Re: [PATCH 05/12] drm/ttm: move the LRU into resource handling

[Andrey Grodzovsky <andrey.grodzovsky@amd.com>]

On 2021-08-30 4:57 a.m., Christian König wrote:
> This way we finally fix the problem that new resource are
> not immediately evict-able after allocation.
>
> That has caused numerous problems including OOM on GDS handling
> and not being able to use TTM as general resource manager.
>
> Signed-off-by: Christian König <christian.koenig@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c  |   8 +-
>   drivers/gpu/drm/i915/gem/i915_gem_ttm.c |   2 +-
>   drivers/gpu/drm/ttm/ttm_bo.c            | 105 ++------------------
>   drivers/gpu/drm/ttm/ttm_bo_util.c       |   1 -
>   drivers/gpu/drm/ttm/ttm_device.c        |   8 +-
>   drivers/gpu/drm/ttm/ttm_resource.c      | 127 ++++++++++++++++++++++++
>   include/drm/ttm/ttm_bo_api.h            |  16 ---
>   include/drm/ttm/ttm_bo_driver.h         |  29 +-----
>   include/drm/ttm/ttm_resource.h          |  35 +++++++
>   9 files changed, 181 insertions(+), 150 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index 6362e861a3f5..70d2cbb1dbb4 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -683,12 +683,12 @@ void amdgpu_vm_move_to_lru_tail(struct amdgpu_device *adev,
>   
>   	if (vm->bulk_moveable) {
>   		spin_lock(&adev->mman.bdev.lru_lock);
> -		ttm_bo_bulk_move_lru_tail(&vm->lru_bulk_move);
> +		ttm_lru_bulk_move_tail(&vm->lru_bulk_move);
>   		spin_unlock(&adev->mman.bdev.lru_lock);
>   		return;
>   	}
>   
> -	memset(&vm->lru_bulk_move, 0, sizeof(vm->lru_bulk_move));
> +	ttm_lru_bulk_move_init(&vm->lru_bulk_move);
>   
>   	spin_lock(&adev->mman.bdev.lru_lock);
>   	list_for_each_entry(bo_base, &vm->idle, vm_status) {
> @@ -698,11 +698,9 @@ void amdgpu_vm_move_to_lru_tail(struct amdgpu_device *adev,
>   		if (!bo->parent)
>   			continue;
>   
> -		ttm_bo_move_to_lru_tail(&bo->tbo, bo->tbo.resource,
> -					&vm->lru_bulk_move);
> +		ttm_bo_move_to_lru_tail(&bo->tbo, &vm->lru_bulk_move);
>   		if (shadow)
>   			ttm_bo_move_to_lru_tail(&shadow->tbo,
> -						shadow->tbo.resource,
>   						&vm->lru_bulk_move);
>   	}
>   	spin_unlock(&adev->mman.bdev.lru_lock);
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> index e646aac9d7a4..41f0de841d72 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> @@ -471,7 +471,7 @@ static void i915_ttm_adjust_lru(struct drm_i915_gem_object *obj)
>   			bo->priority = I915_TTM_PRIO_NO_PAGES;
>   	}
>   
> -	ttm_bo_move_to_lru_tail(bo, bo->resource, NULL);
> +	ttm_bo_move_to_lru_tail(bo, NULL);
>   	spin_unlock(&bo->bdev->lru_lock);
>   }
>   
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 49f4bc97c35a..d5c6e096fd31 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -69,98 +69,16 @@ static void ttm_bo_mem_space_debug(struct ttm_buffer_object *bo,
>   	}
>   }
>   
> -static void ttm_bo_del_from_lru(struct ttm_buffer_object *bo)
> -{
> -	struct ttm_device *bdev = bo->bdev;
> -
> -	list_del_init(&bo->lru);
> -
> -	if (bdev->funcs->del_from_lru_notify)
> -		bdev->funcs->del_from_lru_notify(bo);
> -}
> -
> -static void ttm_bo_bulk_move_set_pos(struct ttm_lru_bulk_move_pos *pos,
> -				     struct ttm_buffer_object *bo)
> -{
> -	if (!pos->first)
> -		pos->first = bo;
> -	pos->last = bo;
> -}
> -
>   void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo,
> -			     struct ttm_resource *mem,
>   			     struct ttm_lru_bulk_move *bulk)
>   {
> -	struct ttm_device *bdev = bo->bdev;
> -	struct ttm_resource_manager *man;
> -
> -	if (!bo->deleted)
> -		dma_resv_assert_held(bo->base.resv);
> -
> -	if (bo->pin_count) {
> -		ttm_bo_del_from_lru(bo);
> -		return;
> -	}
> -
> -	if (!mem)
> -		return;
> -
> -	man = ttm_manager_type(bdev, mem->mem_type);
> -	list_move_tail(&bo->lru, &man->lru[bo->priority]);
> -
> -	if (bdev->funcs->del_from_lru_notify)
> -		bdev->funcs->del_from_lru_notify(bo);
> -
> -	if (bulk && !bo->pin_count) {
> -		switch (bo->resource->mem_type) {
> -		case TTM_PL_TT:
> -			ttm_bo_bulk_move_set_pos(&bulk->tt[bo->priority], bo);
> -			break;
> +	dma_resv_assert_held(bo->base.resv);
>   
> -		case TTM_PL_VRAM:
> -			ttm_bo_bulk_move_set_pos(&bulk->vram[bo->priority], bo);
> -			break;
> -		}
> -	}
> +	if (bo->resource)
> +		ttm_resource_move_to_lru_tail(bo->resource, bulk);
>   }
>   EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
>   
> -void ttm_bo_bulk_move_lru_tail(struct ttm_lru_bulk_move *bulk)
> -{
> -	unsigned i;
> -
> -	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
> -		struct ttm_lru_bulk_move_pos *pos = &bulk->tt[i];
> -		struct ttm_resource_manager *man;
> -
> -		if (!pos->first)
> -			continue;
> -
> -		dma_resv_assert_held(pos->first->base.resv);
> -		dma_resv_assert_held(pos->last->base.resv);
> -
> -		man = ttm_manager_type(pos->first->bdev, TTM_PL_TT);
> -		list_bulk_move_tail(&man->lru[i], &pos->first->lru,
> -				    &pos->last->lru);
> -	}
> -
> -	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
> -		struct ttm_lru_bulk_move_pos *pos = &bulk->vram[i];
> -		struct ttm_resource_manager *man;
> -
> -		if (!pos->first)
> -			continue;
> -
> -		dma_resv_assert_held(pos->first->base.resv);
> -		dma_resv_assert_held(pos->last->base.resv);
> -
> -		man = ttm_manager_type(pos->first->bdev, TTM_PL_VRAM);
> -		list_bulk_move_tail(&man->lru[i], &pos->first->lru,
> -				    &pos->last->lru);
> -	}
> -}
> -EXPORT_SYMBOL(ttm_bo_bulk_move_lru_tail);
> -
>   static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
>   				  struct ttm_resource *mem, bool evict,
>   				  struct ttm_operation_ctx *ctx,
> @@ -342,7 +260,6 @@ static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo,
>   		return ret;
>   	}
>   
> -	ttm_bo_del_from_lru(bo);


Here and in other places this was removed, I assume ttm_resource_fini
should replace it but I don't see where exactly this takes place.

Andrey


>   	list_del_init(&bo->ddestroy);
>   	spin_unlock(&bo->bdev->lru_lock);
>   	ttm_bo_cleanup_memtype_use(bo);
> @@ -443,7 +360,7 @@ static void ttm_bo_release(struct kref *kref)
>   		 */
>   		if (bo->pin_count) {
>   			bo->pin_count = 0;
> -			ttm_bo_move_to_lru_tail(bo, bo->resource, NULL);
> +			ttm_resource_move_to_lru_tail(bo->resource, NULL);
>   		}
>   
>   		kref_init(&bo->kref);
> @@ -456,7 +373,6 @@ static void ttm_bo_release(struct kref *kref)
>   	}
>   
>   	spin_lock(&bo->bdev->lru_lock);
> -	ttm_bo_del_from_lru(bo);
>   	list_del(&bo->ddestroy);
>   	spin_unlock(&bo->bdev->lru_lock);
>   
> @@ -670,15 +586,17 @@ int ttm_mem_evict_first(struct ttm_device *bdev,
>   			struct ww_acquire_ctx *ticket)
>   {
>   	struct ttm_buffer_object *bo = NULL, *busy_bo = NULL;
> +	struct ttm_resource *res;
>   	bool locked = false;
>   	unsigned i;
>   	int ret;
>   
>   	spin_lock(&bdev->lru_lock);
>   	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
> -		list_for_each_entry(bo, &man->lru[i], lru) {
> +		list_for_each_entry(res, &man->lru[i], lru) {
>   			bool busy;
>   
> +			bo = res->bo;
>   			if (!ttm_bo_evict_swapout_allowable(bo, ctx, place,
>   							    &locked, &busy)) {
>   				if (busy && !busy_bo && ticket !=
> @@ -696,7 +614,7 @@ int ttm_mem_evict_first(struct ttm_device *bdev,
>   		}
>   
>   		/* If the inner loop terminated early, we have our candidate */
> -		if (&bo->lru != &man->lru[i])
> +		if (&res->lru != &man->lru[i])
>   			break;
>   
>   		bo = NULL;
> @@ -870,9 +788,6 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
>   	}
>   
>   error:
> -	if (bo->resource->mem_type == TTM_PL_SYSTEM && !bo->pin_count)
> -		ttm_bo_move_to_lru_tail_unlocked(bo);
> -
>   	return ret;
>   }
>   EXPORT_SYMBOL(ttm_bo_mem_space);
> @@ -1012,7 +927,6 @@ int ttm_bo_init_reserved(struct ttm_device *bdev,
>   	bo->destroy = destroy ? destroy : ttm_bo_default_destroy;
>   
>   	kref_init(&bo->kref);
> -	INIT_LIST_HEAD(&bo->lru);
>   	INIT_LIST_HEAD(&bo->ddestroy);
>   	bo->bdev = bdev;
>   	bo->type = type;
> @@ -1062,8 +976,6 @@ int ttm_bo_init_reserved(struct ttm_device *bdev,
>   		return ret;
>   	}
>   
> -	ttm_bo_move_to_lru_tail_unlocked(bo);
> -
>   	return ret;
>   }
>   EXPORT_SYMBOL(ttm_bo_init_reserved);
> @@ -1165,7 +1077,6 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
>   		return 0;
>   	}
>   
> -	ttm_bo_del_from_lru(bo);
>   	/* TODO: Cleanup the locking */
>   	spin_unlock(&bo->bdev->lru_lock);
>   
> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
> index c5d02edaefc0..49b4bedf8715 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> @@ -232,7 +232,6 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
>   
>   	atomic_inc(&ttm_glob.bo_count);
>   	INIT_LIST_HEAD(&fbo->base.ddestroy);
> -	INIT_LIST_HEAD(&fbo->base.lru);
>   	fbo->base.moving = NULL;
>   	drm_vma_node_reset(&fbo->base.base.vma_node);
>   
> diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c
> index 519deea8e39b..9e0dfceff68c 100644
> --- a/drivers/gpu/drm/ttm/ttm_device.c
> +++ b/drivers/gpu/drm/ttm/ttm_device.c
> @@ -134,6 +134,7 @@ int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
>   {
>   	struct ttm_resource_manager *man;
>   	struct ttm_buffer_object *bo;
> +	struct ttm_resource *res;
>   	unsigned i, j;
>   	int ret;
>   
> @@ -144,8 +145,11 @@ int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
>   			continue;
>   
>   		for (j = 0; j < TTM_MAX_BO_PRIORITY; ++j) {
> -			list_for_each_entry(bo, &man->lru[j], lru) {
> -				uint32_t num_pages = PFN_UP(bo->base.size);
> +			list_for_each_entry(res, &man->lru[j], lru) {
> +				uint32_t num_pages;
> +
> +				bo = res->bo;
> +				num_pages = PFN_UP(bo->base.size);
>   
>   				ret = ttm_bo_swapout(bo, ctx, gfp_flags);
>   				/* ttm_bo_swapout has dropped the lru_lock */
> diff --git a/drivers/gpu/drm/ttm/ttm_resource.c b/drivers/gpu/drm/ttm/ttm_resource.c
> index 426e6841fc89..355c542758b5 100644
> --- a/drivers/gpu/drm/ttm/ttm_resource.c
> +++ b/drivers/gpu/drm/ttm/ttm_resource.c
> @@ -29,6 +29,115 @@
>   #include <drm/ttm/ttm_resource.h>
>   #include <drm/ttm/ttm_bo_driver.h>
>   
> +/**
> + * ttm_lru_bulk_move_init - initialize a bulk move structure
> + * @bulk: the structure to init
> + *
> + * For now just memset the structure to zero.
> + */
> +void ttm_lru_bulk_move_init(struct ttm_lru_bulk_move *bulk)
> +{
> +	memset(bulk, 0, sizeof(*bulk));
> +}
> +EXPORT_SYMBOL(ttm_lru_bulk_move_init);
> +
> +/**
> + * ttm_lru_bulk_move_tail
> + *
> + * @bulk: bulk move structure
> + *
> + * Bulk move BOs to the LRU tail, only valid to use when driver makes sure that
> + * resource order never changes. Should be called with ttm_device::lru_lock held.
> + */
> +void ttm_lru_bulk_move_tail(struct ttm_lru_bulk_move *bulk)
> +{
> +	unsigned i;
> +
> +	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
> +		struct ttm_lru_bulk_move_pos *pos = &bulk->tt[i];
> +		struct ttm_resource_manager *man;
> +
> +		if (!pos->first)
> +			continue;
> +
> +		dma_resv_assert_held(pos->first->bo->base.resv);
> +		dma_resv_assert_held(pos->last->bo->base.resv);
> +
> +		man = ttm_manager_type(pos->first->bo->bdev, TTM_PL_TT);
> +		list_bulk_move_tail(&man->lru[i], &pos->first->lru,
> +				    &pos->last->lru);
> +	}
> +
> +	for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
> +		struct ttm_lru_bulk_move_pos *pos = &bulk->vram[i];
> +		struct ttm_resource_manager *man;
> +
> +		if (!pos->first)
> +			continue;
> +
> +		dma_resv_assert_held(pos->first->bo->base.resv);
> +		dma_resv_assert_held(pos->last->bo->base.resv);
> +
> +		man = ttm_manager_type(pos->first->bo->bdev, TTM_PL_VRAM);
> +		list_bulk_move_tail(&man->lru[i], &pos->first->lru,
> +				    &pos->last->lru);
> +	}
> +}
> +EXPORT_SYMBOL(ttm_lru_bulk_move_tail);
> +
> +/* Record a resource position in a bulk move structure */
> +static void ttm_lru_bulk_move_set_pos(struct ttm_lru_bulk_move_pos *pos,
> +				      struct ttm_resource *res)
> +{
> +	if (!pos->first)
> +		pos->first = res;
> +	pos->last = res;
> +}
> +
> +/* Remove a resource from the LRU */
> +static void ttm_resource_del_from_lru(struct ttm_resource *res)
> +{
> +	struct ttm_device *bdev = res->bo->bdev;
> +
> +	list_del_init(&res->lru);
> +
> +	if (bdev->funcs->del_from_lru_notify)
> +		bdev->funcs->del_from_lru_notify(res->bo);
> +}
> +
> +/* Move a resource to the LRU tail and track the bulk position */
> +void ttm_resource_move_to_lru_tail(struct ttm_resource *res,
> +				   struct ttm_lru_bulk_move *bulk)
> +{
> +	struct ttm_buffer_object *bo = res->bo;
> +	struct ttm_device *bdev = bo->bdev;
> +	struct ttm_resource_manager *man;
> +
> +	if (bo->pin_count) {
> +		ttm_resource_del_from_lru(res);
> +		return;
> +	}
> +
> +	man = ttm_manager_type(bdev, res->mem_type);
> +	list_move_tail(&res->lru, &man->lru[bo->priority]);
> +
> +	if (bdev->funcs->del_from_lru_notify)
> +		bdev->funcs->del_from_lru_notify(bo);
> +
> +	if (!bulk)
> +		return;
> +
> +	switch (res->mem_type) {
> +	case TTM_PL_TT:
> +		ttm_lru_bulk_move_set_pos(&bulk->tt[bo->priority], res);
> +		break;
> +
> +	case TTM_PL_VRAM:
> +		ttm_lru_bulk_move_set_pos(&bulk->vram[bo->priority], res);
> +		break;
> +	}
> +}
> +
>   void ttm_resource_init(struct ttm_buffer_object *bo,
>                          const struct ttm_place *place,
>                          struct ttm_resource *res)
> @@ -44,15 +153,33 @@ void ttm_resource_init(struct ttm_buffer_object *bo,
>   	res->bus.is_iomem = false;
>   	res->bus.caching = ttm_cached;
>   	res->bo = bo;
> +	INIT_LIST_HEAD(&res->lru);
>   
>   	man = ttm_manager_type(bo->bdev, place->mem_type);
>   	atomic64_add(bo->base.size, &man->usage);
> +
> +	spin_lock(&bo->bdev->lru_lock);
> +	ttm_resource_move_to_lru_tail(res, NULL);
> +	spin_unlock(&bo->bdev->lru_lock);
>   }
>   EXPORT_SYMBOL(ttm_resource_init);
>   
> +/**
> + * ttm_resource_fini
> + *
> + * @res: the resource to clean up
> + *
> + * Make sure the resource is removed from the LRU before destruction.
> + */
>   void ttm_resource_fini(struct ttm_resource_manager *man,
>   		       struct ttm_resource *res)
>   {
> +	struct ttm_device *bdev = res->bo->bdev;
> +
> +	spin_lock(&bdev->lru_lock);
> +	ttm_resource_del_from_lru(res);
> +	spin_unlock(&bdev->lru_lock);
> +
>   	atomic64_sub(res->bo->base.size, &man->usage);
>   }
>   EXPORT_SYMBOL(ttm_resource_fini);
> diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
> index f681bbdbc698..0928d8cfb45a 100644
> --- a/include/drm/ttm/ttm_bo_api.h
> +++ b/include/drm/ttm/ttm_bo_api.h
> @@ -56,8 +56,6 @@ struct ttm_placement;
>   
>   struct ttm_place;
>   
> -struct ttm_lru_bulk_move;
> -
>   /**
>    * enum ttm_bo_type
>    *
> @@ -95,7 +93,6 @@ struct ttm_tt;
>    * @ttm: TTM structure holding system pages.
>    * @evicted: Whether the object was evicted without user-space knowing.
>    * @deleted: True if the object is only a zombie and already deleted.
> - * @lru: List head for the lru list.
>    * @ddestroy: List head for the delayed destroy list.
>    * @swap: List head for swap LRU list.
>    * @moving: Fence set when BO is moving
> @@ -144,7 +141,6 @@ struct ttm_buffer_object {
>   	 * Members protected by the bdev::lru_lock.
>   	 */
>   
> -	struct list_head lru;
>   	struct list_head ddestroy;
>   
>   	/**
> @@ -308,7 +304,6 @@ void ttm_bo_put(struct ttm_buffer_object *bo);
>    * ttm_bo_move_to_lru_tail
>    *
>    * @bo: The buffer object.
> - * @mem: Resource object.
>    * @bulk: optional bulk move structure to remember BO positions
>    *
>    * Move this BO to the tail of all lru lists used to lookup and reserve an
> @@ -316,19 +311,8 @@ void ttm_bo_put(struct ttm_buffer_object *bo);
>    * held, and is used to make a BO less likely to be considered for eviction.
>    */
>   void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo,
> -			     struct ttm_resource *mem,
>   			     struct ttm_lru_bulk_move *bulk);
>   
> -/**
> - * ttm_bo_bulk_move_lru_tail
> - *
> - * @bulk: bulk move structure
> - *
> - * Bulk move BOs to the LRU tail, only valid to use when driver makes sure that
> - * BO order never changes. Should be called with ttm_global::lru_lock held.
> - */
> -void ttm_bo_bulk_move_lru_tail(struct ttm_lru_bulk_move *bulk);
> -
>   /**
>    * ttm_bo_lock_delayed_workqueue
>    *
> diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
> index 68d6069572aa..fba2f7d3d34e 100644
> --- a/include/drm/ttm/ttm_bo_driver.h
> +++ b/include/drm/ttm/ttm_bo_driver.h
> @@ -45,33 +45,6 @@
>   #include "ttm_tt.h"
>   #include "ttm_pool.h"
>   
> -/**
> - * struct ttm_lru_bulk_move_pos
> - *
> - * @first: first BO in the bulk move range
> - * @last: last BO in the bulk move range
> - *
> - * Positions for a lru bulk move.
> - */
> -struct ttm_lru_bulk_move_pos {
> -	struct ttm_buffer_object *first;
> -	struct ttm_buffer_object *last;
> -};
> -
> -/**
> - * struct ttm_lru_bulk_move
> - *
> - * @tt: first/last lru entry for BOs in the TT domain
> - * @vram: first/last lru entry for BOs in the VRAM domain
> - * @swap: first/last lru entry for BOs on the swap list
> - *
> - * Helper structure for bulk moves on the LRU list.
> - */
> -struct ttm_lru_bulk_move {
> -	struct ttm_lru_bulk_move_pos tt[TTM_MAX_BO_PRIORITY];
> -	struct ttm_lru_bulk_move_pos vram[TTM_MAX_BO_PRIORITY];
> -};
> -
>   /*
>    * ttm_bo.c
>    */
> @@ -182,7 +155,7 @@ static inline void
>   ttm_bo_move_to_lru_tail_unlocked(struct ttm_buffer_object *bo)
>   {
>   	spin_lock(&bo->bdev->lru_lock);
> -	ttm_bo_move_to_lru_tail(bo, bo->resource, NULL);
> +	ttm_bo_move_to_lru_tail(bo, NULL);
>   	spin_unlock(&bo->bdev->lru_lock);
>   }
>   
> diff --git a/include/drm/ttm/ttm_resource.h b/include/drm/ttm/ttm_resource.h
> index 526fe359c603..5f9797f9d64a 100644
> --- a/include/drm/ttm/ttm_resource.h
> +++ b/include/drm/ttm/ttm_resource.h
> @@ -26,10 +26,12 @@
>   #define _TTM_RESOURCE_H_
>   
>   #include <linux/types.h>
> +#include <linux/list.h>
>   #include <linux/mutex.h>
>   #include <linux/atomic.h>
>   #include <linux/dma-buf-map.h>
>   #include <linux/dma-fence.h>
> +
>   #include <drm/drm_print.h>
>   #include <drm/ttm/ttm_caching.h>
>   #include <drm/ttm/ttm_kmap_iter.h>
> @@ -177,6 +179,33 @@ struct ttm_resource {
>   	uint32_t placement;
>   	struct ttm_bus_placement bus;
>   	struct ttm_buffer_object *bo;
> +	struct list_head lru;
> +};
> +
> +/**
> + * struct ttm_lru_bulk_move_pos
> + *
> + * @first: first res in the bulk move range
> + * @last: last res in the bulk move range
> + *
> + * Positions for a lru bulk move.
> + */
> +struct ttm_lru_bulk_move_pos {
> +	struct ttm_resource *first;
> +	struct ttm_resource *last;
> +};
> +
> +/**
> + * struct ttm_lru_bulk_move
> + *
> + * @tt: first/last lru entry for resources in the TT domain
> + * @vram: first/last lru entry for resources in the VRAM domain
> + *
> + * Helper structure for bulk moves on the LRU list.
> + */
> +struct ttm_lru_bulk_move {
> +	struct ttm_lru_bulk_move_pos tt[TTM_MAX_BO_PRIORITY];
> +	struct ttm_lru_bulk_move_pos vram[TTM_MAX_BO_PRIORITY];
>   };
>   
>   /**
> @@ -278,6 +307,12 @@ ttm_resource_manager_usage(struct ttm_resource_manager *man)
>   	return atomic64_read(&man->usage);
>   }
>   
> +void ttm_lru_bulk_move_init(struct ttm_lru_bulk_move *bulk);
> +void ttm_lru_bulk_move_tail(struct ttm_lru_bulk_move *bulk);
> +
> +void ttm_resource_move_to_lru_tail(struct ttm_resource *res,
> +				   struct ttm_lru_bulk_move *bulk);
> +
>   void ttm_resource_init(struct ttm_buffer_object *bo,
>                          const struct ttm_place *place,
>                          struct ttm_resource *res);