On Sun December 13 2009, rek2 wrote: > 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 VIRT includes a lot of shared memory, so it's not a very useful number to look at when trying to gauge how much memory a process is using. > > 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. > > -- > 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 > -- Thomas Fjellstrom tfjellstrom@xxxxxxx -- 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
