SERVER-5739 Fix races in RARELY/OCCASIONALLY.

Switch to using C++ instead of macros.
Fix SERVER-37247: these should fire on first hit.

2 files changed, 30 insertions, 58 deletions

diff --git a/src/mongo/db/stats/counters.cpp b/src/mongo/db/stats/counters.cpp
index 81a77016a8b..0355fa8787b 100644
--- a/src/mongo/db/stats/counters.cpp
+++ b/src/mongo/db/stats/counters.cpp
@@ -36,50 +36,10 @@
 #include "mongo/db/stats/counters.h"
 
 #include "mongo/db/jsobj.h"
-#include "mongo/util/debug_util.h"
 #include "mongo/util/log.h"
 
 namespace mongo {
 
-using std::endl;
-
-OpCounters::OpCounters() {}
-
-void OpCounters::gotInserts(int n) {
-    RARELY _checkWrap();
-    _insert.fetchAndAdd(n);
-}
-
-void OpCounters::gotInsert() {
-    RARELY _checkWrap();
-    _insert.fetchAndAdd(1);
-}
-
-void OpCounters::gotQuery() {
-    RARELY _checkWrap();
-    _query.fetchAndAdd(1);
-}
-
-void OpCounters::gotUpdate() {
-    RARELY _checkWrap();
-    _update.fetchAndAdd(1);
-}
-
-void OpCounters::gotDelete() {
-    RARELY _checkWrap();
-    _delete.fetchAndAdd(1);
-}
-
-void OpCounters::gotGetMore() {
-    RARELY _checkWrap();
-    _getmore.fetchAndAdd(1);
-}
-
-void OpCounters::gotCommand() {
-    RARELY _checkWrap();
-    _command.fetchAndAdd(1);
-}
-
 void OpCounters::gotOp(int op, bool isCommand) {
     switch (op) {
         case dbInsert: /*gotInsert();*/
@@ -104,18 +64,14 @@ void OpCounters::gotOp(int op, bool isCommand) {
         case opReply:
             break;
         default:
-            log() << "OpCounters::gotOp unknown op: " << op << endl;
+            log() << "OpCounters::gotOp unknown op: " << op << std::endl;
     }
 }
 
-void OpCounters::_checkWrap() {
-    const int64_t MAX = 1ULL << 60;
-
-    bool wrap = _insert.loadRelaxed() > MAX || _query.loadRelaxed() > MAX ||
-        _update.loadRelaxed() > MAX || _delete.loadRelaxed() > MAX ||
-        _getmore.loadRelaxed() > MAX || _command.loadRelaxed() > MAX;
-
-    if (wrap) {
+void OpCounters::_checkWrap(CacheAligned<AtomicInt64> OpCounters::*counter, int n) {
+    static constexpr auto maxCount = AtomicInt64::WordType{1} << 60;
+    auto oldValue = (this->*counter).fetchAndAddRelaxed(n);
+    if (oldValue > maxCount) {
         _insert.store(0);
         _query.store(0);
         _update.store(0);
diff --git a/src/mongo/db/stats/counters.h b/src/mongo/db/stats/counters.h
index 07e38b251a9..4d6a057e427 100644
--- a/src/mongo/db/stats/counters.h
+++ b/src/mongo/db/stats/counters.h
@@ -47,14 +47,29 @@ namespace mongo {
  */
 class OpCounters {
 public:
-    OpCounters();
-    void gotInserts(int n);
-    void gotInsert();
-    void gotQuery();
-    void gotUpdate();
-    void gotDelete();
-    void gotGetMore();
-    void gotCommand();
+    OpCounters() = default;
+
+    void gotInserts(int n) {
+        _checkWrap(&OpCounters::_insert, n);
+    }
+    void gotInsert() {
+        _checkWrap(&OpCounters::_insert, 1);
+    }
+    void gotQuery() {
+        _checkWrap(&OpCounters::_query, 1);
+    }
+    void gotUpdate() {
+        _checkWrap(&OpCounters::_update, 1);
+    }
+    void gotDelete() {
+        _checkWrap(&OpCounters::_delete, 1);
+    }
+    void gotGetMore() {
+        _checkWrap(&OpCounters::_getmore, 1);
+    }
+    void gotCommand() {
+        _checkWrap(&OpCounters::_command, 1);
+    }
 
     void gotOp(int op, bool isCommand);
 
@@ -81,7 +96,8 @@ public:
     }
 
 private:
-    void _checkWrap();
+    // Increment member `counter` by `n`, resetting all counters if it was > 2^60.
+    void _checkWrap(CacheAligned<AtomicInt64> OpCounters::*counter, int n);
 
     CacheAligned<AtomicInt64> _insert;
     CacheAligned<AtomicInt64> _query;