drm/nouveau: move io_reserve_lru handling into the driver v5

While working on TTM cleanups I've found that the io_reserve_lru used by
Nouveau is actually not working at all.

In general we should remove driver specific handling from the memory
management, so this patch moves the io_reserve_lru handling into Nouveau
instead.

v2: don't call ttm_bo_unmap_virtual in nouveau_ttm_io_mem_reserve
v3: rebased and use both base and offset in the check
v4: fix small typos and test the patch
v5: rebased and keep the mem.bus init in TTM.

Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Link: https://patchwork.freedesktop.org/patch/388643/

drivers/gpu/drm/nouveau/nouveau_bo.c

@@ -137,6 +137,7 @@ nouveau_bo_del_ttm(struct ttm_buffer_object *bo)
 	struct nouveau_bo *nvbo = nouveau_bo(bo);
 
 	WARN_ON(nvbo->pin_refcnt > 0);
+	nouveau_bo_del_io_reserve_lru(bo);
 	nv10_bo_put_tile_region(dev, nvbo->tile, NULL);
 
 	/*
@@ -304,6 +305,7 @@ nouveau_bo_init(struct nouveau_bo *nvbo, u64 size, int align, u32 flags,
 
 	nvbo->bo.mem.num_pages = size >> PAGE_SHIFT;
 	nouveau_bo_placement_set(nvbo, flags, 0);
+	INIT_LIST_HEAD(&nvbo->io_reserve_lru);
 
 	ret = ttm_bo_init(nvbo->bo.bdev, &nvbo->bo, size, type,
 			  &nvbo->placement, align >> PAGE_SHIFT, false,
@@ -574,6 +576,26 @@ nouveau_bo_sync_for_cpu(struct nouveau_bo *nvbo)
 					PAGE_SIZE, DMA_FROM_DEVICE);
 }
 
+void nouveau_bo_add_io_reserve_lru(struct ttm_buffer_object *bo)
+{
+	struct nouveau_drm *drm = nouveau_bdev(bo->bdev);
+	struct nouveau_bo *nvbo = nouveau_bo(bo);
+
+	mutex_lock(&drm->ttm.io_reserve_mutex);
+	list_move_tail(&nvbo->io_reserve_lru, &drm->ttm.io_reserve_lru);
+	mutex_unlock(&drm->ttm.io_reserve_mutex);
+}
+
+void nouveau_bo_del_io_reserve_lru(struct ttm_buffer_object *bo)
+{
+	struct nouveau_drm *drm = nouveau_bdev(bo->bdev);
+	struct nouveau_bo *nvbo = nouveau_bo(bo);
+
+	mutex_lock(&drm->ttm.io_reserve_mutex);
+	list_del_init(&nvbo->io_reserve_lru);
+	mutex_unlock(&drm->ttm.io_reserve_mutex);
+}
+
 int
 nouveau_bo_validate(struct nouveau_bo *nvbo, bool interruptible,
 		    bool no_wait_gpu)
@@ -888,6 +910,8 @@ nouveau_bo_move_ntfy(struct ttm_buffer_object *bo, bool evict,
 	if (bo->destroy != nouveau_bo_del_ttm)
 		return;
 
+	nouveau_bo_del_io_reserve_lru(bo);
+
 	if (mem && new_reg->mem_type != TTM_PL_SYSTEM &&
 	    mem->mem.page == nvbo->page) {
 		list_for_each_entry(vma, &nvbo->vma_list, head) {
@@ -1018,17 +1042,42 @@ nouveau_bo_verify_access(struct ttm_buffer_object *bo, struct file *filp)
 					  filp->private_data);
 }
 
+static void
+nouveau_ttm_io_mem_free_locked(struct nouveau_drm *drm,
+			       struct ttm_resource *reg)
+{
+	struct nouveau_mem *mem = nouveau_mem(reg);
+
+	if (drm->client.mem->oclass >= NVIF_CLASS_MEM_NV50) {
+		switch (reg->mem_type) {
+		case TTM_PL_TT:
+			if (mem->kind)
+				nvif_object_unmap_handle(&mem->mem.object);
+			break;
+		case TTM_PL_VRAM:
+			nvif_object_unmap_handle(&mem->mem.object);
+			break;
+		default:
+			break;
+		}
+	}
+}
+
 static int
 nouveau_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_resource *reg)
 {
 	struct nouveau_drm *drm = nouveau_bdev(bdev);
 	struct nvkm_device *device = nvxx_device(&drm->client.device);
 	struct nouveau_mem *mem = nouveau_mem(reg);
+	int ret;
 
+	mutex_lock(&drm->ttm.io_reserve_mutex);
+retry:
 	switch (reg->mem_type) {
 	case TTM_PL_SYSTEM:
 		/* System memory */
-		return 0;
+		ret = 0;
+		goto out;
 	case TTM_PL_TT:
 #if IS_ENABLED(CONFIG_AGP)
 		if (drm->agp.bridge) {
@@ -1037,9 +1086,12 @@ nouveau_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_resource *reg)
 			reg->bus.is_iomem = !drm->agp.cma;
 		}
 #endif
-		if (drm->client.mem->oclass < NVIF_CLASS_MEM_NV50 || !mem->kind)
+		if (drm->client.mem->oclass < NVIF_CLASS_MEM_NV50 ||
+		    !mem->kind) {
 			/* untiled */
+			ret = 0;
 			break;
+		}
 		fallthrough;	/* tiled memory */
 	case TTM_PL_VRAM:
 		reg->bus.offset = reg->start << PAGE_SHIFT;
@@ -1052,7 +1104,6 @@ nouveau_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_resource *reg)
 			} args;
 			u64 handle, length;
 			u32 argc = 0;
-			int ret;
 
 			switch (mem->mem.object.oclass) {
 			case NVIF_CLASS_MEM_NV50:
@@ -1078,39 +1129,47 @@ nouveau_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_resource *reg)
 						     &handle, &length);
 			if (ret != 1) {
 				if (WARN_ON(ret == 0))
-					return -EINVAL;
+					ret = -EINVAL;
-				return ret;
+				goto out;
 			}
 
 			reg->bus.base = 0;
 			reg->bus.offset = handle;
+			ret = 0;
 		}
 		break;
 	default:
-		return -EINVAL;
+		ret = -EINVAL;
 	}
-	return 0;
+
+out:
+	if (ret == -ENOSPC) {
+		struct nouveau_bo *nvbo;
+
+		nvbo = list_first_entry_or_null(&drm->ttm.io_reserve_lru,
+						typeof(*nvbo),
+						io_reserve_lru);
+		if (nvbo) {
+			list_del_init(&nvbo->io_reserve_lru);
+			drm_vma_node_unmap(&nvbo->bo.base.vma_node,
+					   bdev->dev_mapping);
+			nouveau_ttm_io_mem_free_locked(drm, &nvbo->bo.mem);
+			goto retry;
+		}
+
+	}
+	mutex_unlock(&drm->ttm.io_reserve_mutex);
+	return ret;
 }
 
 static void
 nouveau_ttm_io_mem_free(struct ttm_bo_device *bdev, struct ttm_resource *reg)
 {
 	struct nouveau_drm *drm = nouveau_bdev(bdev);
-	struct nouveau_mem *mem = nouveau_mem(reg);
 
-	if (drm->client.mem->oclass >= NVIF_CLASS_MEM_NV50) {
+	mutex_lock(&drm->ttm.io_reserve_mutex);
-		switch (reg->mem_type) {
+	nouveau_ttm_io_mem_free_locked(drm, reg);
-		case TTM_PL_TT:
+	mutex_unlock(&drm->ttm.io_reserve_mutex);
-			if (mem->kind)
-				nvif_object_unmap_handle(&mem->mem.object);
-			break;
-		case TTM_PL_VRAM:
-			nvif_object_unmap_handle(&mem->mem.object);
-			break;
-		default:
-			break;
-		}
-	}
 }
 
 static int

drivers/gpu/drm/nouveau/nouveau_bo.h

@@ -18,6 +18,7 @@ struct nouveau_bo {
 	bool force_coherent;
 	struct ttm_bo_kmap_obj kmap;
 	struct list_head head;
+	struct list_head io_reserve_lru;
 
 	/* protected by ttm_bo_reserve() */
 	struct drm_file *reserved_by;
@@ -96,6 +97,8 @@ int  nouveau_bo_validate(struct nouveau_bo *, bool interruptible,
 			 bool no_wait_gpu);
 void nouveau_bo_sync_for_device(struct nouveau_bo *nvbo);
 void nouveau_bo_sync_for_cpu(struct nouveau_bo *nvbo);
+void nouveau_bo_add_io_reserve_lru(struct ttm_buffer_object *bo);
+void nouveau_bo_del_io_reserve_lru(struct ttm_buffer_object *bo);
 
 /* TODO: submit equivalent to TTM generic API upstream? */
 static inline void __iomem *

drivers/gpu/drm/nouveau/nouveau_drv.h

@@ -164,6 +164,8 @@ struct nouveau_drm {
 		int type_vram;
 		int type_host[2];
 		int type_ncoh[2];
+		struct mutex io_reserve_mutex;
+		struct list_head io_reserve_lru;
 	} ttm;
 
 	/* GEM interface support */

drivers/gpu/drm/nouveau/nouveau_ttm.c

@@ -123,13 +123,51 @@ const struct ttm_resource_manager_func nv04_gart_manager = {
 	.free = nouveau_manager_del,
 };
 
+static vm_fault_t nouveau_ttm_fault(struct vm_fault *vmf)
+{
+	struct vm_area_struct *vma = vmf->vma;
+	struct ttm_buffer_object *bo = vma->vm_private_data;
+	pgprot_t prot;
+	vm_fault_t ret;
+
+	ret = ttm_bo_vm_reserve(bo, vmf);
+	if (ret)
+		return ret;
+
+	nouveau_bo_del_io_reserve_lru(bo);
+
+	prot = vm_get_page_prot(vma->vm_flags);
+	ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT, 1);
+	if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
+		return ret;
+
+	nouveau_bo_add_io_reserve_lru(bo);
+
+	dma_resv_unlock(bo->base.resv);
+
+	return ret;
+}
+
+static struct vm_operations_struct nouveau_ttm_vm_ops = {
+	.fault = nouveau_ttm_fault,
+	.open = ttm_bo_vm_open,
+	.close = ttm_bo_vm_close,
+	.access = ttm_bo_vm_access
+};
+
 int
 nouveau_ttm_mmap(struct file *filp, struct vm_area_struct *vma)
 {
 	struct drm_file *file_priv = filp->private_data;
 	struct nouveau_drm *drm = nouveau_drm(file_priv->minor->dev);
+	int ret;
 
-	return ttm_bo_mmap(filp, vma, &drm->ttm.bdev);
+	ret = ttm_bo_mmap(filp, vma, &drm->ttm.bdev);
+	if (ret)
+		return ret;
+
+	vma->vm_ops = &nouveau_ttm_vm_ops;
+	return 0;
 }
 
 static int
@@ -173,7 +211,6 @@ nouveau_ttm_init_vram(struct nouveau_drm *drm)
 		}
 
 		man->func = &nouveau_vram_manager;
-		man->use_io_reserve_lru = true;
 
 		ttm_resource_manager_init(man,
 					  drm->gem.vram_available >> PAGE_SHIFT);
@@ -339,6 +376,9 @@ nouveau_ttm_init(struct nouveau_drm *drm)
 		return ret;
 	}
 
+	mutex_init(&drm->ttm.io_reserve_mutex);
+	INIT_LIST_HEAD(&drm->ttm.io_reserve_lru);
+
 	NV_INFO(drm, "VRAM: %d MiB\n", (u32)(drm->gem.vram_available >> 20));
 	NV_INFO(drm, "GART: %d MiB\n", (u32)(drm->gem.gart_available >> 20));
 	return 0;