Eric Dumazet wrote:
Patrick McHardy a écrit :
I think double entries are not a problem, as you say, there
are already other cases where this can happen. But I think we
should try our best that every entry present at the start and
still present at the end of a dump is also contained in the
dump, otherwise the guantees seem to weak to still be useful.
Your first proposal would do exactly that, right?
If your concern is to not forget entries, and we are allowed to print some entries several times,
then we can just check the final "nulls" value, and if we find a different value than expected for
chain N, go back to begining of chain N.
No need to check hash value (this could help not print several time same entry, we dont care that much)
+ while (is_a_nulls(head)) {
+ if (likely(get_nulls_value(head) == st->bucket)) {
+ if (++st->bucket >= nf_conntrack_htable_size)
+ return NULL;
+ }
Looks perfect :)
[PATCH] conntrack: use SLAB_DESTROY_BY_RCU and get rid of call_rcu()
Use "hlist_nulls" infrastructure we added in 2.6.29 for RCUification of UDP & TCP.
This permits an easy conversion from call_rcu() based hash lists to a
SLAB_DESTROY_BY_RCU one.
Avoiding call_rcu() delay at nf_conn freeing time has numerous gains.
First, it doesnt fill RCU queues (up to 10000 elements per cpu).
This reduces OOM possibility, if queued elements are not taken into account
This reduces latency problems when RCU queue size hits hilimit and triggers
emergency mode.
- It allows fast reuse of just freed elements, permitting better use of
CPU cache.
- We delete rcu_head from "struct nf_conn", shrinking size of this structure
by 8 or 16 bytes.
This patch only takes care of "struct nf_conn".
call_rcu() is still used for less critical conntrack parts, that may
be converted later if necessary.
Applied, thanks a lot.
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
