[Solved] How are my custom kernel images bigger than official ones?

fire100265 · 2020-12-26 08:24:16

Hi,
I am genuinely curious as to why this happens. I use a custom kernel alongside the official linux package. Somehow, my custom kernel's initramfs images are 2 times bigger than the official kernel ones despite the custom one being smaller in every way. Does anyone know why this is the case? For the record, I use the same mkinitcpio configuration for both kernels.

Last edited by fire100265 (2020-12-26 11:53:42)

seth · 2020-12-26 09:05:05

despite the custom one being smaller in every way

Is it?
Did you compare the size of the kernel modules you add to the initramfs?

fire100265 · 2020-12-26 09:06:26

Yes I did. I checked /lib/modules and the official one is much bigger.

V1del · 2020-12-26 11:21:27

That doesn't really answer the question, neither your initramfs nor the official kernels initramfs should include all modules but just the ones necessary for booting.

fire100265 · 2020-12-26 11:27:14

I know about that. The custom kernel's initramfs is very close to the size of its fallback image. About 3MB off. I don't know why this is the case.

Last edited by fire100265 (2020-12-26 11:27:22)

seth · 2020-12-26 11:32:18

seth wrote:

Did you compare the size of the kernel modules you add to the initramfs?

Hint: debug symbols…

Last edited by seth (2020-12-26 11:32:38)

fire100265 · 2020-12-26 11:37:59

Now that you mention it, I found these lines in .config:

CONFIG_DEBUG_KERNEL=y
CONFIG_UNUSED_SYMBOLS=y

Is this the reason?

seth · 2020-12-26 11:39:01

Maybe. Maybe not.

seth wrote:

Did you compare the size of the kernel modules you add to the initramfs?

fire100265 · 2020-12-26 11:42:12

I think I got the answer. The problem was those 2 lines in my previous reply and the module sizes. The modules are bigger in my custom kernel than in the Arch one. Am I right?

seth · 2020-12-26 11:50:14

If the modules are bigger that that's the most likely cause of your bigger initramfs and the most likely cause for that is that you've debugging enabled.

You should™ have gotten a prompt for this during the configuration, though…

https://cateee.net/lkddb/web-lkddb/DEBUG_KERNEL.html
https://cateee.net/lkddb/web-lkddb/UNUSED_SYMBOLS.html

Now you need to decide which options you want/need.

fire100265 · 2020-12-26 11:53:25

Thank you. I didn't get a prompt for disabling symbols and debugging when making .config. I'll mark the thread as Solved now.

Arch Linux

#1 2020-12-26 08:24:16

[Solved] How are my custom kernel images bigger than official ones?

#2 2020-12-26 09:05:05

Re: [Solved] How are my custom kernel images bigger than official ones?

#3 2020-12-26 09:06:26

Re: [Solved] How are my custom kernel images bigger than official ones?

#4 2020-12-26 11:21:27

Re: [Solved] How are my custom kernel images bigger than official ones?

#5 2020-12-26 11:27:14

Re: [Solved] How are my custom kernel images bigger than official ones?

#6 2020-12-26 11:32:18

Re: [Solved] How are my custom kernel images bigger than official ones?

#7 2020-12-26 11:37:59

Re: [Solved] How are my custom kernel images bigger than official ones?

#8 2020-12-26 11:39:01

Re: [Solved] How are my custom kernel images bigger than official ones?

#9 2020-12-26 11:42:12

Re: [Solved] How are my custom kernel images bigger than official ones?

#10 2020-12-26 11:50:14

Re: [Solved] How are my custom kernel images bigger than official ones?

#11 2020-12-26 11:53:25

Re: [Solved] How are my custom kernel images bigger than official ones?

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