Re: [Qemu-devel] [wiki] New wiki page - vhost-user setup with ovs/dpdk backend

[Marcel Apfelbaum]

On 09/18/2015 08:16 PM, chandrasekar kannan wrote:
> http://wiki.qemu.org/Features/vhost-user-ovs-dpdk
>
> I'm running to problems attempting to try this out. qemu errors out with
>
> qemu-system-x86_64: -object 
> memory-backend-file,id=mem,size=1024M,mem-path=/dev/hugepages,share=on: unable 
> to map backing store for hugepages: Cannot allocate memory
>
> http://pastebin.com/raw.php?i=kSkU8S03
>
> Could someone take a look at this and see what might be wrong ?

Hi,

It seems all the huge pages are already allocated:

    HugePages_Total:    2048
=>  HugePages_Free:        0
    HugePages_Rsvd:        0
    HugePages_Surp:        0

You can try to allocate more:
Run as root:
echo 3072 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages

Thanks,
Marcel

> thanks,
> -Chandra
>
> On Thu, Sep 17, 2015 at 01:08:36PM +0300, Marcel Apfelbaum wrote:
> > /On 09/16/2015 08:44 PM, Flavio Leitner wrote:/
> > / >On Thu, Sep 10, 2015 at 10:51:19PM +0300, Marcel Apfelbaum wrote:/
> > / >>Hi,/
> > / >>/
> > / >>The page describes how to setup an environment that allows /
> > / >>testing/developing/
> > / >>vhost-user using ovs (with dpdk) as backend./
> > / >>/
> > / >>A regular pc machine can be used, no need for several hosts, a 'dpdk /
> > / >>enabled' NIC or 1G huge-pages./
> > / >>/
> > / >>The goal is to connect guests' virtio-net devices having vhost-user backend 
> > /
> > / >>to OVS dpdkvhostuser ports/
> > / >>and be able to run any kind of network traffic between them./
> > / >>/
> > / >>The page can be found at:/
> > / >>http://wiki.qemu.org/Features/vhost-user-ovs-dpdk/
> > / >>/
> > / >>I want to keep it as simple as possible./
> > / >>If you see steps that can be skipped or unneeded configuration please let /
> > / >>me know/
> > / >>or feel free to update the page./
> > / >/
> > / >I gave a quick look and found couple issues. It seems to be missing/
> > / >the installing steps for qemu. Also the eventfd_link module is only/
> > / >needed for vhost-cuse, so you don't need to build/install/load at all./
> > /Hi Flavio,/
> > /Thank you for reviewing the document!/
> > //
> > /For some reason I thought we still need eventfd_link to notify the guests/
> > /when new packets arrive. Indeed we don't need this anymore, I updated the /
> > /wiki page./
>
> > We use the one provided by kernel.  The eventfd_link on DPDK is special for
> > vhost-cuse:
> > https://github.com/openvswitch/ovs/blob/master/INSTALL.DPDK.md#dpdk-vhost-cuse-prerequisites
>
>
> > /Regarding QEMU, can you please point me to the missing setup steps?/
> > /(I think I already took care of them, anyway I want to be sure)/
>
> > Yup, I missed that you are running qemu from the builddir, not from
> > the system, so you don't need to install it.
>
> > Thanks again,
> > fbl