From: Zoltan Kiss <[email protected]> Date: Tue, 4 Feb 2014 19:54:37 +0000
> The recent patch to fix receive side flow control > (11b57f90257c1d6a91cee720151b69e0c2020cf6: xen-netback: stop vif thread > spinning if frontend is unresponsive) solved the spinning thread problem, > however caused an another one. The receive side can stall, if: > - [THREAD] xenvif_rx_action sets rx_queue_stopped to true > - [INTERRUPT] interrupt happens, and sets rx_event to true > - [THREAD] then xenvif_kthread sets rx_event to false > - [THREAD] rx_work_todo doesn't return true anymore > > Also, if interrupt sent but there is still no room in the ring, it take quite > a > long time until xenvif_rx_action realize it. This patch ditch that two > variable, > and rework rx_work_todo. If the thread finds it can't fit more skb's into the > ring, it saves the last slot estimation into rx_last_skb_slots, otherwise it's > kept as 0. Then rx_work_todo will check if: > - there is something to send to the ring (like before) > - there is space for the topmost packet in the queue > > I think that's more natural and optimal thing to test than two bool which are > set somewhere else. > > Signed-off-by: Zoltan Kiss <[email protected]> > Reviewed-by: Paul Durrant <[email protected]> > Acked-by: Wei Liu <[email protected]> Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
