| /** |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.hadoop.hbase.util; |
| |
| import java.lang.management.ManagementFactory; |
| import java.lang.management.RuntimeMXBean; |
| import java.lang.reflect.InvocationTargetException; |
| import java.lang.reflect.Method; |
| import java.nio.ByteBuffer; |
| import java.util.List; |
| import java.util.Locale; |
| |
| import javax.management.JMException; |
| import javax.management.MBeanServer; |
| import javax.management.MalformedObjectNameException; |
| import javax.management.ObjectName; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.hbase.classification.InterfaceAudience; |
| import org.apache.hadoop.hbase.classification.InterfaceStability; |
| |
| import com.google.common.base.Preconditions; |
| |
| /** |
| * Utilities for interacting with and monitoring DirectByteBuffer allocations. |
| */ |
| @InterfaceAudience.Private |
| @InterfaceStability.Evolving |
| public class DirectMemoryUtils { |
| private static final Log LOG = LogFactory.getLog(DirectMemoryUtils.class); |
| private static final String MEMORY_USED = "MemoryUsed"; |
| private static final MBeanServer BEAN_SERVER; |
| private static final ObjectName NIO_DIRECT_POOL; |
| private static final boolean HAS_MEMORY_USED_ATTRIBUTE; |
| |
| static { |
| // initialize singletons. Only maintain a reference to the MBeanServer if |
| // we're able to consume it -- hence convoluted logic. |
| ObjectName n = null; |
| MBeanServer s = null; |
| Object a = null; |
| try { |
| n = new ObjectName("java.nio:type=BufferPool,name=direct"); |
| } catch (MalformedObjectNameException e) { |
| LOG.warn("Unable to initialize ObjectName for DirectByteBuffer allocations."); |
| } finally { |
| NIO_DIRECT_POOL = n; |
| } |
| if (NIO_DIRECT_POOL != null) { |
| s = ManagementFactory.getPlatformMBeanServer(); |
| } |
| BEAN_SERVER = s; |
| if (BEAN_SERVER != null) { |
| try { |
| a = BEAN_SERVER.getAttribute(NIO_DIRECT_POOL, MEMORY_USED); |
| } catch (JMException e) { |
| LOG.debug("Failed to retrieve nio.BufferPool direct MemoryUsed attribute: " + e); |
| } |
| } |
| HAS_MEMORY_USED_ATTRIBUTE = a != null; |
| } |
| |
| /** |
| * @return the setting of -XX:MaxDirectMemorySize as a long. Returns 0 if |
| * -XX:MaxDirectMemorySize is not set. |
| */ |
| public static long getDirectMemorySize() { |
| RuntimeMXBean runtimemxBean = ManagementFactory.getRuntimeMXBean(); |
| List<String> arguments = runtimemxBean.getInputArguments(); |
| long multiplier = 1; //for the byte case. |
| for (String s : arguments) { |
| if (s.contains("-XX:MaxDirectMemorySize=")) { |
| String memSize = s.toLowerCase(Locale.ROOT) |
| .replace("-xx:maxdirectmemorysize=", "").trim(); |
| |
| if (memSize.contains("k")) { |
| multiplier = 1024; |
| } |
| |
| else if (memSize.contains("m")) { |
| multiplier = 1048576; |
| } |
| |
| else if (memSize.contains("g")) { |
| multiplier = 1073741824; |
| } |
| memSize = memSize.replaceAll("[^\\d]", ""); |
| |
| long retValue = Long.parseLong(memSize); |
| return retValue * multiplier; |
| } |
| } |
| return 0; |
| } |
| |
| /** |
| * @return the current amount of direct memory used. |
| */ |
| public static long getDirectMemoryUsage() { |
| if (BEAN_SERVER == null || NIO_DIRECT_POOL == null || !HAS_MEMORY_USED_ATTRIBUTE) return 0; |
| try { |
| Long value = (Long) BEAN_SERVER.getAttribute(NIO_DIRECT_POOL, MEMORY_USED); |
| return value == null ? 0 : value; |
| } catch (JMException e) { |
| // should print further diagnostic information? |
| return 0; |
| } |
| } |
| |
| /** |
| * DirectByteBuffers are garbage collected by using a phantom reference and a |
| * reference queue. Every once a while, the JVM checks the reference queue and |
| * cleans the DirectByteBuffers. However, as this doesn't happen |
| * immediately after discarding all references to a DirectByteBuffer, it's |
| * easy to OutOfMemoryError yourself using DirectByteBuffers. This function |
| * explicitly calls the Cleaner method of a DirectByteBuffer. |
| * |
| * @param toBeDestroyed |
| * The DirectByteBuffer that will be "cleaned". Utilizes reflection. |
| * |
| */ |
| public static void destroyDirectByteBuffer(ByteBuffer toBeDestroyed) |
| throws IllegalArgumentException, IllegalAccessException, |
| InvocationTargetException, SecurityException, NoSuchMethodException { |
| |
| Preconditions.checkArgument(toBeDestroyed.isDirect(), |
| "toBeDestroyed isn't direct!"); |
| |
| Method cleanerMethod = toBeDestroyed.getClass().getMethod("cleaner"); |
| cleanerMethod.setAccessible(true); |
| Object cleaner = cleanerMethod.invoke(toBeDestroyed); |
| Method cleanMethod = cleaner.getClass().getMethod("clean"); |
| cleanMethod.setAccessible(true); |
| cleanMethod.invoke(cleaner); |
| } |
| } |