linux/net/dccp
Eric Dumazet 05dbc7b594 tcp/dccp: remove twchain
TCP listener refactoring, part 3 :

Our goal is to hash SYN_RECV sockets into main ehash for fast lookup,
and parallel SYN processing.

Current inet_ehash_bucket contains two chains, one for ESTABLISH (and
friend states) sockets, another for TIME_WAIT sockets only.

As the hash table is sized to get at most one socket per bucket, it
makes little sense to have separate twchain, as it makes the lookup
slightly more complicated, and doubles hash table memory usage.

If we make sure all socket types have the lookup keys at the same
offsets, we can use a generic and faster lookup. It turns out TIME_WAIT
and ESTABLISHED sockets already have common lookup fields for IPv4.

[ INET_TW_MATCH() is no longer needed ]

I'll provide a follow-up to factorize IPv6 lookup as well, to remove
INET6_TW_MATCH()

This way, SYN_RECV pseudo sockets will be supported the same.

A new sock_gen_put() helper is added, doing either a sock_put() or
inet_twsk_put() [ and will support SYN_RECV later ].

Note this helper should only be called in real slow path, when rcu
lookup found a socket that was moved to another identity (freed/reused
immediately), but could eventually be used in other contexts, like
sock_edemux()

Before patch :

dmesg | grep "TCP established"

TCP established hash table entries: 524288 (order: 11, 8388608 bytes)

After patch :

TCP established hash table entries: 524288 (order: 10, 4194304 bytes)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-08 23:19:24 -04:00
..
ccids net/dccp/ccids: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:39:33 -08:00
ackvec.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
ackvec.h net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
ccid.c net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
ccid.h dccp: check ccid before dereferencing 2012-08-15 21:36:31 -07:00
dccp.h net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
diag.c inet_diag: Rename inet_diag_req into inet_diag_req_v2 2012-01-11 12:56:06 -08:00
feat.c net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
feat.h dccp: support for the exchange of NN options in established state 1/2 2011-08-01 07:52:34 -06:00
input.c net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
ipv4.c tcp: Remove TCPCT 2013-03-17 14:35:13 -04:00
ipv6.c net:dccp: do not report ICMP redirects to user space 2013-09-18 12:33:44 -04:00
ipv6.h
Kconfig net/dccp: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:39:34 -08:00
Makefile dccp: Policy-based packet dequeueing infrastructure 2010-12-07 13:47:12 +01:00
minisocks.c tcp: better retrans tracking for defer-accept 2012-11-03 14:45:00 -04:00
options.c net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
output.c net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
probe.c net: proc: change proc_net_remove to remove_proc_entry 2013-02-18 14:53:08 -05:00
proto.c tcp/dccp: remove twchain 2013-10-08 23:19:24 -04:00
qpolicy.c dccp qpolicy: Parameter checking of cmsg qpolicy parameters 2010-12-07 13:47:12 +01:00
sysctl.c net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
timer.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00