From: Eric Dumazet <eric.duma...@gmail.com>
Date: Wed, 07 Mar 2018 08:43:19 -0800
> From: Eric Dumazet <eduma...@google.com>
>
> 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: 8571ab479a6e ("ip6mr: Make mroute_sk rcu-based")
> Signed-off-by: Eric Dumazet <eduma...@google.com>
> Reported-by: Kirill Tkhai <ktk...@virtuozzo.com>
> Cc: Yuval Mintz <yuv...@mellanox.com>
Looks great, applied, thanks everyone.
