return array in VmTool native method, fix jni memory leak problem #1781

2024-11-30 03:07:37 +08:00 · 2021-04-30 16:31:44 +08:00 · 2021-04-30 16:31:44 +08:00 · 6623ef44c6
commit 6623ef44c6
parent 932340eac6
9 changed files with 159 additions and 71 deletions
--- a/arthas-vmtool/src/main/java/arthas/VmTool.java
+++ b/arthas-vmtool/src/main/java/arthas/VmTool.java
@ -1,7 +1,5 @@
 package arthas;

-import java.util.ArrayList;
-
 /**
 * @author ZhangZiCheng 2021-02-12
 * @author hengyunabc 2021-04-26
@ -46,7 +44,7 @@ public class VmTool implements VmToolMXBean {
    /**
     * 获取某个class在jvm中当前所有存活实例
     */
-    private static native <T> ArrayList<T> getInstances0(Class<T> klass);
+    private static native <T> T[] getInstances0(Class<T> klass);

    /**
     * 统计某个class在jvm中当前所有存活实例的总占用内存，单位：Byte
@ -66,13 +64,12 @@ public class VmTool implements VmToolMXBean {
    /**
     * 获取所有已加载的类
     */
-    private static native ArrayList<Class<?>> getAllLoadedClasses0();
+    private static native Class<?>[] getAllLoadedClasses0();

    /**
     * 包括小类型(如int)
     */
-    @SuppressWarnings("all")
-    public static ArrayList<Class> getAllClasses() {
+    public static Class<?>[] getAllClasses() {
        return getInstances0(Class.class);
    }

@ -82,7 +79,7 @@ public class VmTool implements VmToolMXBean {
    }

    @Override
-    public <T> ArrayList<T> getInstances(Class<T> klass) {
+    public <T> T[] getInstances(Class<T> klass) {
        return getInstances0(klass);
    }

@ -102,7 +99,7 @@ public class VmTool implements VmToolMXBean {
    }

    @Override
-    public ArrayList<Class<?>> getAllLoadedClasses() {
+    public Class<?>[] getAllLoadedClasses() {
        return getAllLoadedClasses0();
    }

--- a/arthas-vmtool/src/main/java/arthas/VmToolMXBean.java
+++ b/arthas-vmtool/src/main/java/arthas/VmToolMXBean.java
@ -1,7 +1,5 @@
 package arthas;

-import java.util.ArrayList;
-
 /**
 * VmTool interface for JMX server. How to register VmTool MBean:
 *
@ -24,7 +22,7 @@ public interface VmToolMXBean {
    /**
     * 获取某个class在jvm中当前所有存活实例
     */
-    public <T> ArrayList<T> getInstances(Class<T> klass);
+    public <T> T[] getInstances(Class<T> klass);

    /**
     * 统计某个class在jvm中当前所有存活实例的总占用内存，单位：Byte
@ -44,5 +42,5 @@ public interface VmToolMXBean {
    /**
     * 获取所有已加载的类
     */
-    public ArrayList<Class<?>> getAllLoadedClasses();
+    public Class<?>[] getAllLoadedClasses();
 }
--- a/arthas-vmtool/src/main/native/include/arthas_VmTool.h
+++ b/arthas-vmtool/src/main/native/include/arthas_VmTool.h
@ -9,7 +9,7 @@ extern "C" {
 #endif
 /*
 * Class:     arthas_VmTool
- * Method:    check
+ * Method:    check0
 * Signature: ()Ljava/lang/String;
 */
 JNIEXPORT jstring JNICALL Java_arthas_VmTool_check0
@ -17,42 +17,42 @@ JNIEXPORT jstring JNICALL Java_arthas_VmTool_check0

 /*
 * Class:     arthas_VmTool
- * Method:    getInstances
- * Signature: (Ljava/lang/Class;)Ljava/util/ArrayList;
+ * Method:    getInstances0
+ * Signature: (Ljava/lang/Class;)[Ljava/lang/Object;
 */
-JNIEXPORT jobject JNICALL Java_arthas_VmTool_getInstances
+JNIEXPORT jobjectArray JNICALL Java_arthas_VmTool_getInstances0
  (JNIEnv *, jclass, jclass);

 /*
 * Class:     arthas_VmTool
- * Method:    sumInstanceSize
+ * Method:    sumInstanceSize0
 * Signature: (Ljava/lang/Class;)J
 */
-JNIEXPORT jlong JNICALL Java_arthas_VmTool_sumInstanceSize
+JNIEXPORT jlong JNICALL Java_arthas_VmTool_sumInstanceSize0
  (JNIEnv *, jclass, jclass);

 /*
 * Class:     arthas_VmTool
- * Method:    getInstanceSize
+ * Method:    getInstanceSize0
 * Signature: (Ljava/lang/Object;)J
 */
-JNIEXPORT jlong JNICALL Java_arthas_VmTool_getInstanceSize
+JNIEXPORT jlong JNICALL Java_arthas_VmTool_getInstanceSize0
  (JNIEnv *, jclass, jobject);

 /*
 * Class:     arthas_VmTool
- * Method:    countInstances
+ * Method:    countInstances0
 * Signature: (Ljava/lang/Class;)J
 */
-JNIEXPORT jlong JNICALL Java_arthas_VmTool_countInstances
+JNIEXPORT jlong JNICALL Java_arthas_VmTool_countInstances0
  (JNIEnv *, jclass, jclass);

 /*
 * Class:     arthas_VmTool
- * Method:    getAllLoadedClasses
- * Signature: ()Ljava/util/ArrayList;
+ * Method:    getAllLoadedClasses0
+ * Signature: ()[Ljava/lang/Class;
 */
-JNIEXPORT jobject JNICALL Java_arthas_VmTool_getAllLoadedClasses
+JNIEXPORT jobjectArray JNICALL Java_arthas_VmTool_getAllLoadedClasses0
  (JNIEnv *, jclass);

 #ifdef __cplusplus
--- a/arthas-vmtool/src/main/native/src/jni-library.cpp
+++ b/arthas-vmtool/src/main/native/src/jni-library.cpp
@ -4,6 +4,21 @@
 #include <jvmti.h>
 #include "arthas_VmTool.h"

+//缓存
+static jclass cachedClass = NULL;
+
+extern "C"
+JNIEXPORT jclass JNICALL getClass(JNIEnv *env) {
+    if (cachedClass == NULL) {
+        //通过其签名找到Class的Class
+        jclass theClass = env->FindClass("java/lang/Class");
+        //放入缓存
+        cachedClass = static_cast<jclass>(env->NewGlobalRef(theClass));
+        env->DeleteLocalRef(theClass);
+    }
+    return cachedClass;
+}
+
 extern "C"
 JNIEXPORT jstring JNICALL
 Java_arthas_VmTool_check0(JNIEnv *env, jclass thisClass) {
@ -46,7 +61,7 @@ HeapObjectCallback(jlong class_tag, jlong size, jlong *tag_ptr, void *user_data)
 }

 extern "C"
-JNIEXPORT jobject JNICALL
+JNIEXPORT jobjectArray JNICALL
 Java_arthas_VmTool_getInstances0(JNIEnv *env, jclass thisClass, jclass klass) {

    jvmtiEnv *jvmti = getJvmtiEnv(env);
@ -75,15 +90,13 @@ Java_arthas_VmTool_getInstances0(JNIEnv *env, jclass thisClass, jclass klass) {
        return JNI_FALSE;
    }

-    //通过其签名找到ArrayList的Class
-    jclass arrayListClass = env->FindClass("java/util/ArrayList");
-    jobject arrayList = createJavaInstance(env, arrayListClass);
-    jmethodID addMethod = env->GetMethodID(arrayListClass, "add", "(Ljava/lang/Object;)Z");
-    //添加元素到ArrayList实例
+    jobjectArray array = env->NewObjectArray(count, klass, NULL);
+    //添加元素到数组
    for (int i = 0; i < count; i++) {
-        env->CallObjectMethod(arrayList, addMethod, instances[i]);
+        env->SetObjectArrayElement(array, i, instances[i]);
    }
-    return arrayList;
+    jvmti->Deallocate(reinterpret_cast<unsigned char *>(instances));
+    return array;
 }

 extern "C"
@ -122,6 +135,7 @@ Java_arthas_VmTool_sumInstanceSize0(JNIEnv *env, jclass thisClass, jclass klass)
        jvmti->GetObjectSize(instances[i], &size);
        sum = sum + size;
    }
+    jvmti->Deallocate(reinterpret_cast<unsigned char *>(instances));
    return sum;
 }

@ -172,7 +186,7 @@ Java_arthas_VmTool_countInstances0(JNIEnv *env, jclass thisClass, jclass klass)
 }

 extern "C"
-JNIEXPORT jobject JNICALL Java_arthas_VmTool_getAllLoadedClasses0
+JNIEXPORT jobjectArray JNICALL Java_arthas_VmTool_getAllLoadedClasses0
        (JNIEnv *env, jclass thisClass) {

    jvmtiEnv *jvmti = getJvmtiEnv(env);
@ -186,13 +200,11 @@ JNIEXPORT jobject JNICALL Java_arthas_VmTool_getAllLoadedClasses0
        return JNI_FALSE;
    }

-    //通过其签名找到ArrayList的Class
-    jclass arrayListClass = env->FindClass("java/util/ArrayList");
-    jobject arrayList = createJavaInstance(env, arrayListClass);
-    jmethodID addMethod = env->GetMethodID(arrayListClass, "add", "(Ljava/lang/Object;)Z");
-    //添加元素到ArrayList实例
+    jobjectArray array = env->NewObjectArray(count, getClass(env), NULL);
+    //添加元素到数组
    for (int i = 0; i < count; i++) {
-        env->CallObjectMethod(arrayList, addMethod, classes[i]);
+        env->SetObjectArrayElement(array, i, classes[i]);
    }
-    return arrayList;
+    jvmti->Deallocate(reinterpret_cast<unsigned char *>(classes));
+    return array;
 }
--- a/arthas-vmtool/src/test/java/arthas/VmToolTest.java
+++ b/arthas-vmtool/src/test/java/arthas/VmToolTest.java
@ -6,8 +6,11 @@ import com.taobao.arthas.common.VmToolUtils;

 import java.io.File;
 import java.lang.ref.WeakReference;
-import java.util.ArrayList;
+import java.util.concurrent.atomic.AtomicLong;

+/**
+ * 以下本地测试的jvm参数均为：-Xms128m -Xmx128m
+ */
 public class VmToolTest {

    /**
@ -22,23 +25,18 @@ public class VmToolTest {
     * after instances->[]
     */
    @Test
-    public void test01() {
+    public void testIsSnapshot() {
        try {
-            String path = VmTool.class.getProtectionDomain().getCodeSource().getLocation().getPath();
-            System.err.println(path);
-
-            String libPath = new File(path, VmToolUtils.detectLibName()).getAbsolutePath();
-            VmTool vmtool = VmTool.getInstance(libPath);
-
+            VmTool vmtool = initVmTool();
            //调用native方法，获取已加载的类，不包括小类型(如int)
-            ArrayList<Class<?>> allLoadedClasses = vmtool.getAllLoadedClasses();
-            System.out.println("allLoadedClasses->" + allLoadedClasses.size());
+            Class<?>[] allLoadedClasses = vmtool.getAllLoadedClasses();
+            System.out.println("allLoadedClasses->" + allLoadedClasses.length);

            //通过下面的例子，可以看到getInstances(Class<T> klass)拿到的是当前存活的所有对象
            WeakReference<VmToolTest> weakReference1 = new WeakReference<VmToolTest>(new VmToolTest());
            WeakReference<VmToolTest> weakReference2 = new WeakReference<VmToolTest>(new VmToolTest());
            System.out.println(weakReference1.get() + " " + weakReference2.get());
-            ArrayList<VmTool> beforeInstances = vmtool.getInstances(VmTool.class);
+            VmTool[] beforeInstances = vmtool.getInstances(VmTool.class);
            System.out.println("before instances->" + beforeInstances);
            System.out.println("size->" + vmtool.getInstanceSize(weakReference1.get()));
            System.out.println("count->" + vmtool.countInstances(VmTool.class));
@ -48,10 +46,102 @@ public class VmToolTest {
            System.gc();
            Thread.sleep(100);
            System.out.println(weakReference1.get() + " " + weakReference2.get());
-            ArrayList<VmTool> afterInstances = vmtool.getInstances(VmTool.class);
+            VmTool[] afterInstances = vmtool.getInstances(VmTool.class);
            System.out.println("after instances->" + afterInstances);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
+
+    private VmTool initVmTool() {
+        String path = VmTool.class.getProtectionDomain().getCodeSource().getLocation().getPath();
+        System.err.println(path);
+
+        String libPath = new File(path, VmToolUtils.detectLibName()).getAbsolutePath();
+        return VmTool.getInstance(libPath);
+    }
+
+    @Test
+    public void testGetInstancesMemoryLeak() {
+        //这里睡20s是为了方便用jprofiler连接上进程
+//        try {
+//            Thread.sleep(20000);
+//        } catch (InterruptedException e) {
+//            e.printStackTrace();
+//        }
+        VmTool vmtool = initVmTool();
+        final AtomicLong totalTime = new AtomicLong();
+        //本地测试请改成200000
+        for (int i = 1; i <= 2; i++) {
+            long start = System.currentTimeMillis();
+            WeakReference<Object[]> reference = new WeakReference<Object[]>(vmtool.getInstances(Object.class));
+            Object[] instances = reference.get();
+            long cost = System.currentTimeMillis() - start;
+            totalTime.addAndGet(cost);
+            System.out.println(i + " instance size:" + (instances == null ? 0 : instances.length) + ", cost " + cost + "ms avgCost " + totalTime.doubleValue() / i + "ms");
+            instances = null;
+            System.gc();
+        }
+    }
+
+    @Test
+    public void testSumInstancesMemoryLeak() {
+        //这里睡20s是为了方便用jprofiler连接上进程
+//        try {
+//            Thread.sleep(20000);
+//        } catch (InterruptedException e) {
+//            e.printStackTrace();
+//        }
+        VmTool vmtool = initVmTool();
+        final AtomicLong totalTime = new AtomicLong();
+        //本地测试请改成200000
+        for (int i = 1; i <= 2; i++) {
+            long start = System.currentTimeMillis();
+            long sum = vmtool.sumInstanceSize(Object.class);
+            long cost = System.currentTimeMillis() - start;
+            totalTime.addAndGet(cost);
+            System.out.println(i + " sum:" + sum + ", cost " + cost + "ms avgCost " + totalTime.doubleValue() / i + "ms");
+        }
+    }
+
+    @Test
+    public void testCountInstancesMemoryLeak() {
+        //这里睡20s是为了方便用jprofiler连接上进程
+//        try {
+//            Thread.sleep(20000);
+//        } catch (InterruptedException e) {
+//            e.printStackTrace();
+//        }
+        VmTool vmtool = initVmTool();
+        final AtomicLong totalTime = new AtomicLong();
+        //本地测试请改成200000
+        for (int i = 1; i <= 2; i++) {
+            long start = System.currentTimeMillis();
+            long count = vmtool.countInstances(Object.class);
+            long cost = System.currentTimeMillis() - start;
+            totalTime.addAndGet(cost);
+            System.out.println(i + " count:" + count + ", cost " + cost + "ms avgCost " + totalTime.doubleValue() / i + "ms");
+        }
+    }
+
+    @Test
+    public void testGetAllLoadedClassesMemoryLeak() {
+        //这里睡20s是为了方便用jprofiler连接上进程
+//        try {
+//            Thread.sleep(20000);
+//        } catch (InterruptedException e) {
+//            e.printStackTrace();
+//        }
+        VmTool vmtool = initVmTool();
+        final AtomicLong totalTime = new AtomicLong();
+        //本地测试请改成200000
+        for (int i = 1; i <= 2; i++) {
+            long start = System.currentTimeMillis();
+            Class<?>[] allLoadedClasses = vmtool.getAllLoadedClasses();
+            long cost = System.currentTimeMillis() - start;
+            totalTime.addAndGet(cost);
+            System.out.println(i + " class size:" + allLoadedClasses.length + ", cost " + cost + "ms avgCost " + totalTime.doubleValue() / i + "ms");
+            allLoadedClasses = null;
+        }
+    }
 }
--- a/core/src/main/java/com/taobao/arthas/core/command/monitor200/VmToolCommand.java
+++ b/core/src/main/java/com/taobao/arthas/core/command/monitor200/VmToolCommand.java
@ -38,6 +38,7 @@ import arthas.VmTool;
 /**
 * 
 * @author hengyunabc 2021-04-27
+ * @author ZhangZiCheng 2021-04-29
 *
 */
 //@formatter:off
@ -163,7 +164,7 @@ public class VmToolCommand extends AnnotatedCommand {
                    process.end(-1, "Found more than one class: " + matchedClasses + ".");
                    return;
                } else {
-                    ArrayList<?> instances = vmToolInstance().getInstances(matchedClasses.get(0));
+                    Object[] instances = vmToolInstance().getInstances(matchedClasses.get(0));
                    Object value = instances;
                    if (express != null) {
                        Express unpooledExpress = ExpressFactory.unpooledExpress(classLoader);
--- a/pom.xml
+++ b/pom.xml
@ -217,11 +217,6 @@
                <artifactId>zt-zip</artifactId>
                <version>1.14</version>
            </dependency>
-            <dependency>
-                <groupId>org.scijava</groupId>
-                <artifactId>native-lib-loader</artifactId>
-                <version>2.0.2</version>
-            </dependency>
        </dependencies>
    </dependencyManagement>

--- a/spy/src/main/java/arthas/VmTool.java
+++ b/spy/src/main/java/arthas/VmTool.java
@ -1,7 +1,5 @@
 package arthas;

-import java.util.ArrayList;
-
 /**
 * @author ZhangZiCheng 2021-02-12
 * @author hengyunabc 2021-04-26
@ -46,7 +44,7 @@ public class VmTool implements VmToolMXBean {
    /**
     * 获取某个class在jvm中当前所有存活实例
     */
-    private static native <T> ArrayList<T> getInstances0(Class<T> klass);
+    private static native <T> T[] getInstances0(Class<T> klass);

    /**
     * 统计某个class在jvm中当前所有存活实例的总占用内存，单位：Byte
@ -66,13 +64,12 @@ public class VmTool implements VmToolMXBean {
    /**
     * 获取所有已加载的类
     */
-    private static native ArrayList<Class<?>> getAllLoadedClasses0();
+    private static native Class<?>[] getAllLoadedClasses0();

    /**
     * 包括小类型(如int)
     */
-    @SuppressWarnings("all")
-    public static ArrayList<Class> getAllClasses() {
+    public static Class<?>[] getAllClasses() {
        return getInstances0(Class.class);
    }

@ -82,7 +79,7 @@ public class VmTool implements VmToolMXBean {
    }

    @Override
-    public <T> ArrayList<T> getInstances(Class<T> klass) {
+    public <T> T[] getInstances(Class<T> klass) {
        return getInstances0(klass);
    }

@ -102,7 +99,7 @@ public class VmTool implements VmToolMXBean {
    }

    @Override
-    public ArrayList<Class<?>> getAllLoadedClasses() {
+    public Class<?>[] getAllLoadedClasses() {
        return getAllLoadedClasses0();
    }

--- a/spy/src/main/java/arthas/VmToolMXBean.java
+++ b/spy/src/main/java/arthas/VmToolMXBean.java
@ -1,7 +1,5 @@
 package arthas;

-import java.util.ArrayList;
-
 /**
 * VmTool interface for JMX server. How to register VmTool MBean:
 *
@ -24,7 +22,7 @@ public interface VmToolMXBean {
    /**
     * 获取某个class在jvm中当前所有存活实例
     */
-    public <T> ArrayList<T> getInstances(Class<T> klass);
+    public <T> T[] getInstances(Class<T> klass);

    /**
     * 统计某个class在jvm中当前所有存活实例的总占用内存，单位：Byte
@ -44,5 +42,5 @@ public interface VmToolMXBean {
    /**
     * 获取所有已加载的类
     */
-    public ArrayList<Class<?>> getAllLoadedClasses();
+    public Class<?>[] getAllLoadedClasses();
 }