orphan sockets

orphan sockets

[Denys Fedoryshchenko]

 Hi

 Just after digging orphan sockets problem, that was causing "Address 
 already in use" for bind(),i found that in documentation is mentioned:

 tcp_orphan_retries - INTEGER
         This value influences the timeout of a locally closed TCP 
 connection,
         when RTO retransmissions remain unacknowledged.
         See tcp_retries2 for more details.

         The default value is 7.
         If your machine is a loaded WEB server,
         you should think about lowering this value, such sockets
         may consume significant resources. Cf. tcp_max_orphans.


 But all servers i have, i notice that  tcp_orphan_retries = 0 by 
 default, i check in code, and found that:
         if (retries == 0 && alive)
                 retries = 8;
 is a bit confusing, that tcp_orphan_retries = 0, is in fact = 8, or to 
 be more exact is 8 if socket has rto < RTO_MAX. But nothing like 7 
 mentioned in documentation, i guess it is wrong?. My english too bad to 
 edit that, but maybe someone will take a look :-)


 ---
 System administrator
 Denys Fedoryshchenko
 Virtual ISP S.A.L.

Re: orphan sockets

[Daniel Baluta]

On Fri, Jul 8, 2011 at 6:13 PM, Denys Fedoryshchenko <denys@visp.net.lb> wrote:
> Hi
>
> Just after digging orphan sockets problem, that was causing "Address already
> in use" for bind(),i found that in documentation is mentioned:
>
> tcp_orphan_retries - INTEGER
>        This value influences the timeout of a locally closed TCP connection,
>        when RTO retransmissions remain unacknowledged.
>        See tcp_retries2 for more details.
>
>        The default value is 7.
>        If your machine is a loaded WEB server,
>        you should think about lowering this value, such sockets
>        may consume significant resources. Cf. tcp_max_orphans.

This should be 8. tcp(7) got it wright.

> But all servers i have, i notice that  tcp_orphan_retries = 0 by default, i
> check in code, and found that:
>        if (retries == 0 && alive)
>                retries = 8;
> is a bit confusing, that tcp_orphan_retries = 0, is in fact = 8, or to be
> more exact is 8 if socket has rto < RTO_MAX. But nothing like 7 mentioned in
> documentation, i guess it is wrong?. My english too bad to edit that, but
> maybe someone will take a look :-)

I guess 0 means, let the operating system to choose the default value for this.
Basically, what we should do here is replace 7 with 8 in
Documentation/networking/ip-sysctl.txt
I can try to make a patch for this if you want.

thanks,
Daniel.

Re: orphan sockets

[David Miller]

From: Daniel Baluta <daniel.baluta@gmail.com>
Date: Fri, 8 Jul 2011 19:28:27 +0300

> I can try to make a patch for this if you want.

No need, I'll take care of this, thanks:

--------------------
net: Fix default in docs for tcp_orphan_retries.

Default should be listed at 8 instead of 7.

Reported-by: Denys Fedoryshchenko <denys@visp.net.lb>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 Documentation/networking/ip-sysctl.txt |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index d3d653a..bfe9242 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -346,7 +346,7 @@ tcp_orphan_retries - INTEGER
 	when RTO retransmissions remain unacknowledged.
 	See tcp_retries2 for more details.
 
-	The default value is 7.
+	The default value is 8.
 	If your machine is a loaded WEB server,
 	you should think about lowering this value, such sockets
 	may consume significant resources. Cf. tcp_max_orphans.
-- 
1.7.6

Re: orphan sockets

[Daniel Baluta]

On Fri, Jul 8, 2011 at 7:31 PM, David Miller <davem@davemloft.net> wrote:
> From: Daniel Baluta <daniel.baluta@gmail.com>
> Date: Fri, 8 Jul 2011 19:28:27 +0300
>
>> I can try to make a patch for this if you want.

thanks David.

Daniel.