nginx hanging with state zoneli

[Steven Hartland]

The first time in a while be we just had nginx get stuck in the zoneli
state:
51630 www         1 -16    0 16616K  9396K zoneli 2  24:33  0.00% nginx
51627 www         1 -16    0 16616K  9376K zoneli 1  24:22  0.00% nginx
51629 www         1 -16    0 16616K  9372K zoneli 3  24:09  0.00% nginx
51628 www         1 -16    0 16616K  9104K zoneli 0  24:05  0.00% nginx

Usually I would suspect an mbufs issue but that doesnt seem to have
caused the problem this time, going by the info below, anyone ideas?

Running: 7.0-RELEASE-p11 AMD64

== netstat -m ==
14829/11796/26625 mbufs in use (current/cache/total)
2240/1024/3264/262144 mbuf clusters in use (current/cache/total/max)
1449/727 mbuf+clusters out of packet secondary zone in use (current/cache)
12582/218/12800/12800 4k (page size) jumbo clusters in use (current/cache/total/max)
0/0/0/6400 9k jumbo clusters in use (current/cache/total/max)
0/0/0/3200 16k jumbo clusters in use (current/cache/total/max)
58515K/5869K/64384K bytes allocated to network (current/cache/total)
0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters)
0/0/0 requests for jumbo clusters denied (4k/9k/16k)
0/0/0 sfbufs in use (current/peak/max)
0 requests for sfbufs denied
0 requests for sfbufs delayed
3214 requests for I/O initiated by sendfile
0 calls to protocol drain routines


== /etc/sysctl.con ==
# Large amounts of files in directories fix
vfs.ufs.dirhash_maxmem=8379692

# Network performance tunning
net.inet.tcp.inflight.enable=0
net.inet.tcp.sendspace=65536
kern.ipc.maxsockbuf=16777216
net.inet.tcp.sendbuf_max=16777216
net.inet.tcp.recvbuf_max=16777216

# Prevent nginx issues:-
# Increase backlog max
kern.ipc.somaxconn=1024

# Prevent issue with pmap
vm.pmap.shpgperproc=500

# high server numbers tuning see:
# http://rerepi.wordpress.com/2008/04/19/tuning-freebsd-sysoev-rit/
kern.ipc.nmbclusters=262144
kern.ipc.maxsockets=204800
net.inet.tcp.msl=20000

== /boot/loader.conf ==
accf_http_load="YES"
net.inet.tcp.syncache.hashsize=1024
net.inet.tcp.syncache.bucketlimit=100
net.inet.tcp.tcbhashsize=4096
vm.kmem_size=768M
vm.kmem_size_max=768M
                          

================================================
This e.mail is private and confidential between Multiplay (UK) Ltd. and the person or entity to whom it is addressed. In the event of misdirection, the recipient is prohibited from using, copying, printing or otherwise disseminating it or any information contained in it. 

In the event of misdirection, illegible or incomplete transmission please telephone +44 845 868 1337
or return the E.mail to postmaster at multiplay.co.uk.