Hi,
I found a potential memory leak in ovs-dpdk hw offload, when remove a
dpdk port in datapath,
the dpif will call dpif_port_del and will eventually remove the netdev
from the map *port_to_netdev* (in netdev-offload). Meanwhile, a
resulted datapath reconfiguration will flush all the marked flows by
calling *flow_mark_flush*, however, this function only put the offload
requests on the queue, it does not wait for the flow deletion
finishes. So there could be a case that the offload thread tries to
delete a hw flow, however, since the netdev is removed, it will fail
at *netdev_ports_get* function, thus, will not call *netdev_flow_del*
thus not free the flow entry (ufid_to_rte_flow_data), which will cause
memory leak.
In fact, since any port removal will hold dp->port_mutex, when calling
*flow_mark_flush*, no flow deletion will really happen since the
offload thread cannot get the *dp->port_mutex* to call
*netdev_flow_del*.
To fix this, we'd better design a wait-done mechanism to wait the
offload process to finish all the deletion. I guess we also need to
remove holding dp->port_mutex in offload thread, instead, by holding
netdev->mutex in the offload layer.
I remember that some patch including querying the hw stats also
depends on the dp->port_mutex, these also needs to be fixed.
--
hepeng
Bytedance
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