Re: [RESEND][PATCH v2 2/2] powerpc/fadump: parse fadump reserve memory size based on memory range

On Monday 08 August 2016 02:26 PM, Michael Ellerman wrote:

Hari Bathini [off-list ref] writes:

quoted

On Friday 05 August 2016 12:23 AM, Hari Bathini wrote:

quoted

On Thursday 04 August 2016 03:15 PM, Michael Ellerman wrote:

quoted

The code already knows how to reserve 5% based on the size of the
machine's
memory, as long as no commandline parameter is passed. So why can't we
just use that logic?

That is the default value reserved but not a good enough value for
every case. It is a bit difficult to come up with a robust formula
that works for every case as new kernel changes could make the
values obsolete. But it won't be all that difficult to find values that
work for different memory ranges for a given kernel version.
Passing that as range based input with "fadump_reserve_mem"
parameter would work for every memory configuration on a
given system, which is what this patch is trying to provide..

You want me to add this to the changelog on respin?

Hi Michael,

I'm not really convinced.

Distros are going to want to specify a fixed set of values for different
memory sizes, at least that's what I've seen in the past with kdump. So
I don't see why we can't just do that in the kernel with a formula based
on memory size, and maybe some other information.

Agreed. Such support would be great but this patch is adding support
for a new syntax for an existing parameter which should still be good
to have?

Maybe the formula is more complicated than 5% of RAM, but it shouldn't
be *that* much more complicated.

Depending on what all kernel versions that need support, this can
get ugly? I could be completely wrong though..

Thanks
Hari

cheers

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec