diff --git a/src/server.cpp b/src/server.cpp
index 4d10b478f..f7b7dba3f 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -2146,8 +2146,10 @@ void beforeSleepLite(struct aeEventLoop *eventLoop)
     /* Handle writes with pending output buffers. */
     handleClientsWithPendingWrites(iel);
 
+    aeAcquireLock();
     /* Close clients that need to be closed asynchronous */
     freeClientsInAsyncFreeQueue(iel);
+    aeReleaseLock();
 
     /* Before we are going to sleep, let the threads access the dataset by
      * releasing the GIL. Redis main thread will not touch anything at this
diff --git a/src/server.h b/src/server.h
index f315bdcd8..e2b0fd089 100644
--- a/src/server.h
+++ b/src/server.h
@@ -151,8 +151,6 @@ public:
 #define CONFIG_DEFAULT_TCP_BACKLOG       511    /* TCP listen backlog. */
 #define CONFIG_DEFAULT_CLIENT_TIMEOUT       0   /* Default client timeout: infinite */
 #define CONFIG_DEFAULT_DBNUM     16
-#define CONFIG_DEFAULT_IO_THREADS_NUM 1         /* Single threaded by default */
-#define CONFIG_DEFAULT_IO_THREADS_DO_READS 0    /* Read + parse from threads? */
 #define CONFIG_MAX_LINE    1024
 #define CRON_DBS_PER_CALL 16
 #define NET_MAX_WRITES_PER_EVENT (1024*64)
@@ -1765,7 +1763,6 @@ int writeToClient(int fd, client *c, int handler_installed);
 void linkClient(client *c);
 void protectClient(client *c);
 void unprotectClient(client *c);
-void initThreadedIO(void);
 
 // Special Thread-safe addReply() commands for posting messages to clients from a different thread
 void addReplyAsync(client *c, robj_roptr obj);