[pve-devel] qemu memory hotplug limited to 64 dimm

[Wolfgang Bumiller]

> On December 14, 2016 at 3:45 PM Alexandre DERUMIER <aderumier at odiso.com> wrote:
> 
> 
> >>3) Drop support for hot*UN*plugging altogether and simply always hot-add
> >>one big dimm. ;-)
> >>On that note, my guests currently hang when I unplug memory and I bet
> >>that happens to all of you and nobody ever noticed because nobody needs
> >>that feature anyway ;-)
> 
> yes, it's a linux guest limitation. (qemu implementation is ok), but linux kernel memory is not movable currently, and if it's located on a dimm, you can't unplug it, as the kernel memory can't be move at another location.

Apparently I do have to explicitly mention that I'm talking about *unused* memory, iow. memory where the /sys/../enabled file is 0. I think this was working at some point on modern guest kernels?