SERVER-39960 Simplify opCtx::markKilled

Operation context currently relies on an elaborate dance between the
client lock, _waitMutex, _waitCV and _numKillers to allow markKilled to
tap the condvar an opctx is waiting on.

After the introduction of batons on all opctx's, this is no longer
necessary (as batons have their own support for being woken, while
waiting on a condvar). Removing the special killing code will simplify
opctx, and remove a lot of extra book keeping.

1 files changed, 10 insertions, 12 deletions

diff --git a/src/mongo/db/service_context.cpp b/src/mongo/db/service_context.cpp
index ee26756a642..ac8937dbc6c 100644
--- a/src/mongo/db/service_context.cpp
+++ b/src/mongo/db/service_context.cpp
@@ -248,21 +248,20 @@ ServiceContext::UniqueOperationContext ServiceContext::makeOperationContext(Clie
         opCtx->setRecoveryUnit(std::make_unique<RecoveryUnitNoop>(),
                                WriteUnitOfWork::RecoveryUnitState::kNotInUnitOfWork);
     }
-    {
-        stdx::lock_guard<Client> lk(*client);
-        client->setOperationContext(opCtx.get());
-    }
+    // The baton must be attached before attaching to a client
     if (_transportLayer) {
         _transportLayer->makeBaton(opCtx.get());
     } else {
         makeBaton(opCtx.get());
     }
+    {
+        stdx::lock_guard<Client> lk(*client);
+        client->setOperationContext(opCtx.get());
+    }
     return UniqueOperationContext(opCtx.release());
 };
 
 void ServiceContext::OperationContextDeleter::operator()(OperationContext* opCtx) const {
-    opCtx->getBaton()->detach();
-
     auto client = opCtx->getClient();
     if (client->session()) {
         _numCurrentOps.subtractAndFetch(1);
@@ -272,6 +271,8 @@ void ServiceContext::OperationContextDeleter::operator()(OperationContext* opCtx
         stdx::lock_guard<Client> lk(*client);
         client->resetOperationContext();
     }
+    opCtx->getBaton()->detach();
+
     onDestroy(opCtx, service->_clientObservers);
     delete opCtx;
 }
@@ -413,13 +414,10 @@ void ServiceContext::ServiceContextDeleter::operator()(ServiceContext* service)
 }
 
 BatonHandle ServiceContext::makeBaton(OperationContext* opCtx) const {
-    auto baton = std::make_shared<DefaultBaton>(opCtx);
+    invariant(!opCtx->getBaton());
 
-    {
-        stdx::lock_guard<Client> lk(*opCtx->getClient());
-        invariant(!opCtx->getBaton());
-        opCtx->setBaton(baton);
-    }
+    auto baton = std::make_shared<DefaultBaton>(opCtx);
+    opCtx->setBaton(baton);
 
     return baton;
 }