android如何实现OOM治理

一，原理

static void VMDebug_attachAgent(JNIEnv* env, jclass, jstring agent) {
  if (agent == nullptr) {
    ScopedObjectAccess soa(env);
    ThrowNullPointerException("agent is null");
    return;
  }

  if (!Dbg::IsJdwpAllowed()) {
    ScopedObjectAccess soa(env);
    ThrowSecurityException("Can't attach agent, process is not debuggable.");
    return;
  }

  std::string filename;
  {
    ScopedUtfChars chars(env, agent);
    if (env->ExceptionCheck()) {
      return;
    }
    filename = chars.c_str();
  }

  Runtime::Current()->AttachAgent(filename);
}

二，开启JVMTI监控呢能力

 SetEventNotification(jvmti_env, JVMTI_ENABLE,JVMTI_EVENT_GARBAGE_COLLECTION_START);//监听GC 开始
    SetEventNotification(jvmti_env, JVMTI_ENABLE,JVMTI_EVENT_GARBAGE_COLLECTION_FINISH);//监听GC 结束
    SetEventNotification(jvmti_env, JVMTI_ENABLE,JVMTI_EVENT_NATIVE_METHOD_BIND);//监听native method bind
    SetEventNotification(jvmti_env, JVMTI_ENABLE,JVMTI_EVENT_VM_OBJECT_ALLOC);//监听对象分配
    SetEventNotification(jvmti_env, JVMTI_ENABLE,JVMTI_EVENT_OBJECT_FREE);//监听对象释放
    SetEventNotification(jvmti_env, JVMTI_ENABLE,JVMTI_EVENT_CLASS_FILE_LOAD_HOOK);//监听类文件加载
    SetEventNotification(jvmti_env,JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY);//方法进入
    SetEventNotification(jvmti_env,JVMTI_ENABLE, JVMTI_EVENT_METHOD_EXIT);//方法退出

    SetEventNotification(jvmti_env,JVMTI_ENABLE, JVMTI_EVENT_THREAD_START);//线程开始
    SetEventNotification(jvmti_env,JVMTI_ENABLE, JVMTI_EVENT_THREAD_END);//线程结束

模拟oom

 val bytes = ByteArray(1024 * 1024 * 1024)

2025-02-05 12:04:05.902: methodEntry {Ljava/lang/OutOfMemoryError; <init>} 
2025-02-05 12:04:05.917: methodEntry {Ljava/lang/OutOfMemoryError; <init>} 

 可以看到通过JVMTI技术可以快速的定位到OOM位置