RE: [RFC] /proc/efi_memmap

From: Khalid Aziz <khalid.aziz_at_hp.com>
Date: 2005-09-14 02:05:03
On Sun, 2005-09-11 at 21:34 -0700, Luck, Tony wrote:
> >What does Kexec-people really want ?
> >Excact EFI memory map ? or physical address map with some attributes ?
> 
> Not sure what their exact needs are.

The userspace kexec tools looks at the memory map to verify a new kernel
being loaded in memory will be loaded in memory that is normally
available for it. Same goes for initial ramdisk as well. kexec
opens /proc/iomem on x86 for this. I had sent a patch in July (subject
"[PATCH] /proc/iomem update") that provides same info in /proc/iomem as
x86 does and that will take care of kexec needs. I have already tested
kexec tool for ia64 with that patch and it works fine.

--
Khalid

> 
> >(exporiting just EFI memmap looks easy but...)
> >I think EFI memory map cannot cooperate with memory hotplug and
> >will be obsolete in future.
> >So more generic "physical memory map" looks good.
> 
> Good point.  EFI memory map is static, so the information may
> be wrong in a hot-plug memory world.
> 
> > > 1) Is /proc/efi_memmap a good name?
> >just rename to memory_map and show efi's for now looks good.
> >
> > > +	seq_printf(m, "%4d %16.16lx %16.16lx %lx\n", md->type, 
> >md->phys_addr,
> > > +		efi_md_end(md), md->attribute);
> >
> >and please define more "generic format".
> >If an interface is fixed, we can change implementation.
> 
> If this is a general memory map, rather than EFI map, then
> yes, the EFI type and attributes aren't helpful.
> 
> >BTW, EFI memory map doesn't matches kernel's memory view (by 
> >GRANULE etc..)
> >It isn't problem for kexec-people ?
> 
> I don't see why the new kernel would have the same page and
> granule size.  So it may be able to use memory that the old
> kernel couldn't.
> 
> -Tony
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Received on Wed Sep 14 03:29:25 2005

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