diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-01-14 20:55:27 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-01-15 19:17:03 -0800 |
| commit | 0734d7c3d93cdcb8a56ce914d3c661300f24434d (patch) | |
| tree | 80468bc3418393a591983bbe459a4c1d41f26474 /net/core | |
| parent | 0b6f6593aa8c3a05f155c12fd0e7ad33a5149c31 (diff) | |
net: expedite synchronize_net() for cleanup_net()
cleanup_net() is the single thread responsible
for netns dismantles, and a serious bottleneck.
Before we can get per-netns RTNL, make sure
all synchronize_net() called from this thread
are using rcu_synchronize_expedited().
v3: deal with CONFIG_NET_NS=n
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jesse Brandeburg <jbrandeburg@cloudflare.com>
Link: https://patch.msgid.link/20250114205531.967841-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/dev.c | 11 | ||||
| -rw-r--r-- | net/core/net_namespace.c | 5 |
2 files changed, 15 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 47e6b0f73cfc..115a7a0a1104 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -10099,6 +10099,15 @@ static void dev_index_release(struct net *net, int ifindex) WARN_ON(xa_erase(&net->dev_by_index, ifindex)); } +static bool from_cleanup_net(void) +{ +#ifdef CONFIG_NET_NS + return current == cleanup_net_task; +#else + return false; +#endif +} + /* Delayed registration/unregisteration */ LIST_HEAD(net_todo_list); DECLARE_WAIT_QUEUE_HEAD(netdev_unregistering_wq); @@ -11474,7 +11483,7 @@ EXPORT_SYMBOL_GPL(alloc_netdev_dummy); void synchronize_net(void) { might_sleep(); - if (rtnl_is_locked()) + if (from_cleanup_net() || rtnl_is_locked()) synchronize_rcu_expedited(); else synchronize_rcu(); diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index b5cd3ae4f04c..cb39a12b2f82 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -588,6 +588,8 @@ static void unhash_nsid(struct net *net, struct net *last) static LLIST_HEAD(cleanup_list); +struct task_struct *cleanup_net_task; + static void cleanup_net(struct work_struct *work) { const struct pernet_operations *ops; @@ -596,6 +598,8 @@ static void cleanup_net(struct work_struct *work) LIST_HEAD(net_exit_list); LIST_HEAD(dev_kill_list); + cleanup_net_task = current; + /* Atomically snapshot the list of namespaces to cleanup */ net_kill_list = llist_del_all(&cleanup_list); @@ -670,6 +674,7 @@ static void cleanup_net(struct work_struct *work) put_user_ns(net->user_ns); net_free(net); } + cleanup_net_task = NULL; } /** |