Make slobrok RegisterAPI busy flag polling data race free

2 files changed, 7 insertions, 6 deletions

diff --git a/slobrok/src/vespa/slobrok/sbregister.cpp b/slobrok/src/vespa/slobrok/sbregister.cpp
index a1346feeece..72be5f69538 100644
--- a/slobrok/src/vespa/slobrok/sbregister.cpp
+++ b/slobrok/src/vespa/slobrok/sbregister.cpp
@@ -102,7 +102,7 @@ RegisterAPI::registerName(vespalib::stringref name)
             return;
         }
     }
-    _busy = true;
+    _busy.store(true, std::memory_order_relaxed);
     _names.push_back(name);
     _pending.push_back(name);
     discard(_unreg, name);
@@ -114,7 +114,7 @@ void
 RegisterAPI::unregisterName(vespalib::stringref name)
 {
     std::lock_guard<std::mutex> guard(_lock);
-    _busy = true;
+    _busy.store(true, std::memory_order_relaxed);
     discard(_names, name);
     discard(_pending, name);
     _unreg.push_back(name);
@@ -137,7 +137,7 @@ RegisterAPI::handleReqDone()
                     _target->SubRef();
                 }
                 _target = 0;
-                _busy = true;
+                _busy.store(true, std::memory_order_relaxed);
             } else {
                 LOG(warning, "%s(%s -> %s) failed: %s",
                     _req->GetMethodName(),
@@ -241,7 +241,7 @@ RegisterAPI::handlePending()
         std::lock_guard<std::mutex> guard(_lock);
         _pending = _names;
         LOG(debug, "done, reschedule in 30s");
-        _busy = false;
+        _busy.store(false, std::memory_order_relaxed);
         Schedule(30.0);
     }
 }
diff --git a/slobrok/src/vespa/slobrok/sbregister.h b/slobrok/src/vespa/slobrok/sbregister.h
index 234e6c076d4..8e8614fdf0a 100644
--- a/slobrok/src/vespa/slobrok/sbregister.h
+++ b/slobrok/src/vespa/slobrok/sbregister.h
@@ -6,6 +6,7 @@
 #include "cfg.h"
 #include <vespa/fnet/frt/invoker.h>
 #include <vespa/fnet/frt/invokable.h>
+#include <atomic>
 
 class FRT_Target;
 
@@ -53,7 +54,7 @@ public:
      *
      * @return true if there are outstanding registration requests
      **/
-    bool busy() const { return _busy; }
+    bool busy() const { return _busy.load(std::memory_order_relaxed); }
 
 private:
     class RPCHooks: public FRT_Invokable
@@ -86,7 +87,7 @@ private:
     RPCHooks                 _hooks;
     std::mutex               _lock;
     bool                     _reqDone;
-    bool                     _busy;
+    std::atomic<bool>        _busy;
     SlobrokList              _slobrokSpecs;
     Configurator::UP         _configurator;
     vespalib::string         _currSlobrok;