Commit 99b53bdd authored by Peter Pan(潘卫平)'s avatar Peter Pan(潘卫平) Committed by David S. Miller
Browse files

ipv4:correct description for tcp_max_syn_backlog 



Since commit c5ed63d6(tcp: fix three tcp sysctls tuning),
sysctl_max_syn_backlog is determined by tcp_hashinfo->ehash_mask,
and the minimal value is 128, and it will increase in proportion to the
memory of machine.
The original description for tcp_max_syn_backlog and sysctl_max_syn_backlog
are out of date.

Changelog:
V2: update description for sysctl_max_syn_backlog

Signed-off-by: default avatarWeiping Pan <panweiping3@gmail.com>
Reviewed-by: default avatarShan Wei <shanwei88@gmail.com>
Acked-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 65e9d805

Documentation/networking/ip-sysctl.txt

+5 −5
Original line number Diff line number Diff line
@@ -282,11 +282,11 @@ tcp_max_ssthresh - INTEGER 
	Default: 0 (off)



tcp_max_syn_backlog - INTEGER

	Maximal number of remembered connection requests, which are

	still did not receive an acknowledgment from connecting client.

	Default value is 1024 for systems with more than 128Mb of memory,

	and 128 for low memory machines. If server suffers of overload,

	try to increase this number.

	Maximal number of remembered connection requests, which have not

	received an acknowledgment from connecting client.

	The minimal value is 128 for low memory machines, and it will

	increase in proportion to the memory of machine.

	If server suffers from overload, try increasing this number.



tcp_max_tw_buckets - INTEGER

	Maximal number of timewait sockets held by system simultaneously.

net/core/request_sock.c

+4 −3
Original line number Diff line number Diff line
@@ -26,10 +26,11 @@ 
 * but then some measure against one socket starving all other sockets

 * would be needed.

 *

 * It was 128 by default. Experiments with real servers show, that

 * The minimum value of it is 128. Experiments with real servers show that

 * it is absolutely not enough even at 100conn/sec. 256 cures most

 * of problems. This value is adjusted to 128 for very small machines

 * (<=32Mb of memory) and to 1024 on normal or better ones (>=256Mb).

 * of problems.

 * This value is adjusted to 128 for low memory machines,

 * and it will increase in proportion to the memory of machine.

 * Note : Dont forget somaxconn that may limit backlog too.

 */

int sysctl_max_syn_backlog = 256;

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