From 91e1b3bb6bbfffc62401025a24231cd388992d7c Mon Sep 17 00:00:00 2001
From: Nileema Shingte <nileema.shingte@gmail.com>
Date: Mon, 29 Feb 2016 11:30:56 -0800
Subject: [PATCH] Add workaround for CodeCache not being collected effectively

This problem is seen in jdk8u45+ where the CodeCache becomes full
causing the JIT compiler to be disabled. We'd seen this problem earlier
with Java 7 and implemented this as a workaround. Reviving the old
commit with minor changes.

This reverts commit da9df1eb7f797f8e287fe8e51dcdcbd983d2a85e.
---
 .../presto/server/CodeCacheGcTrigger.java     | 76 +++++++++++++++++++
 .../facebook/presto/server/PrestoServer.java  |  3 +
 2 files changed, 79 insertions(+)
 create mode 100644 presto-main/src/main/java/com/facebook/presto/server/CodeCacheGcTrigger.java

diff --git a/presto-main/src/main/java/com/facebook/presto/server/CodeCacheGcTrigger.java b/presto-main/src/main/java/com/facebook/presto/server/CodeCacheGcTrigger.java
new file mode 100644
index 000000000000..c7051b9a5ae6
--- /dev/null
+++ b/presto-main/src/main/java/com/facebook/presto/server/CodeCacheGcTrigger.java
@@ -0,0 +1,76 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.facebook.presto.server;
+
+import io.airlift.log.Logger;
+
+import java.lang.management.ManagementFactory;
+import java.lang.management.MemoryPoolMXBean;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+final class CodeCacheGcTrigger
+{
+    private static final Logger log = Logger.get(CodeCacheGcTrigger.class);
+    private static final AtomicBoolean installed = new AtomicBoolean();
+
+    private CodeCacheGcTrigger() {}
+
+    public static void installCodeCacheGcTrigger()
+    {
+        if (installed.getAndSet(true)) {
+            return;
+        }
+
+        // Hack to work around bugs in java 8 (8u45+) related to code cache management.
+        // See http://openjdk.5641.n7.nabble.com/JIT-stops-compiling-after-a-while-java-8u45-td259603.html for more info.
+        MemoryPoolMXBean codeCacheMbean = findCodeCacheMBean();
+
+        Thread gcThread = new Thread(() -> {
+            while (!Thread.currentThread().isInterrupted()) {
+                long used = codeCacheMbean.getUsage().getUsed();
+                long max = codeCacheMbean.getUsage().getMax();
+
+                if (used > 0.95 * max) {
+                    log.error("Code Cache is more than 95% full. JIT may stop working.");
+                }
+                if (used > 0.7 * max) {
+                    // Due to some obscure bug in hotspot (java 8), once the code cache fills up the JIT stops compiling
+                    // By forcing a GC, we let the code cache evictor make room before the cache fills up.
+                    log.info("Triggering GC to avoid Code Cache eviction bugs");
+                    System.gc();
+                }
+
+                try {
+                    Thread.sleep(1000);
+                }
+                catch (InterruptedException e) {
+                    Thread.currentThread().interrupt();
+                }
+            }
+        });
+        gcThread.setDaemon(true);
+        gcThread.setName("Code-Cache-GC-Trigger");
+        gcThread.start();
+    }
+
+    private static MemoryPoolMXBean findCodeCacheMBean()
+    {
+        for (MemoryPoolMXBean bean : ManagementFactory.getMemoryPoolMXBeans()) {
+            if (bean.getName().equals("Code Cache")) {
+                return bean;
+            }
+        }
+        throw new RuntimeException("Could not obtain a reference to the 'Code Cache' MemoryPoolMXBean");
+    }
+}
diff --git a/presto-main/src/main/java/com/facebook/presto/server/PrestoServer.java b/presto-main/src/main/java/com/facebook/presto/server/PrestoServer.java
index 99c68965e45c..de138dc25cba 100644
--- a/presto-main/src/main/java/com/facebook/presto/server/PrestoServer.java
+++ b/presto-main/src/main/java/com/facebook/presto/server/PrestoServer.java
@@ -53,6 +53,7 @@
 import java.util.Set;
 
 import static com.facebook.presto.execution.scheduler.NodeSchedulerConfig.LEGACY_NETWORK_TOPOLOGY;
+import static com.facebook.presto.server.CodeCacheGcTrigger.installCodeCacheGcTrigger;
 import static com.facebook.presto.server.ConditionalModule.installModuleIf;
 import static com.facebook.presto.server.PrestoSystemRequirements.verifyJvmRequirements;
 import static com.facebook.presto.server.PrestoSystemRequirements.verifySystemTimeIsReasonable;
@@ -142,6 +143,8 @@ public void run()
             injector.getInstance(Announcer.class).start();
 
             log.info("======== SERVER STARTED ========");
+
+            installCodeCacheGcTrigger();
         }
         catch (Throwable e) {
             log.error(e);