On 12/12/2009 10:37 PM, Thomas Fjellstrom wrote:
I have the opposite happen, when a VM is started, RES is usually lower than -m, which I find slightly odd. But makes sense if qemu/kvm don't actually allocate memory from the host till its requested the first time
That is the case.
(if only it would return some of it afterwards, it would be even better).
Use the balloon driver to return memory to the host.
I just fully shut down and restarted on of my vms, which is set to use 128-256 MB ram max. RES is like 72MB on start, and VIRT is 454M. RES generally gets up around 120MB ram when its doing something. One thing I do find a little odd is one of my VMs which is allocated 512MB ram, has a VIRT of 826MB ram. I didn't realize that qemu had so many lib dependencies.
It's not just libraries, it's mostly glibc malloc() allocating huge pools per thread, as well as large thread stacks.
Due to kvm not supporting giving memory back, besides by swapping large portions of unused guest ram, my host currently has over 1G used swap. Not particularly happy with that, but it doesn't seem to effect performance too much (except that it generally likes to swap host processes first, guest performance is decent, but host, not so much).
The Linux vm prefers anonymous memory, so guests do get an advantage. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
