From 877f94734c5418f794db9ea43d209ad0c4403ed2 Mon Sep 17 00:00:00 2001
From: Kajaruban Surendran <kajaruban.surendran@huawei.com>
Date: Mon, 30 Nov 2020 20:20:37 +0000
Subject: [PATCH] Handling of aeResizeSetSize's return code for current thread

Former-commit-id: c25fb3d74fb9e7adb6ad7ef730355e325e982cd2
---
 src/ae.cpp     |  5 +++++
 src/ae.h       |  1 +
 src/config.cpp | 22 +++++++++++++++++++++-
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/ae.cpp b/src/ae.cpp
index cb500d7b6..0d9bf21e7 100644
--- a/src/ae.cpp
+++ b/src/ae.cpp
@@ -373,6 +373,11 @@ int aeGetSetSize(aeEventLoop *eventLoop) {
     return eventLoop->setsize;
 }
 
+/* Return the current EventLoop. */
+aeEventLoop *aeGetCurrentEventLoop(){
+    return g_eventLoopThisThread;
+}
+
 /* Tells the next iteration/s of the event processing to set timeout of 0. */
 void aeSetDontWait(aeEventLoop *eventLoop, int noWait) {
     if (noWait)
diff --git a/src/ae.h b/src/ae.h
index fdd444d3a..e77abb01f 100644
--- a/src/ae.h
+++ b/src/ae.h
@@ -160,6 +160,7 @@ const char *aeGetApiName(void);
 void aeSetBeforeSleepProc(aeEventLoop *eventLoop, aeBeforeSleepProc *beforesleep, int flags);
 void aeSetAfterSleepProc(aeEventLoop *eventLoop, aeBeforeSleepProc *aftersleep, int flags);
 int aeGetSetSize(aeEventLoop *eventLoop);
+aeEventLoop *aeGetCurrentEventLoop();
 int aeResizeSetSize(aeEventLoop *eventLoop, int setsize);
 void aeSetDontWait(aeEventLoop *eventLoop, int noWait);
 
diff --git a/src/config.cpp b/src/config.cpp
index 88939b001..e00fdf641 100644
--- a/src/config.cpp
+++ b/src/config.cpp
@@ -2273,14 +2273,33 @@ static int updateMaxclients(long long val, long long prev, const char **err) {
             }
             return 0;
         }
+	/* Change the SetSize for the current thread first. 
+	 * If any error, return the error message to the client, otherwise, continue to do the same for other threads */
+        if ((unsigned int) aeGetSetSize(aeGetCurrentEventLoop()) <
+                g_pserver->maxclients + CONFIG_FDSET_INCR)
+        {
+            if (aeResizeSetSize(aeGetCurrentEventLoop(),
+                g_pserver->maxclients + CONFIG_FDSET_INCR) == AE_ERR)
+            {
+                *err = "The event loop API used by Redis is not able to handle the specified number of clients";
+                return 0;
+            }
+	    serverLog(LL_DEBUG,"Successfully changed the setsize for current thread %d", ielFromEventLoop(aeGetCurrentEventLoop()));
+        }
+
         for (int iel = 0; iel < cserver.cthreads; ++iel)
         {
+	    if (g_pserver->rgthreadvar[iel].el == aeGetCurrentEventLoop())
+            {
+                continue;
+            }
+
             if ((unsigned int) aeGetSetSize(g_pserver->rgthreadvar[iel].el) <
                 g_pserver->maxclients + CONFIG_FDSET_INCR)
             {
                 int res = aePostFunction(g_pserver->rgthreadvar[iel].el, [iel] {
                     if (aeResizeSetSize(g_pserver->rgthreadvar[iel].el, g_pserver->maxclients + CONFIG_FDSET_INCR) == AE_ERR) {
-                        serverPanic("Failed to change the setsize for Thread %d", iel);
+                        serverLog(LL_WARNING,"Failed to change the setsize for Thread %d", iel);
                     }
                 });
 
@@ -2290,6 +2309,7 @@ static int updateMaxclients(long long val, long long prev, const char **err) {
                     *err = msg;
                     return 0;
                 }
+		serverLog(LL_DEBUG,"Successfully post the request to change the setsize for thread %d", iel);
             }
         }
     }