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I have a glassfish v4.0 set up on Ubuntu server running on oracle java virtual machine and jvm process resident memory size (got via "top" command) grows up until jvm doesnt have memory to create new thread.

What I have:

  • VPS Server with 1Gb of ram and 1.4GHz processor (1Core)
  • Ubuntu Server 12.04
  • Java(TM) SE Runtime Environment (build 1.7.0_51-b13)
  • Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode)
  • Glassfish v4.0 running my Java EE webapp
  • VM runs with folowwing parameters -XX:MaxPermSize=200m -XX:PermSize=100m -XX:Xmx=512m (I can add all if relevant)

What`s the problem:

Ram usage (res memory) grows all the time, depending on usage 10-100m per hour until jvm cannot allocate native memory.

What have i tried:

  • I`ve lowered max heap space which only saves time until jvm crashes anyway
  • I`ve attached plumbr (https://portal.plumbr.eu/) which does not detect any memory leak in heap
  • I have also set max perm size to lower value.

I would like to have my JVM to be stable, as I measure heap space + perm gen takes only 400-600 mb while "top" command shows java process memory grows until 850mb and then kills itself. I know that JVM need more memory that perm space and heap, but do you think i have still given too much memory to heap space and perm gen? Any help or guide will be highly appreciated.

Log output: http://pakers.lv/logs/hs_err_pid970.log All JVM flgas: http://pakers.lv/logs/jvm_flags.txt

Update

What else I tried (based on suggestions and my own findings):

  • I have reduced and fixed heap space to 256m and then icreased while system is still stable, I noticed that maximum heap I can afford on my system is 512m and 128m perm gen space. (-Xmx512m,-Xms512m ,-XX:PermSize=128m, -XX:MaxPermSize=128m)
  • Reduced java thread size -Xss256k, I was unable to reduce it less than 218k (jvm won`t start)
  • Added -D64 so that jvm runs in 64 bit mode
  • Added -XX:+AggressiveOpts (to enable performance optimization), -XX:+UseCompressedOops (to reduce heap space memory usage), -server flag to launch jvm in server mode
  • As i have very limited heap space size I modified NewRatio to have a little bit bigger tenured generation (1/3 of heap space) -XX:NewRatio=3
  • Added diagnostic options for GC so that i can inspect OOM errors -XX:+PrintTenuringDistribution -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+HeapDumpOnOutOfMemoryError -Xloggc:/home/myuser/garbage.log

Current status With these changes I have finally limited resident memory (RAM usage) for java process which was my target. In my case 512m heap space + 128m perm gen space results in around 750m of resident memory of java process which is stable. Even though I still have memory problems - heap memory gets full from time to time and causes web app to freeze due to continued garbage collection, but OS does not kill the process. So i need now either increase available memory (RAM) for the system or inspect heap usage and lower my application`s footprint. As my webapp is Java EE based (with EJB) i might not be able to reduce it significantly. Anyway thanks for suggestions and feel free to share any other suggestions if any.

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2 Answers 2

up vote 1 down vote accepted

There are a few possibilities given what you've shared, for example:

  • a leaky JNI library, or,
  • a thread-creation leak, or
  • leaky dynamic code proxies (perm-gen leak),

but I can only make a guess because you didn't provide any log output, or indicate whether the JVM was throwing an OutOfMemoryException (OOM), or if some other fault was encountered. Nor did you mention what garbage collector was in use, though if the flags shown above are the only JVM options in use, it's the CMS collector.

The first step is to make actions of the garbage collector observable by adding these flags:

-XX:+PrintTenuringDistribution
-XX:+PrintGCDetails
-XX:+PrintGCTimeStamps
-XX:+HeapDumpOnOutOfMemoryError
-Xloggc:/path/to/garbage.log

If it is indeed an OOM, you one can analyze the heap dump with VisualVM or similar tool. I also use VisualVM to monitor GC action in-situ via JMX. Visibility to JVM internals via can be enabled by these JVM flags:

-Dcom.sun.management.jmxremote
-Dcom.sun.management.jmxremote.port=4231
-Dcom.sun.management.jmxremote.ssl=false
-Dcom.sun.management.jmxremote.authenticate=false

Additional resources:

Update

The log indeed helps. Thank you. That particular log shows that it ran out of physical memory before it could grow heap to it's configured maximum. It tried to malloc ~77M and there was only ~63M physical left:

Native memory allocation (malloc) failed to allocate 77873152 bytes for committing reserved memory.

..

/proc/meminfo: MemTotal: 1018724 kB MemFree: 63048 kB

Here's what I would do:

  1. Reduce heap so that it "fits" on the machine. Set min and max heap to same value so you can tell if it will fit immediately - it won't start up if it doesn't fit.

  2. You could reduce the Java stack size (-Xss), but this thing doesn't seem to be making a whole lot of threads so the savings won't be more than a Mb or two. I think the default for 64-bit Linux is 256k. Reduce it too much and it'll start OOM-ing on stack allocs.

  3. Repeat test.

  4. When it's been running under load for a short while, produce an on-demand heap dump for differential diagnosis using jmap -dump:file=path_to_file <pid>.

  5. One of two things should happen: (a) if there is a leak, it will fail again eventually, but the type of OOM ought to be different, or (b) there isn't a leak such that GC will just work harder and you're done. Given that you tried that before, the former case is likely, unless your reduced max size didn't fit either.

  6. If it does OOM, compare the two dumps to see what grew using jhat or some other heap analyzer.

Good luck!

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Thank you. I will proceed with your suggestions. I added log output and jvm flags if it helps to pinpoint the problem. –  Oskars Pakers Apr 1 at 5:18

Try to run the process in 64bit mode by adding: -D64 to JVM startup flags.

You can run pmap $JVMPID to see how the virtual memory is allocated. Run it before it crashes.

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I`ll give this a try, thanks. –  Oskars Pakers Apr 1 at 9:04

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