Re: [PATCH] [5/8] Fix logic error in 64bit memory hotadd

Andi Kleen
2008-02-12T11:21:09Z

On Tuesday 12 February 2008 11:35:22 Yasunori Goto wrote:
> Hi Ingo-san.
>
> > > Does anyone even
> > > use memory hotplug currently?
> >
> > I don't know.
>
> IBM's powerpc box can memory hot-add/remove by dynamic partitioning.
> And our fujitsu server has memory hot-add feature (Ia-64).
> So, they are concrete user of memory hotplug.
>
> In x86, E8500 chipset has the feature of memory-hotplug.
> (I searched a data-sheet from intel site.)
> http://download.intel.com/design/chipsets/e8500/datashts/30674501.pdf
> (6.3.8 IMI Hot-Plug)
>
> So, it depends on how many server uses it, I think.

With the logic pud error i found and that seems currently will stay
for the forseeable future in the tree I don't think x86-64 64bit hotadds for more
than 1GB have ever worked with the sparsemem method.

Older trees (before 2.6.24) had also a different method that did
preallocate everything based on the SRAT. That one should have worked
for this case.

-Andi