From: Sowmini Varadhan <sowmini.varadhan@xxxxxxxxxx> Date: Fri, 8 Aug 2014 14:55:22 -0400 > On (08/08/14 11:46), David Miller wrote: >> I don't think vnet_walk_rx() is really able to handle any kind of real >> failures from vnet_send_ack() properly. If we send one or more >> VIO_DRING_ACTIVE ACKs and then can't send the VIO_DRING_STOPPED one >> out, the ring will likely be left in an inconsistent state. > > I just found out last week that you dont actually need to set the > VIO_ACK_ENABLE (and thus trigger the ACTIVE acks)- evidently the protocol > is such that the STOPPED ldc message is sufficient. > > So one patch that I'm working on lining up (after due testing etc) > is to not set VIO_ACK_ENABLE in vnet_start_xmit- it also helps perf > slightly because it reduces the trips through ldc (and potentail > for filling up the ldc ring). This only works because we free the packet in the ->ndo_start_xmit() method. If we didn't do that, and we freed it up at ACK time, we'd need to force the ACKs in order to guarentee that we release the SKB in a finite amount of time. -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
