Java: New Generation Used 100%, Eden Space Used 100%, From Space Used 100%

java memory garbage-collection heap-memory jmap
Jasper picture Jasper · Jun 28, 2012 · Viewed 19.4k times · Source

jmap -heap gives me output that says:

New Generation Used 100%, Eden Space Used 100%, From Space Used 100%, To Space Used: 0%, Perm Generation Used: 38%

Is this 100% of New, Eden, From space - a problem?

My JAVA OPTS are: -Xms10240m -Xmx14336m -XX:PermSize=192m -XX:MaxPermSize=256m -XX:NewSize=8192m -XX:MaxNewSize=8192m -XX:-DisableExplicitGC -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=60

I see a lot of quick Garbage Collection. But no memory leaks using tools like JConsole

The Memory Usage can be seen here: http://tinypic.com/view.php?pic=wo213&s=6

JDK 1.6 is in use.

Answer

Alexey Ragozin picture Alexey Ragozin · Jun 29, 2012

Well that is how generational collection works. You have young space (eden, from, to) and old space (tenure, perm). Young space is smaller. Once young space is full (your case) - thing called minor GC (young GC) is happening.

But minor GC should be quick. Once old space is full full GC is happening (which is more time consuming).

Idea is to have more frequent fast minor GCs and much less frequent full GCs.

You can read much more detailed explanation in this article

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