RHEL: TCP(v6) slab objects keep increasing due to application socket leak

Issue

• If this issue is happening the TCPv6 objects will look like following. Note how the 2nd (active_objs) and 3rd (num_objs) values are almost the same. If num_objs is much larger than active_objs. For example 20% or more. Then this could be a slab fragmentation issue. In which case see https://access.redhat.com/solutions/3380691

TCPv6              46901 46911   2176   15    8 : tunables    0    0    0 : slabdata  12000  12000      0

• We are experiencing oom-killer issues on our blades now running RHEL7. Issues occur at about 7 days following the blades rebooting as part of a software upgrade.
• Observed that the TCPv6 cache keeps on growing until it is huge and consuming most of the systems memory by checking the TCPv6 slab in /proc/slabinfo. However /proc/net/sockstat(6) show much less inuse value.