On Mon, 21 Nov 2005 21:56:32 +0100 Aritz Bastida <[EMAIL PROTECTED]> wrote
The network developers don't always read lkml, please move this thread to netdev@vger.kernel.org > Hello everybody. > > What I need is to turn off and on the polling done to a network device > which works with NAPI. I'll explain: the network driver issues > netif_rx_schedule() and inserts itself in that cpu's poll_list. But, > transparently, in higher-layer kernel code, that device could be > extracted from that poll_list (if the machine is in congestion, that's > the research i'm doing) and added again later. Unless that higher-level code is on the same CPU, you will have introduced a race. > To do that, I guess I could just remove the device from the poll_list > and add it again when needed, but then the cpu in which I'm doing this > could be different from the previous (if in SMP context), right? > Anyway, if this is what I have to do, I could just access > per_cpu(softnet_data, cpu), but I guess a lock is required for that > (because I am accessing the info for another cpu). In that case, what > lock? You want to change something down inside and not get your hands dirty? > I've looking if there is any function for that purpose, and found > netif_poll_enable/disable, but I couln't find any information that > explains what it is for and the purpose of the bit > __LINK_STATE_RX_SCHED. Anyone can tell? Did you read Documentation/networking/NAPI_HOWTO.txt? It is long winded, but you can understand the basic flow. The bit is to make sure not to insert a device in the poll list if it is already in one. -- Stephen Hemminger <[EMAIL PROTECTED]> OSDL http://developer.osdl.org/~shemminger - 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
