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>
Signed-off-by: David S. Miller <davem@davemloft.net>
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