Commit 40379792 authored by Andrey Grodzovsky's avatar Andrey Grodzovsky
Browse files

drm/ttm: Fix multihop assert on eviction. 



Problem:
Under memory pressure when GTT domain is almost full multihop assert
will come up when trying to evict LRU BO from VRAM to SYSTEM.

Fix:
Don't assert on multihop error in evict code but rather do a retry
as we do in ttm_bo_move_buffer

Signed-off-by: default avatarAndrey Grodzovsky <andrey.grodzovsky@amd.com>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210622162339.761651-6-andrey.grodzovsky@amd.com
parent 91e99e11

drivers/gpu/drm/ttm/ttm_bo.c

+34 −29
Original line number Diff line number Diff line
@@ -485,6 +485,31 @@ void ttm_bo_unlock_delayed_workqueue(struct ttm_device *bdev, int resched) 
}

EXPORT_SYMBOL(ttm_bo_unlock_delayed_workqueue);



static int ttm_bo_bounce_temp_buffer(struct ttm_buffer_object *bo,

				     struct ttm_resource **mem,

				     struct ttm_operation_ctx *ctx,

				     struct ttm_place *hop)

{

	struct ttm_placement hop_placement;

	struct ttm_resource *hop_mem;

	int ret;



	hop_placement.num_placement = hop_placement.num_busy_placement = 1;

	hop_placement.placement = hop_placement.busy_placement = hop;



	/* find space in the bounce domain */

	ret = ttm_bo_mem_space(bo, &hop_placement, &hop_mem, ctx);

	if (ret)

		return ret;

	/* move to the bounce domain */

	ret = ttm_bo_handle_move_mem(bo, hop_mem, false, ctx, NULL);

	if (ret) {

		ttm_resource_free(bo, &hop_mem);

		return ret;

	}

	return 0;

}



static int ttm_bo_evict(struct ttm_buffer_object *bo,

			struct ttm_operation_ctx *ctx)

{
@@ -524,12 +549,17 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo, 
		goto out;

	}



bounce:

	ret = ttm_bo_handle_move_mem(bo, evict_mem, true, ctx, &hop);

	if (unlikely(ret)) {

		WARN(ret == -EMULTIHOP, "Unexpected multihop in eviction - likely driver bug\n");

		if (ret != -ERESTARTSYS)

	if (ret == -EMULTIHOP) {

		ret = ttm_bo_bounce_temp_buffer(bo, &evict_mem, ctx, &hop);

		if (ret) {

			pr_err("Buffer eviction failed\n");

			ttm_resource_free(bo, &evict_mem);

			goto out;

		}

		/* try and move to final place now. */

		goto bounce;

	}

out:

	return ret;
@@ -844,31 +874,6 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo, 
}

EXPORT_SYMBOL(ttm_bo_mem_space);



static int ttm_bo_bounce_temp_buffer(struct ttm_buffer_object *bo,

				     struct ttm_resource **mem,

				     struct ttm_operation_ctx *ctx,

				     struct ttm_place *hop)

{

	struct ttm_placement hop_placement;

	struct ttm_resource *hop_mem;

	int ret;



	hop_placement.num_placement = hop_placement.num_busy_placement = 1;

	hop_placement.placement = hop_placement.busy_placement = hop;



	/* find space in the bounce domain */

	ret = ttm_bo_mem_space(bo, &hop_placement, &hop_mem, ctx);

	if (ret)

		return ret;

	/* move to the bounce domain */

	ret = ttm_bo_handle_move_mem(bo, hop_mem, false, ctx, NULL);

	if (ret) {

		ttm_resource_free(bo, &hop_mem);

		return ret;

	}

	return 0;

}



static int ttm_bo_move_buffer(struct ttm_buffer_object *bo,

			      struct ttm_placement *placement,

			      struct ttm_operation_ctx *ctx)