Hello Gur!
On Tue, 2024-09-17 at 11:10 +0300, Gur Stavi wrote:
@@ -1594,10 +1592,11 @@ void dsa_switch_shutdown(struct dsa_switch *ds) }
/* Disconnect from further netdevice notifiers on the conduit,
* since netdev_uses_dsa() will now return false.
* from now on, netdev_uses_dsa_currently() will return false.*/ dsa_switch_for_each_cpu_port(dp, ds)
dp->conduit->dsa_ptr = NULL;
rcu_assign_pointer(dp->conduit->dsa_ptr, NULL);- synchronize_rcu();
rtnl_unlock(); out:
Hi, I am a newbie here. Thanks for the opportunity for learning more about rcu. Wouldn't it make more sense to call synchronize_rcu after rtnl_unlock?
This is indeed a question which is usually resolved other way around (making locked section shorter), but in this particular case I thought that: - we actually don't need giving rtnl lock sooner, which would potentially make synchronize_rcu() call longer (if another thread manages to wake up and claim the rtnl lock before synchronize_rcu()) - we are in shutdown phase, we don't need to minimize lock contention, we need to minimize the overall shutdown time