Native memory usage in Linux seems to be much higher than observed through JVM itself (e.g. through JConsole)

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http://stackoverflow.com – We have a customer that uses WebSphere 7.0 on RedHat Linux Server 5.6 (Tikanga) with IBM JVM 1.6. When we look at the OS reports for memory usage, we see very high numbers and OS starts to use SWAP memory in some point due to lack in memory. On the other hand, JConsole graphs show perfectly normal behavior of memory - Heap size increases until GC is invoked when expected and Heap size drops to ~30% in normal cycles. Non heap is as expected and very constant in size. Does anyone have an idea what this extra native memory usage can be attributed to? (HowTos)