doc: Tighten-up and clarify description of tcp_fin_timeout

The description for tcp_fin_timeout should be tigher and more clear.

In addition to being tighter, we should make the spelling of the
state name consistent with what utilities report, remove the now
dated reference to 2.2 and put the default in the consistent place.

Signed-off-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Rick Jones 2012-12-10 11:33:00 +00:00 committed by David S. Miller
parent b146ecd6b5
commit d825da2ede

View File

@ -224,15 +224,14 @@ tcp_fack - BOOLEAN
The value is not used, if tcp_sack is not enabled.
tcp_fin_timeout - INTEGER
Time to hold socket in state FIN-WAIT-2, if it was closed
by our side. Peer can be broken and never close its side,
or even died unexpectedly. Default value is 60sec.
Usual value used in 2.2 was 180 seconds, you may restore
it, but remember that if your machine is even underloaded WEB server,
you risk to overflow memory with kilotons of dead sockets,
FIN-WAIT-2 sockets are less dangerous than FIN-WAIT-1,
because they eat maximum 1.5K of memory, but they tend
to live longer. Cf. tcp_max_orphans.
The length of time an orphaned (no longer referenced by any
application) connection will remain in the FIN_WAIT_2 state
before it is aborted at the local end. While a perfectly
valid "receive only" state for an un-orphaned connection, an
orphaned connection in FIN_WAIT_2 state could otherwise wait
forever for the remote to close its end of the connection.
Cf. tcp_max_orphans
Default: 60 seconds
tcp_frto - INTEGER
Enables Forward RTO-Recovery (F-RTO) defined in RFC4138.