4 files changed, 25 insertions, 4 deletions
diff --git a/include/grpc++/impl/codegen/completion_queue.h b/include/grpc++/impl/codegen/completion_queue.h
index ef00163b7e..944f2c3919 100644
--- a/include/grpc++/impl/codegen/completion_queue.h
+++ b/include/grpc++/impl/codegen/completion_queue.h
@@ -52,6 +52,7 @@
 #include <grpc++/impl/codegen/grpc_library.h>
 #include <grpc++/impl/codegen/status.h>
 #include <grpc++/impl/codegen/time.h>
+#include <grpc/impl/codegen/atm.h>
 
 struct grpc_completion_queue;
 
@@ -101,6 +102,7 @@ class CompletionQueue : private GrpcLibraryCodegen {
   /// instance.
   CompletionQueue() {
     cq_ = g_core_codegen_interface->grpc_completion_queue_create(nullptr);
+    InitialAvalanching();  // reserve this for the future shutdown
   }
 
   /// Wrap \a take, taking ownership of the instance.
@@ -151,7 +153,8 @@ class CompletionQueue : private GrpcLibraryCodegen {
 
   /// Request the shutdown of the queue.
   ///
-  /// \warning This method must be called at some point. Once invoked, \a Next
+  /// \warning This method must be called at some point if this completion queue
+  /// is accessed with Next or AsyncNext. Once invoked, \a Next
   /// will start to return false and \a AsyncNext will return \a
   /// NextStatus::SHUTDOWN. Only once either one of these methods does that
   /// (that is, once the queue has been \em drained) can an instance of this
@@ -165,6 +168,21 @@ class CompletionQueue : private GrpcLibraryCodegen {
   /// owership is performed.
   grpc_completion_queue* cq() { return cq_; }
 
+  /// Manage state of avalanching operations : completion queue tags that
+  /// trigger other completion queue operations. The underlying core completion
+  /// queue should not really shutdown until all avalanching operations have
+  /// been finalized. Note that we maintain the requirement that an avalanche
+  /// registration must take place before CQ shutdown (which must be maintained
+  /// elsehwere)
+  void InitialAvalanching() {
+    gpr_atm_rel_store(&avalanches_in_flight_, static_cast<gpr_atm>(1));
+  }
+  void RegisterAvalanching() {
+    gpr_atm_no_barrier_fetch_add(&avalanches_in_flight_,
+                                 static_cast<gpr_atm>(1));
+  };
+  void CompleteAvalanching();
+
  private:
   // Friend synchronous wrappers so that they can access Pluck(), which is
   // a semi-private API geared towards the synchronous implementation.
@@ -229,6 +247,8 @@ class CompletionQueue : private GrpcLibraryCodegen {
   }
 
   grpc_completion_queue* cq_;  // owned
+
+  gpr_atm avalanches_in_flight_;
 };
 
 /// A specific type of completion queue used by the processing of notifications
diff --git a/include/grpc++/impl/codegen/server_interface.h b/include/grpc++/impl/codegen/server_interface.h
index 41a64bead0..666b9ff66e 100644
--- a/include/grpc++/impl/codegen/server_interface.h
+++ b/include/grpc++/impl/codegen/server_interface.h
@@ -140,7 +140,7 @@ class ServerInterface : public CallHook {
                      ServerAsyncStreamingInterface* stream,
                      CompletionQueue* call_cq, void* tag,
                      bool delete_on_finalize);
-    virtual ~BaseAsyncRequest() {}
+    virtual ~BaseAsyncRequest();
 
     bool FinalizeResult(void** tag, bool* status) override;
 
diff --git a/include/grpc++/resource_quota.h b/include/grpc++/resource_quota.h
index 75e04d4e2f..68a514658d 100644
--- a/include/grpc++/resource_quota.h
+++ b/include/grpc++/resource_quota.h
@@ -37,6 +37,7 @@
 struct grpc_resource_quota;
 
 #include <grpc++/impl/codegen/config.h>
+#include <grpc++/impl/codegen/grpc_library.h>
 
 namespace grpc {
 
@@ -44,7 +45,7 @@ namespace grpc {
 /// A ResourceQuota can be attached to a server (via ServerBuilder), or a client
 /// channel (via ChannelArguments). gRPC will attempt to keep memory used by
 /// all attached entities below the ResourceQuota bound.
-class ResourceQuota final {
+class ResourceQuota final : private GrpcLibraryCodegen {
  public:
   explicit ResourceQuota(const grpc::string& name);
   ResourceQuota();
diff --git a/include/grpc++/server_builder.h b/include/grpc++/server_builder.h
index 9252c6a63a..2ac2f0a1ef 100644
--- a/include/grpc++/server_builder.h
+++ b/include/grpc++/server_builder.h
@@ -187,7 +187,7 @@ class ServerBuilder {
 
   struct SyncServerSettings {
     SyncServerSettings()
-        : num_cqs(GPR_MAX(gpr_cpu_num_cores(), 4)),
+        : num_cqs(1),
           min_pollers(1),
           max_pollers(INT_MAX),
           cq_timeout_msec(1000) {}