From: Yunsheng Lin <linyunsheng@huawei.com>
To: <davem@davemloft.net>, <kuba@kernel.org>
Cc: <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linuxarm@openeuler.org>, <edumazet@google.com>,
<yoshfuji@linux-ipv6.org>, <dsahern@kernel.org>
Subject: [PATCH net-next] tcp: add tcp_tx_skb_cache_key checking in sk_stream_alloc_skb()
Date: Wed, 1 Sep 2021 18:39:04 +0800 [thread overview]
Message-ID: <1630492744-60396-1-git-send-email-linyunsheng@huawei.com> (raw)
Since tcp_tx_skb_cache is disabled by default in:
commit 0b7d7f6b2208 ("tcp: add tcp_tx_skb_cache sysctl")
Add tcp_tx_skb_cache_key checking in sk_stream_alloc_skb() to
avoid possible branch-misses.
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
Also, the sk->sk_tx_skb_cache may be both changed by allocation
and freeing side, I assume there may be some implicit protection
here too, such as the NAPI protection for rx?
---
net/ipv4/tcp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index e8b48df..226ddef 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -866,7 +866,7 @@ struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
{
struct sk_buff *skb;
- if (likely(!size)) {
+ if (static_branch_unlikely(&tcp_tx_skb_cache_key) && likely(!size)) {
skb = sk->sk_tx_skb_cache;
if (skb) {
skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
--
2.7.4
next reply other threads:[~2021-09-01 10:40 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-01 10:39 Yunsheng Lin [this message]
2021-09-01 10:52 ` [PATCH net-next] tcp: add tcp_tx_skb_cache_key checking in sk_stream_alloc_skb() Paolo Abeni
2021-09-01 15:06 ` Eric Dumazet
2021-09-01 15:16 ` Eric Dumazet
2021-09-01 15:25 ` Paolo Abeni
2021-09-01 15:29 ` Eric Dumazet
2021-09-01 16:01 ` Paolo Abeni
2021-09-01 16:02 ` Eric Dumazet
2021-09-02 0:47 ` Yunsheng Lin
2021-09-02 1:13 ` Eric Dumazet
2021-09-02 2:05 ` Yunsheng Lin
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