Restart doesn't help, and, by they way is very slow, which I wouldn't normally expect on this machine (4 cores, 4Gb RAM, RAID1).

Same picture when I try to run other services or applications - all go in swap, top shows that MEM is not used (0.1% maximum for any process). The only process in my top is MySQL, but it is using 0.1% of RAM and 400Mb of swap. But, apparently, it reports that no process is using my RAM. So, I decided to find out who is using all my RAM, and I used top for that. So, I actually have only 42 Mb to use! As far as I understand, -/+ buffers/cache actually doesn't count the disk cache, so I indeed only have 42 Mb, right? I thought, I might be wrong, so I tried to switch off the disk caching and it had no effect - the picture remained the same. When I do free -m, here is what I got: total used free shared buffers cached

Every application in the system is swapping heavily, and the system is very slow. Before actually asking, just to be clear: yes, I know about disk cache, and no, it is not my case :) Sorry, for this preamble :)

Linux show memory usage by process