Execute a script when memory peaks?

Question

I don't have a lot of memory and sometimes, when I play video games, its get full and my computer start freezing, anything I do take more than 1 minutes before getting done that include mouse move and mouse click.

So what I want is to be able to kill some process I use and I know I can kill (like my Internet browser) before the memory get full so I have little more space left. Do you know a way to do it ?

In technical terms, what I want is that when the memory is almost full it trigger a script that will send a SIGTERM (order to close) to my Internet browser so my PC don't freeze and I can choose to save whatever I'm doing and reopen my browser or forget about my browser.

Thanks for your help.

Answer 1

Alright, here goes:

#!/bin/bash
threshold=100          # Minimum amount of memory left when you should start killing, in MB
browser="firefox-bin"  # Change this to whatever you use, firefox is actually firefox-bin
while true; do
    available=$(free -m | head -2 | tail -1 | awk '{print $4}')
    if [ "$threshold" -ge "$available" ]; then
        killall -q $browser  # Will not complain if no processes were killed
    fi
    sleep 20
done

Put this into /home/USERNAME/bin, execute chmod +x ~/bin/SCRIPTNAME, and then add it to your auto-start programs through System->Preferences->Startup Applications.

Then the script will run when you log in, automatically. You can run it manually with ~/bin/SCRIPTNAME &

Answer 2

Killing anything to conserve memory is a bad idea, especially automatically. Make sure that you have enough swap and RAM available - of course, running something that uses 1 gig of memory on a 512MB machine is like trying to win a F1 Grand Prix while driving a Corolla.

By which I mean "don't do it."

Answer 3

The kernel does that automatically when you run out of memory.

If you have swap enabled, however, that will take a lot of grinding.

Answer 4

Try setting vm.swappiness to 100 as per the instructions here (use 100 instead of 0) On a memory starved machine that can improve performance. https://help.ubuntu.com/community/SwapFaq#What%20is%20swappiness%20and%20how%20do%20I%20change%20it?