A small AppVM (say, with 100MB total) can go below prefmem, and
still not be assigned memory, because of the MIN_TOTAL_MEMORY_TRANSFER
threshold.
So, if AppVM is below prefmem, allow for smaller mem-sets.
Make meminfo-writer compute used memory, and report to qmemman only if
it has changed significantly enough. As it is written in C, its code is
much faster that qmemman-server; also in the idle case, it saves on xenstore
communication overhead. Allows to send updates up to 10 times per second,
with CPU load on the VM below 0.1%.
Previously, memory_actual (retrieved from xen) was used; it can be inconsistent.
'Memtotal' can be spoofed, but anyway we rely on other fields from /proc/meminfo.
Apparently even if there is not enough xen memory to balloon up,
balloon driver will try to fulfill the request later, when
some memory is freed. Thus, in do_balloon, do not limit mem_set
to the available memory.
Apparently, it interferes:
INFO (XendCheckpoint:417) ERROR Internal error: Could not get vcpu context
INFO (XendCheckpoint:417) ERROR Internal error: Failed to map/save the p2m frame list
Plus:
- dedicated chain for DNAT to nameservers
- prevent intervm networking. Can be conveniently overriden in necessary cases
by inserting ACCEPT clauses (per VM, probably) at the top of FORWARD
Now the balance() has two different cases: enough memory and low_on_memory.
In the former, distribute memory proportianally; in the former, dont do this, as this
makes a VM go below prefmem.
File "/usr/lib64/python2.6/xmlrpclib.py", line 710, in dump_int
raise OverflowError, "int exceeds XML-RPC limits"
OverflowError: int exceeds XML-RPC limits
How crappy.
It can fail e.g. when a domain is being shutdown with a pretty
message like
File "/usr/lib64/python2.6/site-packages/xen/xend/XendDomainInfo.py", line 1322, in setMemoryTarget
(target * 1024))
Error: (1, 'Operation not permitted')
qubes_prepare_saved_domain.sh now takes optional second argument, the
filename. The content of the file will be copied (via xenstore) to DVM
and executed just before save. This makes it possible to preload memory
with useful apps.
