Hi Jan-Bernd, Jan-Bernd Themann <[EMAIL PROTECTED]> wrote on 09/19/2007 06:53:48 PM:
> If I understood it right the problem you describe (quota update in > __napi_schdule) can cause further problems when you choose the > following numbers: > > CPU1: A. process 99 pkts > CPU1: B. netif_rx_complete() > CPU2: interrupt occures, netif_rx_schedule is called, net_rx_action triggerd: > CPU2: C. set quota = 100 (__napi_schedule) > CPU2: D. call poll(), process 1 pkt > CPU2: D.2 call netif_rx_complete() (quota not exeeded) > CPU2: E. net_rx_action: set quota=99 > CPU1: F. net_rx_action: set qutoa=99 - 99 = 0 > CPU1: G. modify list (list_move_tail) altough netif_rx_complete has been called > > Step G would fail as the device is not in the list due > to netif_rx_complete. This case can occur for all > devices running on an SMP system where interrupts are not pinned. I think list_move should be ok whether device is on the list or not. But it should not come to that code since work (99) != weight (100). If work == weight, then driver would not have done complete, and the next/prev would not be set to POISON. I like the clean changes made by Dave to fix this, and will test it today (if I can get my crashed system to come up). Thanks, - KK - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
