Re: [PATCH] memory hotadd fixes [4/5] avoid check in acpi

[keith mannthey <kmannth@us.ibm.com>]

On Fri, 2006-08-04 at 11:23 +0300, Mika Penttilä wrote:
> keith mannthey wrote:
> > On Fri, 2006-08-04 at 12:48 +0900, KAMEZAWA Hiroyuki wrote:
> >   
> >> On Thu, 03 Aug 2006 20:23:46 -0700
> >> keith mannthey <kmannth@us.ibm.com> wrote:
> >>     
> >
> >   
> >>>>> What keeps 0xa0000000 to 0xa1000000 from being re-onlined by a bad call
> >>>>> to add_memory?
> >>>>>           
> >>>> Usual sparsemem's add_memory() checks whether there are sections in
> >>>> sparse_add_one_section(). then add_pages() returns -EEXIST (nothing to do).
> >>>> And ioresouce collision check will finally find collision because 0-0xbffffff
> >>>> resource will conflict with 0xa0000000 to 0xa10000000 area.
> >>>> But, x86_64 's (not sparsemem) add_pages() doen't do collision check, so it panics.
> >>>>         
> >>> I have paniced with your 5 patches while doing SPARSMEM....  I think
> >>> your 6th patch address the issues I was seeing.  
> >>>
> >>>       
> >
> >
> > with the 6 patches things work as expected.  It is nice to have the
> > sysfs devices online the correct amount of memory.  
> >
> > I was broken without this patch because invalid add_memory calls are
> > made on by box (yet another issue) during boot. 
> >
> > I will build my patch set on top of your 6 patches. 
> >
> > Thanks,
> >   Keith 
> >
> >   
> Keith, are you working on the reserve hotadd case? It looks really 
> broken, at the same time we both assume the hot add region contains RAM 
> per e820 (use of reserve_bootmem_node()) and at the same time in other 
> places (in reserve_hotadd()) that it may not contain RAM. And 
> nodes_cover_memory() is broken no matter what we assume.

I am working that right now... There is handful of things that need
cleaned up with RESERVE.  I am about 1 patch away for a patchset that
make both SPARSEMEM and RESERVE hot-add work on x86_64. It should be out
soon. 

Reserve is in a non-compile state as it stands with 2.6.18. 

Thanks,
 Keith