Re: [RFC v8 PATCH 00/20] memory-hotplug: hot-remove physical memory

At 09/10/2012 09:52 PM, Vasilis Liaskovitis Wrote:

Hi,

On Mon, Sep 10, 2012 at 10:01:44AM +0800, Wen Congyang wrote:

quoted

At 09/10/2012 09:46 AM, Yasuaki Ishimatsu Wrote:

quoted

Hi Wen,

2012/09/01 5:49, Andrew Morton wrote:

quoted

On Tue, 28 Aug 2012 18:00:07 +0800
wency@cn.fujitsu.com wrote:

quoted

This patch series aims to support physical memory hot-remove.

I doubt if many people have hardware which permits physical memory
removal?  How would you suggest that people with regular hardware can
test these chagnes?

How do you test the patch? As Andrew says, for hot-removing memory,
we need a particular hardware. I think so too. So many people may want
to know how to test the patch.
If we apply following patch to kvm guest, can we hot-remove memory on
kvm guest?

http://lists.gnu.org/archive/html/qemu-devel/2012-07/msg01389.html

Yes, if we apply this patchset, we can test hot-remove memory on kvm guest.
But that patchset doesn't implement _PS3, so there is some restriction.

the following repos contain the patchset above, plus 2 more patches that add
PS3 support to the dimm devices in qemu/seabios:

https://github.com/vliaskov/seabios/commits/memhp-v2
https://github.com/vliaskov/qemu-kvm/commits/memhp-v2

I have not posted the PS3 patches yet in the qemu list, but will post them
soon for v3 of the memory hotplug series. If you have issues testing, let me
know.

Hmm, seabios doesn't support ACPI table SLIT. We can specify node it for dimm
device, so I think we should support SLIT in seabios. Otherwise we may meet
the following kernel messages:
[  325.016769] init_memory_mapping: [mem 0x40000000-0x5fffffff]
[  325.018060]  [mem 0x40000000-0x5fffffff] page 2M
[  325.019168] [ffffea0001000000-ffffea00011fffff] potential offnode page_structs
[  325.024172] [ffffea0001200000-ffffea00013fffff] potential offnode page_structs
[  325.028596]  [ffffea0001400000-ffffea00017fffff] PMD -> [ffff880035000000-ffff8800353fffff] on node 1
[  325.031775] [ffffea0001600000-ffffea00017fffff] potential offnode page_structs

Do you have plan to do it?

Thanks
Wen Congyang

thanks,

- Vasilis