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

[Marcel Apfelbaum <marcel.apfelbaum@gmail.com>]

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
>