[Xen-users] Why limit dom0's memory?

["Sandor W. Sklar" <ssklar@xxxxxxxxxxxx>]

Could someone explain why it is recommended to limit the amount of  
memory on the Dom0 via setting dom0_mem=XXX in grub.conf?  Are there  
situations where the dom0 would grab onto more memory then it needs?
I've got two systems (RHEL5.1) running with the Xen kernel; each  
system (X86-64) has 8 GB of RAM.
On one system, as reported by "xm list", the dom0 is using 4978 MiB,  
while the sum of the five domU's memory usage is 2075 MiB, which  
roughly equals full usage of the 8 GB.
On the other, the dom0 is using 2943 MiB, while the sum of the six  
domUs is 5114 MiB, again with a rough total of 8 GB.
So, it appears that the dom0 basically just consumes all memory not  
used by domUs, and will release that memory when it is needed by a new  
guest.  If that is true, then I don't see the advantage of forcing the  
dom0 to a hard memory limit, but there must be one, since the option  
is there and people are using it (or so google tells me.)
Do I have this wrong, or am I not understanding something?

Thanks,
        -s-


_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users