Hi Thanks for the responses, but look:
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
/usr/bin/kvm -S -M pc-0.11 -m 1024 -smp 1 -name vm_hsci -uuid
52ed4c7c-65e4-325e-0f96-87a5be6d854c -monitor
unix:/var/run/libvirt/qemu/vm_hsci.monitor,server,nowait -boot c -drive
file=/var/kvm_images/vm_hsci.img,if=virtio,index=0,boot=on -net
nic,macaddr=00:16:36:5b:c4:e2,vlan=0,name=nic.0 -net
tap,fd=16,vlan=0,name=tap.0 -serial pty -parallel none -usb -vnc
127.0.0.1:0 -k en-us -vga cirrus -soundhw es1370
I have -m 1ith 1024 right?
but if I do a top:
1214m 364m 3360 S 0 4.5 46:55.24 kvm
so is clearly above -m
what could be the issue?
Thanks
is using 1214 at this moment sometimes it goes up a lot more..
On 12/13/09 11:41 AM, Thomas Fjellstrom wrote:
On Sun December 13 2009, Avi Kivity wrote:
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.
Will it actually just free the memory and leave the total memory size in the
VM alone? Last I checked it would just decrease the total memory size, which
isn't that useful. Sometimes it needs more ram, so its given 512M ram, but
most of the time can live on 100M or so.
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.
I think the only thing I'd like to have now is automatic memory return, much
like vmware server has. It doesn't change what the guest VM sees, it just
flushes the unused ram back to the host.
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