[Spread-cvs] commit: r456 - trunk/daemon

[jschultz at spread.org]

Author: jschultz
Date: 2012-01-10 12:40:40 -0500 (Tue, 10 Jan 2012)
New Revision: 456

Modified:
   trunk/daemon/Changelog
   trunk/daemon/session.c
Log:
Changed the way we badger sessions to now also monitor for writeability with LOW_PRIORITY.


Modified: trunk/daemon/Changelog
===================================================================
--- trunk/daemon/Changelog	2012-01-09 20:35:02 UTC (rev 455)
+++ trunk/daemon/Changelog	2012-01-10 17:40:40 UTC (rev 456)
@@ -1,3 +1,17 @@
+Tue Jan 10 12:30:48 2012  John Schultz <jschultz at spreadconcepts.com>
+
+	* session.c: Changed the way we "badger" client sessions that have 
+	blocked.  We now schedule both timeout and write-ability callbacks
+	on the client session.  This should ensure that clients usuaully 
+	don't see long delays in the delivery of their messages due to the 
+	badger timeout.  That old behavior can reassert itself during 
+	memberships where we block LOW_PRIORITY events.  It was felt that 
+	condition is so rare and we will likely block delivery of messages 
+	right around the membership regardless (until EVS closes) as to 
+	be a minimal concern versus treating writeable clients as 
+	MEDIUM or HIGH priority events, which could have unforseen negative
+	effects on Spread's event processing.
+
 Mon Jan  9 12:52:10 2012  John Schultz <jschultz at spreadconcepts.com>
 
 	* sp.c, session.c: Added SO_KEEPALIVE to client sessions.

Modified: trunk/daemon/session.c
===================================================================
--- trunk/daemon/session.c	2012-01-09 20:35:02 UTC (rev 455)
+++ trunk/daemon/session.c	2012-01-10 17:40:40 UTC (rev 456)
@@ -110,7 +110,9 @@
 static	void    Sess_accept( mailbox mbox, int domain, void *dummy );
 static	void	Sess_accept_continue( mailbox, int, void * );
 static	void    Sess_read( mailbox mbox, int domain, void *dummy );
-static	void	Sess_badger( mailbox mbox, void *dummy );
+static	void	Sess_badger( mailbox mbox );
+static	void	Sess_badger_TO( mailbox mbox, void *dummy );
+static  void    Sess_badger_FD( mailbox mbox, int dmy, void *dmy2 );
 static	void	Sess_kill( mailbox mbox );
 static	void	Sess_handle_join( message_link *mess_link );
 static	void	Sess_handle_leave( message_link *mess_link );
@@ -1456,9 +1458,10 @@
                 }
 
                 /* close the mailbox and mark it unoperational */
-                E_dequeue( Sess_badger, mbox, NULL );
+                E_dequeue( Sess_badger_TO, mbox, NULL );
                 E_detach_fd( mbox, READ_FD );
                 E_detach_fd( mbox, EXCEPT_FD );
+		E_detach_fd( mbox, WRITE_FD );
                 close( mbox );
                 /* the mailbox is closed but the entry still points to it */
                 Sessions[ses].status = Clear_op_session( Sessions[ses].status );
@@ -1552,7 +1555,7 @@
 
 	if( Sessions[ses].num_mess > 0 )
 	{
-		Sess_badger( Sessions[ses].mbox , NULL);
+		Sess_badger( Sessions[ses].mbox );
 	}
 
 	msg = mess_link->mess;
@@ -1656,7 +1659,8 @@
                         Message_calculate_current_location(tmp_link->mess, len_sent, &(Sessions[ses].write) );
 
 			/* We will need to badger this guy */
-			E_queue( Sess_badger, Sessions[ses].mbox, NULL, Badger_timeout );
+			E_queue( Sess_badger_TO, Sessions[ses].mbox, NULL, Badger_timeout );
+			E_attach_fd( Sessions[ses].mbox, WRITE_FD, Sess_badger_FD, 0, NULL, LOW_PRIORITY );
 		}else{
 			/* This guy was already badgered */
 			Sessions[ses].last->next = tmp_link;
@@ -1667,7 +1671,7 @@
         Message_Dec_Refcount(msg);
 }
 
-static	void	Sess_badger( mailbox mbox, void *dummy )
+static	void	Sess_badger( mailbox mbox )
 {
 	int		ses;
 	message_link	*mess_link;
@@ -1681,11 +1685,8 @@
 
 	Alarm( SESSION, "Sess_badger: for mbox %d\n", mbox );
 	ses = Sess_get_session_index( mbox );
-	if( ses < 0 || ses >= MAX_SESSIONS ) return;
-	if( !Is_op_session( Sessions[ses].status ) ) return;
+	if( ses < 0 || ses >= MAX_SESSIONS || !Is_op_session( Sessions[ses].status ) || Sessions[ses].num_mess <= 0 ) goto NO_WORK;
 
-	if( Sessions[ses].num_mess <= 0 ) return;
-
 	/* set file descriptor to non blocking */
 	ioctl_cmd = 1;
 	ret = ioctl( mbox, FIONBIO, &ioctl_cmd);
@@ -1751,9 +1752,27 @@
 	ioctl_cmd = 0;
 	ret = ioctl( mbox, FIONBIO, &ioctl_cmd);
 
-	if( Sessions[ses].num_mess > 0 ) E_queue( Sess_badger, mbox, NULL, Badger_timeout );
+	if( Sessions[ses].num_mess > 0 ) {
+	  E_queue( Sess_badger_TO, mbox, NULL, Badger_timeout );
+	  E_attach_fd( mbox, WRITE_FD, Sess_badger_FD, 0, NULL, LOW_PRIORITY );
+
+	}else{
+	NO_WORK:
+	  E_dequeue( Sess_badger_TO, mbox, NULL );
+	  E_detach_fd( mbox, WRITE_FD );
+	}
 }
 
+static void Sess_badger_TO( mailbox mbox, void *dmy )
+{
+        Sess_badger( mbox );
+}
+
+static void Sess_badger_FD( mailbox mbox, int dmy, void *dmy2 )
+{
+        Sess_badger( mbox );
+}
+
 static	void	Sess_kill( mailbox mbox )
 {
 	int		ses;
@@ -1813,9 +1832,10 @@
         Sessions[ses].read_mess = NULL;
 
 	/* close the mailbox and mark it unoperational */
-	E_dequeue( Sess_badger, mbox, NULL );
+	E_dequeue( Sess_badger_TO, mbox, NULL );
 	E_detach_fd( mbox, READ_FD );
 	E_detach_fd( mbox, EXCEPT_FD );
+	E_detach_fd( mbox, WRITE_FD );
         close(mbox);
 	/* the mailbox is closed but the entry still points to it */
 	Sessions[ses].status = Clear_op_session( Sessions[ses].status );