drm/panfrost: Add fdinfo support for memory stats

A new DRM GEM object function is added so that drm_show_memory_stats can
provide more accurate memory usage numbers.

Ideally, in panfrost_gem_status, the BO's purgeable flag would be checked
after locking the driver's shrinker mutex, but drm_show_memory_stats takes
over the drm file's object handle database spinlock, so there's potential
for a race condition here.
Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230929181616.2769345-4-adrian.larumbe@collabora.com

drivers/gpu/drm/panfrost/panfrost_drv.c

@@ -568,6 +568,8 @@ static void panfrost_show_fdinfo(struct drm_printer *p, struct drm_file *file)
 	struct panfrost_device *pfdev = dev->dev_private;
 
 	panfrost_gpu_show_fdinfo(pfdev, file->driver_priv, p);
+
+	drm_show_memory_stats(p, file);
 }
 
 static const struct file_operations panfrost_drm_driver_fops = {

drivers/gpu/drm/panfrost/panfrost_gem.c

@@ -195,6 +195,20 @@ static int panfrost_gem_pin(struct drm_gem_object *obj)
 	return drm_gem_shmem_pin(&bo->base);
 }
 
+static enum drm_gem_object_status panfrost_gem_status(struct drm_gem_object *obj)
+{
+	struct panfrost_gem_object *bo = to_panfrost_bo(obj);
+	enum drm_gem_object_status res = 0;
+
+	if (bo->base.pages)
+		res |= DRM_GEM_OBJECT_RESIDENT;
+
+	if (bo->base.madv == PANFROST_MADV_DONTNEED)
+		res |= DRM_GEM_OBJECT_PURGEABLE;
+
+	return res;
+}
+
 static const struct drm_gem_object_funcs panfrost_gem_funcs = {
 	.free = panfrost_gem_free_object,
 	.open = panfrost_gem_open,
@@ -206,6 +220,7 @@ static const struct drm_gem_object_funcs panfrost_gem_funcs = {
 	.vmap = drm_gem_shmem_object_vmap,
 	.vunmap = drm_gem_shmem_object_vunmap,
 	.mmap = drm_gem_shmem_object_mmap,
+	.status = panfrost_gem_status,
 	.vm_ops = &drm_gem_shmem_vm_ops,
 };