drm/amdgpu: validate VM PTs only on eviction

We don't need to validate them again if the eviction counter didn't changed.

Reviewed-by: Alex Deucher <[e-mail]>
Signed-off-by: Christian König <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/amdgpu.h

···
 	struct amdgpu_bo	*page_directory;
 	unsigned		max_pde_used;
 	struct fence		*page_directory_fence;
+	uint64_t		last_eviction_counter;
 
 	/* array of page tables, one for each page directory entry */
 	struct amdgpu_vm_pt	*page_tables;
···
 void amdgpu_vm_get_pd_bo(struct amdgpu_vm *vm,
 			 struct list_head *validated,
 			 struct amdgpu_bo_list_entry *entry);
-void amdgpu_vm_get_pt_bos(struct amdgpu_vm *vm, struct list_head *duplicates);
+void amdgpu_vm_get_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm,
+			  struct list_head *duplicates);
 void amdgpu_vm_move_pt_bos_in_lru(struct amdgpu_device *adev,
 				  struct amdgpu_vm *vm);
 int amdgpu_vm_grab_id(struct amdgpu_vm *vm, struct amdgpu_ring *ring,

drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c

···
 		list_splice(&need_pages, &p->validated);
 	}
 
-	amdgpu_vm_get_pt_bos(&fpriv->vm, &duplicates);
+	amdgpu_vm_get_pt_bos(p->adev, &fpriv->vm, &duplicates);
 
 	p->bytes_moved_threshold = amdgpu_cs_get_threshold_for_moves(p->adev);
 	p->bytes_moved = 0;
···
 	r = amdgpu_cs_list_validate(p, &p->validated);
 	if (r)
 		goto error_validate;
+
+	fpriv->vm.last_eviction_counter =
+		atomic64_read(&p->adev->num_evictions);
 
 	if (p->bo_list) {
 		struct amdgpu_bo *gds = p->bo_list->gds_obj;

drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c

···
 	if (r)
 		goto error_print;
 
-	amdgpu_vm_get_pt_bos(bo_va->vm, &duplicates);
+	amdgpu_vm_get_pt_bos(adev, bo_va->vm, &duplicates);
 	list_for_each_entry(entry, &list, head) {
 		domain = amdgpu_mem_type_to_domain(entry->bo->mem.mem_type);
 		/* if anything is swapped out don't swap it in here,

drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

···
 /**
  * amdgpu_vm_get_bos - add the vm BOs to a duplicates list
  *
+ * @adev: amdgpu device pointer
  * @vm: vm providing the BOs
  * @duplicates: head of duplicates list
  *
  * Add the page directory to the BO duplicates list
  * for command submission.
  */
-void amdgpu_vm_get_pt_bos(struct amdgpu_vm *vm, struct list_head *duplicates)
+void amdgpu_vm_get_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm,
+			  struct list_head *duplicates)
 {
+	uint64_t num_evictions;
 	unsigned i;
+
+	/* We only need to validate the page tables
+	 * if they aren't already valid.
+	 */
+	num_evictions = atomic64_read(&adev->num_evictions);
+	if (num_evictions == vm->last_eviction_counter)
+		return;
 
 	/* add the vm page table to the list */
 	for (i = 0; i <= vm->max_pde_used; ++i) {
···
 	amdgpu_bo_unreserve(vm->page_directory);
 	if (r)
 		goto error_free_page_directory;
+	vm->last_eviction_counter = atomic64_read(&adev->num_evictions);
 
 	return 0;