linux.git/net/ipv4/proc.c, branch v4.11

net: add LINUX_MIB_PFMEMALLOCDROP counter

2017-02-03T04:34:19+00:00

Debugging issues caused by pfmemalloc is often tedious.

Add a new SNMP counter to more easily diagnose these problems.

Signed-off-by: Eric Dumazet 
Cc: Josef Bacik 
Acked-by: Josef Bacik 
Signed-off-by: David S. Miller

net: remove bh disabling around percpu_counter accesses

2017-01-20T16:27:22+00:00

Shaohua Li made percpu_counter irq safe in commit 098faf5805c8
("percpu_counter: make APIs irq safe")

We can safely remove BH disable/enable sections around various
percpu_counter manipulations.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

ipv4: Namespaceify tcp_tw_recycle and tcp_max_tw_buckets knob

2016-12-29T16:38:31+00:00

Different namespace application might require fast recycling
TIME-WAIT sockets independently of the host.

Signed-off-by: Haishuang Yan 
Signed-off-by: David S. Miller

net: Suppress the "Comparison to NULL could be written" warnings

2016-09-30T05:50:45+00:00

This is to suppress the checkpatch.pl warning "Comparison to NULL
could be written". No functional changes here.

Signed-off-by: Jia He 
Signed-off-by: David S. Miller

proc: Reduce cache miss in snmp_seq_show

2016-09-30T05:50:44+00:00

This is to use the generic interfaces snmp_get_cpu_field{,64}_batch to
aggregate the data by going through all the items of each cpu sequentially.
Then snmp_seq_show is split into 2 parts to avoid build warning "the frame
size" larger than 1024.

Signed-off-by: Jia He 
Signed-off-by: David S. Miller

tcp: md5: add LINUX_MIB_TCPMD5FAILURE counter

2016-08-25T23:43:11+00:00

Adds SNMP counter for drops caused by MD5 mismatches.

The current syslog might help, but a counter is more precise and helps
monitoring.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

ipv4: Namespaceify ip_default_ttl sysctl knob

2016-02-17T01:42:54+00:00

Signed-off-by: Nikolay Borisov 
Signed-off-by: David S. Miller

net: track success and failure of TCP PMTU probing

2015-07-22T05:36:33+00:00

Track success and failure of TCP PMTU probing.

Signed-off-by: Rick Jones 
Signed-off-by: David S. Miller

tcp: add TCPWinProbe and TCPKeepAlive SNMP counters

2015-05-09T20:42:32+00:00

Diagnosing problems related to Window Probes has been hard because
we lack a counter.

TCPWinProbe counts the number of ACK packets a sender has to send
at regular intervals to make sure a reverse ACK packet opening back
a window had not been lost.

TCPKeepAlive counts the number of ACK packets sent to keep TCP
flows alive (SO_KEEPALIVE)

Signed-off-by: Eric Dumazet 
Signed-off-by: Yuchung Cheng 
Acked-by: Neal Cardwell 
Acked-by: Nandita Dukkipati 
Signed-off-by: David S. Miller

tcp/dccp: get rid of central timewait timer

2015-04-13T20:40:05+00:00

Using a timer wheel for timewait sockets was nice ~15 years ago when
memory was expensive and machines had a single processor.

This does not scale, code is ugly and source of huge latencies
(Typically 30 ms have been seen, cpus spinning on death_lock spinlock.)

We can afford to use an extra 64 bytes per timewait sock and spread
timewait load to all cpus to have better behavior.

Tested:

On following test, /proc/sys/net/ipv4/tcp_tw_recycle is set to 1
on the target (lpaa24)

Before patch :

lpaa23:~# ./super_netperf 200 -H lpaa24 -t TCP_CC -l 60 -- -p0,0
419594

lpaa23:~# ./super_netperf 200 -H lpaa24 -t TCP_CC -l 60 -- -p0,0
437171

While test is running, we can observe 25 or even 33 ms latencies.

lpaa24:~# ping -c 1000 -i 0.02 -qn lpaa23
...
1000 packets transmitted, 1000 received, 0% packet loss, time 20601ms
rtt min/avg/max/mdev = 0.020/0.217/25.771/1.535 ms, pipe 2

lpaa24:~# ping -c 1000 -i 0.02 -qn lpaa23
...
1000 packets transmitted, 1000 received, 0% packet loss, time 20702ms
rtt min/avg/max/mdev = 0.019/0.183/33.761/1.441 ms, pipe 2

After patch :

About 90% increase of throughput :

lpaa23:~# ./super_netperf 200 -H lpaa24 -t TCP_CC -l 60 -- -p0,0
810442

lpaa23:~# ./super_netperf 200 -H lpaa24 -t TCP_CC -l 60 -- -p0,0
800992

And latencies are kept to minimal values during this load, even
if network utilization is 90% higher :

lpaa24:~# ping -c 1000 -i 0.02 -qn lpaa23
...
1000 packets transmitted, 1000 received, 0% packet loss, time 19991ms
rtt min/avg/max/mdev = 0.023/0.064/0.360/0.042 ms

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller