[jboss-jira] [JBoss JIRA] Created: (JGRP-656) Flag to determine when a message is considered delivered

[Bela Ban (JIRA)]

Flag to determine when a message is considered delivered
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                 Key: JGRP-656
                 URL: http://jira.jboss.com/jira/browse/JGRP-656
             Project: JGroups
          Issue Type: Feature Request
            Reporter: Bela Ban
         Assigned To: Bela Ban
             Fix For: 2.7
         Attachments: tmp.java

Okay, I know what the problem is.

When a multicast message is received from sender A, then a lock is acquired for A (or we block until A's done processing the message and releases the lock).

When the receive() method would send more messages down the stack, that lock might get held for potentially a long time. So I made the following change: I assume that calling down() from within receive() means that the message has been *delivered*, so I release the lock held for A and someone else can now acquire that lock. If you comment the lines of ProtocolStack.down() and recompile JGroups, then you will always see a count of 1:


public Object down(Event evt) {
        ReentrantLock lock=locks.remove(Thread.currentThread());
        //if(lock != null && lock.isHeldByCurrentThread()) {
          //  lock.unlock();
            //if(log.isTraceEnabled())
              //  log.trace("released lock held by " + Thread.currentThread());
        //}
        if(top_prot != null)
            return top_prot.down(evt);
        return null;
    }


The issue here is that I don't want to block incoming calls just because the receive() method sends other messages. This is described in http://jira.jboss.com/jira/browse/JGRP-535.

I might introduce a flag in ProtocolStack to configure this behavior...

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