[Kimchi-devel] [RFC][Kimchi] Guest Max memory setup and update

[Rodrigo Trujillo]

Hi all,

The guest xml tag <max_memory> is necessary to allow memory hotplug. 
Currently, max_memory is the lesser value among "guest memory X4",  
"Host Memory" or "1TB". It is also not possible to user, to set it.

Proposal: Modify backend and frontend in order to allow users to 
increase/decrease max_memory value. In other words, user will be allowed 
to set the amount of memory that will be possible to hotplug.

BACKEND   (a previous patch was already sent to mailing list, must sent 
new version)
- Remove current settings when guest is created. Set max_memory equal 
guest memory.;
- Does not allow change max_memory when guest is running;
- When hotplug, continue with slots of 1GB, but restrict 32 slots in 
PowerPC;
- Update/Add tests;
- Change JSON memory field to:   memory: { current: XXX, maxmemory: YYYY };


FRONTEND

- In guest edit window,  modify memory input field. Change it to a 
increase/decrease ( +/- ) input box;
- Create a hidden area which will hold max memory input box 
(increase/decrease);
- Increments will be of 1GB;
- Create a "More Options" link besides Memory , that is going to 
show/hide  max memory area;
- If guest is online:
     * max memory field will be disabled;
     * memory will be enabled, allowing hotplug;
- When guest is offline, it is ok to change max memory, enable it;


API CHANGES:

JSON must be changed in requests and responses:
     - When updating guest (PUT), memory field will become:
             memory: { current: <memory new value>, maxmemory: 
<maxmemory new value> }
     - response (GET):
             memory: { current: <memory new value>, maxmemory: 
<maxmemory new value> }

It is not necessary to include maxmemory if was not changed.

Thoughts ?

Rodrigo Trujillo