Messages in this thread | | | Date | Thu, 10 Jan 2019 23:29:20 +0100 | From | Florian Westphal <> | Subject | Re: seqcount usage in xt_replace_table() |
| |
Peter Zijlstra <peterz@infradead.org> wrote: > Would using synchronize_rcu() not also mean you can get rid of that > xt_write_recseq*() stuff entirely?
No, because those are used to synchronize with cpus that read the ruleset counters, see
net/ipv4/netfilter/ip_tables.c:get_counters().
> Anyway, synchronize_rcu() can also take a little while, but I don't > think anywere near 30 seconds.
Ok, I think in that case it would be best to just replace the recseq value sampling with smp_mb + synchronize_rcu plus a comment that explains why its done.
| |