[ovs-git] [openvswitch/ovs] b52877: dpif-netdev: Force port reconfiguration to change ...
noreply at github.com
Wed Mar 25 20:37:02 UTC 2020
Author: Ilya Maximets <i.maximets at ovn.org>
Date: 2020-03-25 (Wed, 25 Mar 2020)
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.
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 at gmail.com>
Fixes: e32971b8ddb4 ("dpif-netdev: Centralized threads and queues handling code.")
Acked-by: Kevin Traynor <ktraynor at redhat.com>
Signed-off-by: Ilya Maximets <i.maximets at ovn.org>
Signed-off-by: William Tu <u9012063 at gmail.com>
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