1
vote
2answers
1k views

How to activate swap on Linux? “swapon -a” doesn't seem to work?

My computer has quite some memory (6GB) which is enough for most of what I do. A while back I was messing with my swap, turning it on and off with sudo swapon -a and sudo swapoff -a. In then end I ...
4
votes
1answer
4k views

Why does limiting my virtual memory to 512MB with ulimit -v crash the JVM?

I am trying to enforce maximum memory a program can consume on a Unix system. I thought ulimit -v should do the trick. Here is a sample Java program I have written for testing : import java.util.*; ...
0
votes
0answers
73 views

Forcing suspended jobs to swap all memory in Ubuntu

Is is possible to suspend a job and force all of its memory to swap? I've got six jobs running, and they're competing with each other for resources. So much gets wasted on system swapping that they ...
8
votes
3answers
5k views

Why does my 32bit ubuntu see 8GB of RAM?

I have just installed a fresh copy of ubuntu 11.04 32 bit and I was surprised to see that the OS can see my 8GB of RAM not like Windows 32 bit OS. How does it work? How is the address mapping ...
3
votes
3answers
1k views

Detecting source of memory usage on a Linux box

I have a toy Linux box with 256mb RAM running Ubuntu 10.04.1 LTS. Here is the output of free -m: total used free shared buffers cached Mem: 245 ...