[PATCH] x86, kdump: crashkernel=X try to reserve below 896M first, then try below 4G, then MAXMEM

[Vivek Goyal]

On Thu, Oct 24, 2013 at 12:15:25PM -0700, Yinghai Lu wrote:
> On Thu, Oct 24, 2013 at 7:02 AM, Vivek Goyal <vgoyal at redhat.com> wrote:
> > On Wed, Oct 23, 2013 at 11:11:51PM -0700, Yinghai Lu wrote:
> >
> > Hence both crashkernel=xM and crashkernel=XM,high have their own usage.
> > We have been using crashkernel=xM and we know it works. So extending it
> > to be able to allocate memory from higher regions, if sufficient memory
> > is not available in lower regions makes sense. Memory reservation below
> > 4G is more efficient due to not requiring swiotlb. And crashkernel=xM
> > has been working for us and users are familiar with it.
> >
> > So I don't see a point that why would you try to block any move to
> > extend crashkernel=xM semantics.
> 
> Make the thing simple.
> Keep them separately, leave crashkernel=xM to old kexec-tools mostly
> and keep crashkernel=xM,high to newer kexec-tools as needed.

I am keeping things simple by making sure that both old kexec-tools and
new kexec-tools can use crashkernel=xM and one does not have to choose
between two based on what kexec-tools version you are using.

Also keeping things simple by not trying to *impose* a new crashkernel=
syntax on existing crashkernel=xM users.

Hence extending the semantics of crashkernel=xM makes sense to me.

Thanks
Vivek