8304074: [JMX] Add an approximation of total bytes allocated on the Java heap by the JVM

Reviewed-by: dholmes, mchung

Author: Paul Hohensee

src/hotspot/share/include/jmm.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2023, Oracle and/or its affiliates. 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
@@ -52,7 +52,8 @@ enum {
   JMM_VERSION_1_2_2 = 0x20010202,
   JMM_VERSION_2   = 0x20020000, // JDK 10
   JMM_VERSION_3   = 0x20030000, // JDK 14
-  JMM_VERSION     = JMM_VERSION_3
+  JMM_VERSION_4   = 0x20040000, // JDK 21
+  JMM_VERSION     = JMM_VERSION_4
 };
 
 typedef struct {
@@ -240,6 +241,8 @@ typedef struct jmmInterface_1_ {
   jobject      (JNICALL *GetMemoryPoolUsage)     (JNIEnv* env, jobject pool);
   jobject      (JNICALL *GetPeakMemoryPoolUsage) (JNIEnv* env, jobject pool);
 
+  jlong        (JNICALL *GetTotalThreadAllocatedMemory)
+                                                 (JNIEnv *env);
   jlong        (JNICALL *GetOneThreadAllocatedMemory)
                                                  (JNIEnv *env,
                                                   jlong thread_id);

src/hotspot/share/runtime/mutexLocker.hpp

@@ -74,7 +74,7 @@ extern Mutex*   G1RareEvent_lock;                // Synchronizes (rare) parallel
 extern Mutex*   G1DetachedRefinementStats_lock;  // Lock protecting detached refinement stats
 extern Mutex*   MarkStackFreeList_lock;          // Protects access to the global mark stack free list.
 extern Mutex*   MarkStackChunkList_lock;         // Protects access to the global mark stack chunk list.
-extern Mutex*   MonitoringSupport_lock;          // Protects updates to the serviceability memory pools.
+extern Mutex*   MonitoringSupport_lock;          // Protects updates to the serviceability memory pools and allocated memory high water mark.
 extern Monitor* ConcurrentGCBreakpoints_lock;    // Protects concurrent GC breakpoint management
 extern Mutex*   Compile_lock;                    // a lock held when Compilation is updating code (used to block CodeCache traversal, CHA updates, etc)
 extern Monitor* MethodCompileQueue_lock;         // a lock held when method compilations are enqueued, dequeued

src/hotspot/share/services/management.cpp

@@ -47,6 +47,7 @@
 #include "runtime/interfaceSupport.inline.hpp"
 #include "runtime/javaCalls.hpp"
 #include "runtime/jniHandles.inline.hpp"
+#include "runtime/mutexLocker.hpp"
 #include "runtime/notificationThread.hpp"
 #include "runtime/os.hpp"
 #include "runtime/thread.inline.hpp"
@@ -428,8 +429,6 @@ static MemoryPool* get_memory_pool_from_jobject(jobject obj, TRAPS) {
   return MemoryService::get_memory_pool(ph);
 }
 
-#endif // INCLUDE_MANAGEMENT
-
 static void validate_thread_id_array(typeArrayHandle ids_ah, TRAPS) {
   int num_threads = ids_ah->length();
 
@@ -455,8 +454,6 @@ static bool is_platform_thread(JavaThread* jt) {
   }
 }
 
-#if INCLUDE_MANAGEMENT
-
 static void validate_thread_info_array(objArrayHandle infoArray_h, TRAPS) {
   // check if the element of infoArray is of type ThreadInfo class
   Klass* threadinfo_klass = Management::java_lang_management_ThreadInfo_klass(CHECK);
@@ -2095,7 +2092,41 @@ jlong Management::ticks_to_ms(jlong ticks) {
   return (jlong)(((double)ticks / (double)os::elapsed_frequency())
                  * (double)1000.0);
 }
-#endif // INCLUDE_MANAGEMENT
+
+// Gets the amount of memory allocated on the Java heap since JVM launch.
+JVM_ENTRY(jlong, jmm_GetTotalThreadAllocatedMemory(JNIEnv *env))
+    // A thread increments exited_allocated_bytes in ThreadService::remove_thread
+    // only after it removes itself from the threads list, and once a TLH is
+    // created, no thread it references can remove itself from the threads
+    // list, so none can update exited_allocated_bytes. We therefore initialize
+    // result with exited_allocated_bytes after after we create the TLH so that
+    // the final result can only be short due to (1) threads that start after
+    // the TLH is created, or (2) terminating threads that escape TLH creation
+    // and don't update exited_allocated_bytes before we initialize result.
+
+    // We keep a high water mark to ensure monotonicity in case threads counted
+    // on a previous call end up in state (2).
+    static jlong high_water_result = 0;
+
+    JavaThreadIteratorWithHandle jtiwh;
+    jlong result = ThreadService::exited_allocated_bytes();
+    for (; JavaThread* thread = jtiwh.next();) {
+      jlong size = thread->cooked_allocated_bytes();
+      result += size;
+    }
+
+    {
+      MutexLocker ml(MonitoringSupport_lock, Mutex::_no_safepoint_check_flag);
+      if (result < high_water_result) {
+        // Encountered (2) above, or result wrapped to a negative value. In
+        // the latter case, it's pegged at the last positive value.
+        result = high_water_result;
+      } else {
+        high_water_result = result;
+      }
+    }
+    return result;
+JVM_END
 
 // Gets the amount of memory allocated on the Java heap for a single thread.
 // Returns -1 if the thread does not exist or has terminated.
@@ -2228,9 +2259,6 @@ JVM_ENTRY(void, jmm_GetThreadCpuTimesWithKind(JNIEnv *env, jlongArray ids,
   }
 JVM_END
 
-
-
-#if INCLUDE_MANAGEMENT
 const struct jmmInterface_1_ jmm_interface = {
   nullptr,
   nullptr,
@@ -2241,6 +2269,7 @@ const struct jmmInterface_1_ jmm_interface = {
   jmm_GetMemoryManagers,
   jmm_GetMemoryPoolUsage,
   jmm_GetPeakMemoryPoolUsage,
+  jmm_GetTotalThreadAllocatedMemory,
   jmm_GetOneThreadAllocatedMemory,
   jmm_GetThreadAllocatedMemory,
   jmm_GetMemoryUsage,

src/hotspot/share/services/threadService.cpp

@@ -45,6 +45,7 @@
 #include "runtime/init.hpp"
 #include "runtime/javaThread.inline.hpp"
 #include "runtime/objectMonitor.inline.hpp"
+#include "runtime/thread.inline.hpp"
 #include "runtime/threads.hpp"
 #include "runtime/threadSMR.inline.hpp"
 #include "runtime/vframe.hpp"
@@ -70,6 +71,8 @@ PerfVariable* ThreadService::_daemon_threads_count = nullptr;
 volatile int ThreadService::_atomic_threads_count = 0;
 volatile int ThreadService::_atomic_daemon_threads_count = 0;
 
+volatile jlong ThreadService::_exited_allocated_bytes = 0;
+
 ThreadDumpResult* ThreadService::_threaddump_list = nullptr;
 
 static const int INITIAL_ARRAY_SIZE = 10;
@@ -157,6 +160,9 @@ void ThreadService::decrement_thread_counts(JavaThread* jt, bool daemon) {
 void ThreadService::remove_thread(JavaThread* thread, bool daemon) {
   assert(Threads_lock->owned_by_self(), "must have threads lock");
 
+  // Include hidden thread allcations in exited_allocated_bytes
+  ThreadService::incr_exited_allocated_bytes(thread->cooked_allocated_bytes());
+
   // Do not count hidden threads
   if (is_hidden_thread(thread)) {
     return;

src/hotspot/share/services/threadService.hpp

@@ -61,6 +61,10 @@ class ThreadService : public AllStatic {
   static PerfVariable* _peak_threads_count;
   static PerfVariable* _daemon_threads_count;
 
+  // As could this...
+  // Number of heap bytes allocated by terminated threads.
+  static volatile jlong _exited_allocated_bytes;
+
   // These 2 counters are like the above thread counts, but are
   // atomically decremented in ThreadService::current_thread_exiting instead of
   // ThreadService::remove_thread, so that the thread count is updated before
@@ -102,6 +106,14 @@ class ThreadService : public AllStatic {
   static jlong get_live_thread_count()        { return _atomic_threads_count; }
   static jlong get_daemon_thread_count()      { return _atomic_daemon_threads_count; }
 
+  static jlong exited_allocated_bytes()       { return Atomic::load(&_exited_allocated_bytes); }
+  static void incr_exited_allocated_bytes(jlong size) {
+    // No need for an atomic add because called under the Threads_lock,
+    // but because _exited_allocated_bytes is read concurrently, need
+    // atomic store to avoid readers seeing a partial update.
+    Atomic::store(&_exited_allocated_bytes, _exited_allocated_bytes + size);
+  }
+
   // Support for thread dump
   static void   add_thread_dump(ThreadDumpResult* dump);
   static void   remove_thread_dump(ThreadDumpResult* dump);

src/java.management/share/classes/sun/management/ThreadImpl.java

@@ -342,6 +342,13 @@ public void setThreadCpuTimeEnabled(boolean enable) {
         }
     }
 
+    protected long getTotalThreadAllocatedBytes() {
+        if (isThreadAllocatedMemoryEnabled()) {
+            return getTotalThreadAllocatedMemory();
+        }
+        return -1;
+    }
+
     protected long getCurrentThreadAllocatedBytes() {
         if (isThreadAllocatedMemoryEnabled() && !Thread.currentThread().isVirtual()) {
             return getThreadAllocatedMemory0(0);
@@ -525,6 +532,7 @@ private static native void getThreadInfo1(long[] ids,
     private static native void getThreadUserCpuTime1(long[] ids, long[] result);
     private static native long getThreadAllocatedMemory0(long id);
     private static native void getThreadAllocatedMemory1(long[] ids, long[] result);
+    private static native long getTotalThreadAllocatedMemory();
     private static native void setThreadCpuTimeEnabled0(boolean enable);
     private static native void setThreadAllocatedMemoryEnabled0(boolean enable);
     private static native void setThreadContentionMonitoringEnabled0(boolean enable);

src/java.management/share/native/libmanagement/ThreadImpl.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2023, Oracle and/or its affiliates. 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
@@ -98,7 +98,7 @@ JNIEXPORT jlong JNICALL
 Java_sun_management_ThreadImpl_getThreadAllocatedMemory0
   (JNIEnv *env, jclass cls, jlong tid)
 {
-  return jmm_interface->GetOneThreadAllocatedMemory(env, tid);
+    return jmm_interface->GetOneThreadAllocatedMemory(env, tid);
 }
 
 JNIEXPORT void JNICALL
@@ -108,6 +108,13 @@ Java_sun_management_ThreadImpl_getThreadAllocatedMemory1
     jmm_interface->GetThreadAllocatedMemory(env, ids, sizeArray);
 }
 
+JNIEXPORT jlong JNICALL
+Java_sun_management_ThreadImpl_getTotalThreadAllocatedMemory
+  (JNIEnv *env, jclass cls)
+{
+    return jmm_interface->GetTotalThreadAllocatedMemory(env);
+}
+
 JNIEXPORT jobjectArray JNICALL
 Java_sun_management_ThreadImpl_findMonitorDeadlockedThreads0
   (JNIEnv *env, jclass cls)

src/jdk.management/share/classes/com/sun/management/ThreadMXBean.java

@@ -105,6 +105,42 @@ public interface ThreadMXBean extends java.lang.management.ThreadMXBean {
      */
     public long[] getThreadUserTime(long[] ids);
 
+    /**
+     * Returns an approximation of the total amount of memory, in bytes, allocated
+     * in heap memory by all threads since the Java virtual machine started.
+     * The returned value is an approximation because some Java virtual machine
+     * implementations may use object allocation mechanisms that result in a
+     * delay between the time an object is allocated and the time its size is
+     * recorded.
+     *
+     * @implSpec The default implementation throws {@code UnsupportedOperationException}
+     * if the Java virtual machine implementation does not support thread
+     * memory allocation measurement, and otherwise acts as though thread
+     * memory allocation measurement is disabled.
+     *
+     * @return an approximation of the total memory allocated, in bytes, in
+     * heap memory since the Java virtual machine was started,
+     * if thread memory allocation measurement is enabled;
+     * {@code -1} otherwise.
+     *
+     * @throws UnsupportedOperationException if the Java virtual
+     *         machine implementation does not support thread memory allocation
+     *         measurement.
+     *
+     * @see #isThreadAllocatedMemorySupported
+     * @see #isThreadAllocatedMemoryEnabled
+     * @see #setThreadAllocatedMemoryEnabled
+     *
+     * @since 21
+     */
+    public default long getTotalThreadAllocatedBytes() {
+        if (!isThreadAllocatedMemorySupported()) {
+            throw new UnsupportedOperationException(
+                "Thread allocated memory measurement is not supported.");
+        }
+        return -1;
+    }
+
     /**
      * Returns an approximation of the total amount of memory, in bytes,
      * allocated in heap memory for the current thread.

src/jdk.management/share/classes/com/sun/management/internal/HotSpotThreadImpl.java

@@ -57,6 +57,11 @@ public long[] getThreadUserTime(long[] ids) {
         return super.getThreadUserTime(ids);
     }
 
+    @Override
+    public long getTotalThreadAllocatedBytes() {
+        return super.getTotalThreadAllocatedBytes();
+    }
+
     @Override
     public long getCurrentThreadAllocatedBytes() {
         return super.getCurrentThreadAllocatedBytes();