[dpdk-stable] vhost: many vhost user ports (backporting to v16.11)

[Robert Wojciechowicz <robertx.wojciechowicz@intel.com>]

Hi,

in DPDK v17.02-rc2 there is available following patch:

commit: 59317cef249c0b23098543df527b3e360ce9764f

"""
vhost: allow many vhost-user ports
Currently select() is used to monitor file descriptors for vhostuser
ports. This limits the number of ports possible to create since the
fd number is used as index in the fd_set and we have seen fds > 1023.
This patch changes select() to poll(). This way we can keep an
packed (pollfd) array for the fds, e.g. as many fds as the size of
the array.
Also see:
http://dpdk.org/ml/archives/dev/2016-April/037024.html
Reported-by: Patrik Andersson <patrik.r.andersson at ericsson.com>
Signed-off-by: Jan Wickbom <jan.wickbom at ericsson.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu at linux.intel.com>
"""

I tested this feature with OVS and DPDK v17.02-rc2.
I applied also this patch to DPDK v16.11 without any issues
and performed the same tests as for v17.02-rc2.
It solves the problem with connecting many VMs to one vSwitch
instance (in my tests 70 VMs) with vhost user ports.

Is it possible to backport this feature to DPDK v16.11?

It is also worth pointing out that OVS 2.7 will use 16.11 
which means we will have this bug for the next 6 months at least 
unless we can backport.

What's your opinion?

Br,
Robert