How To Determine If Initrd Is In Use?

rickster3313 · 01-17-2022, 03:43 PM

Hello. I've configured Slackware 14.2, on an old laptop that dual boots with BunsenLabs Linux(Debian). I've created the initrd.gz, & modified 40_custom grub entry which includes reference to the initrd.gz. I don't see any glaring messages when I select Slackware from the updated menu at boot time. Unfortunately, the messages scroll by so quickly I have knowing if there is any other problem. I can see something that indicates the kernel is being decompressed. Once, Slackware is loaded, I only see one message in Dmesg which references initrd. The gist being "Freeing initrd memory: 6080K." & that is it. Is there any other way to confirm the initrd.gz file is actually being found, & working properly.
Thanks in advance, -Rick

rkelsen · 01-17-2022, 04:39 PM

The main reason for using an initrd is for filesystem support, without which the kernel won't be able to mount your root partition.

I guess the obvious question is: Does your system boot to a login prompt? If so, then chances are that you got it right.

Please note that if you're using the "huge" kernel, then it has filesystem support for the most common ones built in, so the advice above won't apply.

Didier Spaier · 01-17-2022, 04:47 PM

If you see the message "Freeing initrd memory:" indeed an initrd was used. But it is no more in use when you get the login prompt, that's why the memory it used can (and should) be freed for other purposes.

Tonus · 01-18-2022, 02:21 AM

I would hit "e" on the used grub entry to check the last line that should mention the right initrd.

LuckyCyborg · 01-18-2022, 03:00 AM

Quote:

Originally Posted by rkelsen

The main reason for using an initrd is for filesystem support, without which the kernel won't be able to mount your root partition.

I guess the obvious question is: Does your system boot to a login prompt? If so, then chances are that you got it right.

Please note that if you're using the "huge" kernel, then it has filesystem support for the most common ones built in, so the advice above won't apply.

According with our BDFL himself, the usage of "huge" kernels is NOT supported and recommended, see CHANGES_AND_HINTS.TXT of (to be) Slackware 15.0

Code:

Use one of the provided generic kernels for daily use.  Do not report
  bugs until/unless you have reproduced them using one of the stock.
  generic kernels.  You will need to create an initrd in order to boot
  the generic kernels - see /boot/README.initrd for instructions.
  The huge kernels are primarily intended as "installer" and "emergency".
  kernels in case you forget to make an initrd.  For most systems, you.
  should use the generic SMP kernel if it will run, even if your system is.
  not SMP-capable.  Some newer hardware needs the local APIC enabled in the.
  SMP kernel, and theoretically there should not be a performance penalty.
  with using the SMP-capable kernel on a uniprocessor machine, as the SMP.
  kernel tests for this and makes necessary adjustments.  Furthermore, the.
  kernel sources shipped with Slackware are configured for SMP usage, so you.
  won't have to modify those to build external modules (such as NVidia or.
  ATI proprietary drivers) if you use the SMP kernel.

  If you decide to use one of the non-SMP kernels, you will need to follow the
  instructions in /extra/linux-5.13.9-nosmp-sdk/README.TXT to modify your
  kernel sources for non-SMP usage.  Note that this only applies if you are
  using the Slackware-provided non-SMP kernel - if you build a custom kernel,
  the symlinks at /lib/modules/$(uname -r)/{build,source} will point to the
  correct kernel source so long as you don't (re)move it.

So, nope! The people should NOT use the "huge" kernels with Slackware 15.0 and should NOT recommend them in any situation.

rkelsen · 01-18-2022, 06:25 PM

Quote:

Originally Posted by LuckyCyborg

So, nope! The people should NOT use the "huge" kernels with Slackware 15.0 and should NOT recommend them in any situation.

I don't know if you actually read my post, but I was not making any such recommendation.