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From: "D. Wythe" <alibuda@linux.alibaba.com>
To: Karsten Graul <kgraul@linux.ibm.com>
Cc: dust.li@linux.alibaba.com, 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 v2] net/smc: Reduce overflow of smc clcsock listen queue
Date: Wed, 5 Jan 2022 23:06:12 +0800	[thread overview]
Message-ID: <20220105150612.GA75522@e02h04389.eu6sqa> (raw)
In-Reply-To: <b98aefce-e425-9501-aacc-8e5a4a12953e@linux.ibm.com>

LGTM. Fallback makes the restrictions on SMC dangling
connections more meaningful to me, compared to dropping them.

Overall, i see there are two scenario.

1. Drop the overflow connections limited by userspace application
accept.

2. Fallback the overflow connections limited by the heavy process of
current SMC handshake. ( We can also control its behavior through
sysctl.)

I'll follow those advise to improve my patch, more advise will be highly
appreciated.

Thanks all. 


On Wed, Jan 05, 2022 at 02:17:41PM +0100, Karsten Graul wrote:
> On 05/01/2022 09:57, dust.li wrote:
> > On Wed, Jan 05, 2022 at 12:40:49PM +0800, D. Wythe wrote:
> > I'm thinking maybe we can actively fall back to TCP in this case ? Not
> > sure if this is a good idea.
> 
> I think its a good decision to switch new connections to use the TCP fallback when the
> current queue of connections waiting for a SMC handshake is too large.
> With this the application is able to accept all incoming connections and they are not
> dropped. The only thing that is be different compared to TCP is that the order of the
> accepted connections is changed, connections that came in later might reach the user space 
> application earlier than connections that still run the SMC hand shake processing. 
> But I think that is semantically okay.

  reply	other threads:[~2022-01-05 15:06 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-04 13:12 [PATCH net-next v2] net/smc: Reduce overflow of smc clcsock listen queue D. Wythe
2022-01-04 13:45 ` Karsten Graul
2022-01-04 16:17   ` D. Wythe
2022-01-05  4:40   ` D. Wythe
2022-01-05  8:28     ` Tony Lu
2022-01-05  8:57     ` dust.li
2022-01-05 13:17       ` Karsten Graul
2022-01-05 15:06         ` D. Wythe [this message]
2022-01-05 19:13           ` Karsten Graul
2022-01-06  7:05             ` Tony Lu
2022-01-13  8:07               ` Karsten Graul
2022-01-13 18:50                 ` Jakub Kicinski
2022-01-20 13:39                 ` Tony Lu
2022-01-20 16:00                   ` Stefan Raspl
2022-01-21  2:47                     ` Tony Lu
2022-02-16 11:46                 ` dust.li
2022-01-06  3:51           ` D. Wythe
2022-01-06  9:54             ` Karsten Graul

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