hadoop可重入写锁

我的ResourceManager进程崩溃，我发现78个线程正在“等待”，并且没有线程持有对象0x00000005a3abb250

什么事

"658922022@qtp-1157567439-10404" daemon prio=10 tid=0x00007fde30737000 nid=0x305a waiting on condition [0x00007fde3763d000]
   java.lang.Thread.State: WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x00000005a3abb250> (a java.util.concurrent.locks.ReentrantReadWriteLock$NonfairSync)
    at java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:834)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireShared(AbstractQueuedSynchronizer.java:964)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireShared(AbstractQueuedSynchronizer.java:1282)
    at java.util.concurrent.locks.ReentrantReadWriteLock$ReadLock.lock(ReentrantReadWriteLock.java:731)
    at org.apache.hadoop.yarn.server.resourcemanager.rmapp.attempt.RMAppAttemptImpl.getTrackingUrl(RMAppAttemptImpl.java:480)
    at org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMAppImpl.getTrackingUrl(RMAppImpl.java:602)
    at org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.AppInfo.<init>(AppInfo.java:89)
    at org.apache.hadoop.yarn.server.resourcemanager.webapp.AppsBlock.render(AppsBlock.java:86)
    at org.apache.hadoop.yarn.webapp.view.HtmlBlock.render(HtmlBlock.java:66)
    at org.apache.hadoop.yarn.webapp.view.HtmlBlock.renderPartial(HtmlBlock.java:76)
    at org.apache.hadoop.yarn.webapp.View.render(View.java:235)
    at org.apache.hadoop.yarn.webapp.view.HtmlBlock$Block.subView(HtmlBlock.java:40)
    at org.apache.hadoop.yarn.webapp.hamlet.Hamlet._(Hamlet.java:30347)
    at org.apache.hadoop.yarn.server.resourcemanager.webapp.AppsBlockWithMetrics.render(AppsBlockWithMetrics.java:29)
    at org.apache.hadoop.yarn.webapp.view.HtmlBlock.render(HtmlBlock.java:66)
    at org.apache.hadoop.yarn.webapp.view.HtmlBlock.renderPartial(HtmlBlock.java:76)
    at org.apache.hadoop.yarn.webapp.View.render(View.java:235)
    at org.apache.hadoop.yarn.webapp.view.HtmlPage$Page.subView(HtmlPage.java:49)
    at org.apache.hadoop.yarn.webapp.hamlet.HamletImpl$EImp._v(HamletImpl.java:117)
    at org.apache.hadoop.yarn.webapp.hamlet.Hamlet$TD._(Hamlet.java:845)
    at org.apache.hadoop.yarn.webapp.view.TwoColumnLayout.render(TwoColumnLayout.java:56)
    at org.apache.hadoop.yarn.webapp.view.HtmlPage.render(HtmlPage.java:82)
    at org.apache.hadoop.yarn.webapp.Dispatcher.render(Dispatcher.java:197)
    at org.apache.hadoop.yarn.webapp.Dispatcher.service(Dispatcher.java:156)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
    at com.google.inject.servlet.ServletDefinition.doService(ServletDefinition.java:263)
    at com.google.inject.servlet.ServletDefinition.service(ServletDefinition.java:178)
    at com.google.inject.servlet.ManagedServletPipeline.service(ManagedServletPipeline.java:91)
    at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:62)
    at com.sun.jersey.spi.container.servlet.ServletContainer.doFilter(ServletContainer.java:900)
    at com.sun.jersey.spi.container.servlet.ServletContainer.doFilter(ServletContainer.java:834)
    at org.apache.hadoop.yarn.server.resourcemanager.webapp.RMWebAppFilter.doFilter(RMWebAppFilter.java:84)
    at com.sun.jersey.spi.container.servlet.ServletContainer.doFilter(ServletContainer.java:795)
    at com.google.inject.servlet.FilterDefinition.doFilter(FilterDefinition.java:163)
    at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:58)
    at com.google.inject.servlet.ManagedFilterPipeline.dispatch(ManagedFilterPipeline.java:118)
    at com.google.inject.servlet.GuiceFilter.doFilter(GuiceFilter.java:113)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
    at org.apache.hadoop.http.lib.StaticUserWebFilter$StaticUserFilter.doFilter(StaticUserWebFilter.java:109)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
    at org.apache.hadoop.http.HttpServer2$QuotingInputFilter.doFilter(HttpServer2.java:1183)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
    at org.apache.hadoop.http.NoCacheFilter.doFilter(NoCacheFilter.java:45)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
    at org.apache.hadoop.http.NoCacheFilter.doFilter(NoCacheFilter.java:45)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:399)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:766)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:450)
    at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:230)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:928)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:549)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)

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我发现许多线程想要锁定RMAppAttemptImpl对象的readlock，但失败了。但是为什么呢@重写公共字符串getTrackingUrl{this.readLock.lock；尝试{返回getSubmissionContext.getUnmanagedAM？this.originalTrackingUrl:this.proxiedTrackingUrl；}最后{this.readLock.unlock；}RM似乎希望在org.mortbay.thread.QueuedThreadPool$PoolThread中运行新线程，但池中没有空闲线程。这个线程池是干什么用的？