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From: Yunsheng Lin <linyunsheng@huawei.com>
To: <davem@davemloft.net>, <kuba@kernel.org>, <edumazet@google.com>
Cc: <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linuxarm@openeuler.org>, <yoshfuji@linux-ipv6.org>,
	<dsahern@kernel.org>
Subject: Re: [PATCH net-next] tcp: add tcp_tx_skb_cache_key checking in sk_stream_alloc_skb()
Date: Thu, 2 Sep 2021 08:47:51 +0800	[thread overview]
Message-ID: <ba7a0854-6841-2ebc-c329-4c13f1a997df@huawei.com> (raw)
In-Reply-To: <1630492744-60396-1-git-send-email-linyunsheng@huawei.com>

On 2021/9/1 18:39, Yunsheng Lin wrote:
> 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?

Hi, Eric
   Is there any implicit protection for sk->sk_tx_skb_cache?
As my understanding, sk_stream_alloc_skb() seems to be protected
by lock_sock(), and the sk_wmem_free_skb() seems to be mostly
happening in NAPI polling for TCP(when ack packet is received)
without lock_sock(), so it seems there is no protection here?

> 

  parent reply	other threads:[~2021-09-02  0:47 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-01 10:39 [PATCH net-next] tcp: add tcp_tx_skb_cache_key checking in sk_stream_alloc_skb() Yunsheng Lin
2021-09-01 10:52 ` Paolo Abeni
2021-09-01 10:52   ` Paolo Abeni
2021-09-01 15:06   ` Eric Dumazet
2021-09-01 15:06     ` Eric Dumazet
2021-09-01 15:16     ` Eric Dumazet
2021-09-01 15:16       ` Eric Dumazet
2021-09-01 15:25       ` Paolo Abeni
2021-09-01 15:25         ` Paolo Abeni
2021-09-01 15:29         ` Eric Dumazet
2021-09-01 15:29           ` Eric Dumazet
2021-09-01 16:01         ` Paolo Abeni
2021-09-01 16:01           ` Paolo Abeni
2021-09-01 16:02           ` Eric Dumazet
2021-09-01 16:02             ` Eric Dumazet
2021-09-02  0:47 ` Yunsheng Lin [this message]
2021-09-02  1:13   ` Eric Dumazet
2021-09-02  2:05     ` Yunsheng Lin

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