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From: Karsten Graul <kgraul@linux.ibm.com>
To: "D. Wythe" <alibuda@linux.alibaba.com>
Cc: kuba@kernel.org, davem@davemloft.net, netdev@vger.kernel.org,
	linux-s390@vger.kernel.org, linux-rdma@vger.kernel.org
Subject: Re: [PATCH net-next v5 2/5] net/smc: Limit backlog connections
Date: Tue, 8 Feb 2022 18:13:42 +0100	[thread overview]
Message-ID: <c28365d5-72e3-335b-372e-2a9069898df1@linux.ibm.com> (raw)
In-Reply-To: <c597e6c6d004e5b2a26a9535c8099d389214f273.1644323503.git.alibuda@linux.alibaba.com>

On 08/02/2022 13:53, D. Wythe wrote:
> From: "D. Wythe" <alibuda@linux.alibaba.com>
> 
> Current implementation does not handling backlog semantics, one
> potential risk is that server will be flooded by infinite amount
> connections, even if client was SMC-incapable.

In this patch you count the number of inflight SMC handshakes as pending and
check them against the defined max_backlog. I really like this improvement.

There is another queue in af_smc.c, the smc accept queue and any new client 
socket that completed the handshake process is enqueued there (in smc_accept_enqueue() )
and is waiting to get accepted by the user space application. To apply the correct
semantics here, I think the number of sockets waiting in the smc accept queue 
should also be counted as backlog connections, right? I see no limit for this queue
now. What do you think?

  reply	other threads:[~2022-02-08 17:13 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-08 12:53 [PATCH net-next v5 0/5] net/smc: Optimizing performance in short-lived scenarios D. Wythe
2022-02-08 12:53 ` [PATCH net-next v5 1/5] net/smc: Make smc_tcp_listen_work() independent D. Wythe
2022-02-08 17:06   ` Karsten Graul
2022-02-09  6:24     ` D. Wythe
2022-02-08 12:53 ` [PATCH net-next v5 2/5] net/smc: Limit backlog connections D. Wythe
2022-02-08 17:13   ` Karsten Graul [this message]
2022-02-09  7:11     ` D. Wythe
2022-02-09  7:56       ` Karsten Graul
2022-02-08 12:53 ` [PATCH net-next v5 3/5] net/smc: Fallback when handshake workqueue congested D. Wythe
2022-02-08 12:53 ` [PATCH net-next v5 4/5] net/smc: Dynamic control auto fallback by socket options D. Wythe
2022-02-08 17:08   ` Karsten Graul
2022-02-09  6:41     ` D. Wythe
2022-02-09  7:59       ` Karsten Graul
2022-02-09  9:01         ` D. Wythe
2022-02-08 12:53 ` [PATCH net-next v5 5/5] net/smc: Add global configure for auto fallback by netlink D. Wythe
2022-02-09  9:16   ` Tony Lu
2022-02-09  9:53     ` D. Wythe
2022-02-09 11:37       ` Tony Lu
2022-02-09  9:33   ` Tony Lu
2022-02-09  9:41     ` D. Wythe
2022-02-09  9:54       ` Tony Lu
2022-02-09 10:56         ` D. Wythe
2022-02-08 17:04 ` [PATCH net-next v5 0/5] net/smc: Optimizing performance in short-lived scenarios Karsten Graul

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