I have CentOS 5.5 and this is my kernel: 2.6.18-194.11.1.el5.centos.plusxen
Regulary, my comuter have ~2G of memory. After creating Xen DomUs (2 domains 512 M memory each one) it down to ~1G, but it does not return to 2G even after all domains go sleep.
So, this is MemTotal line from /proc/meminfo directly after Dom0 boot:
MemTotal: 1777664 kB
And this is after I boot up and boot down 2 DomUs:
MemTotal: 980992 kB
This is output of xm list after I put domains down:
[~]# xm list Name ID Mem(MiB) VCPUs State Time(s) Domain-0 0 958 2 r----- 1819.9 [~]#
What I need for return the memory to Dom0?