| Message ID | 1307429403.2642.77.camel@edumazet-laptop |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
Le mardi 07 juin 2011 à 08:50 +0200, Eric Dumazet a écrit : > While doing my tests on bnx2x adapter, I found patch was working ok, > but /proc/interrupts still increment interrupt count on my offlined > cpu... go figure... Oh well, "cat /proc/interrupts" skips offlined cpu, of course, thats a false alarm. I was doing "grep eth1 /proc/interrupts" so didnt catch this. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Eric Dumazet <eric.dumazet@gmail.com> Date: Tue, 07 Jun 2011 08:50:03 +0200 > From: Heiko Carstens <heiko.carstens@de.ibm.com> > > Frank Blaschka reported : > <quote> > During heavy network load we turn off/on cpus. > Sometimes this causes a stall on the network device. > Digging into the dump I found out following: > > napi is scheduled but does not run. From the I/O buffers > and the napi state I see napi/rx_softirq processing has stopped > because the budget was reached. napi stays in the > softnet_data poll_list and the rx_softirq was raised again. > > I assume at this time the cpu offline comes in, > the rx softirq is raised/moved to another cpu but napi stays in the > poll_list of the softnet_data of the now offline cpu. > > Reviewing dev_cpu_callback (net/core/dev.c) I did not find the > poll_list is transfered to the new cpu. > </quote> > > This patch is a straightforward implementation of Frank suggestion : > > Transfert poll_list and trigger NET_RX_SOFTIRQ on new cpu. > > Reported-by: Frank Blaschka <blaschka@linux.vnet.ibm.com> > Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> > Tested-by: Eric Dumazet <eric.dumazet@gmail.com> Applied, thanks everyone. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/core/dev.c b/net/core/dev.c index 9393078..095909c 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6178,6 +6178,11 @@ static int dev_cpu_callback(struct notifier_block *nfb, oldsd->output_queue = NULL; oldsd->output_queue_tailp = &oldsd->output_queue; } + /* Append NAPI poll list from offline CPU. */ + if (!list_empty(&oldsd->poll_list)) { + list_splice_init(&oldsd->poll_list, &sd->poll_list); + raise_softirq_irqoff(NET_RX_SOFTIRQ); + } raise_softirq_irqoff(NET_TX_SOFTIRQ); local_irq_enable();