Re: [Qemu-devel] [PATCH v7 0/4] s390: Support for Hotplug of Standby Memory

[Matthew Rosato <mjrosato@linux.vnet.ibm.com>]

On 07/30/2014 02:15 PM, Matthew Rosato wrote:
> This patchset adds support in s390 for a pool of standby memory,
> which can be set online/offline by the guest (ie, via chmem).
> The standby pool of memory is allocated as the difference between 
> the initial memory setting and the maxmem setting.
> As part of this work, additional results are provided for the 
> Read SCP Information SCLP, and new implentation is added for the 
> Read Storage Element Information, Attach Storage Element, 
> Assign Storage and Unassign Storage SCLPs, which enables the s390 
> guest to manipulate the standby memory pool.
> 
> This patchset is based on work originally done by Jeng-Fang (Nick)
> Wang.
> 
> Sample qemu command snippet:
> 
> qemu -machine s390-ccw-virtio  -m 1024M,maxmem=2048M,slots=32 -enable-kvm
> 
> This will allocate 1024M of active memory, and another 1024M 
> of standby memory.  Example output from s390-tools lsmem:
> =============================================================================
> 0x0000000000000000-0x000000000fffffff        256  online   no         0-127
> 0x0000000010000000-0x000000001fffffff        256  online   yes        128-255
> 0x0000000020000000-0x000000003fffffff        512  online   no         256-511
> 0x0000000040000000-0x000000007fffffff       1024  offline  -          512-1023
> 
> Memory device size  : 2 MB
> Memory block size   : 256 MB
> Total online memory : 1024 MB
> Total offline memory: 1024 MB
> 
> 
> The guest can dynamically enable part or all of the standby pool 
> via the s390-tools chmem, for example:
> 
> chmem -e 512M
> 
> And can attempt to dynamically disable:
> 
> chmem -d 512M
> 
> Changes for v7:
>  * Added patch to enforce the same memory alignments in s390-virtio.c,
>    so that shared code (like sclp) doesn't need to be dual paths.  

Ping...

> 
> Changes for v6:
>  * Fix in sclp.h - DeviceState parent --> SysBusDevice parent 
>    in struct sclpMemoryHotplugDev.
>  * Fix in assign_storage - int this_subregion_size, should 
>    be uint64_t.
>  * Added information on how to test in the cover letter.  
> 
> Changes for v5:
>  * Since ACPI memory hotplug is now in, removed Igor's patches 
>    from this set.
>  * Updated sclp.c to use object_resolve_path() instead of 
>    object_property_find().
> 
> Matthew Rosato (4):
>   sclp-s390: Add device to manage s390 memory hotplug
>   virtio-ccw: Include standby memory when calculating storage increment
>   s390-virtio: Apply same memory boundaries as virtio-ccw
>   sclp-s390: Add memory hotplug SCLPs
> 
>  hw/s390x/s390-virtio-ccw.c |   46 +++++--
>  hw/s390x/s390-virtio.c     |   15 ++-
>  hw/s390x/sclp.c            |  289 +++++++++++++++++++++++++++++++++++++++++++-
>  include/hw/s390x/sclp.h    |   20 +++
>  qemu-options.hx            |    3 +-
>  target-s390x/cpu.h         |   18 +++
>  target-s390x/kvm.c         |    5 +
>  7 files changed, 375 insertions(+), 21 deletions(-)
>