From: Casper.Dik@oracle.com
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Alan Burlison <Alan.Burlison@oracle.com>,
David Miller <davem@davemloft.net>,
eric.dumazet@gmail.com, stephen@networkplumber.org,
netdev@vger.kernel.org, dholland-tech@netbsd.org
Subject: Re: [Bug 106241] New: shutdown(3)/close(3) behaviour is incorrect for sockets in accept(3)
Date: Tue, 27 Oct 2015 10:08:07 +0100 [thread overview]
Message-ID: <201510270908.t9R9873a001683@room101.nl.oracle.com> (raw)
In-Reply-To: <20151024023054.GZ22011@ZenIV.linux.org.uk>
>And no, I'm not fond of such irregular ways to pass file descriptors, but
>we can't kill ioctl(2) with all weirdness hiding behind it, more's the pity...
Yeah, there are a number of calls which supposed work on one but have a
second argument which is also a file descriptor; mostly part of ioctl().
>> In those specific cases where a system call needs to convert a file
>> descriptor to a file pointer, there is only one routines which can be used.
>
>Obviously, but the problem is deadlock avoidance using it.
The Solaris algorithm is quite different and as such there is no chance of
having a deadlock using that function (there is a bunch of functions)
>The memory footprint is really scary. Bitmaps are pretty much noise, but
>blowing it by factor of 8 on normal 64bit (or 16 on something like Itanic -
>or Venus for that matter, which is more relevant for you guys)
Fair enough. I think we have some systems with a larger cache line.
>Said that, what's the point of "close won't return until..."? After all,
>you can't guarantee that thread with cancelled syscall won't lose CPU
>immediately upon return to userland, so it *can't* make any assumptions
>about the descriptor not having been already reused. I don't get it - what
>does that buy for userland code?
Generally I wouldn't see that as a problem, but in the case of a socket
blocking on accept indefinitely, I do see it as a problem especially as
the thread actually wants to stop listening.
But in general, this is basically a problem with the application: the file
descriptor space is shared between threads and having one thread sniping
at open files, you do have a problem and whatever the kernel does in that
case perhaps doesn't matter all that much: the application needs to be
fixed anyway.
Casper
next prev parent reply other threads:[~2015-10-27 9:24 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
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 [this message]
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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