[PATCH net-next 5/5] skbuff: refill skb_cache early from deferred-to-consume entries

[Alexander Lobakin <alobakin@pm.me>]

Instead of unconditional queueing of ready-to-consume skbuff_heads
to flush_skb_cache, feed skb_cache with them instead if it's not
full already.
This greatly reduces the frequency of kmem_cache_alloc_bulk() calls.

Signed-off-by: Alexander Lobakin <alobakin@pm.me>
---
 net/core/skbuff.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 57a7307689f3..ba0d5611635e 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -904,6 +904,11 @@ static inline void _kfree_skb_defer(struct sk_buff *skb)
 	/* drop skb->head and call any destructors for packet */
 	skb_release_all(skb);
 
+	if (nc->skb_count < NAPI_SKB_CACHE_SIZE) {
+		nc->skb_cache[nc->skb_count++] = skb;
+		return;
+	}
+
 	/* record skb to CPU local list */
 	nc->flush_skb_cache[nc->flush_skb_count++] = skb;
 
-- 
2.30.0