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af_unix: Remove unix_table_locks.

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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>
This commit is contained in:
Kuniyuki Iwashima 2022-06-21 10:19:13 -07:00 committed by David S. Miller
parent cf2f225e26
commit 2f7ca90a01
3 changed files with 9 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/net/af_unix.h
View File

@ -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;

42
net/unix/af_unix.c
View File

@ -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__);

8
net/unix/diag.c
View File

@ -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;
}