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Re: connection management changes
Hallvard Breien Furuseth wrote:
Howard Chu writes:
We listen for writable sockets if a write attempt returns incomplete. There's
a pair of mutexes and condition variables used to synch up here between the
writing threads and the listener thread. It's quite a lot of lock overhead. As
far as I can tell the main reason we do this is so that we can stop a writer
thread on demand instead of having it just block forever in write().
slapd seems to use non-blocking socket descriptors if it can, so it's
rather that write() to a full socket would otherwise do a busy loop
write()ing 0 bytes until there was room.
My point was that it would have been simpler all around to use a blocking
descriptor and let write() sit and wait, except for the fact that we need the
ability to stop it from waiting.
Of course we also want it to be non-blocking when we read, though we could use
I wonder if slapd can use blocking sockets? Then it could shutdown()
the descriptor to force a blocked write() call to terminate. Unless
there are times when one would want to write something else to the
socket instead - some TLS magic, maybe...
connection_init() does seem to believe slapd can deal with blocking
sockets, since it tests for fcntl NONBLOCK failure but proceeds instead
of aborting the connection.
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/