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Date: Thu, 7 Dec 2017 08:45:48 -0800
From: Tonghao Zhang <xiangxia.m.yue@...il.com>
To: davem@...emloft.net, xiyou.wangcong@...il.com, edumazet@...gle.com,
willemb@...gle.com
Cc: netdev@...r.kernel.org, Tonghao Zhang <xiangxia.m.yue@...il.com>
Subject: [PATCH v5 2/2] sock: Move the socket inuse to namespace.
In some case, we want to know how many sockets are in use in
different _net_ namespaces. It's a key resource metric.
This patch add a member in struct netns_core. This is a counter
for socket-inuse in the _net_ namespace. The patch will add/sub
counter in the sk_alloc, sk_clone_lock and __sk_free.
The main reasons for doing this are that：
1. When linux calls the 'do_exit' for process to exit, the functions
'exit_task_namespaces' and 'exit_task_work' will be called sequentially.
'exit_task_namespaces' may have destroyed the _net_ namespace, but
'sock_release' called in 'exit_task_work' may use the _net_ namespace
if we counter the socket-inuse in sock_release.
2. socket and sock are in pair. More important, sock holds the _net_
namespace. We counter the socket-inuse in sock, for avoiding holding
_net_ namespace again in socket. It's a easy way to maintain the code.
Signed-off-by: Martin Zhang <zhangjunweimartin@...ichuxing.com>
Signed-off-by: Tonghao Zhang <zhangtonghao@...ichuxing.com>
---
include/net/netns/core.h | 1 +
include/net/sock.h | 1 +
net/core/sock.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++--
net/socket.c | 21 ++-----------------
4 files changed, 54 insertions(+), 21 deletions(-)
diff --git a/include/net/netns/core.h b/include/net/netns/core.h
index 45cfb5d..d1b4748f 100644
--- a/include/net/netns/core.h
+++ b/include/net/netns/core.h
@@ -11,6 +11,7 @@ struct netns_core {
int sysctl_somaxconn;
+ int __percpu *sock_inuse;
struct prot_inuse __percpu *prot_inuse;
};
diff --git a/include/net/sock.h b/include/net/sock.h
index 79e1a2c..0809b31 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1266,6 +1266,7 @@ static inline void sk_sockets_allocated_inc(struct sock *sk)
/* Called with local bh disabled */
void sock_prot_inuse_add(struct net *net, struct proto *prot, int inc);
int sock_prot_inuse_get(struct net *net, struct proto *proto);
+int sock_inuse_get(struct net *net);
#else
static inline void sock_prot_inuse_add(struct net *net, struct proto *prot,
int inc)
diff --git a/net/core/sock.c b/net/core/sock.c
index c2dd2d3..a11680a 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -145,6 +145,8 @@
static DEFINE_MUTEX(proto_list_mutex);
static LIST_HEAD(proto_list);
+static void sock_inuse_add(struct net *net, int val);
+
/**
* sk_ns_capable - General socket capability test
* @sk: Socket to use a capability on or through
@@ -1534,6 +1536,7 @@ struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
if (likely(sk->sk_net_refcnt))
get_net(net);
sock_net_set(sk, net);
+ sock_inuse_add(net, 1);
refcount_set(&sk->sk_wmem_alloc, 1);
mem_cgroup_sk_alloc(sk);
@@ -1595,6 +1598,8 @@ void sk_destruct(struct sock *sk)
static void __sk_free(struct sock *sk)
{
+ sock_inuse_add(sock_net(sk), -1);
+
if (unlikely(sock_diag_has_destroy_listeners(sk) && sk->sk_net_refcnt))
sock_diag_broadcast_destroy(sk);
else
@@ -1716,6 +1721,7 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)
newsk->sk_priority = 0;
newsk->sk_incoming_cpu = raw_smp_processor_id();
atomic64_set(&newsk->sk_cookie, 0);
+ sock_inuse_add(sock_net(newsk), 1);
/*
* Before updating sk_refcnt, we must commit prior changes to memory
@@ -3061,15 +3067,53 @@ int sock_prot_inuse_get(struct net *net, struct proto *prot)
}
EXPORT_SYMBOL_GPL(sock_prot_inuse_get);
+static void sock_inuse_add(struct net *net, int val)
+{
+ if (net->core.prot_inuse)
+ this_cpu_add(*net->core.sock_inuse, val);
+}
+
+int sock_inuse_get(struct net *net)
+{
+ int cpu, res = 0;
+
+ if (!net->core.prot_inuse)
+ return 0;
+
+ for_each_possible_cpu(cpu)
+ res += *per_cpu_ptr(net->core.sock_inuse, cpu);
+
+ return res >= 0 ? res : 0;
+}
+EXPORT_SYMBOL_GPL(sock_inuse_get);
+
static int __net_init sock_inuse_init_net(struct net *net)
{
net->core.prot_inuse = alloc_percpu(struct prot_inuse);
- return net->core.prot_inuse ? 0 : -ENOMEM;
+ if (!net->core.prot_inuse)
+ return -ENOMEM;
+
+ net->core.sock_inuse = alloc_percpu(int);
+ if (!net->core.sock_inuse)
+ goto out;
+
+ return 0;
+out:
+ free_percpu(net->core.prot_inuse);
+ return -ENOMEM;
}
static void __net_exit sock_inuse_exit_net(struct net *net)
{
- free_percpu(net->core.prot_inuse);
+ if (net->core.prot_inuse) {
+ free_percpu(net->core.prot_inuse);
+ net->core.prot_inuse = NULL;
+ }
+
+ if (net->core.sock_inuse) {
+ free_percpu(net->core.sock_inuse);
+ net->core.prot_inuse = NULL;
+ }
}
static struct pernet_operations net_inuse_ops = {
@@ -3112,6 +3156,10 @@ static inline void assign_proto_idx(struct proto *prot)
static inline void release_proto_idx(struct proto *prot)
{
}
+
+static void sock_inuse_add(struct net *net, int val)
+{
+}
#endif
static void req_prot_cleanup(struct request_sock_ops *rsk_prot)
diff --git a/net/socket.c b/net/socket.c
index 42d8e9c..183de8f01 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -163,12 +163,6 @@ static ssize_t sock_splice_read(struct file *file, loff_t *ppos,
static const struct net_proto_family __rcu *net_families[NPROTO] __read_mostly;
/*
- * Statistics counters of the socket lists
- */
-
-static DEFINE_PER_CPU(int, sockets_in_use);
-
-/*
* Support routines.
* Move socket addresses back and forth across the kernel/user
* divide and look after the messy bits.
@@ -574,7 +568,6 @@ struct socket *sock_alloc(void)
inode->i_gid = current_fsgid();
inode->i_op = &sockfs_inode_ops;
- this_cpu_add(sockets_in_use, 1);
return sock;
}
EXPORT_SYMBOL(sock_alloc);
@@ -601,7 +594,6 @@ void sock_release(struct socket *sock)
if (rcu_dereference_protected(sock->wq, 1)->fasync_list)
pr_err("%s: fasync list not empty!\n", __func__);
- this_cpu_sub(sockets_in_use, 1);
if (!sock->file) {
iput(SOCK_INODE(sock));
return;
@@ -2644,17 +2636,8 @@ static int __init sock_init(void)
#ifdef CONFIG_PROC_FS
void socket_seq_show(struct seq_file *seq)
{
- int cpu;
- int counter = 0;
-
- for_each_possible_cpu(cpu)
- counter += per_cpu(sockets_in_use, cpu);
-
- /* It can be negative, by the way. 8) */
- if (counter < 0)
- counter = 0;
-
- seq_printf(seq, "sockets: used %d\n", counter);
+ seq_printf(seq, "sockets: used %d\n",
+ sock_inuse_get(seq->private));
}
#endif /* CONFIG_PROC_FS */
--
1.8.3.1
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