On Fri, 2017-06-02 at 11:28 -0500, Shiraz Saleem wrote: > On Wed, May 31, 2017 at 02:10:31PM -0600, Bart Van Assche wrote: > > > > On Wed, 2017-05-31 at 12:42 -0500, Shiraz Saleem wrote: > > > > > > > > > > > 5. I proposed a solution -> go and fix your user space program. > > > > > > This is a kernel patch you are trying to revert, you are breaking > > > existing > > > kernel functionality. Nothing to do with user space. > > > > > > Bottom line, come up with a solution that will address both port > > > mapper > > > functionality and your issue. > > > > Hello Shiraz, > > > > Sorry that this means additional work for you, but I agree with > > Leon that > > user space software should not assume that netlink sockets are a > > reliable > > communication mechanism. > > Hi Bart - Thank you for your response. > > The original problem was that ibnl_unicast, which is used to send nl > messages from > portmapper kernel space to user-space, would occasionally and > momentarily fail under stress. > We could have retried the call for a certain amount of time, but > since netlink_unicast has a > nonblock/block parameter, we chose to use the blocking option with a > timeout. So we thought we > did account for deadlocks with this timeout. Just to be clear, replacing a non-blocking and occasionally dropping function with a blocking function but with a timeout does not actually solve the problem, it merely moves the goal post out. It is entirely possible that you will have the problem again given sufficient load. -- Doug Ledford <dledford@xxxxxxxxxx> GPG KeyID: B826A3330E572FDD Key fingerprint = AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
