JVM throws OutOfMemory during gc though there are plenty memory left

6
votes

I have my java application configured to use 5G memory. I got an OutOfMemory out of blue. I inspected the gc log and found plenty of memory left: young generation occupies 4% allocated space, tenure generation occupancy is 5% and perm generation is 43%. I am puzzled why JVM throws an OutOfMemory at the gc time. Does anyone know why this is happening? Your help is greatly appreciated.

JVM memory and gc settings:

-server -Xms5g -Xmx5g -Xss256k -XX:NewSize=2g -XX:MaxNewSize=2g -XX:+UseParallelOldGC -XX:+UseTLAB -XX:SurvivorRatio=8 -XX:TargetSurvivorRatio=90 -XX:+DisableExplicitGC

gc.log

2009-09-19T03:34:59.741+0000: 92836.778: [GC
Desired survivor size 152567808 bytes, new threshold 1 (max 15)
 [PSYoungGen: 1941492K->144057K(1947072K)] 3138022K->1340830K(5092800K), 0.1947640 secs] [Times: user=0.61 sys=0.01, real=0.19 secs] 
2009-09-19T03:35:29.918+0000: 92866.954: [GC
Desired survivor size 152109056 bytes, new threshold 1 (max 15)
 [PSYoungGen: 1941625K->144049K(1948608K)] 3138398K->1341080K(5094336K), 0.1942000 secs] [Times: user=0.61 sys=0.01, real=0.20 secs] 
2009-09-19T03:35:56.883+0000: 92893.920: [GC
Desired survivor size 156565504 bytes, new threshold 1 (max 15)
 [PSYoungGen: 1567994K->115427K(1915072K)] 2765026K->1312820K(5060800K), 0.1586320 secs] [Times: user=0.50 sys=0.01, real=0.16 secs] 
2009-09-19T03:35:57.042+0000: 92894.079: [GC
Desired survivor size 179961856 bytes, new threshold 1 (max 15)
 [PSYoungGen: 115427K->0K(1898560K)] 1312820K->1313987K(5044288K), 0.0775650 secs] [Times: user=0.42 sys=0.19, real=0.08 secs] 
2009-09-19T03:35:57.120+0000: 92894.157: [Full GC [PSYoungGen: 0K->0K(1898560K)] [ParOldGen: 1313987K->159522K(3145728K)] 1313987K->159522K(5044288K) [PSPermGen: 20025K->19942K(40256K)], 0.56923
00 secs] [Times: user=2.18 sys=0.05, real=0.57 secs] 
2009-09-19T03:35:57.690+0000: 92894.726: [GC
Desired survivor size 197066752 bytes, new threshold 1 (max 15)
 [PSYoungGen: 0K->0K(1745728K)] 159522K->159522K(4891456K), 0.0072590 secs] [Times: user=0.01 sys=0.00, real=0.00 secs] 
2009-09-19T03:35:57.698+0000: 92894.734: [Full GC [PSYoungGen: 0K->0K(1745728K)] [ParOldGen: 159522K->158627K(3145728K)] 159522K->158627K(4891456K) [PSPermGen: 19942K->19934K(45504K)], 0.3280480
 secs] [Times: user=1.46 sys=0.00, real=0.33 secs] 
Heap
 PSYoungGen      total 1745728K, used 87233K [0x00002aab73650000, 0x00002aabf3650000, 0x00002aabf3650000)
  eden space 1745664K, 4% used [0x00002aab73650000,0x00002aab78b80778,0x00002aabddf10000)
  from space 64K, 0% used [0x00002aabddf10000,0x00002aabddf10000,0x00002aabddf20000)
  to   space 192448K, 0% used [0x00002aabe7a60000,0x00002aabe7a60000,0x00002aabf3650000)
 ParOldGen       total 3145728K, used 158627K [0x00002aaab3650000, 0x00002aab73650000, 0x00002aab73650000)
  object space 3145728K, 5% used [0x00002aaab3650000,0x00002aaabd138d28,0x00002aab73650000)
 PSPermGen       total 45504K, used 19965K [0x00002aaaae250000, 0x00002aaab0ec0000, 0x00002aaab3650000)
  object space 45504K, 43% used [0x00002aaaae250000,0x00002aaaaf5cf668,0x00002aaab0ec0000)

I am on 64-bit Linux and JRE 1.6.0_10:

$uname -a
Linux x 2.6.24-etchnhalf.1-amd64 #1 SMP Tue Oct 14 03:11:45 UTC 2008 x86_64 GNU/Linux 

$java -version
java version "1.6.0_10" 
Java(TM) SE Runtime Environment (build 1.6.0_10-b33) 
Java HotSpot(TM) 64-Bit Server VM (build 11.0-b15, mixed mode)
3
javajvmgarbage-collectionout-of-memory
Could you please specify in which machine you are running (Windows, Linux etc)? – Prabhu R
Which JVM you are using too? Presumably it's got to be a 64 bit JVM? – djna
What is the stack trace for the exception? – Martin v. Löwis
Do you use native code by any chance? – Zed
Please edit with the EXACT stack trace. All of it. OutOfMemory exception is used for several purposes, not all of which have to do with heap memory. I'm willing to bet that you're having a problem with thread creation. – kdgregory

3 Answers

3
votes

Okay, probably a stupid answer but your box does have at least 5GB of RAM, right? Just checking. :-) I can't remember if the JVM actually checks whether or not you actually have enough memory until It actually tries to allocate it.

0
votes

Also, what's the detail with the OutOfMemoryException - is it to do with the GC overhead limit? If so, that exception can be disabled (-XX:-UseGCOverheadLimit)

See this page about gc options and their explanation

0
votes

You might want to consider using a profiler and debugger to understand exact state in which out of memory error occurs.

I use Jprofiler for profiling and Eclipse's Debugger for debugging. Both have sufficient features for their purpose.

I would have also liked to see stack trace of error to identify kind of error and where exactly it starts coming. This is very important information missing from question.