Commit 536a2ead authored by Arvind Yadav's avatar Arvind Yadav Committed by Matthew Brost
Browse files

drm/xe/bo: Add purgeable shrinker state helpers 



Encapsulate TTM purgeable flag updates and shrinker page accounting
into helper functions to prevent desynchronization between the TTM
tt->purgeable flag and the shrinker's page bucket counters.

Without these helpers, direct manipulation of xe_ttm_tt->purgeable
risks forgetting to update the corresponding shrinker counters,
leading to incorrect memory pressure calculations.

Update purgeable BO state to PURGED after successful shrinker purge
for DONTNEED BOs.

Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Reviewed-by: default avatarThomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: default avatarArvind Yadav <arvind.yadav@intel.com>
Signed-off-by: default avatarMatthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20260326130843.3545241-11-arvind.yadav@intel.com
parent da857c9a

drivers/gpu/drm/xe/xe_bo.c

+42 −1
Original line number Diff line number Diff line
@@ -838,6 +838,42 @@ static int xe_bo_move_notify(struct xe_bo *bo, 
	return 0;

}



/**

 * xe_bo_set_purgeable_shrinker() - Update shrinker accounting for purgeable state

 * @bo: Buffer object

 * @new_state: New purgeable state being set

 *

 * Transfers pages between shrinkable and purgeable buckets when the BO

 * purgeable state changes. Called automatically from xe_bo_set_purgeable_state().

 */

static void xe_bo_set_purgeable_shrinker(struct xe_bo *bo,

					 enum xe_madv_purgeable_state new_state)

{

	struct ttm_buffer_object *ttm_bo = &bo->ttm;

	struct ttm_tt *tt = ttm_bo->ttm;

	struct xe_device *xe = ttm_to_xe_device(ttm_bo->bdev);

	struct xe_ttm_tt *xe_tt;

	long tt_pages;



	xe_bo_assert_held(bo);



	if (!tt || !ttm_tt_is_populated(tt))

		return;



	xe_tt = container_of(tt, struct xe_ttm_tt, ttm);

	tt_pages = tt->num_pages;



	if (!xe_tt->purgeable && new_state == XE_MADV_PURGEABLE_DONTNEED) {

		xe_tt->purgeable = true;

		/* Transfer pages from shrinkable to purgeable count */

		xe_shrinker_mod_pages(xe->mem.shrinker, -tt_pages, tt_pages);

	} else if (xe_tt->purgeable && new_state == XE_MADV_PURGEABLE_WILLNEED) {

		xe_tt->purgeable = false;

		/* Transfer pages from purgeable to shrinkable count */

		xe_shrinker_mod_pages(xe->mem.shrinker, tt_pages, -tt_pages);

	}

}



/**

 * xe_bo_set_purgeable_state() - Set BO purgeable state with validation

 * @bo: Buffer object
@@ -845,7 +881,8 @@ static int xe_bo_move_notify(struct xe_bo *bo, 
 *

 * Sets the purgeable state with lockdep assertions and validates state

 * transitions. Once a BO is PURGED, it cannot transition to any other state.

 * Invalid transitions are caught with xe_assert().

 * Invalid transitions are caught with xe_assert(). Shrinker page accounting

 * is updated automatically.

 */

void xe_bo_set_purgeable_state(struct xe_bo *bo,

			       enum xe_madv_purgeable_state new_state)
@@ -864,6 +901,7 @@ void xe_bo_set_purgeable_state(struct xe_bo *bo, 
			new_state != XE_MADV_PURGEABLE_PURGED));



	bo->madv_purgeable = new_state;

	xe_bo_set_purgeable_shrinker(bo, new_state);

}



/**
@@ -1246,6 +1284,9 @@ long xe_bo_shrink(struct ttm_operation_ctx *ctx, struct ttm_buffer_object *bo, 
			lret = xe_bo_move_notify(xe_bo, ctx);

		if (!lret)

			lret = xe_bo_shrink_purge(ctx, bo, scanned);

		if (lret > 0 && xe_bo_madv_is_dontneed(xe_bo))

			xe_bo_set_purgeable_state(xe_bo,

						  XE_MADV_PURGEABLE_PURGED);

		goto out_unref;

	}