[GR-52484] Partial support for physical memory usage and JFR tests for periodic native events.

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/heap/PhysicalMemory.java

@@ -24,9 +24,17 @@
  */
 package com.oracle.svm.core.heap;
 
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.lang.management.ManagementFactory;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.concurrent.locks.ReentrantLock;
 
 import org.graalvm.nativeimage.ImageSingletons;
+import org.graalvm.nativeimage.Platform;
 import org.graalvm.word.UnsignedWord;
 import org.graalvm.word.WordFactory;
 
@@ -38,6 +46,7 @@
 import com.oracle.svm.core.thread.VMOperation;
 import com.oracle.svm.core.util.UnsignedUtils;
 import com.oracle.svm.core.util.VMError;
+import com.sun.management.OperatingSystemMXBean;
 
 /**
  * Contains static methods to get configuration of physical memory.
@@ -50,6 +59,8 @@ public interface PhysicalMemorySupport {
         UnsignedWord size();
     }
 
+    private static final long K = 1024;
+
     private static final ReentrantLock LOCK = new ReentrantLock();
     private static final UnsignedWord UNSET_SENTINEL = UnsignedUtils.MAX_VALUE;
     private static UnsignedWord cachedSize = UNSET_SENTINEL;
@@ -107,6 +118,73 @@ public static UnsignedWord size() {
         return cachedSize;
     }
 
+    /** Returns the amount of used physical memory in bytes, or -1 if not supported. */
+    public static long usedSize() {
+        // Windows, macOS, and containerized Linux use the OS bean.
+        if (Platform.includedIn(Platform.WINDOWS.class) ||
+                        Platform.includedIn(Platform.MACOS.class) ||
+                        (Containers.isContainerized() && Containers.memoryLimitInBytes() > 0)) {
+            OperatingSystemMXBean osBean = (com.sun.management.OperatingSystemMXBean) ManagementFactory.getOperatingSystemMXBean();
+            return osBean.getTotalMemorySize() - osBean.getFreeMemorySize();
+        }
+
+        // Non-containerized Linux uses /proc/meminfo.
+        if (Platform.includedIn(Platform.LINUX.class)) {
+            return getUsedSizeFromProcMemInfo();
+        }
+
+        return -1L;
+    }
+
+    // Will be removed as part of GR-51479.
+    private static long getUsedSizeFromProcMemInfo() {
+        try {
+            List<String> lines = readAllLines("/proc/meminfo");
+            for (String line : lines) {
+                if (line.contains("MemAvailable")) {
+                    return size().rawValue() - parseFirstNumber(line) * K;
+                }
+            }
+        } catch (Exception e) {
+            /* Nothing to do. */
+        }
+        return -1L;
+    }
+
+    private static List<String> readAllLines(String fileName) throws IOException {
+        List<String> lines = new ArrayList<>();
+        try (BufferedReader bufferedReader = new BufferedReader(new FileReader(fileName, StandardCharsets.UTF_8))) {
+            String line;
+            while ((line = bufferedReader.readLine()) != null) {
+                lines.add(line);
+            }
+        }
+        return lines;
+    }
+
+    /** Parses the first number in the String as a long value. */
+    private static long parseFirstNumber(String str) {
+        int firstDigit = -1;
+        int lastDigit = -1;
+
+        for (int i = 0; i < str.length(); i++) {
+            if (Character.isDigit(str.charAt(i))) {
+                if (firstDigit == -1) {
+                    firstDigit = i;
+                }
+                lastDigit = i;
+            } else if (firstDigit != -1) {
+                break;
+            }
+        }
+
+        if (firstDigit >= 0) {
+            String number = str.substring(firstDigit, lastDigit + 1);
+            return Long.parseLong(number);
+        }
+        return -1;
+    }
+
     /**
      * Returns the size of physical memory in bytes that has been previously cached. This method
      * must not be called if {@link #isInitialized()} is still false.

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jfr/events/EveryChunkNativePeriodicEvents.java

@@ -51,7 +51,7 @@ public class EveryChunkNativePeriodicEvents extends Event {
 
     public static void emit() {
         emitJavaThreadStats();
-        emitPhysicalMemory();
+        emitPhysicalMemory(PhysicalMemory.usedSize());
         emitClassLoadingStatistics();
         emitPerThreadEvents();
     }
@@ -75,15 +75,15 @@ private static void emitJavaThreadStats() {
     }
 
     @Uninterruptible(reason = "Accesses a JFR buffer.")
-    private static void emitPhysicalMemory() {
+    private static void emitPhysicalMemory(long usedSize) {
         if (JfrEvent.PhysicalMemory.shouldEmit()) {
             JfrNativeEventWriterData data = StackValue.get(JfrNativeEventWriterData.class);
             JfrNativeEventWriterDataAccess.initializeThreadLocalNativeBuffer(data);
 
             JfrNativeEventWriter.beginSmallEvent(data, JfrEvent.PhysicalMemory);
             JfrNativeEventWriter.putLong(data, JfrTicks.elapsedTicks());
             JfrNativeEventWriter.putLong(data, PhysicalMemory.getCachedSize().rawValue());
-            JfrNativeEventWriter.putLong(data, 0); /* used size */
+            JfrNativeEventWriter.putLong(data, usedSize); /* used size */
             JfrNativeEventWriter.endSmallEvent(data);
         }
     }

substratevm/src/com.oracle.svm.test/src/com/oracle/svm/test/jfr/TestEveryChunkNativePeriodicEvents.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2024, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2024, 2024, Red Hat Inc. 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.  Oracle 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.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package com.oracle.svm.test.jfr;
+
+import static org.junit.Assert.assertTrue;
+
+import java.util.List;
+
+import org.junit.Test;
+
+import com.oracle.svm.core.jfr.JfrEvent;
+
+import jdk.jfr.Recording;
+import jdk.jfr.consumer.RecordedEvent;
+
+/**
+ * Tests the VM-level JFR events that are created periodically upon every chunk. Note that the
+ * events ThreadCPULoad and ThreadAllocationStatistics are not tested here since they already have
+ * their own individual tests.
+ */
+public class TestEveryChunkNativePeriodicEvents extends JfrRecordingTest {
+    @Test
+    public void test() throws Throwable {
+        String[] events = new String[]{JfrEvent.JavaThreadStatistics.getName(), JfrEvent.PhysicalMemory.getName(), JfrEvent.ClassLoadingStatistics.getName()};
+        Recording recording = startRecording(events);
+        stopRecording(recording, TestEveryChunkNativePeriodicEvents::validateEvents);
+    }
+
+    private static void validateEvents(List<RecordedEvent> events) {
+        boolean foundJavaThreadStatistics = false;
+        boolean foundPhysicalMemory = false;
+        boolean foundClassLoadingStatistics = false;
+
+        for (RecordedEvent e : events) {
+            String eventName = e.getEventType().getName();
+            if (eventName.equals(JfrEvent.JavaThreadStatistics.getName())) {
+                foundJavaThreadStatistics = true;
+                assertTrue(e.getLong("activeCount") > 1);
+                assertTrue(e.getLong("daemonCount") > 0);
+                assertTrue(e.getLong("accumulatedCount") > 1);
+                assertTrue(e.getLong("peakCount") > 1);
+            } else if (eventName.equals(JfrEvent.PhysicalMemory.getName())) {
+                foundPhysicalMemory = true;
+                assertTrue(e.getLong("totalSize") > 0);
+                assertTrue(e.getLong("usedSize") > 0);
+            } else if (eventName.equals(JfrEvent.ClassLoadingStatistics.getName())) {
+                foundClassLoadingStatistics = true;
+                assertTrue(e.getLong("loadedClassCount") > 0);
+            }
+        }
+
+        assertTrue(foundJavaThreadStatistics);
+        assertTrue(foundPhysicalMemory);
+        assertTrue(foundClassLoadingStatistics);
+    }
+}