| |
|
 |
|
 |
|
|
|
| |
|
|
xen-devel
RE: [Xen-devel] Re: how to change the memory size of a VM
|
There
must be a balloon driver in the guest for memory to be dynamically removed from
the guest. Then when Xen tells the balloon driver to take
memory, the guest decides which pages of memory to give away (thinking that
it is giving the memory to an especially hungry device driver). Google for
"balloon driver" for more info on how this works on Xen, VMware, other
VMMs.
If
you are interested in much more detail on this, google for "self-ballooning Xen"
and "transcendent memory".
I
am looking into a problem that when the memory size of a VM is changed which
part of the original memory is taken away by xen.
For example, if I
change the memory size of a VM from 2048MB --> 1024MB, how can I tell
which are the 1024M byte that will be taken away (I do not want the xen to
take the memory spaces that are caching useful data).
The command for
memory size reconfiguration is "xm mem-set", so I looked the source code of
xm.
It turned out to be the following python
calls:
tools/python/xen/xm/main.py: setMemoryTarget(dom,
mem_target)
tools/python/xen/xend/XendDomainInfo.py:
setMemoryTarget:
self._safe_set_memory('memory_dynamic_min', target *
MiB)
self._safe_set_memory('memory_dynamic_max', target *
MiB)
xen.xend.XendDomain.instance().managed_config_save(self)
tools/python/xen/xend/XendDomainInfo.py:
_safe_set_memory
self.info[‘memory_dynamic_min’] =
target
self.info[‘memory_dynamic_max’] =
target It seems that to change the memory size of a VM, you just need
to save the new size in somewhere, xenstore? How would the new size take
effect? the memory mapping of the VM must be modified somewhere. Look
forward to replies, sorry if the question is stupid, a newbie here
^_^ Thanks in advance
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
|
|
| |
|
Home