我们遇到了一个奇怪的问题ConcurrentHashMap
,其中两个线程似乎呼吁put()
,然后在方法Unsafe.park()
内永远等待。从外部看,它看起来像ConcurrentHashMap
内部的一个死锁。ConcurrentHashMap可能“死锁”吗?
到目前为止,我们只看到过这种情况。
任何人都可以想到任何可能导致这些症状的东西吗?
编辑:对于相关的线程的线程转储是在这里:
"[redacted] Thread 2" prio=10 tid=0x000000005bbbc800 nid=0x921 waiting on condition [0x0000000040e93000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00002aaaf1207b40> (a java.util.concurrent.locks.ReentrantLock$NonfairSync) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:158) at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:747) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:778) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1114) at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:186) at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:262) at java.util.concurrent.ConcurrentHashMap$Segment.put(ConcurrentHashMap.java:417) at java.util.concurrent.ConcurrentHashMap.put(ConcurrentHashMap.java:883) at [redacted] "[redacted] Thread 0" prio=10 tid=0x000000005bf38000 nid=0x91f waiting on condition [0x000000004151d000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00002aaaf1207b40> (a java.util.concurrent.locks.ReentrantLock$NonfairSync) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:158) at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:747) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:778) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1114) at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:186) at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:262) at java.util.concurrent.ConcurrentHashMap$Segment.put(ConcurrentHashMap.java:417) at java.util.concurrent.ConcurrentHashMap.put(ConcurrentHashMap.java:883) at [redacted]
你有线程转储吗? – 2010-07-20 17:26:55
@John W .:好点。我会尽快将其从服务器上下载。 – 2010-07-20 18:52:42
线程转储的任何其他部分是否显示哪个线程实际拥有该锁?这些线程正在等待获取。找出他们在等待什么可以提供帮助。 – 2010-07-22 15:22:47