drm/i915: Implement fdinfo memory stats printing

Use the newly added drm_print_memory_stats helper to show memory
utilisation of our objects in drm/driver specific fdinfo output.

To collect the stats we walk the per memory regions object lists
and accumulate object size into the respective drm_memory_stats
categories.

v2:
 * Only account against the active region.
 * Use DMA_RESV_USAGE_BOOKKEEP when testing for active. (Tejas)

v3:
 * Update commit text. (Aravind)
 * Update to use memory regions uabi names.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Tejas Upadhyay <tejas.upadhyay@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231107101806.608990-6-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/i915_drm_client.c

@@ -45,6 +45,68 @@ void __i915_drm_client_free(struct kref *kref)
 }
 
 #ifdef CONFIG_PROC_FS
+static void
+obj_meminfo(struct drm_i915_gem_object *obj,
+	    struct drm_memory_stats stats[INTEL_REGION_UNKNOWN])
+{
+	const enum intel_region_id id = obj->mm.region ?
+					obj->mm.region->id : INTEL_REGION_SMEM;
+	const u64 sz = obj->base.size;
+
+	if (obj->base.handle_count > 1)
+		stats[id].shared += sz;
+	else
+		stats[id].private += sz;
+
+	if (i915_gem_object_has_pages(obj)) {
+		stats[id].resident += sz;
+
+		if (!dma_resv_test_signaled(obj->base.resv,
+					    DMA_RESV_USAGE_BOOKKEEP))
+			stats[id].active += sz;
+		else if (i915_gem_object_is_shrinkable(obj) &&
+			 obj->mm.madv == I915_MADV_DONTNEED)
+			stats[id].purgeable += sz;
+	}
+}
+
+static void show_meminfo(struct drm_printer *p, struct drm_file *file)
+{
+	struct drm_memory_stats stats[INTEL_REGION_UNKNOWN] = {};
+	struct drm_i915_file_private *fpriv = file->driver_priv;
+	struct i915_drm_client *client = fpriv->client;
+	struct drm_i915_private *i915 = fpriv->i915;
+	struct drm_i915_gem_object *obj;
+	struct intel_memory_region *mr;
+	struct list_head *pos;
+	unsigned int id;
+
+	/* Public objects. */
+	spin_lock(&file->table_lock);
+	idr_for_each_entry(&file->object_idr, obj, id)
+		obj_meminfo(obj, stats);
+	spin_unlock(&file->table_lock);
+
+	/* Internal objects. */
+	rcu_read_lock();
+	list_for_each_rcu(pos, &client->objects_list) {
+		obj = i915_gem_object_get_rcu(list_entry(pos, typeof(*obj),
+							 client_link));
+		if (!obj)
+			continue;
+		obj_meminfo(obj, stats);
+		i915_gem_object_put(obj);
+	}
+	rcu_read_unlock();
+
+	for_each_memory_region(mr, i915, id)
+		drm_print_memory_stats(p,
+				       &stats[id],
+				       DRM_GEM_OBJECT_RESIDENT |
+				       DRM_GEM_OBJECT_PURGEABLE,
+				       mr->uabi_name);
+}
+
 static const char * const uabi_class_names[] = {
 	[I915_ENGINE_CLASS_RENDER] = "render",
 	[I915_ENGINE_CLASS_COPY] = "copy",
@@ -106,6 +168,8 @@ void i915_drm_client_fdinfo(struct drm_printer *p, struct drm_file *file)
 	 * ******************************************************************
 	 */
 
+	show_meminfo(p, file);
+
 	if (GRAPHICS_VER(i915) < 8)
 		return;