++
>   drivers/gpu/drm/ttm/ttm_bo.c         |   3 +-
>   drivers/gpu/drm/ttm/ttm_bo_util.c    | 250 +++++++++-
>   drivers/gpu/drm/ttm/ttm_pool.c       | 718 +++++++++++++++++++++++----
>   drivers/gpu/drm/ttm/ttm_resource.c   |  35 +-
>   drivers/gpu/drm/ttm/ttm_tt.c         |  83 ++++
>   drivers/gpu/drm/xe/Makefile          |   1 +
>   drivers/gpu/drm/xe/tests/xe_bo.c     |   6 +-
>   drivers/gpu/drm/xe/xe_bo.c           | 202 +++++++-
>   drivers/gpu/drm/xe/xe_bo.h           |  36 ++
>   drivers/gpu/drm/xe/xe_device.c       |   8 +
>   drivers/gpu/drm/xe/xe_device_types.h |   2 +
>   drivers/gpu/drm/xe/xe_shrinker.c     | 258 ++++++++++
>   drivers/gpu/drm/xe/xe_shrinker.h     |  18 +
>   drivers/gpu/drm/xe/xe_ttm_sys_mgr.c  |   3 +-
>   include/drm/ttm/ttm_backup.h         |  74 +++
>   include/drm/ttm/ttm_bo.h             |  93 ++++
>   include/drm/ttm/ttm_pool.h           |   8 +
>   include/drm/ttm/ttm_resource.h       |  11 +-
>   include/drm/ttm/ttm_tt.h             |  69 ++-
>   21 files changed, 1935 insertions(+), 152 deletions(-)
>   create mode 100644 drivers/gpu/drm/ttm/ttm_backup.c
>   create mode 100644 drivers/gpu/drm/xe/xe_shrinker.c
>   create mode 100644 drivers/gpu/drm/xe/xe_shrinker.h
>   create mode 100644 include/drm/ttm/ttm_backup.h
>