diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-01-14 20:55:31 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-01-15 19:17:05 -0800 |
| commit | 83419b61d187ce22aa3da5ffdda850fca3a12600 (patch) | |
| tree | 088f7dd9001f389f6e540363e0e92110a3b1b49f | |
| parent | ae646f1a0bb97401bac0044bbe2a179a1e38b408 (diff) | |
net: reduce RTNL hold duration in unregister_netdevice_many_notify() (part 2)
One synchronize_net() call is currently done while holding RTNL.
This is source of RTNL contention in workloads adding and deleting
many network namespaces per second, because synchronize_rcu()
and synchronize_rcu_expedited() can use 60+ ms in some cases.
For cleanup_net() use, temporarily release RTNL
while calling the last synchronize_net().
This should be safe, because devices are no longer visible
to other threads after unlist_netdevice() call
and setting dev->reg_state to NETREG_UNREGISTERING.
In any case, the new netdev_lock() / netdev_unlock()
infrastructure that we are adding should allow
to fix potential issues, with a combination
of a per-device mutex and dev->reg_state awareness.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jesse Brandeburg <jbrandeburg@cloudflare.com>
Link: https://patch.msgid.link/20250114205531.967841-6-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/core/dev.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 3924a4af68b8..3c87cb1cb877 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -11628,9 +11628,8 @@ void unregister_netdevice_many_notify(struct list_head *head, rtnl_drop_if_cleanup_net(); flush_all_backlogs(); - rtnl_acquire_if_cleanup_net(); - /* TODO: move this before the prior rtnl_acquire_if_cleanup_net() */ synchronize_net(); + rtnl_acquire_if_cleanup_net(); list_for_each_entry(dev, head, unreg_list) { struct sk_buff *skb = NULL; |