Java / Tomcat memory leak in RedHat Linux?

Clearly, top is telling you that Tomcat is only using 38% of your available memory. Your problem (if there is a problem) is with whatever is using the remaining 62% of memory I suspect that it is being used for disc block / file system caching. (Run the free command and I expect that you should see a high value for "cached" that roughly corresponds in size to the missing pages.) If your system has a large number of pages in the cache, it is a GOOD THING All those cached disc blocks will make read access to your file system nice and fast.

(And if the OS needs physical pages for something more important ... like running applications ... it can quickly reclaim them from the disc cache. ).

Clearly, top is telling you that Tomcat is only using 38% of your available memory. Your problem (if there is a problem) is with whatever is using the remaining 62% of memory. I suspect that it is being used for disc block / file system caching.(Run the free command and I expect that you should see a high value for "cached" that roughly corresponds in size to the missing pages.) If your system has a large number of pages in the cache, it is a GOOD THING.

All those cached disc blocks will make read access to your file system nice and fast.(And if the OS needs physical pages for something more important ... like running applications ... it can quickly reclaim them from the disc cache. ).

Thanks Stephen C, I have added the free command screenshot. I guess I don't have to worry about it then as caching is a good thing. – blackrocky Jun 1 '10 at 2:04 Is there a way to figure out which process is taking up the cache?

– blackrocky Jun 1 '10 at 2:15 @black-rocky - no. The OS does not associate stuff in the disc block cache with any process. But it really doesn't matter because, as I said, pages in the cache will be reclaimed on demand.

– Stephen C Jun 1 '10 at 3:16.

The system monitor is showing how memory is being used by the tomcat process which is 2Gmax heap size yo have set is allocated. On linux try comparing it with free -m which shows current free memory.

I wonder if one of the figures is including cached file system data (which is used memory in the sense it's physically used for something, but free in the sense that it can be cleared out at any moment if necessary).

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