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Message-ID: <1339167801.6001.111.camel@edumazet-glaptop>
Date: Fri, 08 Jun 2012 17:03:21 +0200
From: Eric Dumazet <eric.dumazet@...il.com>
To: David Miller <davem@...emloft.net>
Cc: netdev <netdev@...r.kernel.org>,
Steven Whitehouse <swhiteho@...hat.com>,
Pavel Emelyanov <xemul@...allels.com>
Subject: [PATCH net-next] af_unix: speedup /proc/net/unix
From: Eric Dumazet <edumazet@...gle.com>
/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: Eric Dumazet <edumazet@...gle.com>
Cc: Steven Whitehouse <swhiteho@...hat.com>
Cc: Pavel Emelyanov <xemul@...allels.com>
---
include/net/af_unix.h | 3 -
net/unix/af_unix.c | 110 +++++++++++++++++++++++-----------------
net/unix/diag.c | 6 +-
3 files changed, 70 insertions(+), 49 deletions(-)
diff --git a/include/net/af_unix.h b/include/net/af_unix.h
index 2ee33da..b5f8988 100644
--- a/include/net/af_unix.h
+++ b/include/net/af_unix.h
@@ -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;
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 641f2e4..cf83f6b 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -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)
diff --git a/net/unix/diag.c b/net/unix/diag.c
index 47d3002..7e8a24b 100644
--- a/net/unix/diag.c
+++ b/net/unix/diag.c
@@ -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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