diff --git a/arthas-vmtool/src/main/java/arthas/VmTool.java b/arthas-vmtool/src/main/java/arthas/VmTool.java index a54974ba..4e277564 100644 --- a/arthas-vmtool/src/main/java/arthas/VmTool.java +++ b/arthas-vmtool/src/main/java/arthas/VmTool.java @@ -46,12 +46,12 @@ public class VmTool implements VmToolMXBean { /** * 获取某个class在jvm中当前所有存活实例 */ - private static synchronized native T[] getInstances0(Class klass); + private static synchronized native T[] getInstances0(Class klass, int limit); /** * 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 */ - private static native long sumInstanceSize0(Class klass); + private static synchronized native long sumInstanceSize0(Class klass); /** * 获取某个实例的占用内存，单位：Byte @@ -77,7 +77,15 @@ public class VmTool implements VmToolMXBean { @Override public T[] getInstances(Class klass) { - return getInstances0(klass); + return getInstances0(klass, -1); + } + + @Override + public T[] getInstances(Class klass, int limit) { + if (limit == 0) { + throw new IllegalArgumentException("limit can not be 0"); + } + return getInstances0(klass, limit); } @Override diff --git a/arthas-vmtool/src/main/java/arthas/VmToolMXBean.java b/arthas-vmtool/src/main/java/arthas/VmToolMXBean.java index d1a18ab8..f2100011 100644 --- a/arthas-vmtool/src/main/java/arthas/VmToolMXBean.java +++ b/arthas-vmtool/src/main/java/arthas/VmToolMXBean.java @@ -20,10 +20,16 @@ public interface VmToolMXBean { */ public void forceGc(); + public T[] getInstances(Class klass); + /** * 获取某个class在jvm中当前所有存活实例 + * @param + * @param klass + * @param limit 如果小于 0 ，则不限制 + * @return */ - public T[] getInstances(Class klass); + public T[] getInstances(Class klass, int limit); /** * 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 diff --git a/arthas-vmtool/src/main/native/src/jni-library.cpp b/arthas-vmtool/src/main/native/src/jni-library.cpp index d1dd5d43..c0bbc33a 100644 --- a/arthas-vmtool/src/main/native/src/jni-library.cpp +++ b/arthas-vmtool/src/main/native/src/jni-library.cpp @@ -8,6 +8,30 @@ static jvmtiEnv *jvmti; static jlong tagCounter = 0; +struct LimitCounter { + jint currentCounter; + jint limitValue; + + void init(jint limit) { + currentCounter = 0; + limitValue = limit; + } + + void countDown() { + currentCounter++; + } + + bool allow() { + if (limitValue < 0) { + return true; + } + return limitValue > currentCounter; + } +}; + +// 每次 IterateOverInstancesOfClass 调用前需要先 init +static LimitCounter limitCounter = {0, 0}; + extern "C" int init_agent(JavaVM *vm, void *reserved) { jint rc; @@ -61,13 +85,20 @@ jvmtiIterationControl JNICALL HeapObjectCallback(jlong class_tag, jlong size, jlong *tag_ptr, void *user_data) { jlong *data = static_cast(user_data); *tag_ptr = *data; - return JVMTI_ITERATION_CONTINUE; + + limitCounter.countDown(); + if (limitCounter.allow()) { + return JVMTI_ITERATION_CONTINUE; + }else { + return JVMTI_ITERATION_ABORT; + } } extern "C" JNIEXPORT jobjectArray JNICALL -Java_arthas_VmTool_getInstances0(JNIEnv *env, jclass thisClass, jclass klass) { +Java_arthas_VmTool_getInstances0(JNIEnv *env, jclass thisClass, jclass klass, jint limit) { jlong tag = getTag(); + limitCounter.init(limit); jvmtiError error = jvmti->IterateOverInstancesOfClass(klass, JVMTI_HEAP_OBJECT_EITHER, HeapObjectCallback, &tag); if (error) { @@ -96,6 +127,7 @@ extern "C" JNIEXPORT jlong JNICALL Java_arthas_VmTool_sumInstanceSize0(JNIEnv *env, jclass thisClass, jclass klass) { jlong tag = getTag(); + limitCounter.init(-1); jvmtiError error = jvmti->IterateOverInstancesOfClass(klass, JVMTI_HEAP_OBJECT_EITHER, HeapObjectCallback, &tag); if (error) { @@ -136,6 +168,7 @@ extern "C" JNIEXPORT jlong JNICALL Java_arthas_VmTool_countInstances0(JNIEnv *env, jclass thisClass, jclass klass) { jlong tag = getTag(); + limitCounter.init(-1); jvmtiError error = jvmti->IterateOverInstancesOfClass(klass, JVMTI_HEAP_OBJECT_EITHER, HeapObjectCallback, &tag); if (error) { diff --git a/arthas-vmtool/src/test/java/arthas/VmToolTest.java b/arthas-vmtool/src/test/java/arthas/VmToolTest.java index 7cdc2f04..3cc02f69 100644 --- a/arthas-vmtool/src/test/java/arthas/VmToolTest.java +++ b/arthas-vmtool/src/test/java/arthas/VmToolTest.java @@ -2,6 +2,7 @@ package arthas; import java.io.File; import java.lang.ref.WeakReference; +import java.util.ArrayList; import java.util.concurrent.atomic.AtomicLong; import org.assertj.core.api.Assertions; @@ -9,6 +10,8 @@ import org.junit.Test; import com.taobao.arthas.common.VmToolUtils; +import arthas.VmToolTest.LimitTest; + /** * 以下本地测试的jvm参数均为：-Xms128m -Xmx128m */ @@ -146,6 +149,25 @@ public class VmToolTest { } } + class LimitTest { + } + + @Test + public void test_getInstances_lmiit() { + VmTool vmtool = initVmTool(); + + ArrayList list = new ArrayList(); + for (int i = 0; i < 10; ++i) { + list.add(new LimitTest()); + } + LimitTest[] instances = vmtool.getInstances(LimitTest.class, 5); + Assertions.assertThat(instances).hasSize(5); + LimitTest[] instances2 = vmtool.getInstances(LimitTest.class, -1); + Assertions.assertThat(instances2).hasSize(10); + LimitTest[] instances3 = vmtool.getInstances(LimitTest.class, 1); + Assertions.assertThat(instances3).hasSize(1); + } + interface III { } diff --git 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 index 05ab8cd1..e053b59f 100644 --- 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 @@ -47,6 +47,8 @@ import arthas.VmTool; @Description(Constants.EXAMPLE + " vmtool --action getInstances --className demo.MathGame\n" + " vmtool --action getInstances --className demo.MathGame --express 'instances.length'\n" + + " vmtool --action getInstances --className demo.MathGame --express 'instances[0]'\n" + + " vmtool --action getInstances --className java.lang.String --limit 10\n" + " vmtool --action forceGc\n" + Constants.WIKI + Constants.WIKI_HOME + "vmtool") //@formatter:on @@ -64,6 +66,11 @@ public class VmToolCommand extends AnnotatedCommand { */ private int expand; + /** + * default value 10 + */ + private int limit; + private static String libPath; private static VmTool vmTool = null; @@ -117,6 +124,13 @@ public class VmToolCommand extends AnnotatedCommand { this.classLoaderClass = classLoaderClass; } + @Option(shortName = "l", longName = "limit") + @Description("Set the limit value of the getInstances action, default value is 10, set to -1 is unlimited") + @DefaultValue("10") + public void setLimit(int limit) { + this.limit = limit; + } + @Option(longName = "express", required = false) @Description("The ognl expression, default valueis `instances`.") public void setExpress(String express) { @@ -165,7 +179,7 @@ public class VmToolCommand extends AnnotatedCommand { process.end(-1, "Found more than one class: " + matchedClasses + "."); return; } else { - Object[] instances = vmToolInstance().getInstances(matchedClasses.get(0)); + Object[] instances = vmToolInstance().getInstances(matchedClasses.get(0), limit); Object value = instances; if (express != null) { Express unpooledExpress = ExpressFactory.unpooledExpress(classLoader); diff --git a/lib/libArthasJniLibrary-x64.dylib b/lib/libArthasJniLibrary-x64.dylib index 5547993f..bf5f6ef1 100644 Binary files a/lib/libArthasJniLibrary-x64.dylib and b/lib/libArthasJniLibrary-x64.dylib differ diff --git a/spy/src/main/java/arthas/VmTool.java b/spy/src/main/java/arthas/VmTool.java index d530a06d..4e277564 100644 --- a/spy/src/main/java/arthas/VmTool.java +++ b/spy/src/main/java/arthas/VmTool.java @@ -41,17 +41,17 @@ public class VmTool implements VmToolMXBean { */ private static native String check0(); - private static native void forceGc0(); + private static synchronized native void forceGc0(); /** * 获取某个class在jvm中当前所有存活实例 */ - private static native T[] getInstances0(Class klass); + private static synchronized native T[] getInstances0(Class klass, int limit); /** * 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 */ - private static native long sumInstanceSize0(Class klass); + private static synchronized native long sumInstanceSize0(Class klass); /** * 获取某个实例的占用内存，单位：Byte @@ -61,24 +61,14 @@ public class VmTool implements VmToolMXBean { /** * 统计某个class在jvm中当前所有存活实例的总个数 */ - private static native long countInstances0(Class klass); + private static synchronized native long countInstances0(Class klass); /** * 获取所有已加载的类 + * @param klass 这个参数必须是 Class.class + * @return */ - private static native Class[] getAllLoadedClasses0(); - - /** - * 包括小类型(如int) - */ - public static Class[] getAllClasses() { - return getInstances0(Class.class); - } - - @Override - public String check() { - return check0(); - } + private static synchronized native Class[] getAllLoadedClasses0(Class klass); @Override public void forceGc() { @@ -87,7 +77,15 @@ public class VmTool implements VmToolMXBean { @Override public T[] getInstances(Class klass) { - return getInstances0(klass); + return getInstances0(klass, -1); + } + + @Override + public T[] getInstances(Class klass, int limit) { + if (limit == 0) { + throw new IllegalArgumentException("limit can not be 0"); + } + return getInstances0(klass, limit); } @Override @@ -107,7 +105,7 @@ public class VmTool implements VmToolMXBean { @Override public Class[] getAllLoadedClasses() { - return getAllLoadedClasses0(); + return getAllLoadedClasses0(Class.class); } } diff --git a/spy/src/main/java/arthas/VmToolMXBean.java b/spy/src/main/java/arthas/VmToolMXBean.java index 92df09be..f2100011 100644 --- a/spy/src/main/java/arthas/VmToolMXBean.java +++ b/spy/src/main/java/arthas/VmToolMXBean.java @@ -14,20 +14,22 @@ package arthas; * @author hengyunabc 2021-04-26 */ public interface VmToolMXBean { - /** - * 检测jni-lib是否正常，如果正常，应该输出OK - */ - public String check(); /** * https://docs.oracle.com/javase/8/docs/platform/jvmti/jvmti.html#ForceGarbageCollection */ public void forceGc(); + public T[] getInstances(Class klass); + /** * 获取某个class在jvm中当前所有存活实例 + * @param + * @param klass + * @param limit 如果小于 0 ，则不限制 + * @return */ - public T[] getInstances(Class klass); + public T[] getInstances(Class klass, int limit); /** * 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