netfilter: nf_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.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c
index 805cfdd..30b8e90 100644
--- a/net/netfilter/nf_conntrack_helper.c
+++ b/net/netfilter/nf_conntrack_helper.c
@@ -159,6 +159,7 @@
struct nf_conntrack_tuple_hash *h;
struct nf_conntrack_expect *exp;
const struct hlist_node *n, *next;
+ const struct hlist_nulls_node *nn;
unsigned int i;
/* Get rid of expectations */
@@ -175,10 +176,10 @@
}
/* Get rid of expecteds, set helpers to NULL. */
- hlist_for_each_entry(h, n, &net->ct.unconfirmed, hnode)
+ hlist_for_each_entry(h, nn, &net->ct.unconfirmed, hnnode)
unhelp(h, me);
for (i = 0; i < nf_conntrack_htable_size; i++) {
- hlist_for_each_entry(h, n, &net->ct.hash[i], hnode)
+ hlist_nulls_for_each_entry(h, nn, &net->ct.hash[i], hnnode)
unhelp(h, me);
}
}
@@ -218,7 +219,7 @@
nf_ct_helper_hsize = 1; /* gets rounded up to use one page */
nf_ct_helper_hash = nf_ct_alloc_hashtable(&nf_ct_helper_hsize,
- &nf_ct_helper_vmalloc);
+ &nf_ct_helper_vmalloc, 0);
if (!nf_ct_helper_hash)
return -ENOMEM;