From e067fff4e3f3079d070ec168f32c24db9a51a944 Mon Sep 17 00:00:00 2001
From: Geert Bosch <geert@mongodb.com>
Date: Wed, 10 Dec 2014 17:15:45 -0500
Subject: SERVER-16493: Have Client own Locker to amortize initialization cost

---
 src/mongo/db/client.cpp | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

(limited to 'src/mongo/db/client.cpp')

diff --git a/src/mongo/db/client.cpp b/src/mongo/db/client.cpp
index f7722b7dbec..1b4efbb5281 100644
--- a/src/mongo/db/client.cpp
+++ b/src/mongo/db/client.cpp
@@ -51,8 +51,10 @@
 #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/global_environment_experiment.h"
 #include "mongo/db/instance.h"
 #include "mongo/db/json.h"
 #include "mongo/db/jsobj.h"
@@ -107,6 +109,17 @@ namespace mongo {
         clients.insert(client);
     }
 
+namespace {
+    //  Create an appropriate new locker for the storage engine in use. Caller owns.
+    Locker* newLocker() {
+        if (isMMAPV1()) {
+            return new MMAPV1LockerImpl();
+        }
+
+        return new LockerImpl<false>();
+    }
+}
+
     Client::Client(const string& desc, AbstractMessagingPort *p)
         : ClientBasic(p),
           _desc(desc),
@@ -114,6 +127,7 @@ namespace mongo {
           _connectionId(p ? p->connectionId() : 0),
           _god(0),
           _txn(NULL),
+          _locker(newLocker()),
           _lastOp(0),
           _shutdown(false) {
 
@@ -335,13 +349,19 @@ namespace mongo {
     }
 
     void Client::setOperationContext(OperationContext* txn) {
-        // We can only set or unset the OperationContexts, never swap them.
-        invariant((txn == NULL) ^ (_txn == NULL));
+        // We can only set the OperationContext once before resetting it.
+        invariant(txn != NULL && _txn == NULL);
 
         boost::unique_lock<SpinLock> uniqueLock(_lock);
         _txn = txn;
     }
 
+    void Client::resetOperationContext() {
+        invariant(_txn != NULL);
+        boost::unique_lock<SpinLock> uniqueLock(_lock);
+        _txn = NULL;
+    }
+
     string Client::clientAddress(bool includePort) const {
         if( _curOp )
             return _curOp->getRemoteString(includePort);
-- 
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