diff options
| author | Qiliang Yuan <realwujing@gmail.com> | 2026-02-04 02:48:42 -0500 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-02-06 20:01:31 -0800 |
| commit | 7acee67a6bce02e0af8a4bf7b412e2164d5a48e9 (patch) | |
| tree | c80805b1aa16de4d99edb4d3011bfdf1f981184c /include | |
| parent | 24cf78c738318f3d2b961a1ab4b3faf1eca860d7 (diff) | |
netns: optimize netns cleaning by batching unhash_nsid calls
Currently, unhash_nsid() scans the entire system for each netns being
killed, leading to O(L_dying_net * M_alive_net * N_id) complexity, as
__peernet2id() also performs a linear search in the IDR.
Optimize this to O(M_alive_net * N_id) by batching unhash operations. Move
unhash_nsid() out of the per-netns loop in cleanup_net() to perform a
single-pass traversal over survivor namespaces.
Identify dying peers by an 'is_dying' flag, which is set under net_rwsem
write lock after the netns is removed from the global list. This batches
the unhashing work and eliminates the O(L_dying_net) multiplier.
To minimize the impact on struct net size, 'is_dying' is placed in an
existing hole after 'hash_mix' in struct net.
Use a restartable idr_get_next() loop for iteration. This avoids the
unsafe modification issue inherent to idr_for_each() callbacks and allows
dropping the nsid_lock to safely call sleepy rtnl_net_notifyid().
Clean up redundant nsid_lock and simplify the destruction loop now that
unhashing is centralized.
Signed-off-by: Qiliang Yuan <yuanql9@chinatelecom.cn>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260204074854.3506916-1-realwujing@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/net_namespace.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 66d3de1d935f..d7bec49ee9ea 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -121,6 +121,7 @@ struct net { * it is critical that it is on a read_mostly cache line. */ u32 hash_mix; + bool is_dying; struct net_device *loopback_dev; /* The loopback */ |