netdev - [PATCH net-next 1/4] net: increase default NAPI_SKB_CACHE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20251118070646.61344-2-kerneljasonxing@gmail.com>
Date: Tue, 18 Nov 2025 15:06:43 +0800
From: Jason Xing <kerneljasonxing@...il.com>
To: davem@...emloft.net,
	edumazet@...gle.com,
	kuba@...nel.org,
	pabeni@...hat.com,
	horms@...nel.org
Cc: netdev@...r.kernel.org,
	Jason Xing <kernelxing@...cent.com>
Subject: [PATCH net-next 1/4] net: increase default NAPI_SKB_CACHE_SIZE to 128

From: Jason Xing <kernelxing@...cent.com>

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@...gle.com>
Signed-off-by: Jason Xing <kernelxing@...cent.com>
---
 net/core/skbuff.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 9feea830a4db..e4abf0e56776 100644
--- 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)

-- 
2.41.3