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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Bui Quang Minh <minhquangbui99@gmail.com>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Cc: davem@davemloft.net, kuba@kernel.org, yoshfuji@linux-ipv6.org,
	dsahern@kernel.org, willemb@google.com, pabeni@redhat.com,
	avagin@gmail.com, alexander@mihalicyn.com,
	lesedorucalin01@gmail.com
Subject: Re: [PATCH v2 1/2] udp: UDP socket send queue repair
Date: Thu, 12 Aug 2021 17:51:00 +0200	[thread overview]
Message-ID: <489f0200-b030-97de-cf3a-2d715b07dfa4@gmail.com> (raw)
In-Reply-To: <7f3ecbaf-7759-88ae-53d3-2cc5b1623aff@gmail.com>



On 8/12/21 3:46 PM, Bui Quang Minh wrote:
> 
> 
> On 8/11/2021 11:14 PM, Eric Dumazet wrote:
>>
>>
>> On 8/11/21 5:45 PM, Bui Quang Minh wrote:
>>> In this patch, I implement UDP_REPAIR sockoption and a new path in
>>> udp_recvmsg for dumping the corked packet in UDP socket's send queue.
>>>
>>> A userspace program can use recvmsg syscall to get the packet's data and
>>> the msg_name information of the packet. Currently, other related
>>> information in inet_cork that are set in cmsg are not dumped.
>>>
>>> While working on this, I was aware of Lese Doru Calin's patch and got some
>>> ideas from it.
>>
>>
>> What is the use case for this feature, adding a test in UDP fast path ?
> 
> This feature is used to help CRIU to dump CORKed UDP packet in send queue. I'm sorry for being not aware of the performance perspective here.

UDP is not reliable.

I find a bit strange we add so many lines of code
for a feature trying very hard to to drop _one_ packet.

I think a much better changelog would be welcomed.

> 
>> IMO, TCP_REPAIR hijacking standard system calls was a design error,
>> we should have added new system calls.
> 
> You are right that adding new system calls is a better approach. What do you think about adding a new option in getsockopt approach?
> 
> Thanks,
> Quang Minh.

  reply	other threads:[~2021-08-12 15:51 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-11 15:45 Bui Quang Minh
2021-08-11 16:14 ` Eric Dumazet
2021-08-12 13:46   ` Bui Quang Minh
2021-08-12 15:51     ` Eric Dumazet [this message]
2021-08-13 11:08       ` Bui Quang Minh
2021-08-13 13:00         ` David Laight
2021-08-17 16:22           ` avagin
2021-08-16 14:35         ` Willem de Bruijn
2021-08-16 14:38 ` Willem de Bruijn

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