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authorEric Dumazet <edumazet@google.com>2022-01-18 14:43:40 +0300
committerDavid S. Miller <davem@davemloft.net>2022-01-18 16:40:58 +0300
commit2836615aa22de55b8fca5e32fe1b27a67cda625e (patch)
tree541675ed7f85c3ee3af1933caebd2d6c1501af38 /net/core/net_namespace.c
parent5765cee119bf5a36c94d20eceb37c445508934be (diff)
downloadlinux-2836615aa22de55b8fca5e32fe1b27a67cda625e.tar.xz
netns: add schedule point in ops_exit_list()
When under stress, cleanup_net() can have to dismantle netns in big numbers. ops_exit_list() currently calls many helpers [1] that have no schedule point, and we can end up with soft lockups, particularly on hosts with many cpus. Even for moderate amount of netns processed by cleanup_net() this patch avoids latency spikes. [1] Some of these helpers like fib_sync_up() and fib_sync_down_dev() are very slow because net/ipv4/fib_semantics.c uses host-wide hash tables, and ifindex is used as the only input of two hash functions. ifindexes tend to be the same for all netns (lo.ifindex==1 per instance) This will be fixed in a separate patch. Fixes: 72ad937abd0a ("net: Add support for batching network namespace cleanups") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/net_namespace.c')
-rw-r--r--net/core/net_namespace.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 9b7171c40434..a5b5bb99c644 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -164,8 +164,10 @@ static void ops_exit_list(const struct pernet_operations *ops,
{
struct net *net;
if (ops->exit) {
- list_for_each_entry(net, net_exit_list, exit_list)
+ list_for_each_entry(net, net_exit_list, exit_list) {
ops->exit(net);
+ cond_resched();
+ }
}
if (ops->exit_batch)
ops->exit_batch(net_exit_list);