A simple command line tool for jailbroken devices to modify the Jetsam configuration for a process.
It uses the same syscalls as launchd does when spawning a new process. This would not have been possible without Jonathan Levin's fantastic article on Jetsam.
The latest Debian package can be downloaded from the Releases section.
You can use jetsamctl to set the per process memory limit or Jetsam priority for a process.
Limit the Phone app to 48 MB of memory:
# jetsamctl -l 48 MobilePhone
Set the priority of the Photos app to that of an iOS keyboard extension:
# jetsamctl -p 8 MobileSlideShow
Here is a table of all of the priorities and their numerical values:
| Priority | Value | Examples |
|---|---|---|
| Idle | 0 | |
| Idle (Deferred) | 1 | |
| Background (Opportunistic) | 2 | |
| Background | 3 | |
| 4 | Apple Mail | |
| Phone | 5 | Phone app |
| UI Support | 8 | Keyboard extension |
| Foreground Support | 9 | Share extension |
| Foreground | 10 | Foreground application |
| Audio and Accessory | 12 | |
| Conductor | 13 | |
| Home | 16 | SpringBoard |
| Executive | 17 | |
| Important | 18 | |
| Critical | 19 |
jetsamctl is available under the MIT license. See the LICENSE file for more info.