[PATCH v2 net-next 0/4] net: reduce RTNL pressure in unregister_netdevice()

[Eric Dumazet <edumazet@google.com>]

One major source of RTNL contention resides in unregister_netdevice()

Due to RCU protection of various network structures, and
unregister_netdevice() being a synchronous function,
it is calling potentially slow functions while holding RTNL.

I think we can release RTNL in two points, so that three
slow functions are called while RTNL can be used
by other threads.

v2: Only temporarily release RTNL from cleanup_net()
v1: https://lore.kernel.org/netdev/20250107130906.098fc8d6@kernel.org/T/#m398c95f5778e1ff70938e079d3c4c43c050ad2a6

Eric Dumazet (4):
  net: expedite synchronize_net() for cleanup_net()
  net: no longer assume RTNL is held in flush_all_backlogs()
  net: no longer hold RTNL while calling flush_all_backlogs()
  net: reduce RTNL hold duration in unregister_netdevice_many_notify()

 include/net/net_namespace.h |  2 +
 net/core/dev.c              | 78 +++++++++++++++++++++++++++----------
 net/core/net_namespace.c    |  5 +++
 3 files changed, 65 insertions(+), 20 deletions(-)

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2.47.1.613.gc27f4b7a9f-goog