Remove channelz linkage. (#27514)

* Remove channelz linkage.

* one more removal.

src/core/ext/filters/client_channel/lb_policy/xds/xds_cluster_resolver.cc

@@ -572,13 +572,6 @@ XdsClusterResolverLb::XdsClusterResolverLb(RefCountedPtr<XdsClient> xds_client,
   }
   // EDS-only flow.
   if (!is_xds_uri_) {
-    // Setup channelz linkage.
-    channelz::ChannelNode* parent_channelz_node =
-        grpc_channel_args_find_pointer<channelz::ChannelNode>(
-            args.args, GRPC_ARG_CHANNELZ_CHANNEL_NODE);
-    if (parent_channelz_node != nullptr) {
-      xds_client_->AddChannelzLinkage(parent_channelz_node);
-    }
     // Couple polling.
     grpc_pollset_set_add_pollset_set(xds_client_->interested_parties(),
                                      interested_parties());
@@ -602,13 +595,6 @@ void XdsClusterResolverLb::ShutdownLocked() {
   MaybeDestroyChildPolicyLocked();
   discovery_mechanisms_.clear();
   if (!is_xds_uri_) {
-    // Remove channelz linkage.
-    channelz::ChannelNode* parent_channelz_node =
-        grpc_channel_args_find_pointer<channelz::ChannelNode>(
-            args_, GRPC_ARG_CHANNELZ_CHANNEL_NODE);
-    if (parent_channelz_node != nullptr) {
-      xds_client_->RemoveChannelzLinkage(parent_channelz_node);
-    }
     // Decouple polling.
     grpc_pollset_set_del_pollset_set(xds_client_->interested_parties(),
                                      interested_parties());

src/core/ext/filters/client_channel/resolver/xds/xds_resolver.cc

@@ -766,12 +766,6 @@ void XdsResolver::StartLocked() {
   }
   grpc_pollset_set_add_pollset_set(xds_client_->interested_parties(),
                                    interested_parties_);
-  channelz::ChannelNode* parent_channelz_node =
-      grpc_channel_args_find_pointer<channelz::ChannelNode>(
-          args_, GRPC_ARG_CHANNELZ_CHANNEL_NODE);
-  if (parent_channelz_node != nullptr) {
-    xds_client_->AddChannelzLinkage(parent_channelz_node);
-  }
   auto watcher = absl::make_unique<ListenerWatcher>(Ref());
   listener_watcher_ = watcher.get();
   xds_client_->WatchListenerData(server_name_, std::move(watcher));
@@ -790,12 +784,6 @@ void XdsResolver::ShutdownLocked() {
       xds_client_->CancelRouteConfigDataWatch(
           server_name_, route_config_watcher_, /*delay_unsubscription=*/false);
     }
-    channelz::ChannelNode* parent_channelz_node =
-        grpc_channel_args_find_pointer<channelz::ChannelNode>(
-            args_, GRPC_ARG_CHANNELZ_CHANNEL_NODE);
-    if (parent_channelz_node != nullptr) {
-      xds_client_->RemoveChannelzLinkage(parent_channelz_node);
-    }
     grpc_pollset_set_del_pollset_set(xds_client_->interested_parties(),
                                      interested_parties_);
     xds_client_.reset();

src/core/ext/xds/xds_client.cc

@@ -1878,12 +1878,10 @@ grpc_millis GetRequestTimeout(const grpc_channel_args* args) {
 }
 
 grpc_channel_args* ModifyChannelArgs(const grpc_channel_args* args) {
-  absl::InlinedVector<grpc_arg, 2> args_to_add = {
+  absl::InlinedVector<grpc_arg, 1> args_to_add = {
       grpc_channel_arg_integer_create(
           const_cast<char*>(GRPC_ARG_KEEPALIVE_TIME_MS),
           5 * 60 * GPR_MS_PER_SEC),
-      grpc_channel_arg_integer_create(
-          const_cast<char*>(GRPC_ARG_CHANNELZ_IS_INTERNAL_CHANNEL), 1),
   };
   return grpc_channel_args_copy_and_add(args, args_to_add.data(),
                                         args_to_add.size());
@@ -1920,26 +1918,6 @@ XdsClient::~XdsClient() {
   grpc_pollset_set_destroy(interested_parties_);
 }
 
-void XdsClient::AddChannelzLinkage(
-    channelz::ChannelNode* parent_channelz_node) {
-  MutexLock lock(&mu_);
-  channelz::ChannelNode* xds_channelz_node =
-      grpc_channel_get_channelz_node(chand_->channel());
-  if (xds_channelz_node != nullptr) {
-    parent_channelz_node->AddChildChannel(xds_channelz_node->uuid());
-  }
-}
-
-void XdsClient::RemoveChannelzLinkage(
-    channelz::ChannelNode* parent_channelz_node) {
-  MutexLock lock(&mu_);
-  channelz::ChannelNode* xds_channelz_node =
-      grpc_channel_get_channelz_node(chand_->channel());
-  if (xds_channelz_node != nullptr) {
-    parent_channelz_node->RemoveChildChannel(xds_channelz_node->uuid());
-  }
-}
-
 void XdsClient::Orphan() {
   if (GRPC_TRACE_FLAG_ENABLED(grpc_xds_client_trace)) {
     gpr_log(GPR_INFO, "[xds_client %p] shutting down xds client", this);

src/core/ext/xds/xds_client.h

@@ -102,18 +102,6 @@ class XdsClient : public DualRefCounted<XdsClient> {
 
   grpc_pollset_set* interested_parties() const { return interested_parties_; }
 
-  // TODO(roth): When we add federation, there will be multiple channels
-  // inside the XdsClient, and the set of channels may change over time,
-  // but not every channel may use every one of the child channels, so
-  // this API will need to change.  At minumum, we will need to hold a
-  // ref to the parent channelz node so that we can update its list of
-  // children as the set of xDS channels changes.  However, we may also
-  // want to make this a bit more selective such that only those
-  // channels on which a given parent channel is actually requesting
-  // resources will actually be marked as its children.
-  void AddChannelzLinkage(channelz::ChannelNode* parent_channelz_node);
-  void RemoveChannelzLinkage(channelz::ChannelNode* parent_channelz_node);
-
   void Orphan() override;
 
   // Start and cancel listener data watch for a listener.