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From: Alan Burlison <Alan.Burlison@oracle.com>
To: David Miller <davem@davemloft.net>, viro@ZenIV.linux.org.uk
Cc: eric.dumazet@gmail.com, stephen@networkplumber.org,
	netdev@vger.kernel.org, dholland-tech@netbsd.org,
	casper.dik@oracle.com
Subject: Re: [Bug 106241] New: shutdown(3)/close(3) behaviour is incorrect for sockets in accept(3)
Date: Thu, 22 Oct 2015 05:17:50 +0100	[thread overview]
Message-ID: <5628636E.1020107@oracle.com> (raw)
In-Reply-To: <20151021.182955.1434243485706993231.davem@davemloft.net>

On 22/10/2015 02:29, David Miller wrote:

> From: Al Viro <viro@ZenIV.linux.org.uk>
> Date: Wed, 21 Oct 2015 19:51:04 +0100
>
>> Sure, but the upkeep of data structures it would need is there
>> whether you actually end up triggering it or not.  Both in
>> memory footprint and in cacheline pingpong...
>
> +1

It's been said that the current mechanisms in Linux & some BSD variants 
can be subject to races, and the behaviour exhibited doesn't conform to 
POSIX, for example requiring the use of shutdown() on unconnected 
sockets because close() doesn't kick off other threads accept()ing on 
the same fd. I'd be interested to hear if there's a better and more 
performant way of handling the situation that doesn't involve doing the 
sort of bookkeeping Casper described,.

To quote one of my colleague's favourite sayings: Performance is a goal, 
correctness is a constraint.

-- 
Alan Burlison
--

  reply	other threads:[~2015-10-22  4:17 UTC|newest]

Thread overview: 138+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-19 16:59 Fw: [Bug 106241] New: shutdown(3)/close(3) behaviour is incorrect for sockets in accept(3) Stephen Hemminger
2015-10-19 23:33 ` Eric Dumazet
2015-10-20  1:12   ` Alan Burlison
2015-10-20  1:45     ` Eric Dumazet
2015-10-20  9:59       ` Alan Burlison
2015-10-20 11:24         ` David Miller
2015-10-20 11:39           ` Alan Burlison
2015-10-20 13:19         ` Fw: " Eric Dumazet
2015-10-20 13:45           ` Alan Burlison
2015-10-20 15:30             ` Eric Dumazet
2015-10-20 18:31               ` Alan Burlison
2015-10-20 18:42                 ` Eric Dumazet
2015-10-21 10:25                 ` David Laight
2015-10-21 10:49                   ` Alan Burlison
2015-10-21 11:28                     ` Eric Dumazet
2015-10-21 13:03                       ` Alan Burlison
2015-10-21 13:29                         ` Eric Dumazet
2015-10-21  3:49       ` Al Viro
2015-10-21 14:38         ` Alan Burlison
2015-10-21 15:30           ` David Miller
2015-10-21 16:04             ` Casper.Dik
2015-10-21 21:18               ` Eric Dumazet
2015-10-21 21:28                 ` Al Viro
2015-10-21 16:32           ` Fw: " Eric Dumazet
2015-10-21 18:51           ` Al Viro
2015-10-21 20:33             ` Casper.Dik
2015-10-22  4:21               ` Al Viro
2015-10-22 10:55                 ` Alan Burlison
2015-10-22 18:16                   ` Al Viro
2015-10-22 20:15                     ` Alan Burlison
2015-11-02 10:03               ` David Laight
2015-11-02 10:29                 ` Al Viro
2015-10-21 22:28             ` Alan Burlison
2015-10-22  1:29             ` David Miller
2015-10-22  4:17               ` Alan Burlison [this message]
2015-10-22  4:44                 ` Al Viro
2015-10-22  6:03                   ` Al Viro
2015-10-22  6:34                     ` Casper.Dik
2015-10-22 17:21                       ` Al Viro
2015-10-22 18:24                         ` Casper.Dik
2015-10-22 19:07                           ` Al Viro
2015-10-22 19:51                             ` Casper.Dik
2015-10-22 21:57                               ` Al Viro
2015-10-23  9:52                                 ` Casper.Dik
2015-10-23 13:02                                   ` Eric Dumazet
2015-10-23 13:20                                     ` Casper.Dik
2015-10-23 13:48                                       ` Eric Dumazet
2015-10-23 14:13                                       ` Eric Dumazet
2015-10-23 13:35                                     ` Alan Burlison
2015-10-23 14:21                                       ` Eric Dumazet
2015-10-23 15:46                                         ` Alan Burlison
2015-10-23 16:00                                           ` Eric Dumazet
2015-10-23 16:07                                             ` Alan Burlison
2015-10-23 16:19                                             ` Eric Dumazet
2015-10-23 16:40                                               ` Alan Burlison
2015-10-23 17:47                                                 ` Eric Dumazet
2015-10-23 17:59                                                   ` [PATCH net-next] af_unix: do not report POLLOUT on listeners Eric Dumazet
2015-10-25 13:45                                                     ` David Miller
2015-10-24  2:30                                   ` [Bug 106241] New: shutdown(3)/close(3) behaviour is incorrect for sockets in accept(3) Al Viro
2015-10-27  9:08                                     ` Casper.Dik
2015-10-27 10:52                                       ` Alan Burlison
2015-10-27 12:01                                         ` Eric Dumazet
2015-10-27 12:27                                           ` Alan Burlison
2015-10-27 12:44                                             ` Eric Dumazet
2015-10-27 13:42                                         ` David Miller
2015-10-27 13:37                                           ` Alan Burlison
2015-10-27 13:59                                             ` David Miller
2015-10-27 14:13                                               ` Alan Burlison
2015-10-27 14:39                                                 ` David Miller
2015-10-27 14:39                                                   ` Alan Burlison
2015-10-27 15:04                                                     ` David Miller
2015-10-27 15:53                                                       ` Alan Burlison
2015-10-27 23:17                                         ` Al Viro
2015-10-28  0:13                                           ` Eric Dumazet
2015-10-28 12:35                                             ` Al Viro
2015-10-28 13:24                                               ` Eric Dumazet
2015-10-28 14:47                                                 ` Eric Dumazet
2015-10-28 21:13                                                   ` Al Viro
2015-10-28 21:44                                                     ` Eric Dumazet
2015-10-28 22:33                                                       ` Al Viro
2015-10-28 23:08                                                         ` Eric Dumazet
2015-10-29  0:15                                                           ` Al Viro
2015-10-29  3:29                                                             ` Eric Dumazet
2015-10-29  4:16                                                               ` Al Viro
2015-10-29 12:35                                                                 ` Eric Dumazet
2015-10-29 13:48                                                                   ` Eric Dumazet
2015-10-30 17:18                                                                   ` Linus Torvalds
2015-10-30 21:02                                                                     ` Al Viro
2015-10-30 21:23                                                                       ` Linus Torvalds
2015-10-30 21:50                                                                         ` Linus Torvalds
2015-10-30 22:33                                                                           ` Al Viro
2015-10-30 23:52                                                                             ` Linus Torvalds
2015-10-31  0:09                                                                               ` Al Viro
2015-10-31 15:59                                                                               ` Eric Dumazet
2015-10-31 19:34                                                                               ` Al Viro
2015-10-31 19:54                                                                                 ` Linus Torvalds
2015-10-31 20:29                                                                                   ` Al Viro
2015-11-02  0:24                                                                                     ` Al Viro
2015-11-02  0:59                                                                                       ` Linus Torvalds
2015-11-02  2:14                                                                                       ` Eric Dumazet
2015-11-02  6:22                                                                                         ` Al Viro
2015-10-31 20:45                                                                                   ` Eric Dumazet
2015-10-31 21:23                                                                                     ` Linus Torvalds
2015-10-31 21:51                                                                                       ` Al Viro
2015-10-31 22:34                                                                                       ` Eric Dumazet
2015-10-31  1:07                                                                           ` Eric Dumazet
2015-10-28 16:04                                           ` Alan Burlison
2015-10-29 14:58                                         ` David Holland
2015-10-29 15:18                                           ` Alan Burlison
2015-10-29 16:01                                             ` David Holland
2015-10-29 16:15                                               ` Alan Burlison
2015-10-29 17:07                                                 ` Al Viro
2015-10-29 17:12                                                   ` Alan Burlison
2015-10-30  1:54                                                     ` David Miller
2015-10-30  1:55                                                   ` David Miller
2015-10-30  5:44                                                 ` David Holland
2015-10-30 17:43                                           ` David Laight
2015-10-30 21:09                                             ` Al Viro
2015-11-04 15:54                                               ` David Laight
2015-11-04 16:27                                                 ` Al Viro
2015-11-06 15:07                                                   ` David Laight
2015-11-06 19:31                                                     ` Al Viro
2015-10-22  6:51                   ` Casper.Dik
2015-10-22 11:18                     ` Alan Burlison
2015-10-22 11:15                   ` Alan Burlison
2015-10-22  6:15                 ` Casper.Dik
2015-10-22 11:30                   ` Eric Dumazet
2015-10-22 11:58                     ` Alan Burlison
2015-10-22 12:10                       ` Eric Dumazet
2015-10-22 13:12                         ` David Miller
2015-10-22 13:14                         ` Alan Burlison
2015-10-22 17:05                           ` Al Viro
2015-10-22 17:39                             ` Alan Burlison
2015-10-22 18:56                               ` Al Viro
2015-10-22 19:50                                 ` Casper.Dik
2015-10-23 17:09                                   ` Al Viro
2015-10-23 18:30           ` Fw: " David Holland
2015-10-23 19:51             ` Al Viro

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