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ix packet stuck problem for lockless qdisc
This patchset fixes the packet stuck problem mentioned in [1].
Patch 1: Add STATE_MISSED flag to fix packet stuck problem.
Patch 2: Fix a tx_action rescheduling problem after STATE_MISSED
flag is added in patch 1.
Patch 3: Fix the significantly higher CPU consumption problem when
multiple threads are competing on a saturated outgoing
device.
V8: Change function name as suggested by Jakub and fix some typo
in patch 3, adjust commit log in patch 2, and add Acked-by
from Jakub.
V7: Fix netif_tx_wake_queue() data race noted by Jakub.
V6: Some performance optimization in patch 1 suggested by Jakub
and drop NET_XMIT_DROP checking in patch 3.
V5: add patch 3 to fix the problem reported by Michal Kubecek.
V4: Change STATE_NEED_RESCHEDULE to STATE_MISSED and add patch 2.