I wondered if someone can help me do this math...

I have 16GiB of Ram according to my Bios
I use fedora which reports only 9GiB total Ram and reports 8.5 Free
I use Xen which reports its using 100% of 15.49 GiB Ram

How in the hell is the system coming to these numbers? Is fedora really only seeing 9 GiB?

Before we get too far, what command did use?

'cat /proc/meminfo'
'top'

Though the Xen data came from virt-manager and may be just saying that it makes that much available if a vm uses it. Not sure but it doesn't make senses that virt-manager sees all the ram and top / meminfo dont.

What does xm info say?

Not sure about the 9G issue. I'd boot to memtest and see what it says.

xm info says 16104 total mem

Ok ok.. figured it out.
I decided to try and turn of one of my VM's just to see what happened. At first the Memory didn't change. So this whole time I'm thinking well its not just allocating all the memory a virt machine asks for it must do it on the fly.... wrong. After a reboot ,with the VM turned off, the Mem total in meminfo changed to 11GiB. That's 2GiB more then it was and exactly the amount I had allocated to the VM. What I don't understand is... If I shut down a VM why am I not getting that memory back unless I reboot my entire machine.

---------- Post added 05-03-12 at 12:00 AM ----------

Ok ok.. figured it out.
I decided to try and turn of one of my VM's just to see what happened. At first the Memory didn't change. So this whole time I'm thinking well its not just allocating all the memory a virt machine asks for it must do it on the fly.... wrong. After a reboot ,with the VM turned off, the Mem total in meminfo changed to 11GiB. That's 2GiB more then it was and exactly the amount I had allocated to the VM. What I don't understand is... If I shut down a VM why am I not getting that memory back unless I reboot my entire machine.

memtest?????