SERVER-18277 Track elapsed time on cursors using microsecond resolution on OperationContext.

This completes the mechanics of moving max-time tracking to OperationContext and
switching the checkForInterrupt checks to use the service context's fast clock
source, while tracking the amount of execution time remaining on a cursor with
microsecond granularity to ensure that remaining execution time always declines,
even for very brief operations on cursors.

This patch does not complete the transition from wait_for waiting to wait_until
waiting in all places that do waiting based on operation deadlines.

3 files changed, 9 insertions, 24 deletions

diff --git a/src/mongo/db/s/operation_sharding_state.cpp b/src/mongo/db/s/operation_sharding_state.cpp
index 01a0132df07..c6fe82ff6d0 100644
--- a/src/mongo/db/s/operation_sharding_state.cpp
+++ b/src/mongo/db/s/operation_sharding_state.cpp
@@ -40,7 +40,7 @@ const OperationContext::Decoration<OperationShardingState> shardingMetadataDecor
     OperationContext::declareDecoration<OperationShardingState>();
 
 // Max time to wait for the migration critical section to complete
-const Minutes kMaxWaitForMigrationCriticalSection(5);
+const Microseconds kMaxWaitForMigrationCriticalSection = Minutes(5);
 
 }  // namespace mongo
 
@@ -101,12 +101,10 @@ bool OperationShardingState::waitForMigrationCriticalSection(OperationContext* t
     invariant(!txn->lockState()->isLocked());
 
     if (_migrationCriticalSection) {
-        const Microseconds operationRemainingTime(
-            Microseconds(static_cast<int64_t>(txn->getRemainingMaxTimeMicros())));
         _migrationCriticalSection->waitUntilOutOfCriticalSection(
-            durationCount<Microseconds>(operationRemainingTime)
-                ? operationRemainingTime
-                : Microseconds{kMaxWaitForMigrationCriticalSection});
+            txn->hasDeadline()
+                ? std::min(txn->getRemainingMaxTimeMicros(), kMaxWaitForMigrationCriticalSection)
+                : kMaxWaitForMigrationCriticalSection);
         _migrationCriticalSection = nullptr;
         return true;
     }
diff --git a/src/mongo/db/s/sharding_state.cpp b/src/mongo/db/s/sharding_state.cpp
index 0d89f81f678..c69fe446a90 100644
--- a/src/mongo/db/s/sharding_state.cpp
+++ b/src/mongo/db/s/sharding_state.cpp
@@ -122,20 +122,6 @@ VersionChoice chooseNewestVersion(ChunkVersion prevLocalVersion,
     return VersionChoice::Remote;
 }
 
-Date_t getDeadlineFromMaxTimeMS(OperationContext* txn) {
-    auto remainingTime = txn->getRemainingMaxTimeMicros();
-    if (remainingTime == 0) {
-        return Date_t::max();
-    }
-
-    if (remainingTime == 1) {
-        // 1 means maxTimeMS has exceeded.
-        return Date_t::now();
-    }
-
-    return Date_t::now() + Microseconds(static_cast<int64_t>(remainingTime));
-}
-
 /**
  * Updates the config server field of the shardIdentity document with the given connection string
  * if setName is equal to the config server replica set name.
@@ -401,7 +387,7 @@ void ShardingState::initializeFromConfigConnString(OperationContext* txn, const
         }
     }
 
-    uassertStatusOK(_waitForInitialization(getDeadlineFromMaxTimeMS(txn)));
+    uassertStatusOK(_waitForInitialization(txn->getDeadline()));
     uassertStatusOK(reloadShardRegistryUntilSuccess(txn));
     updateConfigServerOpTimeFromMetadata(txn);
 }
@@ -432,8 +418,7 @@ Status ShardingState::initializeFromShardIdentity(OperationContext* txn) {
         return parseStatus.getStatus();
     }
 
-    auto status =
-        initializeFromShardIdentity(parseStatus.getValue(), getDeadlineFromMaxTimeMS(txn));
+    auto status = initializeFromShardIdentity(parseStatus.getValue(), txn->getDeadline());
     if (!status.isOK()) {
         return status;
     }
@@ -636,7 +621,7 @@ Status ShardingState::_refreshMetadata(OperationContext* txn,
                                        ChunkVersion* latestShardVersion) {
     invariant(!txn->lockState()->isLocked());
 
-    Status status = _waitForInitialization(getDeadlineFromMaxTimeMS(txn));
+    Status status = _waitForInitialization(txn->getDeadline());
     if (!status.isOK())
         return status;
 
diff --git a/src/mongo/db/s/sharding_state_test.cpp b/src/mongo/db/s/sharding_state_test.cpp
index 1f5eecf6f21..44d5cb7de24 100644
--- a/src/mongo/db/s/sharding_state_test.cpp
+++ b/src/mongo/db/s/sharding_state_test.cpp
@@ -52,6 +52,7 @@
 #include "mongo/s/query/cluster_cursor_manager.h"
 #include "mongo/unittest/unittest.h"
 #include "mongo/util/clock_source_mock.h"
+#include "mongo/util/tick_source_mock.h"
 
 
 namespace mongo {
@@ -117,6 +118,7 @@ public:
     void setUp() override {
         _service.setFastClockSource(stdx::make_unique<ClockSourceMock>());
         _service.setPreciseClockSource(stdx::make_unique<ClockSourceMock>());
+        _service.setTickSource(stdx::make_unique<TickSourceMock>());
 
         serverGlobalParams.clusterRole = ClusterRole::ShardServer;
         _client = _service.makeClient("ShardingStateTest");