Add experimental API for resetting connection backoff.

1 files changed, 18 insertions, 0 deletions

diff --git a/src/core/ext/filters/client_channel/subchannel.cc b/src/core/ext/filters/client_channel/subchannel.cc
index 71ef8c518b..48c6030c89 100644
--- a/src/core/ext/filters/client_channel/subchannel.cc
+++ b/src/core/ext/filters/client_channel/subchannel.cc
@@ -132,6 +132,8 @@ struct grpc_subchannel {
   bool have_alarm;
   /** have we started the backoff loop */
   bool backoff_begun;
+  // reset_backoff() was called while alarm was pending
+  bool deferred_reset_backoff;
   /** our alarm */
   grpc_timer alarm;
 
@@ -438,6 +440,9 @@ static void on_alarm(void* arg, grpc_error* error) {
   if (c->disconnected) {
     error = GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING("Disconnected",
                                                              &error, 1);
+  } else if (c->deferred_reset_backoff) {
+    c->deferred_reset_backoff = false;
+    error = GRPC_ERROR_NONE;
   } else {
     GRPC_ERROR_REF(error);
   }
@@ -675,6 +680,19 @@ static void on_subchannel_connected(void* arg, grpc_error* error) {
   grpc_channel_args_destroy(delete_channel_args);
 }
 
+void grpc_subchannel_reset_backoff(grpc_subchannel* subchannel) {
+  gpr_mu_lock(&subchannel->mu);
+  if (subchannel->have_alarm) {
+    subchannel->deferred_reset_backoff = true;
+    grpc_timer_cancel(&subchannel->alarm);
+  } else {
+    subchannel->backoff_begun = false;
+    subchannel->backoff->Reset();
+    maybe_start_connecting_locked(subchannel);
+  }
+  gpr_mu_unlock(&subchannel->mu);
+}
+
 /*
  * grpc_subchannel_call implementation
  */