[jboss-jira] [JBoss JIRA] Commented: (JBREM-890) Fix thread pool eviction in socket transport

[Ron Sigal (JIRA)]

    [ http://jira.jboss.com/jira/browse/JBREM-890?page=comments#action_12393337 ] 
            
Ron Sigal commented on JBREM-890:
---------------------------------

Various changes have been made to the server side of the socket transport in response to JBREM-821 "JBoss Remoting fails under load".  In particular, 

   2) The connector close process is not clean. I would suggest the code should be changed so the server threads are shut down at the beginning of the connector close process.  I.e.
      a) Wait for current invocations on that server invoker to complete - and don't allow any more.
      b) Once all are complete shut it down. 

Additional synchronization was added in response.  However, one mistake was to synchronize ServerThread.evict().  The problem is that the SocketServerInvoker AcceptorThread could call ServerThread.evict() while the ServerThread was in the synchronized method completeInvocation(), which could leave the AcceptorThread blocked while a different ServerThread returned itself to the threadpool.  

ServerThread has been changed so that ServerThread.evict() is not synchronized, but a synchronized flag is added so that evict() will shut down the ServerThread's SocketWrapper only if the ServerThread is in Acknowledge() or readVersion().

ServerThread.evict() has also been changed to return a boolean value which indicates if the eviction attempt (i.e., closing the SocketWrapper) was attempted.

org.jboss.remoting.transport.socket.LRUPool, which is the type of SocketServerInvoker.clientpool - which holds ServerThreads currently in use, has been changed to loop through the used threads until a call to ServerThread.evict() returns true.  If no such ServerThread exists, LRUPool will set a flag which can be retrieved with the new method LRUPool.getEvictionNeeded().  At the top of each loop in doRun(), ServerThread will call LRUPool.getEvictionNeeded() and return itself to SocketServerInvoker.threadpool - which holds unused ServerThreads - if getEvictionNeeded() returns true.

> Fix thread pool eviction in socket transport
> --------------------------------------------
>
>                 Key: JBREM-890
>                 URL: http://jira.jboss.com/jira/browse/JBREM-890
>             Project: JBoss Remoting
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>    Affects Versions: 2.4.0.Beta1 (Pinto), 2.2.2.SP4
>            Reporter: Ron Sigal
>         Assigned To: Ron Sigal
>             Fix For: 2.4.0.Beta1 (Pinto)
>
>
> Currently org.jboss.rermoting.transport.socket.ServerThread.evict() attempts to interrupt a thread blocked on i/o in acknowledge() or readVersion() and return it to SocketServerInvoker.threadpool where it can be reused.  However, interrupt() will not normally unblock a thread in an i/o call.  

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