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author | Ilya Maximets <i.maximets@ovn.org> | 2020-03-25 00:50:45 +0100 |
---|---|---|
committer | William Tu <u9012063@gmail.com> | 2020-03-25 13:35:00 -0700 |
commit | f598f46212d698f091408abd6ff6905a16980169 (patch) | |
tree | 66381c49feb66cc8ca0d275f897e38c750e000ad | |
parent | edc2055a2bf73258d5731a8f8853397190348b04 (diff) | |
download | openvswitch-f598f46212d698f091408abd6ff6905a16980169.tar.gz |
dpif-netdev: Force port reconfiguration to change dynamic_txqs.
In case number of polling threads goes from exact number of Tx queues
in port to higher value while set_tx_multiq() not implemented or not
requesting reconfiguration, port will not be reconfigured and datapath
will continue using static Tx queue ids leading to crash.
Ex.:
Assuming that port p0 supports up to 4 Tx queues and doesn't support
set_tx_multiq() method. For example, netdev-afxdp could be the case,
because it could have multiple Tx queues, but doesn't have
set_tx_multiq() implementation because number of Tx queues always
equals to number of Rx queues.
1. Configuring pmd-cpu-mask to have 3 pmd threads.
2. Adding port p0 to OVS.
At this point wanted_txqs = 4 (3 for pmd threads + 1 for non-pmd).
Port reconfigured to have 4 Tx queues successfully.
dynamic_txqs = (4 < 4) = false;
3. Configuring pmd-cpu-mask to have 10 pmd threads.
At this point wanted_txqs = 11 (10 for pmd threads + 1 for non-pmd).
Since set_tx_multiq() is not implemented, netdev doesn't request
reconfiguration and 'dynamic_txqs' remains in 'false' state.
4. Since 'dynamic_txqs == false', dpif-netdev uses static Tx queue
ids that are in range [0, 10] while device only supports 4 leading
to unwanted behavior and crashes.
Fix that by marking for reconfiguration all the ports that will likely
change their 'dynamic_txqs' value.
It looks like the issue could be reproduced only with afxdp ports,
because all other non-dpdk ports ignores Tx queue ids and dpdk ports
requests for reconfiguration on set_tx_multiq().
Reported-by: William Tu <u9012063@gmail.com>
Reported-at: https://mail.openvswitch.org/pipermail/ovs-dev/2020-March/368364.html
Fixes: e32971b8ddb4 ("dpif-netdev: Centralized threads and queues handling code.")
Acked-by: Kevin Traynor <ktraynor@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: William Tu <u9012063@gmail.com>
-rw-r--r-- | lib/dpif-netdev.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c index a798db45d..e456cc9be 100644 --- a/lib/dpif-netdev.c +++ b/lib/dpif-netdev.c @@ -4941,9 +4941,17 @@ reconfigure_datapath(struct dp_netdev *dp) /* Check for all the ports that need reconfiguration. We cache this in * 'port->need_reconfigure', because netdev_is_reconf_required() can - * change at any time. */ + * change at any time. + * Also mark for reconfiguration all ports which will likely change their + * 'dynamic_txqs' parameter. It's required to stop using them before + * changing this setting and it's simpler to mark ports here and allow + * 'pmd_remove_stale_ports' to remove them from threads. There will be + * no actual reconfiguration in 'port_reconfigure' because it's + * unnecessary. */ HMAP_FOR_EACH (port, node, &dp->ports) { - if (netdev_is_reconf_required(port->netdev)) { + if (netdev_is_reconf_required(port->netdev) + || (port->dynamic_txqs + != (netdev_n_txq(port->netdev) < wanted_txqs))) { port->need_reconfigure = true; } } |