af_unix: Remove unix_table_locks.

unix_table_locks are to protect the global hash table, unix_socket_table.
The previous commit removed it, so let's clean up the unnecessary locks.

Here is a test result on EC2 c5.9xlarge where 10 processes run concurrently
in different netns and bind 100,000 sockets for each.

  without this series : 1m 38s
  with this series    :    11s

It is ~10x faster because the global hash table is split into 10 netns in
this case.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/af_unix.h b/include/net/af_unix.h
index b1748c9..480fa57 100644 (file)
--- a/include/net/af_unix.h
+++ b/include/net/af_unix.h
@@ -21,7 +21,6 @@ struct sock *unix_peer_get(struct sock *sk);
 #define UNIX_HASH_BITS 8
 
 extern unsigned int unix_tot_inflight;
-extern spinlock_t unix_table_locks[UNIX_HASH_SIZE];
 
 struct unix_address {
        refcount_t      refcnt;

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 9d0b072..49f6626 100644 (file)
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -118,13 +118,11 @@
 
 #include "scm.h"
 
-spinlock_t unix_table_locks[UNIX_HASH_SIZE];
-EXPORT_SYMBOL_GPL(unix_table_locks);
 static atomic_long_t unix_nr_socks;
 
 /* SMP locking strategy:
- *    hash table is protected with spinlock unix_table_locks
- *    each socket state is protected by separate spin lock.
+ *    hash table is protected with spinlock.
+ *    each socket state is protected by separate spinlock.
  */
 
 static unsigned int unix_unbound_hash(struct sock *sk)
@@ -166,9 +164,6 @@ static void unix_table_double_lock(struct net *net,
        if (hash1 > hash2)
                swap(hash1, hash2);
 
-       spin_lock(&unix_table_locks[hash1]);
-       spin_lock_nested(&unix_table_locks[hash2], SINGLE_DEPTH_NESTING);
-
        spin_lock(&net->unx.table.locks[hash1]);
        spin_lock_nested(&net->unx.table.locks[hash2], SINGLE_DEPTH_NESTING);
 }
@@ -178,9 +173,6 @@ static void unix_table_double_unlock(struct net *net,
 {
        spin_unlock(&net->unx.table.locks[hash1]);
        spin_unlock(&net->unx.table.locks[hash2]);
-
-       spin_unlock(&unix_table_locks[hash1]);
-       spin_unlock(&unix_table_locks[hash2]);
 }
 
 #ifdef CONFIG_SECURITY_NETWORK
@@ -324,20 +316,16 @@ static void __unix_set_addr_hash(struct net *net, struct sock *sk,
 
 static void unix_remove_socket(struct net *net, struct sock *sk)
 {
-       spin_lock(&unix_table_locks[sk->sk_hash]);
        spin_lock(&net->unx.table.locks[sk->sk_hash]);
        __unix_remove_socket(sk);
        spin_unlock(&net->unx.table.locks[sk->sk_hash]);
-       spin_unlock(&unix_table_locks[sk->sk_hash]);
 }
 
 static void unix_insert_unbound_socket(struct net *net, struct sock *sk)
 {
-       spin_lock(&unix_table_locks[sk->sk_hash]);
        spin_lock(&net->unx.table.locks[sk->sk_hash]);
        __unix_insert_socket(net, sk);
        spin_unlock(&net->unx.table.locks[sk->sk_hash]);
-       spin_unlock(&unix_table_locks[sk->sk_hash]);
 }
 
 static struct sock *__unix_find_socket_byname(struct net *net,
@@ -362,13 +350,11 @@ static inline struct sock *unix_find_socket_byname(struct net *net,
 {
        struct sock *s;
 
-       spin_lock(&unix_table_locks[hash]);
        spin_lock(&net->unx.table.locks[hash]);
        s = __unix_find_socket_byname(net, sunname, len, hash);
        if (s)
                sock_hold(s);
        spin_unlock(&net->unx.table.locks[hash]);
-       spin_unlock(&unix_table_locks[hash]);
        return s;
 }
 
@@ -377,7 +363,6 @@ static struct sock *unix_find_socket_byinode(struct net *net, struct inode *i)
        unsigned int hash = unix_bsd_hash(i);
        struct sock *s;
 
-       spin_lock(&unix_table_locks[hash]);
        spin_lock(&net->unx.table.locks[hash]);
        sk_for_each(s, &net->unx.table.buckets[hash]) {
                struct dentry *dentry = unix_sk(s)->path.dentry;
@@ -385,12 +370,10 @@ static struct sock *unix_find_socket_byinode(struct net *net, struct inode *i)
                if (dentry && d_backing_inode(dentry) == i) {
                        sock_hold(s);
                        spin_unlock(&net->unx.table.locks[hash]);
-                       spin_unlock(&unix_table_locks[hash]);
                        return s;
                }
        }
        spin_unlock(&net->unx.table.locks[hash]);
-       spin_unlock(&unix_table_locks[hash]);
        return NULL;
 }
 
@@ -1551,9 +1534,9 @@ restart:
         *
         * The contents of *(otheru->addr) and otheru->path
         * are seen fully set up here, since we have found
-        * otheru in hash under unix_table_locks.  Insertion
-        * into the hash chain we'd found it in had been done
-        * in an earlier critical area protected by unix_table_locks,
+        * otheru in hash under its lock.  Insertion into the
+        * hash chain we'd found it in had been done in an
+        * earlier critical area protected by the chain's lock,
         * the same one where we'd set *(otheru->addr) contents,
         * as well as otheru->path and otheru->addr itself.
         *
@@ -3253,7 +3236,6 @@ static struct sock *unix_get_first(struct seq_file *seq, loff_t *pos)
        struct sock *sk;
 
        while (bucket < UNIX_HASH_SIZE) {
-               spin_lock(&unix_table_locks[bucket]);
                spin_lock(&net->unx.table.locks[bucket]);
 
                sk = unix_from_bucket(seq, pos);
@@ -3261,7 +3243,6 @@ static struct sock *unix_get_first(struct seq_file *seq, loff_t *pos)
                        return sk;
 
                spin_unlock(&net->unx.table.locks[bucket]);
-               spin_unlock(&unix_table_locks[bucket]);
 
                *pos = set_bucket_offset(++bucket, 1);
        }
@@ -3280,7 +3261,6 @@ static struct sock *unix_get_next(struct seq_file *seq, struct sock *sk,
 
 
        spin_unlock(&seq_file_net(seq)->unx.table.locks[bucket]);
-       spin_unlock(&unix_table_locks[bucket]);
 
        *pos = set_bucket_offset(++bucket, 1);
 
@@ -3309,10 +3289,8 @@ static void unix_seq_stop(struct seq_file *seq, void *v)
 {
        struct sock *sk = v;
 
-       if (sk) {
+       if (sk)
                spin_unlock(&seq_file_net(seq)->unx.table.locks[sk->sk_hash]);
-               spin_unlock(&unix_table_locks[sk->sk_hash]);
-       }
 }
 
 static int unix_seq_show(struct seq_file *seq, void *v)
@@ -3337,7 +3315,7 @@ static int unix_seq_show(struct seq_file *seq, void *v)
                        (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
                        sock_i_ino(s));
 
-               if (u->addr) {  // under unix_table_locks here
+               if (u->addr) {  // under a hash table lock here
                        int i, len;
                        seq_putc(seq, ' ');
 
@@ -3416,7 +3394,6 @@ static int bpf_iter_unix_hold_batch(struct seq_file *seq, struct sock *start_sk)
        }
 
        spin_unlock(&seq_file_net(seq)->unx.table.locks[start_sk->sk_hash]);
-       spin_unlock(&unix_table_locks[start_sk->sk_hash]);
 
        return expected;
 }
@@ -3705,13 +3682,10 @@ static void __init bpf_iter_register(void)
 
 static int __init af_unix_init(void)
 {
-       int i, rc = -1;
+       int rc = -1;
 
        BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof_field(struct sk_buff, cb));
 
-       for (i = 0; i < UNIX_HASH_SIZE; i++)
-               spin_lock_init(&unix_table_locks[i]);
-
        rc = proto_register(&unix_dgram_proto, 1);
        if (rc != 0) {
                pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);

diff --git a/net/unix/diag.c b/net/unix/diag.c
index 4d0f0ca..105f522 100644 (file)
--- a/net/unix/diag.c
+++ b/net/unix/diag.c
@@ -13,7 +13,7 @@
 
 static int sk_diag_dump_name(struct sock *sk, struct sk_buff *nlskb)
 {
-       /* might or might not have unix_table_locks */
+       /* might or might not have a hash table lock */
        struct unix_address *addr = smp_load_acquire(&unix_sk(sk)->addr);
 
        if (!addr)
@@ -208,7 +208,6 @@ static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
                struct sock *sk;
 
                num = 0;
-               spin_lock(&unix_table_locks[slot]);
                spin_lock(&net->unx.table.locks[slot]);
                sk_for_each(sk, &net->unx.table.buckets[slot]) {
                        if (num < s_num)
@@ -220,14 +219,12 @@ static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
                                         cb->nlh->nlmsg_seq,
                                         NLM_F_MULTI) < 0) {
                                spin_unlock(&net->unx.table.locks[slot]);
-                               spin_unlock(&unix_table_locks[slot]);
                                goto done;
                        }
 next:
                        num++;
                }
                spin_unlock(&net->unx.table.locks[slot]);
-               spin_unlock(&unix_table_locks[slot]);
        }
 done:
        cb->args[0] = slot;
@@ -242,18 +239,15 @@ static struct sock *unix_lookup_by_ino(struct net *net, unsigned int ino)
        int i;
 
        for (i = 0; i < UNIX_HASH_SIZE; i++) {
-               spin_lock(&unix_table_locks[i]);
                spin_lock(&net->unx.table.locks[i]);
                sk_for_each(sk, &net->unx.table.buckets[i]) {
                        if (ino == sock_i_ino(sk)) {
                                sock_hold(sk);
                                spin_unlock(&net->unx.table.locks[i]);
-                               spin_unlock(&unix_table_locks[i]);
                                return sk;
                        }
                }
                spin_unlock(&net->unx.table.locks[i]);
-               spin_unlock(&unix_table_locks[i]);
        }
        return NULL;
 }