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authorMartin KaFai Lau <kafai@fb.com>2022-05-12 03:06:05 +0300
committerJakub Kicinski <kuba@kernel.org>2022-05-13 02:52:18 +0300
commitcae3873c5b3a4fcd9706fb461ff4e91bdf1f0120 (patch)
tree54650bd157a612c462c1fb7856c1800babd1790b /include/net/inet_hashtables.h
parente8d0059000b20c4745c5b6a713f6adb269cff8ff (diff)
downloadlinux-cae3873c5b3a4fcd9706fb461ff4e91bdf1f0120.tar.xz
net: inet: Retire port only listening_hash
The listen sk is currently stored in two hash tables, listening_hash (hashed by port) and lhash2 (hashed by port and address). After commit 0ee58dad5b06 ("net: tcp6: prefer listeners bound to an address") and commit d9fbc7f6431f ("net: tcp: prefer listeners bound to an address"), the TCP-SYN lookup fast path does not use listening_hash. The commit 05c0b35709c5 ("tcp: seq_file: Replace listening_hash with lhash2") also moved the seq_file (/proc/net/tcp) iteration usage from listening_hash to lhash2. There are still a few listening_hash usages left. One of them is inet_reuseport_add_sock() which uses the listening_hash to search a listen sk during the listen() system call. This turns out to be very slow on use cases that listen on many different VIPs at a popular port (e.g. 443). [ On top of the slowness in adding to the tail in the IPv6 case ]. The latter patch has a selftest to demonstrate this case. This patch takes this chance to move all remaining listening_hash usages to lhash2 and then retire listening_hash. Since most changes need to be done together, it is hard to cut the listening_hash to lhash2 switch into small patches. The changes in this patch is highlighted here for the review purpose. 1. Because of the listening_hash removal, lhash2 can use the sk->sk_nulls_node instead of the icsk->icsk_listen_portaddr_node. This will also keep the sk_unhashed() check to work as is after stop adding sk to listening_hash. The union is removed from inet_listen_hashbucket because only nulls_head is needed. 2. icsk->icsk_listen_portaddr_node and its helpers are removed. 3. The current lhash2 users needs to iterate with sk_nulls_node instead of icsk_listen_portaddr_node. One case is in the inet[6]_lhash2_lookup(). Another case is the seq_file iterator in tcp_ipv4.c. One thing to note is sk_nulls_next() is needed because the old inet_lhash2_for_each_icsk_continue() does a "next" first before iterating. 4. Move the remaining listening_hash usage to lhash2 inet_reuseport_add_sock() which this series is trying to improve. inet_diag.c and mptcp_diag.c are the final two remaining use cases and is moved to lhash2 now also. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include/net/inet_hashtables.h')
-rw-r--r--include/net/inet_hashtables.h41
1 files changed, 1 insertions, 40 deletions
diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index 103fc7a30e60..1b8706719d4f 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -111,10 +111,7 @@ struct inet_bind_hashbucket {
#define LISTENING_NULLS_BASE (1U << 29)
struct inet_listen_hashbucket {
spinlock_t lock;
- union {
- struct hlist_head head;
- struct hlist_nulls_head nulls_head;
- };
+ struct hlist_nulls_head nulls_head;
};
/* This is for listening sockets, thus all sockets which possess wildcards. */
@@ -142,32 +139,8 @@ struct inet_hashinfo {
/* The 2nd listener table hashed by local port and address */
unsigned int lhash2_mask;
struct inet_listen_hashbucket *lhash2;
-
- /* All the above members are written once at bootup and
- * never written again _or_ are predominantly read-access.
- *
- * Now align to a new cache line as all the following members
- * might be often dirty.
- */
- /* All sockets in TCP_LISTEN state will be in listening_hash.
- * This is the only table where wildcard'd TCP sockets can
- * exist. listening_hash is only hashed by local port number.
- * If lhash2 is initialized, the same socket will also be hashed
- * to lhash2 by port and address.
- */
- struct inet_listen_hashbucket listening_hash[INET_LHTABLE_SIZE]
- ____cacheline_aligned_in_smp;
};
-#define inet_lhash2_for_each_icsk_continue(__icsk) \
- hlist_for_each_entry_continue(__icsk, icsk_listen_portaddr_node)
-
-#define inet_lhash2_for_each_icsk(__icsk, list) \
- hlist_for_each_entry(__icsk, list, icsk_listen_portaddr_node)
-
-#define inet_lhash2_for_each_icsk_rcu(__icsk, list) \
- hlist_for_each_entry_rcu(__icsk, list, icsk_listen_portaddr_node)
-
static inline struct inet_listen_hashbucket *
inet_lhash2_bucket(struct inet_hashinfo *h, u32 hash)
{
@@ -229,23 +202,11 @@ static inline u32 inet_bhashfn(const struct net *net, const __u16 lport,
void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
const unsigned short snum);
-/* These can have wildcards, don't try too hard. */
-static inline u32 inet_lhashfn(const struct net *net, const unsigned short num)
-{
- return (num + net_hash_mix(net)) & (INET_LHTABLE_SIZE - 1);
-}
-
-static inline int inet_sk_listen_hashfn(const struct sock *sk)
-{
- return inet_lhashfn(sock_net(sk), inet_sk(sk)->inet_num);
-}
-
/* Caller must disable local BH processing. */
int __inet_inherit_port(const struct sock *sk, struct sock *child);
void inet_put_port(struct sock *sk);
-void inet_hashinfo_init(struct inet_hashinfo *h);
void inet_hashinfo2_init(struct inet_hashinfo *h, const char *name,
unsigned long numentries, int scale,
unsigned long low_limit,