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I had install ubuntu 64 bit on my system (ubuntu 12.04 lts).

When I do free -m

             total       used       free     shared    buffers     cached
Mem:          5859       5284        574          0        251       4012
-/+ buffers/cache:       1021       4838
Swap:         6032          0       6032

I have total 6GB of RAM, now even I had just one application in used it show me 5284 are totally used, only 574 MB of memory is free.

What to do to resolved it or to debug it ?

Also when I fire TOP command, it show only few application running as in my system, but occupied memory are very much?

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marked as duplicate by mikewhatever, Alvar, Braiam, psusi, minerz029 Jan 3 '14 at 21:07

This question was marked as an exact duplicate of an existing question. – falconer Jan 3 '14 at 10:04
No, it is showing you that 1 GB is used. Pay attention to the -/+ buffers/cache line. – psusi Jan 3 '14 at 19:27

Use system monitor to see which process is devouring all your memory to get a possible idea of what you should do next.


You can do the same with top; use Shift + < / > key combos to select the memory usage column, and Shift + R to toggle the reverse-state of column sort.


You can then kill the process that's causing the problem.

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