Re: seqcount usage in xt_replace_table()

[Florian Westphal]

Anatol Pomozov <anatol.pomozov@xxxxxxxxx> wrote:
> Or maybe xt_replace_table() can be enhanced? When I hear that
> something waits until an event happens on all CPUs I think about
> wait_event() function. Would it be better for xt_replace_table() to
> introduce an atomic counter that is decremented by CPUs, and the main
> CPU waits until the counter gets zero?

That would mean placing an additional atomic op into the
iptables evaluation path (ipt_do_table and friends).

Only alternative I see that might work is synchronize_rcu (the
_do_table functions are called with rcu read lock held).

I guess current scheme is cheaper though.