Kirill found that recently added synchronize_rcu() call in
ip6mr_sk_done()
was slowing down netns dismantle and posted a patch to use it only if
the socket
was found.
I instead suggested to get rid of this call, and use instead
SOCK_RCU_FREE
We might later change IPv4 side to use the same technique and unify
both stacks. IPv4 does not use synchronize_rcu() but has a call_rcu()
that could be replaced by SOCK_RCU_FREE.
Tested:
time for i in {1..1000}; do unshare -n /bin/false;done
Before : real 7m18.911s
After : real 10.187s
Fixes: 8571ab479a ("ip6mr: Make mroute_sk rcu-based")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Yuval Mintz <yuvalm@mellanox.com>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
a366e300ae