I have a number of headless AML S905 / S912 1GB Ram TV boxes running a bastardised Armbian for systems monitoring. I have a 200MB zram compressed block device setup to store temporary data which gets processed locally then synced to a command server every hour because the eMMC's on these cheap boxes do not last very long under sustained write scenarios. I would like to increase the zram filesystem size to 500MB so I only have to sync daily instead of hourly but because 25% of the RAM is allocate
I have created a new dtb with the following change:
compatible = "shared-dma-pool";
reusable; size = <0x0 0x2000000>;
alignment = <0x0 0x400000>;
This should reduce the cma size to 32MB (0x2000000) if I understand correctly?
However even with that change I still see "cma: Reserved 256 MiB" in dmesg, not 32MB as I would expect. I have also tried various different "cma=x" values on the kernel