diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-06-30 09:35:38 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-07-02 14:22:02 -0700 |
| commit | 998642e999d23324c5dbf38149606d09cec2c377 (patch) | |
| tree | 193d01be8d1645ffa13c80a50ca3a61281798313 | |
| parent | 3715b5df09b92168a4492b48bb7ea70d89f9d8f3 (diff) | |
net: move net_cookie into net_aligned_data
Using per-cpu data for net->net_cookie generation is overkill,
because even busy hosts do not create hundreds of netns per second.
Make sure to put net_cookie in a private cache line to avoid
potential false sharing.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250630093540.3052835-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | include/net/aligned_data.h | 2 | ||||
| -rw-r--r-- | net/core/net_namespace.c | 8 |
2 files changed, 4 insertions, 6 deletions
diff --git a/include/net/aligned_data.h b/include/net/aligned_data.h index cf3329d7c227..5c7badf71f04 100644 --- a/include/net/aligned_data.h +++ b/include/net/aligned_data.h @@ -2,6 +2,7 @@ #ifndef _NET_ALIGNED_DATA_H #define _NET_ALIGNED_DATA_H +#include <linux/atomic.h> #include <linux/types.h> /* Structure holding cacheline aligned fields on SMP builds. @@ -9,6 +10,7 @@ * attribute to ensure no accidental false sharing can happen. */ struct net_aligned_data { + atomic64_t net_cookie ____cacheline_aligned_in_smp; }; extern struct net_aligned_data net_aligned_data; diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 419604d9cf32..f58ef920a3a1 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -19,9 +19,9 @@ #include <linux/net_namespace.h> #include <linux/sched/task.h> #include <linux/uidgid.h> -#include <linux/cookie.h> #include <linux/proc_fs.h> +#include <net/aligned_data.h> #include <net/sock.h> #include <net/netlink.h> #include <net/net_namespace.h> @@ -64,8 +64,6 @@ DECLARE_RWSEM(pernet_ops_rwsem); static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS; -DEFINE_COOKIE(net_cookie); - static struct net_generic *net_alloc_generic(void) { unsigned int gen_ptrs = READ_ONCE(max_gen_ptrs); @@ -434,9 +432,7 @@ static __net_init int setup_net(struct net *net) LIST_HEAD(net_exit_list); int error = 0; - preempt_disable(); - net->net_cookie = gen_cookie_next(&net_cookie); - preempt_enable(); + net->net_cookie = atomic64_inc_return(&net_aligned_data.net_cookie); list_for_each_entry(ops, &pernet_list, list) { error = ops_init(ops, net); |