diff options
Diffstat (limited to 'storage')
| -rw-r--r-- | storage/src/vespa/storage/storageserver/communicationmanager.cpp | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/storage/src/vespa/storage/storageserver/communicationmanager.cpp b/storage/src/vespa/storage/storageserver/communicationmanager.cpp index 621f8a2ecc0..4458bf8a92d 100644 --- a/storage/src/vespa/storage/storageserver/communicationmanager.cpp +++ b/storage/src/vespa/storage/storageserver/communicationmanager.cpp @@ -396,6 +396,7 @@ void CommunicationManager::configure(std::unique_ptr<CommunicationManagerConfig> mbus::DestinationSessionParams dstParams; dstParams.setName("default"); dstParams.setBroadcastName(true); + dstParams.defer_registration(true); // Deferred session registration; see rationale below dstParams.setMessageHandler(*this); _messageBusSession = _mbus->getMessageBus().createDestinationSession(dstParams); @@ -403,6 +404,14 @@ void CommunicationManager::configure(std::unique_ptr<CommunicationManagerConfig> srcParams.setThrottlePolicy(mbus::IThrottlePolicy::SP()); srcParams.setReplyHandler(*this); _sourceSession = _mbus->getMessageBus().createSourceSession(srcParams); + + // Creating a DestinationSession that is immediately registered as available for business + // means we may theoretically start receiving messages over the session even before the call returns + // to the caller. Either way there would be no memory barrier that ensures that _messageBusSession + // would be fully visible to the MessageBus threads (since it's written after return). + // To avoid this sneaky scenario, defer registration (and thus introduce a barrier) until + // _after_ we've initialized our internal member variables. + _messageBusSession->register_session_deferred(); } } |