On Fri, 2005-02-18 at 16:52 -0500, Rik van Riel wrote:

On Thu, 17 Feb 2005, Dave Hansen wrote:

quoted

The attached patch is a prototype implementation of memory hot-add.  It
allows you to boot your system, and add memory to it later.  Why would
you want to do this?

I want it so I can grow Xen guests after they have been booted
up.  Being able to hot-add memory is essential for dynamically
resizing the memory of various guest OSes, to readjust them for
the workload.

That's the same thing we like about it on ppc64 partitions.

Memory hot-remove isn't really needed with Xen, the balloon
driver takes care of that.

You can free up individual pages back to the hypervisor, but you might
also want the opportunity to free up some unused mem_map if you shrink
the partition by a large amount.

quoted

I can post individual patches if anyone would like to comment on them.

I'm interested.  I want to get this stuff working with Xen ;)

You can either pull them from here:

	http://www.sr71.net/patches/2.6.11/2.6.11-rc3-mhp1/broken-out/

or grab the whole tarball:

http://www.sr71.net/patches/2.6.11/2.6.11-rc3-mhp1/broken-out-2.6.11-rc3-mhp1.tar.gz

Or, I could always post the whole bunch to lhms.  Nobody there should
mind too much. :)

The largest part of porting hot-add to a new architecture is usually the
sparsemem portion.  You'll pretty much have to #ifdef pfn_to_page() and
friends, declare a few macros, and then do a bit of debugging.  Here's
ppc64 as an example:

http://www.sr71.net/patches/2.6.11/2.6.11-rc3-mhp1/broken-out/B-sparse-170-sparsemem-ppc64.patch

-- Dave

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