checkpoint: let each checkpoint schedule its own timeout

Instead of scheduling one timeout only, let each checkpoint instance
individually schedule a timeout. This has some overhead, but glib
is supposed to make scheduling many timers efficient. Otherwise,
glib should be fixed.

This simplifies in my opinion the code, because it's up to each
checkpoint to maintain its own timeout.

Later we will also add a AdjustRollbackTimeout operation, which
allow to reschedule the timeout. It also seems slightly simpler,
if scheduling of the timeout is done by the NMCheckpoint instance
itself.

src/nm-checkpoint-manager.c

@@ -36,7 +36,6 @@ struct _NMCheckpointManager {
 	NMManager *_manager;
 	GParamSpec *property_spec;
 	CList checkpoints_lst_head;
-	guint rollback_timeout_id;
 };
 
 #define GET_MANAGER(self) \
@@ -57,10 +56,6 @@ struct _NMCheckpointManager {
 
 /*****************************************************************************/
 
-static void update_rollback_timeout (NMCheckpointManager *self);
-
-/*****************************************************************************/
-
 static void
 notify_checkpoints (NMCheckpointManager *self) {
 	g_object_notify_by_pspec ((GObject *) GET_MANAGER (self),
@@ -74,6 +69,8 @@ destroy_checkpoint (NMCheckpointManager *self, NMCheckpoint *checkpoint)
 	nm_assert (nm_dbus_object_is_exported (NM_DBUS_OBJECT (checkpoint)));
 	nm_assert (c_list_contains (&self->checkpoints_lst_head, &checkpoint->checkpoints_lst));
 
+	nm_checkpoint_set_timeout_callback (checkpoint, NULL, NULL);
+
 	c_list_unlink (&checkpoint->checkpoints_lst);
 
 	notify_checkpoints (self);
@@ -92,51 +89,14 @@ rollback_checkpoint (NMCheckpointManager *self, NMCheckpoint *checkpoint)
 	return result;
 }
 
-static gboolean
-rollback_timeout_cb (NMCheckpointManager *self)
-{
-	NMCheckpoint *checkpoint, *checkpoint_safe;
-	gint64 ts, now;
-
-	self->rollback_timeout_id = 0;
-
-	now = nm_utils_get_monotonic_timestamp_ms ();
-
-	c_list_for_each_entry_safe (checkpoint, checkpoint_safe, &self->checkpoints_lst_head, checkpoints_lst) {
-		ts = nm_checkpoint_get_rollback_ts (checkpoint);
-		if (ts && ts <= now) {
-			gs_unref_variant GVariant *result = NULL;
-
-			result = rollback_checkpoint (self, checkpoint);
-		}
-	}
-
-	update_rollback_timeout (self);
-
-	return G_SOURCE_REMOVE;
-}
-
 static void
-update_rollback_timeout (NMCheckpointManager *self)
+rollback_timeout_cb (NMCheckpoint *checkpoint,
+                     gpointer user_data)
 {
-	NMCheckpoint *checkpoint;
+	NMCheckpointManager *self = user_data;
-	gint64 ts, delta, next = G_MAXINT64;
+	gs_unref_variant GVariant *result = NULL;
 
-	c_list_for_each_entry (checkpoint, &self->checkpoints_lst_head, checkpoints_lst) {
+	result = rollback_checkpoint (self, checkpoint);
-		ts = nm_checkpoint_get_rollback_ts (checkpoint);
-		if (ts && ts < next)
-			next = ts;
-	}
-
-	nm_clear_g_source (&self->rollback_timeout_id);
-
-	if (next != G_MAXINT64) {
-		delta = MAX (next - nm_utils_get_monotonic_timestamp_ms (), 0);
-		self->rollback_timeout_id = g_timeout_add (delta,
-		                                           (GSourceFunc) rollback_timeout_cb,
-		                                           self);
-		_LOGT ("update timeout: next check in %" G_GINT64_FORMAT " ms", delta);
-	}
 }
 
 static NMCheckpoint *
@@ -224,9 +184,9 @@ nm_checkpoint_manager_create (NMCheckpointManager *self,
 
 	nm_dbus_object_export (NM_DBUS_OBJECT (checkpoint));
 
+	nm_checkpoint_set_timeout_callback (checkpoint, rollback_timeout_cb, self);
 	c_list_link_tail (&self->checkpoints_lst_head, &checkpoint->checkpoints_lst);
 	notify_checkpoints (self);
-	update_rollback_timeout (self);
 	return checkpoint;
 }
 
@@ -361,6 +321,5 @@ nm_checkpoint_manager_free (NMCheckpointManager *self)
 		return;
 
 	nm_checkpoint_manager_destroy_all (self);
-	nm_clear_g_source (&self->rollback_timeout_id);
 	g_slice_free (NMCheckpointManager, self);
 }

src/nm-checkpoint.c

@@ -57,13 +57,17 @@ NM_GOBJECT_PROPERTIES_DEFINE_BASE (
 struct _NMCheckpointPrivate {
 	/* properties */
 	GHashTable *devices;
-	gint64 created;
+	gint64 created_at_ms;
-	guint32 rollback_timeout;
+	guint32 rollback_timeout_s;
+	guint timeout_id;
+	/* private members */
 	/* private members */
 	NMManager *manager;
-	gint64 rollback_ts;
 	NMCheckpointCreateFlags flags;
 	GHashTable *connection_uuids;
+
+	NMCheckpointTimeoutCallback timeout_cb;
+	gpointer timeout_data;
 };
 
 struct _NMCheckpointClass {
@@ -96,12 +100,18 @@ G_DEFINE_TYPE (NMCheckpoint, nm_checkpoint, NM_TYPE_DBUS_OBJECT)
 
 /*****************************************************************************/
 
-guint64
+void
-nm_checkpoint_get_rollback_ts (NMCheckpoint *self)
+nm_checkpoint_set_timeout_callback (NMCheckpoint *self,
+                                    NMCheckpointTimeoutCallback callback,
+                                    gpointer user_data)
 {
-	g_return_val_if_fail (NM_IS_CHECKPOINT (self), 0);
+	NMCheckpointPrivate *priv = NM_CHECKPOINT_GET_PRIVATE (self);
 
-	return NM_CHECKPOINT_GET_PRIVATE (self)->rollback_ts;
+	/* in glib world, we would have a GSignal for this. But as there
+	 * is only one subscriber, it's simpler to just set and unset(!)
+	 * the callback this way. */
+	priv->timeout_cb = callback;
+	priv->timeout_data = user_data;
 }
 
 gboolean
@@ -374,6 +384,7 @@ device_checkpoint_create (NMDevice *device)
 	NMActRequest *act_request;
 
 	nm_assert (NM_IS_DEVICE (device));
+	nm_assert (nm_device_is_real (device));
 
 	path = nm_dbus_object_get_path (NM_DBUS_OBJECT (device));
 
@@ -421,6 +432,21 @@ device_checkpoint_destroy (gpointer data)
 	g_slice_free (DeviceCheckpoint, dev_checkpoint);
 }
 
+static gboolean
+_timeout_cb (gpointer user_data)
+{
+	NMCheckpoint *self = user_data;
+	NMCheckpointPrivate *priv = NM_CHECKPOINT_GET_PRIVATE (self);
+
+	priv->timeout_id = 0;
+
+	if (priv->timeout_cb)
+		priv->timeout_cb (self, priv->timeout_data);
+
+	/* beware, @self likely got destroyed! */
+	return G_SOURCE_REMOVE;
+}
+
 /*****************************************************************************/
 
 static void
@@ -437,10 +463,12 @@ get_property (GObject *object, guint prop_id,
 		                                                 FALSE);
 		break;
 	case PROP_CREATED:
-		g_value_set_int64 (value, priv->created);
+		g_value_set_int64 (value,
+		                   nm_utils_monotonic_timestamp_as_boottime (priv->created_at_ms,
+		                                                             NM_UTILS_NS_PER_MSEC));
 		break;
 	case PROP_ROLLBACK_TIMEOUT:
-		g_value_set_uint (value, priv->rollback_timeout);
+		g_value_set_uint (value, priv->rollback_timeout_s);
 		break;
 	default:
 		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
@@ -466,12 +494,13 @@ nm_checkpoint_init (NMCheckpoint *self)
 }
 
 NMCheckpoint *
-nm_checkpoint_new (NMManager *manager, GPtrArray *devices, guint32 rollback_timeout,
+nm_checkpoint_new (NMManager *manager, GPtrArray *devices, guint32 rollback_timeout_s,
                    NMCheckpointCreateFlags flags, GError **error)
 {
 	NMCheckpoint *self;
 	NMCheckpointPrivate *priv;
 	NMSettingsConnection *const *con;
+	gint64 rollback_timeout_ms;
 	guint i;
 
 	g_return_val_if_fail (manager, NULL);
@@ -490,14 +519,17 @@ nm_checkpoint_new (NMManager *manager, GPtrArray *devices, guint32 rollback_time
 
 	priv = NM_CHECKPOINT_GET_PRIVATE (self);
 	priv->manager = manager;
-	priv->created = nm_utils_monotonic_timestamp_as_boottime (nm_utils_get_monotonic_timestamp_ms (),
+	priv->rollback_timeout_s = rollback_timeout_s;
-	                                                          NM_UTILS_NS_PER_MSEC);
+	priv->created_at_ms = nm_utils_get_monotonic_timestamp_ms ();
-	priv->rollback_timeout = rollback_timeout;
-	priv->rollback_ts = rollback_timeout ?
-	    (nm_utils_get_monotonic_timestamp_ms () + ((gint64) rollback_timeout * 1000)) :
-	    0;
 	priv->flags = flags;
 
+	if (rollback_timeout_s != 0) {
+		rollback_timeout_ms = ((gint64) rollback_timeout_s) * 1000;
+		priv->timeout_id = g_timeout_add (NM_MIN (rollback_timeout_ms, (gint64) G_MAXUINT32),
+		                                  _timeout_cb,
+		                                  self);
+	}
+
 	if (NM_FLAGS_HAS (flags, NM_CHECKPOINT_CREATE_FLAG_DELETE_NEW_CONNECTIONS)) {
 		priv->connection_uuids = g_hash_table_new_full (nm_str_hash, g_str_equal, g_free, NULL);
 		for (con = nm_settings_get_connections (nm_settings_get (), NULL); *con; con++) {
@@ -528,6 +560,8 @@ dispose (GObject *object)
 	g_clear_pointer (&priv->devices, g_hash_table_unref);
 	g_clear_pointer (&priv->connection_uuids, g_hash_table_unref);
 
+	nm_clear_g_source (&priv->timeout_id);
+
 	G_OBJECT_CLASS (nm_checkpoint_parent_class)->dispose (object);
 }
 

src/nm-checkpoint.h

@@ -50,7 +50,13 @@ GType nm_checkpoint_get_type (void);
 NMCheckpoint *nm_checkpoint_new (NMManager *manager, GPtrArray *devices, guint32 rollback_timeout,
                                  NMCheckpointCreateFlags flags, GError **error);
 
-guint64 nm_checkpoint_get_rollback_ts (NMCheckpoint *checkpoint);
+typedef void (*NMCheckpointTimeoutCallback) (NMCheckpoint *self,
+                                             gpointer user_data);
+
+void nm_checkpoint_set_timeout_callback (NMCheckpoint *self,
+                                         NMCheckpointTimeoutCallback callback,
+                                         gpointer user_data);
+
 gboolean nm_checkpoint_includes_device (NMCheckpoint *checkpoint, NMDevice *device);
 GVariant *nm_checkpoint_rollback (NMCheckpoint *self);