Re: [Qemu-devel] [RFC PATCH v0 0/5] spapr-next: Memory hotplug updates

[David Gibson]

On Mon, Aug 03, 2015 at 11:05:38AM +0530, Bharata B Rao wrote:
> This patchset includes some updates to sPAPR memory hotplug code that
> currently resides in spapr-next branch of David Gibson's tree.
> 
> The main change here is to use drc-count hotplug identifier type for memory
> hotplug. Currently we use drc-index type of hotplug identifier for
> memory, which means that we send one EPOW event to guest on hotplug
> of each LMB. Guest kernel has limited buffer space to hold these events
> and we can easily overflow this buffer leading to missing of memory
> hotplug events. After we switch to drc-count type of hotplug identifier,
> we will send only one event to guest on hotplugging each pc-dimm device
> thereby reducing the chances of guest rtas buffer overflow. This change
> allows us to hotplug huge amounts of memory (>16G) in one pc-dimm
> hotplug request.
> 
> Another change here is to not include information about memory specified
> using -m option in ibm,drc-names, ibm,drc-indexes and
> ibm,dynamic-memory-reconfiguration nodes thus having only truly DR capable
> memory in these DT nodes/properties.
> 
> Bharata B Rao (5):
>   spapr: Provide better error message when slots exceed max allowed
>   spapr: Populate ibm,associativity-lookup-arrays correctly for non-NUMA
>   spapr: Revert to address@hidden representation for non-hotplugged memory
>   spapr: Support hotplug by specifying DRC count
>   spapr: Move memory hotplug to RTAS_LOG_V6_HP_ID_DRC_COUNT type
> 
>  hw/ppc/spapr.c         | 58 
> +++++++++++++-------------------------------------
>  hw/ppc/spapr_events.c  | 47 ++++++++++++++++++++++++++++++++--------
>  hw/ppc/spapr_pci.c     |  4 ++--
>  include/hw/ppc/spapr.h |  8 +++++--
>  4 files changed, 61 insertions(+), 56 deletions(-)

I've merged patches 1..3/5 into spapr-next.  4 & 5 I need to think
about a bit more.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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