xend: Balloon 4MB memory slop when creating a domain

I've found some problems when running 2 guests with and then trying
to install a new machine (no matter whether using virt-manager or
virt-install).

Signed-off-by: Michal Novotny <minovotn@redhat.com>

diff --git a/tools/python/xen/xend/XendDomainInfo.py b/tools/python/xen/xend/XendDomainInfo.py
index 8cc2084acfac564f8f4fbd420aaf797b71731fa0..815fed65e05acf1da8f25cc6666f8944c5991599 100644 (file)
--- a/tools/python/xen/xend/XendDomainInfo.py
+++ b/tools/python/xen/xend/XendDomainInfo.py
@@ -2253,8 +2253,9 @@ class XendDomainInfo:
         # There is an implicit memory overhead for any domain creation. This
         # overhead is greater for some types of domain than others. For
         # example, an x86 HVM domain will have a default shadow-pagetable
-        # allocation of 1MB. We free up 2MB here to be on the safe side.
-        balloon.free(2*1024, self) # 2MB should be plenty
+        # allocation of 1MB. We free up 4MB here to be on the safe side.
+        # 2MB memory allocation was not enough in some cases, so it's 4MB now
+        balloon.free(4*1024, self) # 4MB should be plenty
 
         ssidref = 0
         if security.on() == xsconstants.XS_POLICY_USE: