On Tue, 2017-08-15 at 19:42 +0200, Paweł Staszewski wrote:
> # To display the perf.data header info, please use
> --header/--header-only options.
> #
> #
> # Total Lost Samples: 0
> #
> # Samples: 2M of event 'cycles'
> # Event count (approx.): 1585571545969
> #
> # Children Self Command Shared Object Symbol
> # ........ ........ .............. ....................
> ..............................................
> #
> 1.82% 0.00% ksoftirqd/43 [kernel.vmlinux] [k]
> __softirqentry_text_start
> |
> --1.82%--__softirqentry_text_start
> |
> --1.82%--net_rx_action
> |
> --1.82%--mlx5e_napi_poll
> |
> --1.81%--mlx5e_poll_rx_cq
> |
> --1.81%--mlx5e_handle_rx_cqe
> |
> --1.79%--napi_gro_receive
> |
> --1.78%--netif_receive_skb_internal
> |
> --1.78%--__netif_receive_skb
> |
> --1.78%--__netif_receive_skb_core
> |
> --1.78%--ip_rcv
> |
> --1.78%--ip_rcv_finish
> |
> --1.76%--ip_forward
> |
> --1.76%--ip_forward_finish
> |
> --1.76%--ip_output
> |
> --1.76%--ip_finish_output
> |
> --1.76%--ip_finish_output2
> |
> --1.73%--neigh_resolve_output
> |
> --1.73%--neigh_event_send
> |
> --1.73%--__neigh_event_send
> |
> --1.70%--_raw_write_lock_bh
> queued_write_lock
> queued_write_lock_slowpath
> |
> --1.67%--queued_spin_lock_slowpath
>
>
Please try this :
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index
16a1a4c4eb57fa1147f230916e2e62e18ef89562..95e0d7702029b583de8229e3c3eb923f6395b072
100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -991,14 +991,18 @@ static void neigh_timer_handler(unsigned long arg)
int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
{
- int rc;
bool immediate_probe = false;
+ int rc;
+
+ /* We _should_ test this under write_lock_bh(&neigh->lock),
+ * but this is too costly.
+ */
+ if (READ_ONCE(neigh->nud_state) & (NUD_CONNECTED | NUD_DELAY |
NUD_PROBE))
+ return 0;
write_lock_bh(&neigh->lock);
rc = 0;
- if (neigh->nud_state & (NUD_CONNECTED | NUD_DELAY | NUD_PROBE))
- goto out_unlock_bh;
if (neigh->dead)
goto out_dead;
