net: increase default NAPI_SKB_CACHE_SIZE to 128

After commit b61785852ed0 ("net: increase skb_defer_max default to 128")
changed the value sysctl_skb_defer_max to avoid many calls to
kick_defer_list_purge(), the same situation can be applied to
NAPI_SKB_CACHE_SIZE that was proposed in 2016. It's a trade-off between
using pre-allocated memory in skb_cache and saving more a bit heavy
function calls in the softirq context.

With this patch applied, we can have more skbs per-cpu to accelerate the
sending path that needs to acquire new skbs.

Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://patch.msgid.link/20251118070646.61344-2-kerneljasonxing@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 9feea830a4dbb61c1c661e802ed315eaeebcc809..e4abf0e567767eac6abbcf003804d85e60b0726f 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -223,7 +223,7 @@ static void skb_under_panic(struct sk_buff *skb, unsigned int sz, void *addr)
        skb_panic(skb, sz, addr, __func__);
 }
 
-#define NAPI_SKB_CACHE_SIZE    64
+#define NAPI_SKB_CACHE_SIZE    128
 #define NAPI_SKB_CACHE_BULK    16
 #define NAPI_SKB_CACHE_HALF    (NAPI_SKB_CACHE_SIZE / 2)