Moving to GitHub, slowly

The software on this pages will slowly be moved to GitHub https://github.com/hilbix/. The CVS repository will be migrated to GIT as well, so the history will be preserved, a bit. See FAQ.

Scylla and Charybdis, killmem - Tools

The tools are developed under Linux with ESR's paradigm release early, release often in mind.
So you can consider this beta software, or alpha, or pre-alpha, or even worse ;)

Have a look in the download directory for all downloads.
As always here, all you get is the source. No binaries here.

killmem 0.2.0-20081101-104442

Protect some memory against paging until you need free memory

⇒ ⇒ ⇒ The development shifted to another location. All future versions will be published at https://github.com/hilbix/killmem   ⇐ ⇐ ⇐

This applications pins some memory, such that it cannot be paged out. If you need this memory you can free it such that you can perform some system tasks to get the machine back to normal operation more quickly.

Note that killmem must be run as root in order to be able to lock memory.

I have a funny problem here. The machine has enough RAM for normal operation, but somtimes some nasty applications make the machine into heavy thrashing, such that everything goes slow-motion and even slower.

Neither nice nor slowdown can help, as paging is done by the system and not application controlled. So each time a page becomes filled it is nearly immediately thrashed out again into paging space because those applications do heavy RAM walking over gigabytes of memory.

One thing would be to add 3*number_of_nasty_applications GB of RAM into the machine so that these applications can all have their process memory maxed out. But the machine already is maxed out at 640 MB total RAM (it was a huge amount some years ago).

However it's easy to protect against this. With killmem you can lock 10% of the memory against paging, and with a press of a button you can free it again. This means for some seconds the machine has free ram to do maintainance tasks, such like sending a 'killall app' to the heavy applications. Don't be too slow as in such situations the free memory fills up in seconds!

And beware. If the machine already is on the edge, starting killmem makes the situation worse. It might even make your kernel go nuts, which happened several times. You have been warned.

Note that there are some other tools out there which have similiar goals:

• Fallback Reboot locks it's memory
• Standalone Shell statically linked

History:

License and Disclaimer All you can see here is free software according to the GNU GPL. Copyright (C)2000-2011 by Valentin Hilbig Note that the software comes with absolutely no warranty of any kind. You use the software at your own risk. Valentin Hilbig cannot be hold responsible for any unintended damage, lost data or malfunction of the software you can find here.