From d490d491ffdb00761acc2b90190dff4ea130e7fc Mon Sep 17 00:00:00 2001 From: Shevchik Date: Sat, 14 Mar 2020 14:20:50 +0300 Subject: [PATCH] Prevent blocking on adding a new network manager (#3027) Previous solution could still block network thread (while addPending is executing). This window is small, but removing it completely is better. This should probably also speed up concurrent adds, because no locking will be performed anymore. The only possible downside is that adding elements one by one to synchronized list might be slower (But it's done while already locked, so maybe jvm will avoid additional locking?), --- .../Avoid-blocking-on-Network-Manager-creation.patch | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/Spigot-Server-Patches/Avoid-blocking-on-Network-Manager-creation.patch b/Spigot-Server-Patches/Avoid-blocking-on-Network-Manager-creation.patch index 6063e3d59..aa825694c 100644 --- a/Spigot-Server-Patches/Avoid-blocking-on-Network-Manager-creation.patch +++ b/Spigot-Server-Patches/Avoid-blocking-on-Network-Manager-creation.patch @@ -6,7 +6,7 @@ Subject: [PATCH] Avoid blocking on Network Manager creation Per Paper issue 294 diff --git a/src/main/java/net/minecraft/server/ServerConnection.java b/src/main/java/net/minecraft/server/ServerConnection.java -index e7e216850..9cd7c9064 100644 +index e7e21685..404e7834 100644 --- a/src/main/java/net/minecraft/server/ServerConnection.java +++ b/src/main/java/net/minecraft/server/ServerConnection.java @@ -0,0 +0,0 @@ public class ServerConnection { @@ -14,11 +14,11 @@ index e7e216850..9cd7c9064 100644 private final List listeningChannels = Collections.synchronizedList(Lists.newArrayList()); private final List connectedChannels = Collections.synchronizedList(Lists.newArrayList()); + // Paper start - prevent blocking on adding a new network manager while the server is ticking -+ private final List pending = Collections.synchronizedList(Lists.newArrayList()); ++ private final java.util.Queue pending = new java.util.concurrent.ConcurrentLinkedQueue<>(); + private void addPending() { -+ synchronized (pending) { -+ connectedChannels.addAll(pending); -+ pending.clear(); ++ NetworkManager manager = null; ++ while ((manager = pending.poll()) != null) { ++ connectedChannels.add(manager); + } + } + // Paper end