提交 7123aaa3 编写于 作者: E Eric Dumazet 提交者: David S. Miller

af_unix: speedup /proc/net/unix

/proc/net/unix has quadratic behavior, and can hold unix_table_lock for
a while if high number of unix sockets are alive. (90 ms for 200k
sockets...)

We already have a hash table, so its quite easy to use it.

Problem is unbound sockets are still hashed in a single hash slot
(unix_socket_table[UNIX_HASH_TABLE])

This patch also spreads unbound sockets to 256 hash slots, to speedup
both /proc/net/unix and unix_diag.

Time to read /proc/net/unix with 200k unix sockets :
(time dd if=/proc/net/unix of=/dev/null bs=4k)

before : 520 secs
after : 2 secs
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
上级 54db0cc2
......@@ -14,10 +14,11 @@ extern struct sock *unix_get_socket(struct file *filp);
extern struct sock *unix_peer_get(struct sock *);
#define UNIX_HASH_SIZE 256
#define UNIX_HASH_BITS 8
extern unsigned int unix_tot_inflight;
extern spinlock_t unix_table_lock;
extern struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
extern struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
struct unix_address {
atomic_t refcnt;
......
......@@ -115,15 +115,24 @@
#include <net/checksum.h>
#include <linux/security.h>
struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
EXPORT_SYMBOL_GPL(unix_socket_table);
DEFINE_SPINLOCK(unix_table_lock);
EXPORT_SYMBOL_GPL(unix_table_lock);
static atomic_long_t unix_nr_socks;
#define unix_sockets_unbound (&unix_socket_table[UNIX_HASH_SIZE])
#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash != UNIX_HASH_SIZE)
static struct hlist_head *unix_sockets_unbound(void *addr)
{
unsigned long hash = (unsigned long)addr;
hash ^= hash >> 16;
hash ^= hash >> 8;
hash %= UNIX_HASH_SIZE;
return &unix_socket_table[UNIX_HASH_SIZE + hash];
}
#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash < UNIX_HASH_SIZE)
#ifdef CONFIG_SECURITY_NETWORK
static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
......@@ -645,7 +654,7 @@ static struct sock *unix_create1(struct net *net, struct socket *sock)
INIT_LIST_HEAD(&u->link);
mutex_init(&u->readlock); /* single task reading lock */
init_waitqueue_head(&u->peer_wait);
unix_insert_socket(unix_sockets_unbound, sk);
unix_insert_socket(unix_sockets_unbound(sk), sk);
out:
if (sk == NULL)
atomic_long_dec(&unix_nr_socks);
......@@ -2239,47 +2248,58 @@ static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
}
#ifdef CONFIG_PROC_FS
static struct sock *first_unix_socket(int *i)
{
for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
if (!hlist_empty(&unix_socket_table[*i]))
return __sk_head(&unix_socket_table[*i]);
}
return NULL;
}
static struct sock *next_unix_socket(int *i, struct sock *s)
{
struct sock *next = sk_next(s);
/* More in this chain? */
if (next)
return next;
/* Look for next non-empty chain. */
for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
if (!hlist_empty(&unix_socket_table[*i]))
return __sk_head(&unix_socket_table[*i]);
}
return NULL;
}
#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
#define get_bucket(x) ((x) >> BUCKET_SPACE)
#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
struct unix_iter_state {
struct seq_net_private p;
int i;
};
static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
{
struct unix_iter_state *iter = seq->private;
loff_t off = 0;
struct sock *s;
unsigned long offset = get_offset(*pos);
unsigned long bucket = get_bucket(*pos);
struct sock *sk;
unsigned long count = 0;
for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
if (sock_net(s) != seq_file_net(seq))
for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
if (sock_net(sk) != seq_file_net(seq))
continue;
if (off == pos)
return s;
++off;
if (++count == offset)
break;
}
return sk;
}
static struct sock *unix_next_socket(struct seq_file *seq,
struct sock *sk,
loff_t *pos)
{
unsigned long bucket;
while (sk > (struct sock *)SEQ_START_TOKEN) {
sk = sk_next(sk);
if (!sk)
goto next_bucket;
if (sock_net(sk) == seq_file_net(seq))
return sk;
}
do {
sk = unix_from_bucket(seq, pos);
if (sk)
return sk;
next_bucket:
bucket = get_bucket(*pos) + 1;
*pos = set_bucket_offset(bucket, 1);
} while (bucket < ARRAY_SIZE(unix_socket_table));
return NULL;
}
......@@ -2287,22 +2307,20 @@ static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(unix_table_lock)
{
spin_lock(&unix_table_lock);
return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
if (!*pos)
return SEQ_START_TOKEN;
if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
return NULL;
return unix_next_socket(seq, NULL, pos);
}
static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct unix_iter_state *iter = seq->private;
struct sock *sk = v;
++*pos;
if (v == SEQ_START_TOKEN)
sk = first_unix_socket(&iter->i);
else
sk = next_unix_socket(&iter->i, sk);
while (sk && (sock_net(sk) != seq_file_net(seq)))
sk = next_unix_socket(&iter->i, sk);
return sk;
return unix_next_socket(seq, v, pos);
}
static void unix_seq_stop(struct seq_file *seq, void *v)
......
......@@ -195,7 +195,9 @@ static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
num = s_num = cb->args[1];
spin_lock(&unix_table_lock);
for (slot = s_slot; slot <= UNIX_HASH_SIZE; s_num = 0, slot++) {
for (slot = s_slot;
slot < ARRAY_SIZE(unix_socket_table);
s_num = 0, slot++) {
struct sock *sk;
struct hlist_node *node;
......@@ -228,7 +230,7 @@ static struct sock *unix_lookup_by_ino(int ino)
struct sock *sk;
spin_lock(&unix_table_lock);
for (i = 0; i <= UNIX_HASH_SIZE; i++) {
for (i = 0; i < ARRAY_SIZE(unix_socket_table); i++) {
struct hlist_node *node;
sk_for_each(sk, node, &unix_socket_table[i])
......
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