SERVER-17817 Move Locker cache in Client onto a decoration.

3 files changed, 28 insertions, 35 deletions

diff --git a/src/mongo/db/client.cpp b/src/mongo/db/client.cpp
index ea7ad692dc0..85617b55df5 100644
--- a/src/mongo/db/client.cpp
+++ b/src/mongo/db/client.cpp
@@ -49,7 +49,6 @@
 #include "mongo/db/auth/privilege.h"
 #include "mongo/db/catalog/database_holder.h"
 #include "mongo/db/commands.h"
-#include "mongo/db/concurrency/lock_state.h"
 #include "mongo/db/curop.h"
 #include "mongo/db/dbwebserver.h"
 #include "mongo/db/instance.h"
@@ -71,21 +70,6 @@ namespace mongo {
 
     using logger::LogComponent;
 
-namespace {
-
-    /**
-     * Create an appropriate new locker for the storage engine in use. Caller owns the return.
-     */
-    Locker* newLocker() {
-        if (isMMAPV1()) {
-            return new MMAPV1LockerImpl();
-        }
-
-        return new LockerImpl<false>();
-    }
-
-} // namespace
-
     boost::mutex Client::clientsMutex;
     ClientSet Client::clients;
 
@@ -164,14 +148,6 @@ namespace {
         return false;
     }
 
-    Locker* Client::getLocker() {
-        if (!_locker) {
-            _locker.reset(newLocker());
-        }
-
-        return _locker.get();
-    }
-
     void Client::reportState(BSONObjBuilder& builder) {
         builder.append("desc", desc());
 
diff --git a/src/mongo/db/client.h b/src/mongo/db/client.h
index 90cc2ff669f..b37b86bb4e9 100644
--- a/src/mongo/db/client.h
+++ b/src/mongo/db/client.h
@@ -40,7 +40,6 @@
 #include <boost/thread/thread.hpp>
 
 #include "mongo/db/client_basic.h"
-#include "mongo/db/concurrency/d_concurrency.h"
 #include "mongo/db/lasterror.h"
 #include "mongo/db/namespace_string.h"
 #include "mongo/db/operation_context.h"
@@ -53,7 +52,6 @@ namespace mongo {
     class CurOp;
     class Collection;
     class AbstractMessagingPort;
-    class Locker;
 
     TSP_DECLARE(Client, currentClient)
 
@@ -103,9 +101,6 @@ namespace mongo {
         CurOp* curop() const { return _curOp; }
         const std::string& desc() const { return _desc; }
 
-        // Return a reference to the Locker for this client. Client retains ownership.
-        Locker* getLocker();
-
         void reportState(BSONObjBuilder& builder);
 
         // Ensures stability of the client's OperationContext. When the client is locked,
@@ -153,10 +148,6 @@ namespace mongo {
         // Changes, based on what operation is running. Some of this should be in OperationContext.
         CurOp* _curOp;
 
-        // By having Client, rather than the OperationContext, own the Locker, setup cost such as
-        // allocating OS resources can be amortized over multiple operations.
-        boost::scoped_ptr<Locker> _locker;
-
         // Tracks if Client::shutdown() gets called (TODO: Is this necessary?)
         bool _shutdown;
     };
diff --git a/src/mongo/db/operation_context_impl.cpp b/src/mongo/db/operation_context_impl.cpp
index 47a04b191d5..8c7a793ca86 100644
--- a/src/mongo/db/operation_context_impl.cpp
+++ b/src/mongo/db/operation_context_impl.cpp
@@ -32,6 +32,8 @@
 
 #include "mongo/db/operation_context_impl.h"
 
+#include <memory>
+
 #include "mongo/db/client.h"
 #include "mongo/db/concurrency/lock_state.h"
 #include "mongo/db/curop.h"
@@ -40,16 +42,40 @@
 #include "mongo/db/repl/replication_coordinator_global.h"
 #include "mongo/db/storage/storage_engine.h"
 #include "mongo/platform/random.h"
-#include "mongo/util/log.h"
+#include "mongo/stdx/memory.h"
 #include "mongo/util/fail_point_service.h"
+#include "mongo/util/log.h"
 
 namespace mongo {
 
+namespace {
+    std::unique_ptr<Locker> newLocker() {
+        if (isMMAPV1()) return stdx::make_unique<MMAPV1LockerImpl>();
+        return stdx::make_unique<DefaultLockerImpl>();
+    }
+
+    class ClientOperationInfo {
+    public:
+        Locker* getLocker() {
+            if (!_locker) {
+                _locker = newLocker();
+            }
+            return _locker.get();
+        }
+
+    private:
+        std::unique_ptr<Locker> _locker;
+    };
+
+    const auto clientOperationInfoDecoration = Client::declareDecoration<ClientOperationInfo>();
+
+}  // namespace
+
     using std::string;
 
     OperationContextImpl::OperationContextImpl()
         : _client(currentClient.get()),
-          _locker(_client->getLocker()) {
+          _locker(clientOperationInfoDecoration(_client).getLocker()) {
 
         invariant(_locker);