From: Kirill Tkhai <ktkhai@virtuozzo.com>
To: davem@davemloft.net, vyasevic@redhat.com,
kstewart@linuxfoundation.org, pombredanne@nexb.com,
vyasevich@gmail.com, mark.rutland@arm.com,
gregkh@linuxfoundation.org, adobriyan@gmail.com, fw@strlen.de,
nicolas.dichtel@6wind.com, xiyou.wangcong@gmail.com,
roman.kapl@sysgo.com, paul@paul-moore.com, dsahern@gmail.com,
daniel@iogearbox.net, lucien.xin@gmail.com,
mschiffer@universe-factory.net, rshearma@brocade.com,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
ktkhai@virtuozzo.com, ebiederm@xmission.com,
avagin@virtuozzo.com, gorcunov@virtuozzo.com,
eric.dumazet@gmail.com, stephen@networkplumber.org,
ktkhai@virtuozzo.com
Subject: [PATCH v2 05/31] net: Allow pernet_operations to be executed in parallel
Date: Mon, 20 Nov 2017 21:32:55 +0300 [thread overview]
Message-ID: <151120277590.3159.12461615068657469111.stgit@localhost.localdomain> (raw)
In-Reply-To: <151120175301.3159.9577108443167812854.stgit@localhost.localdomain>
This adds new pernet_operations::async flag to indicate operations,
which ->init(), ->exit() and ->exit_batch() methods are allowed
to be executed in parallel with the methods of any other pernet_operations.
When there are only asynchronous pernet_operations in the system,
net_mutex won't be taken for a net construction and destruction.
Also, remove BUG_ON(mutex_is_locked()) from net_assign_generic()
without replacing with the equivalent net_sem check, as there is
one more lockdep assert below.
Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
---
include/net/net_namespace.h | 6 ++++++
net/core/net_namespace.c | 29 +++++++++++++++++++----------
2 files changed, 25 insertions(+), 10 deletions(-)
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 10f99dafd5ac..db978c4755f7 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -303,6 +303,12 @@ struct pernet_operations {
void (*exit_batch)(struct list_head *net_exit_list);
unsigned int *id;
size_t size;
+ /*
+ * Indicates above methods are allowe to be executed in parallel
+ * with methods of any other pernet_operations, i.e. they are not
+ * need synchronization via net_mutex.
+ */
+ bool async;
};
/*
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index c4f7452906bb..550c766f73aa 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -41,8 +41,9 @@ struct net init_net = {
EXPORT_SYMBOL(init_net);
static bool init_net_initialized;
+static unsigned nr_sync_pernet_ops;
/*
- * net_sem: protects: pernet_list, net_generic_ids,
+ * net_sem: protects: pernet_list, net_generic_ids, nr_sync_pernet_ops,
* init_net_initialized and first_device pointer.
*/
DECLARE_RWSEM(net_sem);
@@ -70,11 +71,10 @@ static int net_assign_generic(struct net *net, unsigned int id, void *data)
{
struct net_generic *ng, *old_ng;
- BUG_ON(!mutex_is_locked(&net_mutex));
BUG_ON(id < MIN_PERNET_OPS_ID);
old_ng = rcu_dereference_protected(net->gen,
- lockdep_is_held(&net_mutex));
+ lockdep_is_held(&net_sem));
if (old_ng->s.len > id) {
old_ng->ptr[id] = data;
return 0;
@@ -419,11 +419,14 @@ struct net *copy_net_ns(unsigned long flags,
rv = down_read_killable(&net_sem);
if (rv < 0)
goto put_userns;
- rv = mutex_lock_killable(&net_mutex);
- if (rv < 0)
- goto up_read;
+ if (nr_sync_pernet_ops) {
+ rv = mutex_lock_killable(&net_mutex);
+ if (rv < 0)
+ goto up_read;
+ }
rv = setup_net(net, user_ns);
- mutex_unlock(&net_mutex);
+ if (nr_sync_pernet_ops)
+ mutex_unlock(&net_mutex);
up_read:
up_read(&net_sem);
if (rv < 0) {
@@ -453,7 +456,8 @@ static void cleanup_net(struct work_struct *work)
spin_unlock_irq(&cleanup_list_lock);
down_read(&net_sem);
- mutex_lock(&net_mutex);
+ if (nr_sync_pernet_ops)
+ mutex_lock(&net_mutex);
/* Don't let anyone else find us. */
rtnl_lock();
@@ -489,7 +493,8 @@ static void cleanup_net(struct work_struct *work)
list_for_each_entry_reverse(ops, &pernet_list, list)
ops_exit_list(ops, &net_exit_list);
- mutex_unlock(&net_mutex);
+ if (nr_sync_pernet_ops)
+ mutex_unlock(&net_mutex);
/* Free the net generic variables */
list_for_each_entry_reverse(ops, &pernet_list, list)
@@ -961,6 +966,9 @@ static int register_pernet_operations(struct list_head *list,
rcu_barrier();
if (ops->id)
ida_remove(&net_generic_ids, *ops->id);
+ } else if (!ops->async) {
+ pr_info_once("Pernet operations %ps are sync.\n", ops);
+ nr_sync_pernet_ops++;
}
return error;
@@ -968,7 +976,8 @@ static int register_pernet_operations(struct list_head *list,
static void unregister_pernet_operations(struct pernet_operations *ops)
{
-
+ if (!ops->async)
+ BUG_ON(nr_sync_pernet_ops-- == 0);
__unregister_pernet_operations(ops);
rcu_barrier();
if (ops->id)
next prev parent reply other threads:[~2017-11-20 18:32 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-20 18:32 [PATCH v2 00/31] Replacing net_mutex with rw_semaphore Kirill Tkhai
2017-11-20 18:32 ` [PATCH v2 01/31] net: Assign net to net_namespace_list in setup_net() Kirill Tkhai
2017-11-20 18:32 ` [PATCH v2 02/31] net: Cleanup copy_net_ns() Kirill Tkhai
2017-11-20 18:32 ` [PATCH v2 03/31] net: Introduce net_sem for protection of pernet_list Kirill Tkhai
2018-01-17 20:04 ` Andrei Vagin
2018-01-18 10:14 ` Kirill Tkhai
2017-11-20 18:32 ` [PATCH v2 04/31] net: Move mutex_unlock() in cleanup_net() up Kirill Tkhai
2017-11-20 18:32 ` Kirill Tkhai [this message]
2018-01-17 18:34 ` [PATCH v2 05/31] net: Allow pernet_operations to be executed in parallel Andrei Vagin
2018-01-18 10:16 ` Kirill Tkhai
2017-11-20 18:33 ` [PATCH v2 06/31] net: Convert proc_net_ns_ops Kirill Tkhai
2017-11-20 18:33 ` [PATCH v2 07/31] net: Convert net_ns_ops methods Kirill Tkhai
2017-11-20 18:33 ` [PATCH v2 08/31] net: Convert sysctl_pernet_ops Kirill Tkhai
2017-11-20 18:33 ` [PATCH v2 09/31] net: Convert netfilter_net_ops Kirill Tkhai
2017-11-20 18:33 ` [PATCH v2 10/31] net: Convert nf_log_net_ops Kirill Tkhai
2017-11-20 18:33 ` [PATCH v2 11/31] net: Convert net_inuse_ops Kirill Tkhai
2017-11-20 18:34 ` [PATCH v2 12/31] net: Convert net_defaults_ops Kirill Tkhai
2017-11-20 18:34 ` [PATCH v2 13/31] net: Convert netlink_net_ops Kirill Tkhai
2017-11-20 18:34 ` [PATCH v2 14/31] net: Convert rtnetlink_net_ops Kirill Tkhai
2017-11-20 18:34 ` [PATCH v2 15/31] net: Convert audit_net_ops Kirill Tkhai
2017-11-20 18:34 ` [PATCH v2 16/31] net: Convert uevent_net_ops Kirill Tkhai
2017-11-20 18:34 ` [PATCH v2 17/31] net: Convert proto_net_ops Kirill Tkhai
2017-11-20 18:35 ` [PATCH v2 18/31] net: Convert pernet_subsys ops, registered via net_dev_init() Kirill Tkhai
2017-11-20 18:35 ` [PATCH v2 19/31] net: Convert fib_* pernet_operations, registered via subsys_initcall Kirill Tkhai
2017-11-20 18:35 ` [PATCH v2 20/31] net: Convert subsys_initcall() registered pernet_operations from net/sched Kirill Tkhai
2017-11-20 18:35 ` [PATCH v2 21/31] net: Convert genl_pernet_ops Kirill Tkhai
2017-11-20 18:35 ` [PATCH v2 22/31] net: Convert wext_pernet_ops Kirill Tkhai
2017-11-20 18:35 ` [PATCH v2 23/31] net: Convert sysctl_core_ops Kirill Tkhai
2017-11-20 18:35 ` [PATCH v2 24/31] net: Convert pernet_subsys, registered from inet_init() Kirill Tkhai
2017-11-20 18:36 ` [PATCH v2 25/31] net: Convert unix_net_ops Kirill Tkhai
2017-11-20 18:36 ` [PATCH v2 26/31] net: Convert packet_net_ops Kirill Tkhai
2017-11-20 18:36 ` [PATCH v2 27/31] net: Convert ipv4_sysctl_ops Kirill Tkhai
2017-11-20 18:36 ` [PATCH v2 28/31] net: Convert addrconf_ops Kirill Tkhai
2017-11-20 18:36 ` [PATCH v2 29/31] net: Convert loopback_net_ops Kirill Tkhai
2017-11-20 18:36 ` [PATCH v2 30/31] net: Convert default_device_ops Kirill Tkhai
2017-11-20 18:37 ` [PATCH v2 31/31] net: Convert diag_net_ops Kirill Tkhai
2017-12-04 15:54 ` [PATCH v2 00/31] Replacing net_mutex with rw_semaphore Kirill Tkhai
2017-12-04 16:10 ` David Miller
2017-12-04 16:11 ` Kirill Tkhai
2018-01-18 17:43 ` Andrei Vagin
2018-01-19 8:25 ` Kirill Tkhai
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