On Tue, Jan 30, 2018 at 08:37:06PM +0000, Shahaf Shuler wrote: > Tuesday, January 30, 2018 11:40 AM, Adrien Mazarguil: > > Unfortunately I didn't get a chance to review this patch before it was > > applied. > > I'm not sure a stopped port is supposed to report events (interrupts). Will > > applications expect them to occur at this point? > > Why not? > > Stopped port is still counted as attached. The fact the application stopped > the packet receive on it doesn't mean it should not receive a sync events > (such as the remove event). > async events, by definition, are not related to traffic being flows through > the port.
My comment is based on my understanding of rte_eth_dev_stop(), which is a device (or port) is completely stopped, in a suspended state and no interrupts shall occur, as a means for applications to temporarily not be bothered by them until restarted. Think about it that way: applications do not want to get interrupts immediately after the device is initialized, because they might not be ready to process them at this point. An explicit call to rte_eth_dev_start() tells the PMD when it's OK to do so. The converse is rte_eth_dev_stop(). Stopping traffic can already be achieved by not polling from the application side, calling rte_eth_dev_[rt]x_queue_stop() and/or toggling RX/TX interrupts through rte_eth_dev_[rt]x_intr_enable(). rte_eth_dev_stop() provides lower-level device control. Perhaps documentation is not clear, however that's how LSC seems implemented in all PMDs; it gets disabled after rte_eth_dev_stop() and one should explicitly use rte_eth_link_get() to retrieve link status afterward. I think RMV should behave similarly with rte_eth_dev_is_removed(). Adapting fail-safe should be easier than modifying all the remaining PMDs. > > In my opinion it's not a fix, as in, it doesn't address an issue introduced > > by the > > mentioned patch whose behavior was correct. > > > > It's probably too late to change it now and it does address an issue seen > > with > > a use case involving this PMD, however I think the fail-safe PMD could as > > well > > poll using the recently-added rte_eth_dev_is_removed() when it's aware > > the underlying port is stopped instead of expecting interrupts. > > > > -- > > Adrien Mazarguil > > 6WIND -- Adrien Mazarguil 6WIND
