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From: "Michael Kerrisk (man-pages)" <mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	"linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	lkml <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Linux-Fsdevel
	<linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>
Cc: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Subject: OFD locks and deadlock detection
Date: Mon, 19 May 2014 15:18:13 +0200	[thread overview]
Message-ID: <537A0495.60107@gmail.com> (raw)

Hi Jeff,

I just happened to notice :

    commit 57b65325fe34ec4c917bc4e555144b4a94d9e1f7
    Author: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
    Date:   Mon Feb 3 12:13:09 2014 -0500

        locks: skip deadlock detection on FL_FILE_PVT locks

And then this thread:

    http://thread.gmane.org/gmane.linux.file-systems/81318/focus=81327
    From: Jeff Layton <jlayton <at> redhat.com>
    Subject: [PATCH v5 13/14] locks: skip deadlock detection on FL_FILE_PVT locks
    Date: 2014-01-09 14:19:46 GMT

I think it's pretty important to document that. All implementations
of traditional process-associated (.k.a. "POSIX") locks that I've ever 
come across do detect deadlocks, so it's important to note that OFD locks 
do not.

I plan to add the following text to the fcntl(2) page:

[[
In the current implementation,
no deadlock detection is performed for open file description locks.
(This contrasts with process-associated record locks,
for which the kernel does perform deadlock detection.)
]]

Okay?

cheers,

Michael


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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WARNING: multiple messages have this Message-ID (diff)
From: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
To: Jeff Layton <jlayton@redhat.com>,
	"linux-man@vger.kernel.org" <linux-man@vger.kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	Linux-Fsdevel <linux-fsdevel@vger.kernel.org>,
	Andy Lutomirski <luto@amacapital.net>
Cc: mtk.manpages@gmail.com
Subject: OFD locks and deadlock detection
Date: Mon, 19 May 2014 15:18:13 +0200	[thread overview]
Message-ID: <537A0495.60107@gmail.com> (raw)

Hi Jeff,

I just happened to notice :

    commit 57b65325fe34ec4c917bc4e555144b4a94d9e1f7
    Author: Jeff Layton <jlayton@redhat.com>
    Date:   Mon Feb 3 12:13:09 2014 -0500

        locks: skip deadlock detection on FL_FILE_PVT locks

And then this thread:

    http://thread.gmane.org/gmane.linux.file-systems/81318/focus=81327
    From: Jeff Layton <jlayton <at> redhat.com>
    Subject: [PATCH v5 13/14] locks: skip deadlock detection on FL_FILE_PVT locks
    Date: 2014-01-09 14:19:46 GMT

I think it's pretty important to document that. All implementations
of traditional process-associated (.k.a. "POSIX") locks that I've ever 
come across do detect deadlocks, so it's important to note that OFD locks 
do not.

I plan to add the following text to the fcntl(2) page:

[[
In the current implementation,
no deadlock detection is performed for open file description locks.
(This contrasts with process-associated record locks,
for which the kernel does perform deadlock detection.)
]]

Okay?

cheers,

Michael


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/

             reply	other threads:[~2014-05-19 13:18 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-19 13:18 Michael Kerrisk (man-pages) [this message]
2014-05-19 13:18 ` OFD locks and deadlock detection Michael Kerrisk (man-pages)
     [not found] ` <537A0495.60107-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2014-05-19 14:28   ` Jeff Layton
2014-05-19 14:28     ` Jeff Layton
     [not found]     ` <20140519102802.16dee141-9yPaYZwiELC+kQycOl6kW4xkIHaj4LzF@public.gmane.org>
2014-05-19 18:36       ` Michael Kerrisk (man-pages)
2014-05-19 18:36         ` Michael Kerrisk (man-pages)
2014-05-20  9:54         ` Jeff Layton
     [not found]           ` <20140520055402.6c132d60-9yPaYZwiELC+kQycOl6kW4xkIHaj4LzF@public.gmane.org>
2014-05-20 20:22             ` Michael Kerrisk (man-pages)
2014-05-20 20:22               ` Michael Kerrisk (man-pages)
2014-05-21 20:58               ` Jeff Layton

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