Merge branch 'optimise-local-cpu-skb_attempt_defer_free'

Pavel Begunkov says:

====================
optimise local CPU skb_attempt_defer_free

Optimise the case when an skb comes to skb_attempt_defer_free()
on the same CPU it was allocated on. The patch 1 enables skb caches
and gives frags a chance to hit the page pool's fast path.
CPU bound benchmarking with perfect skb_attempt_defer_free()
gives around 1% of extra throughput.
====================

Link: https://lore.kernel.org/r/cover.1712711977.git.asml.silence@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/core/skbuff.c

@@ -6974,6 +6974,19 @@ void __skb_ext_put(struct skb_ext *ext)
 EXPORT_SYMBOL(__skb_ext_put);
 #endif /* CONFIG_SKB_EXTENSIONS */
 
+static void kfree_skb_napi_cache(struct sk_buff *skb)
+{
+	/* if SKB is a clone, don't handle this case */
+	if (skb->fclone != SKB_FCLONE_UNAVAILABLE) {
+		__kfree_skb(skb);
+		return;
+	}
+
+	local_bh_disable();
+	__napi_kfree_skb(skb, SKB_CONSUMED);
+	local_bh_enable();
+}
+
 /**
  * skb_attempt_defer_free - queue skb for remote freeing
  * @skb: buffer
@@ -6992,7 +7005,7 @@ void skb_attempt_defer_free(struct sk_buff *skb)
 	if (WARN_ON_ONCE(cpu >= nr_cpu_ids) ||
 	    !cpu_online(cpu) ||
 	    cpu == raw_smp_processor_id()) {
-nodefer:	__kfree_skb(skb);
+nodefer:	kfree_skb_napi_cache(skb);
 		return;
 	}