Only 768MB RAM, Kali 2.0.1 on Rpi2, gpu_mem=16 has no effect

[ovosodo]

Hi all,
in a text based Rpi application it's useful to dedicate as much RAM as possible to ARM, lowering GPU RAM to the minimum.
Lot of people solved this in raspbian by configuring gpu_mem parameter in config.txt in the boot partition.
I added config.txt in the 64MB boot partition, with gpu_mem=16 without any change in total ARM memory.

Here is my config.txt

# GPU memory in megabytes. Sets the memory split between the CPU and GPU; the CPU gets the remaining memory. Minimum value is 16; maximum value is either 192, 448 or 944 depending on whether you're using a 256M, 512MB or 1024MB Pi. The default value is 64.
# Setting gpu_mem to low values may automatically disable certain firmware features (as there are some things the GPU simply can't do with too little memory). So if a certain feature you're trying to use isn't working, try setting a larger GPU memory split.
gpu_mem=16

RAM remains the same:

# free
             total       used       free     shared    buffers     cached
Mem:        762468      96340     666128       5416      10140      44308
-/+ buffers/cache:      41892     720576
Swap:            0          0          0

Any hint?
Thank you,
OS

[steev]

Due to the SonicPi ( http://sonic-pi.net/ ) breaking when using HIGHMEM, it is currently disabled - see https://www.raspberrypi.org/forums/v...685622#p685622 - you can build your own kernel and enable HIGHMEM in the config. I'll look into enabling it when I move to a newer kernel, but for now, it's not enabled.

[ovosodo]

Due to the SonicPi ( http://sonic-pi.net/ ) breaking when using HIGHMEM, it is currently disabled - see https://www.raspberrypi.org/forums/v...685622#p685622 - you can build your own kernel and enable HIGHMEM in the config. I'll look into enabling it when I move to a newer kernel, but for now, it's not enabled.

steev, I saw that thread and I will build a HIGHMEM enabled kernel, but:
* raspbian users can simply apt-get install rpi-update to get their full 1GB RAM, accepting the risks of breaking some apps;
* stock rpi-update doesn't seem usable by kali, as it bumps to rpi-4.1 linux tree;
* while it's conservative to support even those apps out of the box, IMHO very few Kali users use SonicPi and it would make sense not to waste 256MB precious ram, both for graphical and text mode usages.

If it doesn't yet exists, in the spare time I will build and test such patched kernel, and I will make it available to Kali users.

Thank you,
OS

[steev]

Unless you're doing packet injection, running the stock kernel is fine. The only difference between stock and us are a few extra kernel options turned on for things people may do, and patching for packet injection.

[ovosodo]

Due to the SonicPi ( http://sonic-pi.net/ ) breaking when using HIGHMEM, it is currently disabled - see https://www.raspberrypi.org/forums/v...685622#p685622 - you can build your own kernel and enable HIGHMEM in the config. I'll look into enabling it when I move to a newer kernel, but for now, it's not enabled.

Waiting for the next Kali release , I tried the solution and posted a detailed how-to here: https://forums.kali.org/showthread.p...-of-only-750MB