Re: [PATCH] kdump: add default crashkernel reserve kernel config options

[Petr Tesarik <ptesarik@suse.cz>]

On Thu, 24 May 2018 15:26:27 +0800
Dave Young <dyoung@redhat.com> wrote:

> On 05/24/18 at 08:57am, Petr Tesarik wrote:
>[...]
> > What is "a very minimal initrd"? Last time I had to make a significant
> > adjustment to the estimation for openSUSE, this was caused by growing
> > user-space requirements (systemd in this case, but I don't want to
> > start flamewars on that topic, please).  
> 
> Still I think we have agreement and same feeling about the userspace
> memory requirement.   I think although it is hard, we have been still
> trying to shrink the initramfs memory use.
> 
> Besides of distribution use,  why people can not use some minimal
> initrd?  For example only a basic shell and some necessary tools and
> basic storage eg. raw disks supported, and he/she can just collect the
> panic infomation by himself in a shell.

Again, I'm having trouble with the definition of a "minimal initrd" and
also with the definition of a "workstation". I have already seen a sad
case where kdump started going OOM after connecting a 4K monitor,
because, well, it needed a bigger framebuffer...

OTOH you wrote in another mail that RH has tested some values on a
variety of hardware, so you seem to have a clue. Good for you. I still
believe it is moving policy into the kernel.

Based on past experience, I expect that certain users will argue that
"crashkernel=auto" should work out of the box on their HPE Superdome
with 600+ LUNs attached...

As you wrote elsewhere in the thread:

> I means this patch is not trying to force add a fixed value for crashkernel
> in kernel code. It provides another way one can use on kernel build time
> the value just works.

I don't mind if it is added, although I don't find it very useful.

Petr T