[Misc] fix Metaspace info in gc log

Summary:
- The original GC printing did not change in the gc log after a full gc, this patch will fix this printing problem
- port D65612 to dragonwell

Test Plan: hotspot/test/gc/metaspace/TestMetaspaceGCLogSize.java

Reviewers: 传胜

Differential Revision: https://aone.alibaba-inc.com/code/D851703

src/share/vm/memory/genCollectedHeap.cpp

@@ -546,15 +546,6 @@ void GenCollectedHeap::do_collection(bool  full,
       post_full_gc_dump(NULL);   // do any post full gc dumps
     }
 
-    if (PrintGCDetails) {
-      print_heap_change(gch_prev_used);
-
-      // Print metaspace info for full GC with PrintGCDetails flag.
-      if (complete) {
-        MetaspaceAux::print_metaspace_change(metadata_prev_used);
-      }
-    }
-
     for (int j = max_level_collected; j >= 0; j -= 1) {
       // Adjust generation sizes.
       _gens[j]->compute_new_size();
@@ -569,6 +560,15 @@ void GenCollectedHeap::do_collection(bool  full,
       update_full_collections_completed();
     }
 
+    if (PrintGCDetails) {
+      print_heap_change(gch_prev_used);
+
+      // Print metaspace info for full GC with PrintGCDetails flag.
+      if (complete) {
+        MetaspaceAux::print_metaspace_change(metadata_prev_used);
+      }
+    }
+
     // Track memory usage and detect low memory after GC finishes
     MemoryService::track_memory_usage();
 

test/gc/metaspace/TestMetaspaceGCLogSize.java

+/*
+ * Copyright (c) 2019 Alibaba Group Holding Limited. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Alibaba designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+/*
+ * @test
+ * @summary test the fix of metaspace gc log size
+ * @library /testlibrary
+ * @build TestMetaspaceGCLogSize
+ * @run main/othervm -Xmx1g -Xmn500m -XX:+UseConcMarkSweepGC TestMetaspaceGCLogSize
+ *
+ */
+
+import java.lang.management.ManagementFactory;
+import java.lang.management.MemoryManagerMXBean;
+import java.lang.management.MemoryPoolMXBean;
+import java.lang.management.MemoryUsage;
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import com.oracle.java.testlibrary.*;
+import static com.oracle.java.testlibrary.Asserts.*;
+
+public class TestMetaspaceGCLogSize {
+    public static long used = 0;
+
+    // the metaspace log is [Metaspace: pre_metadata_used->used_byte(reserved byte)]
+    // in original gc log, pre_metadata_used is always equal with used_byte because it prints log before cheaning and resizing metaspace
+    // after the fix, the used_byte in gc log will be the value after the metaspace cleaned and resized
+    public static void main (String[] args) throws Exception {
+        if (!Platform.isLinux()) { return; }
+        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder("-Xmx1g",
+                "-Xmn500m",
+                "-XX:+PrintGCDetails",
+                "-verbose:gc",
+                "-XX:+UseConcMarkSweepGC",
+                TestMetaspaceGCLog.class.getName());
+        pb.environment().put("LC_ALL", "");
+        OutputAnalyzer output = new OutputAnalyzer(pb.start());
+        // the top 2-12 logs are the System GC log, the 13'th row is the  metaspace used bytes, and the last is the summary of the heap
+        // here only consider the top 13 rows in the stdout
+        // the 12'th row is the last system.gc log
+        // the 13'th row is the metaspace used size after doing the last system.gc which obtained by the JMX bean
+        String stdout = output.getStdout();
+        String [] strOut = stdout.split("\n");
+        String result = strOut[12];
+        assertTrue(strOut[11].contains(result));
+
+        // same test when doing the LC_ALL=C
+        pb.environment().put("LC_ALL", "C");
+        output = new OutputAnalyzer(pb.start());
+        stdout = output.getStdout();
+        strOut = stdout.split("\n");
+        result = strOut[12];
+        assertTrue(strOut[11].contains(result));
+    }
+
+    // class for test the metaspace gc log after system.gc
+    public static class TestMetaspaceGCLog {
+        private static final Map<String, Foo> loadedClasses = new HashMap<>();
+
+        private static int counter = 0;
+
+        protected static MemoryPoolMXBean pool = getMemoryPool();
+
+        protected static void loadNewClasses(int times, boolean keepRefs) {
+            for (int i = 0; i < times; i++) {
+                try {
+                    String jarUrl = "file:" + counter +".jar";
+                    counter++;
+                    URL[] urls = new URL[]{new URL(jarUrl)};
+                    URLClassLoader cl = new URLClassLoader(urls);
+                    TestMetaspaceGCLog.Foo foo = (TestMetaspaceGCLog.Foo) Proxy.newProxyInstance(cl,
+                            new Class[]{TestMetaspaceGCLog.Foo.class},
+                            new TestMetaspaceGCLog.FooInvocationHandler(new TestMetaspaceGCLog.FooBar()));
+                    if (keepRefs) {
+                        loadedClasses.put(jarUrl, foo);
+                    }
+                } catch (MalformedURLException e) {
+                    e.printStackTrace();
+                }
+            }
+        }
+
+        protected static void cleanLoadedClasses() {
+            loadedClasses.clear();
+        }
+
+        protected static void printUsedSize() {
+            MemoryUsage mu = pool.getUsage();
+            System.out.println(mu.getUsed()/1024 + "K");
+        }
+
+        protected static MemoryPoolMXBean getMemoryPool () {
+            List<MemoryPoolMXBean> pools  = ManagementFactory.getMemoryPoolMXBeans();
+            MemoryPoolMXBean mpool = null;
+            for (MemoryPoolMXBean pool : pools) {
+                if (pool.getName().equals("Metaspace")) {
+                    mpool = pool;
+                }
+            }
+            return mpool;
+        }
+
+        public static void checkMetaspaceGC() {
+            // the "printUsedSize" here is for loaded JMX and stdout class previously
+            printUsedSize();
+            // the metaspace used size will change a little between System.gc and the MemoryPoolMXBean at the beginning
+            // here is a loop to make the metaspace stabilizing
+            for (int i = 0; i < 10; i++) {
+                loadNewClasses(1000, true);
+                cleanLoadedClasses();
+                System.gc();
+            }
+            loadNewClasses(1000, true);
+            cleanLoadedClasses();
+            System.gc();
+            printUsedSize();
+        }
+
+        public static void main(String[] args) {
+            checkMetaspaceGC();
+        }
+
+        public static interface Foo {}
+
+        static public class FooBar implements Foo {}
+
+        static public class FooInvocationHandler implements InvocationHandler {
+            private final Foo foo;
+
+            FooInvocationHandler(TestMetaspaceGCLog.Foo foo) {
+                this.foo = foo;
+            }
+
+            @Override
+            public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
+                return method.invoke(foo, args);
+            }
+        }
+    }
+}
+