Eliminate needless lock

Former-commit-id: 60f972d463f202edb33ff9a25bc2bd3e2558105c

src/db.cpp

@@ -2834,9 +2834,9 @@ bool redisDbPersistentData::removeCachedValue(const char *key)
 
 void redisDbPersistentData::trackChanges(bool fBulk)
 {
-    m_fTrackingChanges++;
+    m_fTrackingChanges.fetch_add(1, std::memory_order_relaxed);
     if (fBulk)
-        m_fAllChanged++;
+        m_fAllChanged.fetch_add(1, std::memory_order_acq_rel);
 }
 
 void redisDbPersistentData::removeAllCachedValues()

src/server.cpp

@@ -2650,10 +2650,8 @@ void afterSleep(struct aeEventLoop *eventLoop) {
 
     serverAssert(serverTL->gcEpoch.isReset());
     serverTL->gcEpoch = g_pserver->garbageCollector.startEpoch();
-    aeAcquireLock();
     for (int idb = 0; idb < cserver.dbnum; ++idb)
         g_pserver->db[idb]->trackChanges(false);
-    aeReleaseLock();
 }
 
 /* =========================== Server initialization ======================== */

src/server.h

@@ -1172,8 +1172,8 @@ private:
     // Keyspace
     dict *m_pdict = nullptr;                 /* The keyspace for this DB */
     dict *m_pdictTombstone = nullptr;        /* Track deletes when we have a snapshot */
-    int m_fTrackingChanges = 0;     // Note: Stack based
-    int m_fAllChanged = 0;
+    std::atomic<int> m_fTrackingChanges {0};     // Note: Stack based
+    std::atomic<int> m_fAllChanged {0};
     std::set<changedesc, changedescCmp> m_setchanged;
     size_t m_cnewKeysPending = 0;
     std::shared_ptr<StorageCache> m_spstorage = nullptr;