net: make napi_threaded_poll() aware of sd->defer_list

If we call skb_defer_free_flush() from napi_threaded_poll(),
we can avoid to raise IPI from skb_attempt_defer_free()
when the list becomes too big.

This allows napi_threaded_poll() to rely less on softirqs,
and lowers latency caused by a too big list.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/dev.c b/net/core/dev.c
index 81ded215731bdbb3a025fe40ed9638123d97a347..7d9ec23f97c6ec80ec9f971f740a9da747f78ceb 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6622,6 +6622,7 @@ static void skb_defer_free_flush(struct softnet_data *sd)
 static int napi_threaded_poll(void *data)
 {
        struct napi_struct *napi = data;
+       struct softnet_data *sd;
        void *have;
 
        while (!napi_thread_wait(napi)) {
@@ -6629,11 +6630,13 @@ static int napi_threaded_poll(void *data)
                        bool repoll = false;
 
                        local_bh_disable();
+                       sd = this_cpu_ptr(&softnet_data);
 
                        have = netpoll_poll_lock(napi);
                        __napi_poll(napi, &repoll);
                        netpoll_poll_unlock(have);
 
+                       skb_defer_free_flush(sd);
                        local_bh_enable();
 
                        if (!repoll)