Re: [Haskell-cafe] sendfile leaking descriptors on Linux?

Hello, It will be interesting to see if that makes any difference -- it shouldn't. In happstack-server we use 'listenOn'. According to the documentation listenOn already sets ReuseAddr: http://hackage.haskell.org/packages/archive/network/2.2.1.7/doc/html/Network... A quick look at the source code confirms it is calling: setSocketOption sock ReuseAddr 1 It sounds to be like you are getting the socket in use error because you have 2 processes running. Seems like the first one hasn't really died, but the second one is started anyway. How is it that your loop starts a second server when the first one has not finished? - jeremy On Fri, Feb 26, 2010 at 1:43 PM, Thomas Hartman wrote:

Thanks, I altered my top level request handler as follows

mysmartserver conf h stateProxy = do socket <- bindPort conf

webserverTid <- forkIO $ simpleHTTPWithSocket socket conf h putStrLn . ( "starting happs server" ++ ) =<< time

control <- startSystemState stateProxy -- start the HAppS state system putStrLn . ( "happs state started" ++ ) =<< time

waitForTermination killThread webserverTid stateShutdown control

I can't replicate the error reliably so I won't know if it actually fixed the problem for a while, therefore just leaving this cookie crumb trail in case others may find it helpful.

2010/2/26 Brandon S. Allbery KF8NH :

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On Feb 26, 2010, at 04:28 , Thomas Hartman wrote:

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me: Like mightybyte, I run my app in a shell loop that will just restart it after a crash. But every once in a while it won't restart because of the busy socket and I need to do a manual restart, killing multiple processes (usually 2).

the error I get is:

bind: resource busy (Address already in use)

This is on application restart? It's not out of file descriptors, it's just the system keeping the socket around (netstat will show it in TIME_WAIT, or possibly in a shutdown negotiation state such as LAST_ACK, FIN_WAIT, etc. TCP lacks *reliable* socket shutdown negotiation).

You want to configure the socket with SO_REUSEADDR before trying to bind it (setSocketOption socket ReuseAddr 1).

As to the portable version of sendfile, it's because not all systems offer a sendfile() system call. Linux and *BSD do, and can use the native implementation; the portable version emulates sendfile() when it doesn't exist, at the price of additional CPU usage/system load (sendfile() having been created specifically to reduce system load in the common case for web servers).

-- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH