1 files changed, 30 insertions, 0 deletions
diff --git a/patches/server/0397-Set-cap-on-JDK-per-thread-native-byte-buffer-cache.patch b/patches/server/0397-Set-cap-on-JDK-per-thread-native-byte-buffer-cache.patch
new file mode 100644
index 0000000000..6e0cb176e9
--- /dev/null
+++ b/patches/server/0397-Set-cap-on-JDK-per-thread-native-byte-buffer-cache.patch
@@ -0,0 +1,30 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Aikar <[email protected]>
+Date: Mon, 4 May 2020 01:08:56 -0400
+Subject: [PATCH] Set cap on JDK per-thread native byte buffer cache
+
+See: https://www.evanjones.ca/java-bytebuffer-leak.html
+
+This is potentially a source of lots of native memory usage.
+
+We are clearly seeing native usage upwards to 1-4GB which doesn't make sense.
+
+Region File usage fixed in previous patch should of tecnically only been somewhat
+temporary until GC finally gets it some time later, but between all the various
+plugins doing IO on various threads, this hidden detail of the JDK could be
+keeping long lived large direct buffers in cache.
+
+Set system properly at server startup if not set already to help protect from this.
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/Main.java b/src/main/java/org/bukkit/craftbukkit/Main.java
+index cce6886bb3973eed8f0c7ca7b1189547324fd4e2..0aef4fc4a89e627bc80504d7402f1ca2cdc95a74 100644
+--- a/src/main/java/org/bukkit/craftbukkit/Main.java
++++ b/src/main/java/org/bukkit/craftbukkit/Main.java
+@@ -28,6 +28,7 @@ public class Main {
+         }
+         // Paper end
+         // Todo: Installation script
++        if (System.getProperty("jdk.nio.maxCachedBufferSize") == null) System.setProperty("jdk.nio.maxCachedBufferSize", "262144"); // Paper - cap per-thread NIO cache size
+         OptionParser parser = new OptionParser() {
+             {
+                 acceptsAll(Main.asList("?", "help"), "Show the help");