Re: [PATCH] kdumpctrl: kdump feasibility should fail if no crash memory

[Dave Young]

On 04/29/16 at 02:50pm, Pratyush Anand wrote:
> Hi Xunlei,
>
> Thanks for the review
>
> On Fri, Apr 29, 2016 at 2:04 PM, Xunlei Pang  wrote:
> > On 2016/04/29 at 15:57, Pratyush Anand wrote:
> > > Currently initramfs is rebuilt even when crash kernel memory is not
> > > available and then latter on kdump service is failed.
> > >
> > > Its better to fail during feasibility itself when crash memory is not
> > > reserved.
> > > Signed-off-by: Pratyush Anand
> > >
> > > kdumpctl | 25 ++++++++++++++++++-------
> > >  1 file changed, 18 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/kdumpctl b/kdumpctl
> > > index c7abaafdda27..38f29d2a305d 100755
> > > --- a/kdumpctl
> > > +++ b/kdumpctl
> > > @@ -545,13 +545,6 @@ need_64bit_headers()
> > >  # as the currently running kernel.
> > >  load_kdump()
> > >  {
> > > MEM_RESERVED=$(cat /sys/kernel/kexec_crash_size)
> > > if [ $MEM_RESERVED -eq 0 ]
> > > then
> > >         echo "No memory reserved for crash kernel." >&2
> > >         return 1
> > > fi
> > > ARCH=`uname -m`
> > > if [ "$ARCH" == "i686" -o "$ARCH" == "i386" ]
> > > then
> > >
> > > @@ -876,8 +869,26 @@ check_fence_kdump_config()
> > >       return 0
> > >  }
> > >
> > > +is_crash_mem_reserved()
> > > +{
> > > MEM_RESERVED=$(cat /sys/kernel/kexec_crash_size)
> > > if [ $MEM_RESERVED -eq 0 ]
> > > then
> > >         echo "No memory reserved for crash kernel." >&2
> > >         return 0
> > > fi
> > > return 1
> > >
> > > +}
> > >
> > > check_dump_feasibility()
> > >  {
> > > is_crash_mem_reserved
> > > if [ $? -eq 0 ];then
> > >         return 1
> > > fi
> >
> > I don't know if fadump needs reserved memory like kdump?
>
> I am also not sure, but it looks like that fadump also uses same
> memory reservation model. Documentation says:  "Fadump uses the same
> firmware interfaces and memory reservation model as phyp assisted
> dump."

phyp assisten dump is not kdump, it is another firmware assisted dump
in powerpc. I think fadump does not need check crash_mem.

We need it only in check_kdump_feasibility, Ccing Hari anyway.

Thanks
Dave