[PATCH] makedumpfile/arm64: get SECTIONS_SIZE_BITS from sysfs

[Pingfan Liu]

On Tue, Jun 8, 2021 at 3:17 PM HAGIO KAZUHITO(萩尾　一仁) <k-hagio-ab at nec.com> wrote:
>
> -----Original Message-----
> > On Tue, Jun 8, 2021 at 2:07 PM HAGIO KAZUHITO(萩尾　一仁) <k-hagio-ab at nec.com> wrote:
> > >
> > > -----Original Message-----
> > > > On arm64, memory section size changes due to the kernel commit
> > > > f0b13ee23241 ("arm64/sparsemem: reduce SECTION_SIZE_BITS")
> > > >
> > > > To tackle the compatibility, it is safe to read this info from sysfs
> > > > "/sys/devices/system/memory/block_size_bytes"
> > >
> > > Thanks for the patch, but the place where we should put/get such
> > > necessary information first is vmcoreinfo, which exists for that.
> > > Can we add an entry for the SECTIONS_SIZE_BITS there?
> > >
> > OK, I will send a patch to kernel for it.
>
> FWIW, my expectation is that it will be added to kernel/crash_core.c, i.e.
> not only for arm64, because some architectures like arm and mips also have
> multiple values like arm64 and that will help use makedumpfile, and also
> will make it adaptable to future changes on all architectures.
>
Thanks for your suggestion. I have composed one and run some test now.

Will cc you when sending it.

Thanks,
Pingfan