SERVER-15901: Periodically cleanup unused lock heads

1 files changed, 21 insertions, 0 deletions

diff --git a/src/mongo/db/concurrency/lock_state.cpp b/src/mongo/db/concurrency/lock_state.cpp
index 2ceb854be1c..6d3aa4f6467 100644
--- a/src/mongo/db/concurrency/lock_state.cpp
+++ b/src/mongo/db/concurrency/lock_state.cpp
@@ -35,6 +35,7 @@
 #include "mongo/db/service_context.h"
 #include "mongo/db/namespace_string.h"
 #include "mongo/platform/compiler.h"
+#include "mongo/util/background.h"
 #include "mongo/util/concurrency/synchronization.h"
 #include "mongo/util/debug_util.h"
 #include "mongo/util/log.h"
@@ -867,6 +868,26 @@ namespace {
     }
 
 
+namespace {
+    /**
+     *  Periodically purges unused lock buckets. The first time the lock is used again after
+     *  cleanup it needs to be allocated, and similarly, every first use by a client for an intent
+     *  mode may need to create a partitioned lock head. Cleanup is done roughtly once a minute.
+     */
+    class UnusedLockCleaner : PeriodicTask {
+    public:
+        std::string taskName() const {
+            return "UnusedLockCleaner";
+        }
+
+        void taskDoWork() {
+            LOG(2) << "cleaning up unused lock buckets of the global lock manager";
+            getGlobalLockManager()->cleanupUnusedLocks();
+        }
+    } unusedLockCleaner;
+} // namespace
+
+
     //
     // Standalone functions
     //