BMC/Intel-BMC/linux.git/net/ipv4/inet_hashtables.c, branch dev

tcp: suppress a division by zero warning

2015-07-22T05:13:13+00:00

Andrew Morton reported following warning on one ARM build with gcc-4.4 : net/ipv4/inet_hashtables.c: In function 'inet_ehash_locks_alloc': net/ipv4/inet_hashtables.c:617: warning: division by zero Even guarded with a test on sizeof(spinlock_t), compiler does not like current construct on a !CONFIG_SMP build. Remove the warning by using a temporary variable. Fixes: 095dc8e0c368 ("tcp: fix/cleanup inet_ehash_locks_alloc()") Reported-by: Andrew Morton Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

tcp: connect() from bound sockets can be faster

2015-05-27T18:30:10+00:00

__inet_hash_connect() does not use its third argument (port_offset) if socket was already bound to a source port. No need to perform useless but expensive md5 computations. Reported-by: Crestez Dan Leonard Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

tcp/dccp: try to not exhaust ip_local_port_range in connect()

2015-05-27T17:30:44+00:00

A long standing problem on busy servers is the tiny available TCP port range (/proc/sys/net/ipv4/ip_local_port_range) and the default sequential allocation of source ports in connect() system call. If a host is having a lot of active TCP sessions, chances are very high that all ports are in use by at least one flow, and subsequent bind(0) attempts fail, or have to scan a big portion of space to find a slot. In this patch, I changed the starting point in __inet_hash_connect() so that we try to favor even [1] ports, leaving odd ports for bind() users. We still perform a sequential search, so there is no guarantee, but if connect() targets are very different, end result is we leave more ports available to bind(), and we spread them all over the range, lowering time for both connect() and bind() to find a slot. This strategy only works well if /proc/sys/net/ipv4/ip_local_port_range is even, ie if start/end values have different parity. Therefore, default /proc/sys/net/ipv4/ip_local_port_range was changed to 32768 - 60999 (instead of 32768 - 61000) There is no change on security aspects here, only some poor hashing schemes could be eventually impacted by this change. [1] : The odd/even property depends on ip_local_port_range values parity Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

tcp: fix/cleanup inet_ehash_locks_alloc()

2015-05-26T23:48:46+00:00

If tcp ehash table is constrained to a very small number of buckets (eg boot parameter thash_entries=128), then we can crash if spinlock array has more entries. While we are at it, un-inline inet_ehash_locks_alloc() and make following changes : - Budget 2 cache lines per cpu worth of 'spinlocks' - Try to kmalloc() the array to avoid extra TLB pressure. (Most servers at Google allocate 8192 bytes for this hash table) - Get rid of various #ifdef Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

inet_hashinfo: remove bsocket counter

2015-05-21T22:55:32+00:00

We no longer need bsocket atomic counter, as inet_csk_get_port() calls bind_conflict() regardless of its value, after commit 2b05ad33e1e624e ("tcp: bind() fix autoselection to share ports") This patch removes overhead of maintaining this counter and double inet_csk_get_port() calls under pressure. Signed-off-by: Eric Dumazet Cc: Marcelo Ricardo Leitner Cc: Flavio Leitner Acked-by: Flavio Leitner 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

ipv4: coding style: comparison for inequality with NULL

2015-04-03T16:11:15+00:00

The ipv4 code uses a mixture of coding styles. In some instances check for non-NULL pointer is done as x != NULL and sometimes as x. x is preferred according to checkpatch and this patch makes the code consistent by adopting the latter form. No changes detected by objdiff. Signed-off-by: Ian Morris Signed-off-by: David S. Miller

inet: get rid of last __inet_hash_connect() argument

2015-03-19T02:00:35+00:00

We now always call __inet_hash_nolisten(), no need to pass it as an argument. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

ipv6: get rid of __inet6_hash()

2015-03-19T02:00:35+00:00

We can now use inet_hash() and __inet_hash() instead of private functions. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

inet: add IPv6 support to sk_ehashfn()

2015-03-19T02:00:34+00:00

Intent is to converge IPv4 & IPv6 inet_hash functions to factorize code. IPv4 sockets initialize sk_rcv_saddr and sk_v6_daddr in this patch, thanks to new sk_daddr_set() and sk_rcv_saddr_set() helpers. __inet6_hash can now use sk_ehashfn() instead of a private inet6_sk_ehashfn() and will simply use __inet_hash() in a following patch. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller