Freeing up some of the reserved memory

Autonomous Machines Jetson & Embedded Systems Jetson Orin NX
1

Hi!

I’m working on a project that involves a model that barely does not fit into the memory even if I disable things like desktop and a few services to free up the memory. htop shows only 15GB of the memory is available and:

daniel@orinnx:~$ cat /var/log/dmesg | grep Memory
[ 0.000000] kernel: Memory: 15483820K/16420928K available (18432K kernel code, 3168K rwdata, 7164K rodata, 3968K init, 1110K bss, 674964K reserved, 262144K cma-reserved)

so 256 MB is cma-reserved and ~660MB is reserved. How can I reclaim part of this memory? I understand something could stop working if I do so, but my goal is to run a model and I need the most of the memory available and I’m close to have just enough to run the model. A few more 100s of MB is what I need.

3

There are some reserved memory for some coprocessor suppose it’s necessary reserved.

4

Do we know what coprocessor and how to eventually disable it if it’s not necessary for the task that I am working on? I read a thread about the Xavier NX with JP 5.x where the user was able to free up a few hundred megabytes by disabling a feature they did not need (however the same thing was not applicable here).

6

try disabling vpr region from the device tree node.
vpr-carveout {
status = “disabled”;
};

7

Hi Bibek,
Thank you for your reply.
I tried to extract the device tree and with:

dtc -I fs -O dts -o extracted.dts /proc/device-tree

there’s no vpr-carveout, so I verified with:

dtc -I dtb -O dts -o kernel_tegra234-p3767-0000-p3768-0000-a0.dts /boot/dtb/kernel_tegra234-p3767-0000-p3768-0000-a0.dtb

I can already see:

 		vpr-carveout {
 			compatible = "nvidia,vpr-carveout";
 			status = "disabled";
 			phandle = <0x45>;
 		};

The rest of the reserved memory (from /device/tree) if it can be helpful:

	reserved-memory {
		#address-cells = <0x02>;
		#size-cells = <0x02>;
		ranges;

		linux,cma {
			linux,cma-default;
			alignment = <0x00 0x10000>;
			compatible = "shared-dma-pool";
			size = <0x00 0x10000000>;
			status = "okay";
			reusable;
		};

		generic_carveout {
			alignment = <0x00 0x100000>;
			alloc-ranges = <0x01 0x00 0x01 0x00>;
			compatible = "nvidia,generic_carveout";
			size = <0x00 0x00>;
			status = "disabled";
			phandle = <0x2d7>;
			no-map;
		};

		camdbg_carveout {
			alignment = <0x00 0x100000>;
			alloc-ranges = <0x01 0x00 0x01 0x00>;
			compatible = "nvidia,camdbg_carveout";
			size = <0x00 0x6400000>;
			status = "disabled";
			phandle = <0x2db>;
		};

		ramoops_carveout {
			alignment = <0x00 0x10000>;
			record-size = <0x10000>;
			alloc-ranges = <0x00 0x00 0x01 0x00>;
			compatible = "ramoops";
			size = <0x00 0x200000>;
			console-size = <0x80000>;
			status = "okay";
			reg = <0x04 0x68000000 0x00 0x200000>;
			phandle = <0x2d9>;
			no-map;
		};
	};

Thank you! :)

- Daniel

8

you can disable the cma region also

9

I tried that and blindly disabled a few other carveouts (left only grid-of-semaphores and the result is:

daniel@orinnx3:~$ cat /var/log/dmesg | grep Memory
[ 0.000000] kernel: Memory: 15679168K/16420928K available (18496K kernel code, 3168K rwdata, 7172K rodata, 3968K init, 1418K bss, 676224K reserved, 65536K cma-reserved)

but htop and tegrastats still show 15GB of the available memory:

06-28-2023 17:30:09 RAM 511/15388MB (lfb 3556x4MB) SWAP 0/7694MB (cached 0MB) …

- Daniel

10

yes, you can not get that 676224K reclaimed because that’s used for UEFI and OPTEE

12

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