Re: [PATCH v4 1/2] drm/ttm: Move swapped objects off the manager's LRU list

[Christian König <christian.koenig@xxxxxxx>]

Am 04.09.24 um 10:54 schrieb Thomas Hellström:
> On Wed, 2024-09-04 at 10:50 +0200, Christian König wrote:
> > Am 04.09.24 um 09:08 schrieb Thomas Hellström:
> > > Resources of swapped objects remains on the TTM_PL_SYSTEM manager's
> > > LRU list, which is bad for the LRU walk efficiency.
> > >
> > > Rename the device-wide "pinned" list to "unevictable" and move
> > > also resources of swapped-out objects to that list.
> > >
> > > An alternative would be to create an "UNEVICTABLE" priority to
> > > be able to keep the pinned- and swapped objects on their
> > > respective manager's LRU without affecting the LRU walk efficiency.
> > >
> > > v2:
> > > - Remove a bogus WARN_ON (Christian König)
> > > - Update ttm_resource_[add|del] bulk move (Christian König)
> > > - Fix TTM KUNIT tests (Intel CI)
> > > v3:
> > > - Check for non-NULL bo->resource in ttm_bo_populate().
> > > v4:
> > > - Don't move to LRU tail during swapout until the resource
> > >     is properly swapped or there was a swapout failure.
> > >     (Intel Ci)
> > > - Add a newline after checkpatch check.
> > >
> > > Cc: Christian König <christian.koenig@xxxxxxx>
> > > Cc: Matthew Brost <matthew.brost@xxxxxxxxx>
> > > Cc: <dri-devel@xxxxxxxxxxxxxxxxxxxxx>
> > > Signed-off-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
> > I really wonder if having a SWAPPED wouldn't be cleaner in the long
> > run.
> >
> > Anyway, that seems to work for now. So patch is Reviewed-by:
> > Christian
> > König <christian.koenig@xxxxxxx>.
> Thanks. Are you ok with the changes to the pinning patch that happened
> after yoour R-B as well?

I was already wondering why the increment used to be separate while 
reviewing the initial version. So yes that looks better now.

> Ack to merge through drm-misc-next once CI is clean?

Yeah, works for me.

Christian.

> /Thomas
>
>
> > Regards,
> > Christian.
> >
> > > ---
> > >    drivers/gpu/drm/i915/gem/i915_gem_ttm.c       |  2 +-
> > >    drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c  |  2 +-
> > >    drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c    |  4 +-
> > >    drivers/gpu/drm/ttm/tests/ttm_bo_test.c       |  4 +-
> > >    drivers/gpu/drm/ttm/tests/ttm_resource_test.c |  6 +-
> > >    drivers/gpu/drm/ttm/ttm_bo.c                  | 59
> > > ++++++++++++++++++-
> > >    drivers/gpu/drm/ttm/ttm_bo_util.c             |  6 +-
> > >    drivers/gpu/drm/ttm/ttm_bo_vm.c               |  2 +-
> > >    drivers/gpu/drm/ttm/ttm_device.c              |  4 +-
> > >    drivers/gpu/drm/ttm/ttm_resource.c            | 15 +++--
> > >    drivers/gpu/drm/ttm/ttm_tt.c                  |  3 +
> > >    drivers/gpu/drm/xe/xe_bo.c                    |  4 +-
> > >    include/drm/ttm/ttm_bo.h                      |  2 +
> > >    include/drm/ttm/ttm_device.h                  |  5 +-
> > >    include/drm/ttm/ttm_tt.h                      |  5 ++
> > >    15 files changed, 96 insertions(+), 27 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> > > b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> > > index 5c72462d1f57..7de284766f82 100644
> > > --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> > > +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> > > @@ -808,7 +808,7 @@ static int __i915_ttm_get_pages(struct
> > > drm_i915_gem_object *obj,
> > >    	}
> > >    
> > >    	if (bo->ttm && !ttm_tt_is_populated(bo->ttm)) {
> > > -		ret = ttm_tt_populate(bo->bdev, bo->ttm, &ctx);
> > > +		ret = ttm_bo_populate(bo, &ctx);
> > >    		if (ret)
> > >    			return ret;
> > >    
> > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
> > > b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
> > > index 03b00a03a634..041dab543b78 100644
> > > --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
> > > +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
> > > @@ -624,7 +624,7 @@ int i915_ttm_move(struct ttm_buffer_object *bo,
> > > bool evict,
> > >    
> > >    	/* Populate ttm with pages if needed. Typically system
> > > memory. */
> > >    	if (ttm && (dst_man->use_tt || (ttm->page_flags &
> > > TTM_TT_FLAG_SWAPPED))) {
> > > -		ret = ttm_tt_populate(bo->bdev, ttm, ctx);
> > > +		ret = ttm_bo_populate(bo, ctx);
> > >    		if (ret)
> > >    			return ret;
> > >    	}
> > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
> > > b/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
> > > index ad649523d5e0..61596cecce4d 100644
> > > --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
> > > +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
> > > @@ -90,7 +90,7 @@ static int i915_ttm_backup(struct
> > > i915_gem_apply_to_region *apply,
> > >    		goto out_no_lock;
> > >    
> > >    	backup_bo = i915_gem_to_ttm(backup);
> > > -	err = ttm_tt_populate(backup_bo->bdev, backup_bo->ttm,
> > > &ctx);
> > > +	err = ttm_bo_populate(backup_bo, &ctx);
> > >    	if (err)
> > >    		goto out_no_populate;
> > >    
> > > @@ -189,7 +189,7 @@ static int i915_ttm_restore(struct
> > > i915_gem_apply_to_region *apply,
> > >    	if (!backup_bo->resource)
> > >    		err = ttm_bo_validate(backup_bo,
> > > i915_ttm_sys_placement(), &ctx);
> > >    	if (!err)
> > > -		err = ttm_tt_populate(backup_bo->bdev, backup_bo-
> > > > ttm, &ctx);
> > > +		err = ttm_bo_populate(backup_bo, &ctx);
> > >    	if (!err) {
> > >    		err = i915_gem_obj_copy_ttm(obj, backup, pm_apply-
> > > > allow_gpu,
> > >    					    false);
> > > diff --git a/drivers/gpu/drm/ttm/tests/ttm_bo_test.c
> > > b/drivers/gpu/drm/ttm/tests/ttm_bo_test.c
> > > index f0a7eb62116c..3139fd9128d8 100644
> > > --- a/drivers/gpu/drm/ttm/tests/ttm_bo_test.c
> > > +++ b/drivers/gpu/drm/ttm/tests/ttm_bo_test.c
> > > @@ -308,11 +308,11 @@ static void ttm_bo_unreserve_pinned(struct
> > > kunit *test)
> > >    	err = ttm_resource_alloc(bo, place, &res2);
> > >    	KUNIT_ASSERT_EQ(test, err, 0);
> > >    	KUNIT_ASSERT_EQ(test,
> > > -			list_is_last(&res2->lru.link, &priv-
> > > > ttm_dev->pinned), 1);
> > > +			list_is_last(&res2->lru.link, &priv-
> > > > ttm_dev->unevictable), 1);
> > >    
> > >    	ttm_bo_unreserve(bo);
> > >    	KUNIT_ASSERT_EQ(test,
> > > -			list_is_last(&res1->lru.link, &priv-
> > > > ttm_dev->pinned), 1);
> > > +			list_is_last(&res1->lru.link, &priv-
> > > > ttm_dev->unevictable), 1);
> > >    
> > >    	ttm_resource_free(bo, &res1);
> > >    	ttm_resource_free(bo, &res2);
> > > diff --git a/drivers/gpu/drm/ttm/tests/ttm_resource_test.c
> > > b/drivers/gpu/drm/ttm/tests/ttm_resource_test.c
> > > index 22260e7aea58..a9f4b81921c3 100644
> > > --- a/drivers/gpu/drm/ttm/tests/ttm_resource_test.c
> > > +++ b/drivers/gpu/drm/ttm/tests/ttm_resource_test.c
> > > @@ -164,18 +164,18 @@ static void ttm_resource_init_pinned(struct
> > > kunit *test)
> > >    
> > >    	res = kunit_kzalloc(test, sizeof(*res), GFP_KERNEL);
> > >    	KUNIT_ASSERT_NOT_NULL(test, res);
> > > -	KUNIT_ASSERT_TRUE(test, list_empty(&bo->bdev->pinned));
> > > +	KUNIT_ASSERT_TRUE(test, list_empty(&bo->bdev-
> > > > unevictable));
> > >    
> > >    	dma_resv_lock(bo->base.resv, NULL);
> > >    	ttm_bo_pin(bo);
> > >    	ttm_resource_init(bo, place, res);
> > > -	KUNIT_ASSERT_TRUE(test, list_is_singular(&bo->bdev-
> > > > pinned));
> > > +	KUNIT_ASSERT_TRUE(test, list_is_singular(&bo->bdev-
> > > > unevictable));
> > >    
> > >    	ttm_bo_unpin(bo);
> > >    	ttm_resource_fini(man, res);
> > >    	dma_resv_unlock(bo->base.resv);
> > >    
> > > -	KUNIT_ASSERT_TRUE(test, list_empty(&bo->bdev->pinned));
> > > +	KUNIT_ASSERT_TRUE(test, list_empty(&bo->bdev-
> > > > unevictable));
> > >    }
> > >    
> > >    static void ttm_resource_fini_basic(struct kunit *test)
> > > diff --git a/drivers/gpu/drm/ttm/ttm_bo.c
> > > b/drivers/gpu/drm/ttm/ttm_bo.c
> > > index 320592435252..875b024913a0 100644
> > > --- a/drivers/gpu/drm/ttm/ttm_bo.c
> > > +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> > > @@ -139,7 +139,7 @@ static int ttm_bo_handle_move_mem(struct
> > > ttm_buffer_object *bo,
> > >    			goto out_err;
> > >    
> > >    		if (mem->mem_type != TTM_PL_SYSTEM) {
> > > -			ret = ttm_tt_populate(bo->bdev, bo->ttm,
> > > ctx);
> > > +			ret = ttm_bo_populate(bo, ctx);
> > >    			if (ret)
> > >    				goto out_err;
> > >    		}
> > > @@ -1128,9 +1128,20 @@ ttm_bo_swapout_cb(struct ttm_lru_walk *walk,
> > > struct ttm_buffer_object *bo)
> > >    	if (bo->bdev->funcs->swap_notify)
> > >    		bo->bdev->funcs->swap_notify(bo);
> > >    
> > > -	if (ttm_tt_is_populated(bo->ttm))
> > > +	if (ttm_tt_is_populated(bo->ttm)) {
> > > +		spin_lock(&bo->bdev->lru_lock);
> > > +		ttm_resource_del_bulk_move(bo->resource, bo);
> > > +		spin_unlock(&bo->bdev->lru_lock);
> > > +
> > >    		ret = ttm_tt_swapout(bo->bdev, bo->ttm,
> > > swapout_walk->gfp_flags);
> > >    
> > > +		spin_lock(&bo->bdev->lru_lock);
> > > +		if (ret)
> > > +			ttm_resource_add_bulk_move(bo->resource,
> > > bo);
> > > +		ttm_resource_move_to_lru_tail(bo->resource);
> > > +		spin_unlock(&bo->bdev->lru_lock);
> > > +	}
> > > +
> > >    out:
> > >    	/* Consider -ENOMEM and -ENOSPC non-fatal. */
> > >    	if (ret == -ENOMEM || ret == -ENOSPC)
> > > @@ -1180,3 +1191,47 @@ void ttm_bo_tt_destroy(struct
> > > ttm_buffer_object *bo)
> > >    	ttm_tt_destroy(bo->bdev, bo->ttm);
> > >    	bo->ttm = NULL;
> > >    }
> > > +
> > > +/**
> > > + * ttm_bo_populate() - Ensure that a buffer object has backing
> > > pages
> > > + * @bo: The buffer object
> > > + * @ctx: The ttm_operation_ctx governing the operation.
> > > + *
> > > + * For buffer objects in a memory type whose manager uses
> > > + * struct ttm_tt for backing pages, ensure those backing pages
> > > + * are present and with valid content. The bo's resource is also
> > > + * placed on the correct LRU list if it was previously swapped
> > > + * out.
> > > + *
> > > + * Return: 0 if successful, negative error code on failure.
> > > + * Note: May return -EINTR or -ERESTARTSYS if @ctx::interruptible
> > > + * is set to true.
> > > + */
> > > +int ttm_bo_populate(struct ttm_buffer_object *bo,
> > > +		    struct ttm_operation_ctx *ctx)
> > > +{
> > > +	struct ttm_tt *tt = bo->ttm;
> > > +	bool swapped;
> > > +	int ret;
> > > +
> > > +	dma_resv_assert_held(bo->base.resv);
> > > +
> > > +	if (!tt)
> > > +		return 0;
> > > +
> > > +	swapped = ttm_tt_is_swapped(tt);
> > > +	ret = ttm_tt_populate(bo->bdev, tt, ctx);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	if (swapped && !ttm_tt_is_swapped(tt) && !bo->pin_count &&
> > > +	    bo->resource) {
> > > +		spin_lock(&bo->bdev->lru_lock);
> > > +		ttm_resource_add_bulk_move(bo->resource, bo);
> > > +		ttm_resource_move_to_lru_tail(bo->resource);
> > > +		spin_unlock(&bo->bdev->lru_lock);
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +EXPORT_SYMBOL(ttm_bo_populate);
> > > diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c
> > > b/drivers/gpu/drm/ttm/ttm_bo_util.c
> > > index 3c07f4712d5c..d939925efa81 100644
> > > --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> > > +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> > > @@ -163,7 +163,7 @@ int ttm_bo_move_memcpy(struct ttm_buffer_object
> > > *bo,
> > >    	src_man = ttm_manager_type(bdev, src_mem->mem_type);
> > >    	if (ttm && ((ttm->page_flags & TTM_TT_FLAG_SWAPPED) ||
> > >    		    dst_man->use_tt)) {
> > > -		ret = ttm_tt_populate(bdev, ttm, ctx);
> > > +		ret = ttm_bo_populate(bo, ctx);
> > >    		if (ret)
> > >    			return ret;
> > >    	}
> > > @@ -350,7 +350,7 @@ static int ttm_bo_kmap_ttm(struct
> > > ttm_buffer_object *bo,
> > >    
> > >    	BUG_ON(!ttm);
> > >    
> > > -	ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
> > > +	ret = ttm_bo_populate(bo, &ctx);
> > >    	if (ret)
> > >    		return ret;
> > >    
> > > @@ -507,7 +507,7 @@ int ttm_bo_vmap(struct ttm_buffer_object *bo,
> > > struct iosys_map *map)
> > >    		pgprot_t prot;
> > >    		void *vaddr;
> > >    
> > > -		ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
> > > +		ret = ttm_bo_populate(bo, &ctx);
> > >    		if (ret)
> > >    			return ret;
> > >    
> > > diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c
> > > b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> > > index 4212b8c91dd4..2c699ed1963a 100644
> > > --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
> > > +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> > > @@ -224,7 +224,7 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct
> > > vm_fault *vmf,
> > >    		};
> > >    
> > >    		ttm = bo->ttm;
> > > -		err = ttm_tt_populate(bdev, bo->ttm, &ctx);
> > > +		err = ttm_bo_populate(bo, &ctx);
> > >    		if (err) {
> > >    			if (err == -EINTR || err == -ERESTARTSYS
> > > ||
> > >    			    err == -EAGAIN)
> > > diff --git a/drivers/gpu/drm/ttm/ttm_device.c
> > > b/drivers/gpu/drm/ttm/ttm_device.c
> > > index e7cc4954c1bc..02e797fd1891 100644
> > > --- a/drivers/gpu/drm/ttm/ttm_device.c
> > > +++ b/drivers/gpu/drm/ttm/ttm_device.c
> > > @@ -216,7 +216,7 @@ int ttm_device_init(struct ttm_device *bdev,
> > > const struct ttm_device_funcs *func
> > >    
> > >    	bdev->vma_manager = vma_manager;
> > >    	spin_lock_init(&bdev->lru_lock);
> > > -	INIT_LIST_HEAD(&bdev->pinned);
> > > +	INIT_LIST_HEAD(&bdev->unevictable);
> > >    	bdev->dev_mapping = mapping;
> > >    	mutex_lock(&ttm_global_mutex);
> > >    	list_add_tail(&bdev->device_list, &glob->device_list);
> > > @@ -283,7 +283,7 @@ void ttm_device_clear_dma_mappings(struct
> > > ttm_device *bdev)
> > >    	struct ttm_resource_manager *man;
> > >    	unsigned int i, j;
> > >    
> > > -	ttm_device_clear_lru_dma_mappings(bdev, &bdev->pinned);
> > > +	ttm_device_clear_lru_dma_mappings(bdev, &bdev-
> > > > unevictable);
> > >    
> > >    	for (i = TTM_PL_SYSTEM; i < TTM_NUM_MEM_TYPES; ++i) {
> > >    		man = ttm_manager_type(bdev, i);
> > > diff --git a/drivers/gpu/drm/ttm/ttm_resource.c
> > > b/drivers/gpu/drm/ttm/ttm_resource.c
> > > index 6d764ba88aab..93b44043b428 100644
> > > --- a/drivers/gpu/drm/ttm/ttm_resource.c
> > > +++ b/drivers/gpu/drm/ttm/ttm_resource.c
> > > @@ -30,6 +30,7 @@
> > >    #include <drm/ttm/ttm_bo.h>
> > >    #include <drm/ttm/ttm_placement.h>
> > >    #include <drm/ttm/ttm_resource.h>
> > > +#include <drm/ttm/ttm_tt.h>
> > >    
> > >    #include <drm/drm_util.h>
> > >    
> > > @@ -239,7 +240,8 @@ static void ttm_lru_bulk_move_del(struct
> > > ttm_lru_bulk_move *bulk,
> > >    void ttm_resource_add_bulk_move(struct ttm_resource *res,
> > >    				struct ttm_buffer_object *bo)
> > >    {
> > > -	if (bo->bulk_move && !bo->pin_count)
> > > +	if (bo->bulk_move && !bo->pin_count &&
> > > +	    (!bo->ttm || !ttm_tt_is_swapped(bo->ttm)))
> > >    		ttm_lru_bulk_move_add(bo->bulk_move, res);
> > >    }
> > >    
> > > @@ -247,7 +249,8 @@ void ttm_resource_add_bulk_move(struct
> > > ttm_resource *res,
> > >    void ttm_resource_del_bulk_move(struct ttm_resource *res,
> > >    				struct ttm_buffer_object *bo)
> > >    {
> > > -	if (bo->bulk_move && !bo->pin_count)
> > > +	if (bo->bulk_move && !bo->pin_count &&
> > > +	    (!bo->ttm || !ttm_tt_is_swapped(bo->ttm)))
> > >    		ttm_lru_bulk_move_del(bo->bulk_move, res);
> > >    }
> > >    
> > > @@ -259,8 +262,8 @@ void ttm_resource_move_to_lru_tail(struct
> > > ttm_resource *res)
> > >    
> > >    	lockdep_assert_held(&bo->bdev->lru_lock);
> > >    
> > > -	if (bo->pin_count) {
> > > -		list_move_tail(&res->lru.link, &bdev->pinned);
> > > +	if (bo->pin_count || (bo->ttm && ttm_tt_is_swapped(bo-
> > > > ttm))) {
> > > +		list_move_tail(&res->lru.link, &bdev-
> > > > unevictable);
> > >    
> > >    	} else	if (bo->bulk_move) {
> > >    		struct ttm_lru_bulk_move_pos *pos =
> > > @@ -301,8 +304,8 @@ void ttm_resource_init(struct ttm_buffer_object
> > > *bo,
> > >    
> > >    	man = ttm_manager_type(bo->bdev, place->mem_type);
> > >    	spin_lock(&bo->bdev->lru_lock);
> > > -	if (bo->pin_count)
> > > -		list_add_tail(&res->lru.link, &bo->bdev->pinned);
> > > +	if (bo->pin_count || (bo->ttm && ttm_tt_is_swapped(bo-
> > > > ttm)))
> > > +		list_add_tail(&res->lru.link, &bo->bdev-
> > > > unevictable);
> > >    	else
> > >    		list_add_tail(&res->lru.link, &man->lru[bo-
> > > > priority]);
> > >    	man->usage += res->size;
> > > diff --git a/drivers/gpu/drm/ttm/ttm_tt.c
> > > b/drivers/gpu/drm/ttm/ttm_tt.c
> > > index 4b51b9023126..3baf215eca23 100644
> > > --- a/drivers/gpu/drm/ttm/ttm_tt.c
> > > +++ b/drivers/gpu/drm/ttm/ttm_tt.c
> > > @@ -367,7 +367,10 @@ int ttm_tt_populate(struct ttm_device *bdev,
> > >    	}
> > >    	return ret;
> > >    }
> > > +
> > > +#if IS_ENABLED(CONFIG_DRM_TTM_KUNIT_TEST)
> > >    EXPORT_SYMBOL(ttm_tt_populate);
> > > +#endif
> > >    
> > >    void ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt
> > > *ttm)
> > >    {
> > > diff --git a/drivers/gpu/drm/xe/xe_bo.c
> > > b/drivers/gpu/drm/xe/xe_bo.c
> > > index a8e4d46d9123..f34daae2cf2b 100644
> > > --- a/drivers/gpu/drm/xe/xe_bo.c
> > > +++ b/drivers/gpu/drm/xe/xe_bo.c
> > > @@ -892,7 +892,7 @@ int xe_bo_evict_pinned(struct xe_bo *bo)
> > >    		}
> > >    	}
> > >    
> > > -	ret = ttm_tt_populate(bo->ttm.bdev, bo->ttm.ttm, &ctx);
> > > +	ret = ttm_bo_populate(&bo->ttm, &ctx);
> > >    	if (ret)
> > >    		goto err_res_free;
> > >    
> > > @@ -945,7 +945,7 @@ int xe_bo_restore_pinned(struct xe_bo *bo)
> > >    	if (ret)
> > >    		return ret;
> > >    
> > > -	ret = ttm_tt_populate(bo->ttm.bdev, bo->ttm.ttm, &ctx);
> > > +	ret = ttm_bo_populate(&bo->ttm, &ctx);
> > >    	if (ret)
> > >    		goto err_res_free;
> > >    
> > > diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h
> > > index 7b56d1ca36d7..5804408815be 100644
> > > --- a/include/drm/ttm/ttm_bo.h
> > > +++ b/include/drm/ttm/ttm_bo.h
> > > @@ -462,5 +462,7 @@ int ttm_bo_pipeline_gutting(struct
> > > ttm_buffer_object *bo);
> > >    pgprot_t ttm_io_prot(struct ttm_buffer_object *bo, struct
> > > ttm_resource *res,
> > >    		     pgprot_t tmp);
> > >    void ttm_bo_tt_destroy(struct ttm_buffer_object *bo);
> > > +int ttm_bo_populate(struct ttm_buffer_object *bo,
> > > +		    struct ttm_operation_ctx *ctx);
> > >    
> > >    #endif
> > > diff --git a/include/drm/ttm/ttm_device.h
> > > b/include/drm/ttm/ttm_device.h
> > > index c22f30535c84..438358f72716 100644
> > > --- a/include/drm/ttm/ttm_device.h
> > > +++ b/include/drm/ttm/ttm_device.h
> > > @@ -252,9 +252,10 @@ struct ttm_device {
> > >    	spinlock_t lru_lock;
> > >    
> > >    	/**
> > > -	 * @pinned: Buffer objects which are pinned and so not on
> > > any LRU list.
> > > +	 * @unevictable Buffer objects which are pinned or swapped
> > > and as such
> > > +	 * not on an LRU list.
> > >    	 */
> > > -	struct list_head pinned;
> > > +	struct list_head unevictable;
> > >    
> > >    	/**
> > >    	 * @dev_mapping: A pointer to the struct address_space for
> > > invalidating
> > > diff --git a/include/drm/ttm/ttm_tt.h b/include/drm/ttm/ttm_tt.h
> > > index 2b9d856ff388..991edafdb2dd 100644
> > > --- a/include/drm/ttm/ttm_tt.h
> > > +++ b/include/drm/ttm/ttm_tt.h
> > > @@ -129,6 +129,11 @@ static inline bool ttm_tt_is_populated(struct
> > > ttm_tt *tt)
> > >    	return tt->page_flags & TTM_TT_FLAG_PRIV_POPULATED;
> > >    }
> > >    
> > > +static inline bool ttm_tt_is_swapped(const struct ttm_tt *tt)
> > > +{
> > > +	return tt->page_flags & TTM_TT_FLAG_SWAPPED;
> > > +}
> > > +
> > >    /**
> > >     * ttm_tt_create
> > >     *