On Tue, 2015-12-15 at 17:14 +0100, Willy Tarreau wrote: > Hi Eric, > > On Wed, Nov 11, 2015 at 05:09:01PM -0800, Eric Dumazet wrote: > > On Wed, 2015-11-11 at 10:43 -0800, Eric Dumazet wrote: > > > On Wed, 2015-11-11 at 10:23 -0800, Tom Herbert wrote: > > > > > > > How about doing this in shutdown called for a listener? > > > > > > Seems a good idea, I will try it, thanks ! > > > > > > > Arg, I forgot about this shutdown() discussion we had recently > > with Oracle guys. > > > > It is currently used in linux to unblock potential threads in accept() > > system call. > > > > This would prevent syn_recv sockets to be finally accepted. > > I had a conversation with an haproxy user who's concerned with the > connection drops during the reload operation and we stumbled upon > this thread. I was considering improving shutdown() as well for this > as haproxy already performs a shutdown(RD) during a "pause" operation > (ie: workaround for kernels missing SO_REUSEPORT). > > And I found that the code clearly doesn't make this possible since > shutdown(RD) flushes the queue and stops the listening. > > However I found what I consider an elegant solution which works > pretty well : by simply adding a test in compute_score(), we can > ensure that a previous socket ranks lower than the current ones, > and is never considered as long as the new ones are present. Here I > achieved this using setsockopt(SO_LINGER). The old process just has > to do this with a non-zero value on the socket it wants to put into > lingering mode and that's all. > > I find this elegant since it keeps the same semantics as for a > connected socket in that it avoids killing the queue, and that it > doesn't change the behaviour for existing applications. It just > turns out that listening sockets are set up without any lingering > by default so we don't need to add any new socket options nor > anything. > > Please let me know what you think about it (patch attached), if > it's accepted it's trivial to adapt haproxy to this new behaviour.
Well, problem is : some applications use LINGER on the listener, you can not really hijack this flag. Thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
