topic Re: [iMX8M Plus] CMA alloc failed during gst-launch in i.MX Processors

[iMX8M Plus] CMA alloc failed during gst-launch

khang_letruong — Wed, 08 Mar 2023 05:02:04 GMT

Hi NXP Community,

256MB of CMA memory has been successfully allocated in our iMX8M Plus based system with 1GB of DDR4:

root@viperimx8mp:~# dmesg | grep -i cma [ 0.000000] Reserved memory: created CMA memory pool at 0x0000000070000000, size 256 MiB [ 0.000000] OF: reserved mem: initialized node linux,cma, compatible id shared-dma-pool [ 0.000000] Memory: 703092K/1015808K available (17920K kernel code, 1506K rwdata, 6920K rodata, 2880K init, 553K bss, 50572K reserved, 262144K cma-reserved)

However, I am struggling with following errors while streaming the camera with gstreamer :

root@viperimx8mp:~# gst-launch-1.0 v4l2src device=/dev/video2 ! video/x-raw, width=1920, height=1080, framerate=15/1 ! autovideos

On the debug console side :

root@viperimx8mp:~# [ 425.307460] enter isp_mi_stop [ 425.942933] enter isp_mi_stop [ 426.134422] cma: cma_alloc: alloc failed, req-size: 1013 pages, ret: -12 [ 426.143351] cma: cma_alloc: alloc failed, req-size: 1013 pages, ret: -12 [ 426.152091] cma: cma_alloc: alloc failed, req-size: 1013 pages, ret: -12 [ 426.160775] cma: cma_alloc: alloc failed, req-size: 1013 pages, ret: -12 [ 426.171442] cma: cma_alloc: alloc failed, req-size: 64 pages, ret: -12 [ 426.178547] cma: cma_alloc: alloc failed, req-size: 1013 pages, ret: -12 [ 426.189008] cma: cma_alloc: alloc failed, req-size: 1013 pages, ret: -12 [ 426.199560] cma: cma_alloc: alloc failed, req-size: 1013 pages, ret: -12 [ 426.209896] cma: cma_alloc: alloc failed, req-size: 1013 pages, ret: -12 [ 426.251559] enter isp_mi_stop [ 426.381644] jxf355_set_fps : current frame length: 2252, current line length: 1280 [ 426.399852] enter isp_s_comp [ 426.402763] enter isp_s_comp [ 426.405644] enter isp_s_comp [ 426.427504] enter wdr3_hw_init [ 426.430580] wdr3 res: 1920 1080 [ 426.434753] enter isp_mi_start

Could you help if 256MB is sufficient for streaming single 1080p camera or the problem is somewhere else ?

Best Regards,

Khang

Re: [iMX8M Plus] CMA alloc failed during gst-launch

Holger75 — Wed, 08 Mar 2023 08:21:43 GMT

Hi Khang,

I was facing same topic with my SoM. I found this link usefull

https://developer.toradex.com/software/linux-resources/linux-features/contiguous-memory-allocator-cma-linux/

I assume it is controlled in the DTS in your case and you have to slightly increase your memsize.

resmem: reserved-memory {
/* global autoconfigured region for contiguous allocations */
linux,cma {
compatible = "shared-dma-pool";
reusable;
size = <0 0x38000000>;
alloc-ranges = <0 0x40000000 0 0x80000000>;
linux,cma-default;
};

Best regards

Holger

Re: [iMX8M Plus] CMA alloc failed during gst-launch

khang_letruong — Fri, 10 Mar 2023 03:02:19 GMT

Hi @Holger75 ,

Thanks for sharing your experience. I temporarily solved the issue by setting the CMA size to 512MiB, which is a half of the available DDR memory in the system. I am not sure if the remain 512MiB would be sufficient for other running stuffs.

Best Regards,
Khang

Re: [iMX8M Plus] CMA alloc failed during gst-launch

malik_cisse — Mon, 02 Oct 2023 15:34:50 GMT

Hi Khang,

Can you please explain how you increased CMA size to 512MiB?

I have currently 640MiB allocated and I want to increase it as can be seen here:
~# dmesg | grep -i cma
[ 0.000000] Reserved memory: created CMA memory pool at 0x000000006a000000, size 640 MiB
[ 0.000000] OF: reserved mem: initialized node linux,cma, compatible id shared-dma-pool
[ 0.000000] Memory: 1034564K/2064384K available (18560K kernel code, 1644K rwdata, 7292K rodata, 3072K init, 552K bss, 374460K reserved, 655360K cma-reserved)

However the CMA size in the device tree does not correspond to 640MiB:
linux-imx/arch/arm64/boot/dts/freescale/imx8mp.dtsi

/* global autoconfigured region for contiguous allocations */

linux,cma {

compatible = "shared-dma-pool";

reusable;

size = <0 0x3c000000>;

alloc-ranges = <0 0x40000000 0 0xC0000000>;

linux,cma-default;

};

What is the correct way to increase this?
Thx

Re: [iMX8M Plus] CMA alloc failed during gst-launch

khang_letruong — Tue, 03 Oct 2023 09:15:44 GMT

Hi @malik_cisse ,

Below is how I define 512MiB of CMA over 1024MiB (1 GiB) of DDR memory :

+ /* global autoconfigured region for contiguous allocations */ + linux,cma { + compatible = "shared-dma-pool"; + reusable; + size = <0 0x20000000>; + alloc-ranges = <0 0x40000000 0 0x40000000>; + linux,cma-default; + }; + };

Small conversion : 0x20000000 = 536870912 B = 536870912/1024/1024=512 MiB.

In your initial case, it seemed that the size ranged from 0 to 960MiB = 1006632960/1024/1024 = 1006632960 B = 0x3c000000. But it resulted in 640MiB (less than expected 960MiB) because the alloc-range was not enough or not contiguous (the first allocable region has 1024MiB in size).

Regards,

Re: [iMX8M Plus] CMA alloc failed during gst-launch

malik_cisse — Tue, 03 Oct 2023 10:39:21 GMT

Hi @khang_letruong ,
Thank you for your insight. This clarifies things to a certain extend.

My SOM has 2GB of DDR memory and it should be possible to alloc 960MiB to CMA (that would be less than 50% of available DDR memory).

Would it make sense to set the alloc-range to the full 2GB DDR size (similarly to what you set in your DT) like this:

alloc-ranges = <0 0x80000000 0 0x80000000>; ??

PS:
I have the feeling the initial alloc-range in my device tree does not even reflect my actual DDR size
alloc-ranges = <0 0x40000000 0 0xC0000000>;
to me means that two DDR regions can be used for CMA
region1: 0 to 0x40000000 : 0x40000000 = 1073741824 Dec = 1073741824/1024/1024=1024MiB.
region2: 0 to 0xC0000000 :0xC0000000 = 3221225472 Dec = 3221225472/1024/1024=3072MiB.
1024MiB + 3072MiB = 4096MiB
Thus total DDR memory is 4GB and not expected 2GB. This can be an error from my SOM provider.

Re: [iMX8M Plus] CMA alloc failed during gst-launch

khang_letruong — Tue, 03 Oct 2023 16:23:31 GMT

Hi @malik_cisse ,

I also have 2GB of DDR :

+ /* global autoconfigured region for contiguous allocations */ + linux,cma { + compatible = "shared-dma-pool"; + reusable; + size = <0 0x3c000000>; + alloc-ranges = <0 0x40000000 0 0x80000000>; + linux,cma-default; + };

and CMA is successfully allocated :

[ 0.000000] Reserved memory: created CMA memory pool at 0x000000005c000000, size 960 MiB [ 0.000000] OF: reserved mem: initialized node linux,cma, compatible id shared-dma-pool [ 0.000000] Memory: 714344K/2064384K available (19584K kernel code, 1608K rwdata, 6708K rodata, 3328K init, 644K bss, 367000K reserved, 983040K cma-reserved)

Brgs,

Khang

Re: [iMX8M Plus] CMA alloc failed during gst-launch

malik_cisse — Tue, 03 Oct 2023 16:34:28 GMT

You must be right. I just found a mistake on my side.
I just found a dtsi file that overrules and includes settings in imx8mp.dtsi and that sets the 640MiB.

&{/reserved-memory/linux,cma} {
size = <0 0x28000000>;
alloc-ranges = <0 0x40000000 0 0x60000000>;
};

I will now update the CMA setting here and give it a try.
Thank you again for the precious feedback.

Re: [iMX8M Plus] CMA alloc failed during gst-launch

malik_cisse — Thu, 05 Oct 2023 07:29:44 GMT

Hi @khang_letruong
This is just to confirm that CMA size is overwritten with other DTS. I can now change CMA also.
On the other side I found the root cause of my CMA memory leak:
Not freeing properly gstreamer appsink upon new pipeline stop/start cycle.
Thank you for sharing your thoughts.