net: Convert TCP & DCCP hash tables to use RCU / hlist_nulls
RCU was added to UDP lookups, using a fast infrastructure :
- sockets kmem_cache use SLAB_DESTROY_BY_RCU and dont pay the
price of call_rcu() at freeing time.
- hlist_nulls permits to use few memory barriers.
This patch uses same infrastructure for TCP/DCCP established
and timewait sockets.
Thanks to SLAB_DESTROY_BY_RCU, no slowdown for applications
using short lived TCP connections. A followup patch, converting
rwlocks to spinlocks will even speedup this case.
__inet_lookup_established() is pretty fast now we dont have to
dirty a contended cache line (read_lock/read_unlock)
Only established and timewait hashtable are converted to RCU
(bind table and listen table are still using traditional locking)
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index cb31fbf..4818960 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -41,8 +41,8 @@
* I'll experiment with dynamic table growth later.
*/
struct inet_ehash_bucket {
- struct hlist_head chain;
- struct hlist_head twchain;
+ struct hlist_nulls_head chain;
+ struct hlist_nulls_head twchain;
};
/* There are a few simple rules, which allow for local port reuse by
diff --git a/include/net/inet_timewait_sock.h b/include/net/inet_timewait_sock.h
index 80e4977..4b8ece2 100644
--- a/include/net/inet_timewait_sock.h
+++ b/include/net/inet_timewait_sock.h
@@ -110,7 +110,7 @@
#define tw_state __tw_common.skc_state
#define tw_reuse __tw_common.skc_reuse
#define tw_bound_dev_if __tw_common.skc_bound_dev_if
-#define tw_node __tw_common.skc_node
+#define tw_node __tw_common.skc_nulls_node
#define tw_bind_node __tw_common.skc_bind_node
#define tw_refcnt __tw_common.skc_refcnt
#define tw_hash __tw_common.skc_hash
@@ -137,10 +137,10 @@
struct hlist_node tw_death_node;
};
-static inline void inet_twsk_add_node(struct inet_timewait_sock *tw,
- struct hlist_head *list)
+static inline void inet_twsk_add_node_rcu(struct inet_timewait_sock *tw,
+ struct hlist_nulls_head *list)
{
- hlist_add_head(&tw->tw_node, list);
+ hlist_nulls_add_head_rcu(&tw->tw_node, list);
}
static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
@@ -175,7 +175,7 @@
}
#define inet_twsk_for_each(tw, node, head) \
- hlist_for_each_entry(tw, node, head, tw_node)
+ hlist_nulls_for_each_entry(tw, node, head, tw_node)
#define inet_twsk_for_each_inmate(tw, node, jail) \
hlist_for_each_entry(tw, node, jail, tw_death_node)