On the regression testcase theme, it got me thinking as to whether we've
any java APIs which can query what the native heap usage of the JVM. Is
that available over JMX ?
I tried the MBeanServer approach but didn't get the expected results.
Queried the "NonHeapMemoryUsage" object.
something like.
MBeanServer server = ManagementFactory.getPlatformMBeanServer();
ObjectName memory = new ObjectName(MEMORY_MXBEAN_NAME);
Object ob = server.getAttribute(memory, "NonHeapMemoryUsage");
MemoryUsage mu = MemoryUsage.from((CompositeData) ob);
System.out.println("Nonheap : " + mu.getUsed());
What exactly is JMX measuring in "NonHeapMemoryUsage" mode ? Any pointers ?
regards,
Sean.
On 08/08/13 23:19, Michael McMahon wrote:
Ivan,
Right, it's not worth trying to do the equivalent, whatever it is, for
Windows.
The test is fine with me.
Thanks
Michael
On 08/08/13 23:15, Ivan Gerasimov wrote:
Michael,
The test uses /proc/self/stat file to detect changes in virtual
memory usage.
This approach is specific for Linux.
That's why I included the check of OS in the test.
Sincerely yours,
Ivan
On 09.08.2013 1:38, Michael McMahon wrote:
Yes, definitely "othervm" would be required for the test. Also, why
skip other OS'es?
The fix is only for Linux, but it might catch future leaks on Windows.
The trouble with tests like this, is they sometimes don't age well.
Future changes in OS kernel behavior could cause problems but I
guess 32MB is a fairly large difference.
So, it should be okay
Michael
On 08/08/13 22:15, David Holmes wrote:
Main fix looks good to me.
Regression test may need some tweaking eg I think othervm will be
needed.
Also this:
System.out.println("WARNING: Cannot perform memory leak detection
on this OS");
should probably just say something like "Test skipped on this OS" -
there are other tests that do this so just check if there is common
terminology. (In the future we may have keyword tags to flag this
as linux only etc.)
Thanks,
David
On 9/08/2013 4:41 AM, Ivan Gerasimov wrote:
Chris, if it's not too late, I'd like to include a regtest in the
fix.
Here's webrev that includes the test:
http://cr.openjdk.java.net/~igerasim/8022584/3/webrev/
The test gets past with the fixed jdk8 and fails with jdk8-b101
and jdk7
as expected.
Sincerely yours,
Ivan
On 08.08.2013 17:50, Chris Hegarty wrote:
Looks good to me. Thanks Ivan.
-Chris.
On 08/08/2013 02:33 PM, Ivan Gerasimov wrote:
Hello Chris!
Here's the update:
http://cr.openjdk.java.net/~igerasim/8022584/2/webrev/
Thanks for offering the sponsorship!
Here's the hg-export
http://cr.openjdk.java.net/~igerasim/2commit/8022584-jdk8-Memleak-in-NetworkInterface.patch
Sincerely yours,
Ivan
On 08.08.2013 12:43, Chris Hegarty wrote:
Thanks for taking this Ivan.
Can you please make the changes suggested by both David and Alan (
simply return NULL/-1/JNI_FALSE, as appropriate, if
GetStringUTFChars
fails ( returns NULL ), then I will sponsor this change into
jdk8 for
you.
Please post an update webrev to cr.openjdk.java.net.
-Chris.
On 08/08/2013 06:01 AM, David Holmes wrote:
Ivan,
On 8/08/2013 2:05 PM, Ivan Gerasimov wrote:
David, Alan,
I added checking for NULL results and throwing OOMException if
necessary.
You don't need to throw it yourself:
JNU_ThrowOutOfMemoryError(env, NULL);
Assuming a correct VM implementation if NULL is returned then
an OOME
should already be pending and will be thrown as soon as your
native
code
returns to Java.
Thanks,
David
I've also added some spaces along the code to improve
indentation.
Would you please review the updated webrev?
http://washi.ru.oracle.com/~igerasim/webrevs/8022584/1/webrev/
Sincerely yours,
Ivan
On 08.08.2013 5:35, David Holmes wrote:
On 8/08/2013 11:20 AM, Ivan Gerasimov wrote:
Thanks Alan!
I've checked that and it turns out that GetStringUTFChars
cannot
return
NULL.
For allocation of the result string it calls AllocateHeap()
with
the
default EXIT_OOM fail strategy.
Thus, in case of being unable to allocate memory it simply
stops
VM.
Ouch! That is a hotspot bug. GetStringUTFChars is supposed
to throw
OutOfMemoryError if it has memory issues, not abort the VM!
I recommend that you check for NULL and/or a pending exception.
David
Sincerely yours,
Ivan
On 08.08.2013 5:05, Alan Bateman wrote:
(cc'ing net-dev).
The change looks okay to me. One suggestion (while you are
there) is
to check the return from GetStringUTFChars so that the name
returns
when it fails with NULL.
-Alan.
On 07/08/2013 17:46, Ivan Gerasimov wrote:
Hello everybody!
Some methods of NetworkInterface class were reported to leak
memory.
http://bugs.sun.com/view_bug.do?bug_id=JDK-8022584 (not yet
available.)
Examples are isUp() and isLoopback().
Affected versions of jdk are 6, 7 and 8
Would you please review a simple fix that removes the
unnecessary
allocation?
http://cr.openjdk.java.net/~igerasim/8022584/0/webrev/
Sincerely yours,
Ivan
