From 0734d7c3d93cdcb8a56ce914d3c661300f24434d Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 14 Jan 2025 20:55:27 +0000 Subject: 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 Reviewed-by: Jesse Brandeburg Link: https://patch.msgid.link/20250114205531.967841-2-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/core/net_namespace.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'net/core/net_namespace.c') 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; } /** -- cgit v1.2.3 From e57a6320215c3967f51ab0edeff87db2095440e4 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Mon, 17 Feb 2025 11:11:27 -0800 Subject: net: Add net_passive_inc() and net_passive_dec(). net_drop_ns() is NULL when CONFIG_NET_NS is disabled. The next patch introduces a function that increments and decrements net->passive. As a prep, let's rename and export net_free() to net_passive_dec() and add net_passive_inc(). Suggested-by: Eric Dumazet Link: https://lore.kernel.org/netdev/CANn89i+oUCt2VGvrbrweniTendZFEh+nwS=uonc004-aPkWy-Q@mail.gmail.com/ Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250217191129.19967-2-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- include/net/net_namespace.h | 11 +++++++++++ net/core/net_namespace.c | 8 ++++---- 2 files changed, 15 insertions(+), 4 deletions(-) (limited to 'net/core/net_namespace.c') diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 7ba1402ca779..f467a66abc6b 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -297,6 +297,7 @@ static inline int check_net(const struct net *net) } void net_drop_ns(void *); +void net_passive_dec(struct net *net); #else @@ -326,8 +327,18 @@ static inline int check_net(const struct net *net) } #define net_drop_ns NULL + +static inline void net_passive_dec(struct net *net) +{ + refcount_dec(&net->passive); +} #endif +static inline void net_passive_inc(struct net *net) +{ + refcount_inc(&net->passive); +} + /* Returns true if the netns initialization is completed successfully */ static inline bool net_initialized(const struct net *net) { diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index cb39a12b2f82..4303f2a49262 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -464,7 +464,7 @@ static void net_complete_free(void) } -static void net_free(struct net *net) +void net_passive_dec(struct net *net) { if (refcount_dec_and_test(&net->passive)) { kfree(rcu_access_pointer(net->gen)); @@ -482,7 +482,7 @@ void net_drop_ns(void *p) struct net *net = (struct net *)p; if (net) - net_free(net); + net_passive_dec(net); } struct net *copy_net_ns(unsigned long flags, @@ -523,7 +523,7 @@ put_userns: key_remove_domain(net->key_domain); #endif put_user_ns(user_ns); - net_free(net); + net_passive_dec(net); dec_ucounts: dec_net_namespaces(ucounts); return ERR_PTR(rv); @@ -672,7 +672,7 @@ static void cleanup_net(struct work_struct *work) key_remove_domain(net->key_domain); #endif put_user_ns(net->user_ns); - net_free(net); + net_passive_dec(net); } cleanup_net_task = NULL; } -- cgit v1.2.3