Re: [PATCH] x86, acpi memory hotplug, add parameter to disable memory hotplug

Vivek Goyal
2014-01-14T15:26:27Z

On Tue, Jan 14, 2014 at 06:05:15AM -0500, Prarit Bhargava wrote:

[..]
> >>> As mentioned, self-NAK. I have seen a system that I needed to specify
> >>> memmap=exactmap & had hotplug memory. I will only keep the acpi_no_memhotplug
> >>> option in the next version of the patch.
> >>
> >>
> >> Your following first patch is simply and makes sense.
> >>
> >> http://marc.info/?l=linux-acpi&m=138922019607796&w=2
> >>
> >
> > In this option, it also requires changing kexec-tools to specify the new
> > option for kdump. It won't be simpler.
>
> It will be simpler for the kernel and those of us who have to debug busted e820
> maps ;)
>
> Unfortunately I may not be able to give you the automatic disable. I did
> contemplate adding a !is_kdump_kernel() to the ACPI memory hotplug init call,
> but it seems like that is unacceptable as well.

I think everybody agrees that there has to be a stand alone command line
option to disable memory hotplug.

Whether to tie it into memmap=exactmap and mem=X is the contentious bit.
So I would suggest that just post a patch to disable memory hotplut using
a command line and later more patches can go in if people strongly feel
the need to tie it into memmap=exactmap.

In the mean time, we will modify /etc/sysconfig/kdump to pass
acpi_no_memhotplug so that user does not have to worry about passing this
parameter and kexec-tools will not have to be modified either.

Thanks
Vivek