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authorKuniyuki Iwashima <kuniyu@amazon.co.jp>2021-11-24 05:14:30 +0300
committerJakub Kicinski <kuba@kernel.org>2021-11-27 05:01:58 +0300
commitafd20b9290e184c203fe22f2d6b80dc7127ba724 (patch)
tree26608b7fc089541250d5cb8e17b6c40659726284 /net/unix/diag.c
parente6b4b873896f0e9298f70d25726f4bb1e1b265ba (diff)
downloadlinux-afd20b9290e184c203fe22f2d6b80dc7127ba724.tar.xz
af_unix: Replace the big lock with small locks.
The hash table of AF_UNIX sockets is protected by the single lock. This patch replaces it with per-hash locks. The effect is noticeable when we handle multiple sockets simultaneously. Here is a test result on an EC2 c5.24xlarge instance. It shows latency (under 10us only) in unix_insert_unbound_socket() while 64 CPUs creating 1024 sockets for each in parallel. Without this patch: nsec : count distribution 0 : 179 | | 500 : 3021 |********* | 1000 : 6271 |******************* | 1500 : 6318 |******************* | 2000 : 5828 |***************** | 2500 : 5124 |*************** | 3000 : 4426 |************* | 3500 : 3672 |*********** | 4000 : 3138 |********* | 4500 : 2811 |******** | 5000 : 2384 |******* | 5500 : 2023 |****** | 6000 : 1954 |***** | 6500 : 1737 |***** | 7000 : 1749 |***** | 7500 : 1520 |**** | 8000 : 1469 |**** | 8500 : 1394 |**** | 9000 : 1232 |*** | 9500 : 1138 |*** | 10000 : 994 |*** | With this patch: nsec : count distribution 0 : 1634 |**** | 500 : 13170 |****************************************| 1000 : 13156 |*************************************** | 1500 : 9010 |*************************** | 2000 : 6363 |******************* | 2500 : 4443 |************* | 3000 : 3240 |********* | 3500 : 2549 |******* | 4000 : 1872 |***** | 4500 : 1504 |**** | 5000 : 1247 |*** | 5500 : 1035 |*** | 6000 : 889 |** | 6500 : 744 |** | 7000 : 634 |* | 7500 : 498 |* | 8000 : 433 |* | 8500 : 355 |* | 9000 : 336 |* | 9500 : 284 | | 10000 : 243 | | Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/unix/diag.c')
-rw-r--r--net/unix/diag.c20
1 files changed, 10 insertions, 10 deletions
diff --git a/net/unix/diag.c b/net/unix/diag.c
index db555f267407..bb0b5ea1655f 100644
--- 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_lock */
+ /* might or might not have unix_table_locks */
struct unix_address *addr = smp_load_acquire(&unix_sk(sk)->addr);
if (!addr)
@@ -204,13 +204,13 @@ static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
s_slot = cb->args[0];
num = s_num = cb->args[1];
- spin_lock(&unix_table_lock);
for (slot = s_slot;
slot < ARRAY_SIZE(unix_socket_table);
s_num = 0, slot++) {
struct sock *sk;
num = 0;
+ spin_lock(&unix_table_locks[slot]);
sk_for_each(sk, &unix_socket_table[slot]) {
if (!net_eq(sock_net(sk), net))
continue;
@@ -221,14 +221,16 @@ static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
if (sk_diag_dump(sk, skb, req,
NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq,
- NLM_F_MULTI) < 0)
+ NLM_F_MULTI) < 0) {
+ spin_unlock(&unix_table_locks[slot]);
goto done;
+ }
next:
num++;
}
+ spin_unlock(&unix_table_locks[slot]);
}
done:
- spin_unlock(&unix_table_lock);
cb->args[0] = slot;
cb->args[1] = num;
@@ -237,21 +239,19 @@ done:
static struct sock *unix_lookup_by_ino(unsigned int ino)
{
- int i;
struct sock *sk;
+ int i;
- spin_lock(&unix_table_lock);
for (i = 0; i < ARRAY_SIZE(unix_socket_table); i++) {
+ spin_lock(&unix_table_locks[i]);
sk_for_each(sk, &unix_socket_table[i])
if (ino == sock_i_ino(sk)) {
sock_hold(sk);
- spin_unlock(&unix_table_lock);
-
+ spin_unlock(&unix_table_locks[i]);
return sk;
}
+ spin_unlock(&unix_table_locks[i]);
}
-
- spin_unlock(&unix_table_lock);
return NULL;
}