From: Pavel Machek <pavel@suse.cz>
To: "Serge E. Hallyn" <serue@us.ibm.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>,
Arnd Bergmann <arnd@arndb.de>,
containers@lists.linux-foundation.org,
Theodore Tso <tytso@mit.edu>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH 1/4] checkpoint-restart: general infrastructure
Date: Thu, 14 Aug 2008 07:53:02 +0200 [thread overview]
Message-ID: <20080814055301.GH6995@ucw.cz> (raw)
In-Reply-To: <20080811150703.GA25930@us.ibm.com>
Hi!
> > > > I have to wonder if this is just a symptom of us trying to do this the
> > > > wrong way. We're trying to talk the kernel into writing internal gunk
> > > > into a FD. You're right, it is like a splice where one end of the pipe
> > > > is in the kernel.
> > > >
> > > > Any thoughts on a better way to do this?
> > >
> > > Maybe you can invert the logic and let the new syscalls create a file
> > > descriptor, and then have user space read or splice the checkpoint
> > > data from it, and restore it by writing to the file descriptor.
> > > It's probably easy to do using anon_inode_getfd() and would solve this
> > > problem, but at the same time make checkpointing the current thread
> > > hard if not impossible.
> >
> > Yeah, it does seem kinda backwards. But, instead of even having to
> > worry about the anon_inode stuff, why don't we just put it in a fs like
> > everything else? checkpointfs!
>
> One reason is that I suspect that stops us from being able to send that
> data straight to a pipe to compress and/or send on the network, without
> hitting local disk. Though if the checkpointfs was ram-based maybe not?
>
> As Oren has pointed out before, passing in an fd means we can pass a
> socket into the syscall.
If you do pass a socket, will it handle blocking correctly? Getting
deadlocked task would be bad. What happens if I try to snapshot into
/proc/self/fd/0 ? Or maybe restore from /proc/cmdline?
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2008-08-14 11:05 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-07 22:40 [RFC][PATCH 0/4] kernel-based checkpoint restart Dave Hansen
2008-08-07 22:40 ` [RFC][PATCH 1/4] checkpoint-restart: general infrastructure Dave Hansen
2008-08-08 9:46 ` Arnd Bergmann
2008-08-08 18:50 ` Dave Hansen
2008-08-08 20:59 ` Oren Laadan
2008-08-08 22:17 ` Dave Hansen
2008-08-08 23:27 ` Oren Laadan
2008-08-08 22:23 ` Arnd Bergmann
2008-08-14 8:09 ` [Devel] " Pavel Emelyanov
2008-08-14 15:16 ` Dave Hansen
2008-08-08 22:13 ` Arnd Bergmann
2008-08-08 22:26 ` Dave Hansen
2008-08-08 22:39 ` Arnd Bergmann
2008-08-09 0:43 ` Dave Hansen
2008-08-09 6:37 ` Arnd Bergmann
2008-08-09 13:39 ` Dave Hansen
2008-08-11 15:07 ` Serge E. Hallyn
2008-08-11 15:25 ` Arnd Bergmann
2008-08-14 5:53 ` Pavel Machek [this message]
2008-08-14 15:12 ` Dave Hansen
2008-08-20 21:40 ` Oren Laadan
2008-08-11 15:22 ` Serge E. Hallyn
2008-08-11 16:53 ` Arnd Bergmann
2008-08-11 17:11 ` Dave Hansen
2008-08-11 19:48 ` checkpoint/restart ABI Dave Hansen
2008-08-11 21:47 ` Arnd Bergmann
2008-08-11 23:14 ` Jonathan Corbet
2008-08-11 23:23 ` Dave Hansen
2008-08-21 5:56 ` Oren Laadan
2008-08-21 8:43 ` Arnd Bergmann
2008-08-21 15:43 ` Oren Laadan
2008-08-11 21:54 ` Oren Laadan
2008-08-11 23:38 ` Jeremy Fitzhardinge
2008-08-11 23:54 ` Peter Chubb
2008-08-12 14:49 ` Serge E. Hallyn
2008-08-28 23:40 ` Eric W. Biederman
2008-08-12 15:11 ` Dave Hansen
2008-08-12 14:58 ` Dave Hansen
2008-08-12 16:32 ` Jeremy Fitzhardinge
2008-08-12 16:46 ` Dave Hansen
2008-08-12 17:04 ` Jeremy Fitzhardinge
2008-08-20 21:52 ` Oren Laadan
2008-08-20 21:54 ` Oren Laadan
2008-08-20 22:11 ` Dave Hansen
2008-08-11 18:03 ` [RFC][PATCH 1/4] checkpoint-restart: general infrastructure Jonathan Corbet
2008-08-11 18:38 ` Dave Hansen
2008-08-12 3:44 ` Oren Laadan
2008-08-18 9:26 ` [Devel] " Pavel Emelyanov
2008-08-20 19:10 ` Dave Hansen
2008-08-07 22:40 ` [RFC][PATCH 2/4] checkpoint/restart: x86 support Dave Hansen
2008-08-08 12:09 ` Arnd Bergmann
2008-08-08 20:28 ` Oren Laadan
2008-08-08 22:29 ` Arnd Bergmann
2008-08-08 23:04 ` Oren Laadan
2008-08-09 0:38 ` Dave Hansen
2008-08-09 1:20 ` Oren Laadan
2008-08-09 2:20 ` Dave Hansen
2008-08-09 2:35 ` Oren Laadan
2008-08-10 14:55 ` Jeremy Fitzhardinge
2008-08-11 15:36 ` Dave Hansen
2008-08-11 16:07 ` Jeremy Fitzhardinge
2008-08-09 6:43 ` Arnd Bergmann
2008-08-07 22:40 ` [RFC][PATCH 3/4] checkpoint/restart: memory management Dave Hansen
2008-08-08 12:12 ` Arnd Bergmann
2008-08-07 22:40 ` [RFC][PATCH 4/4] introduce sys_checkpoint and sys_restore Dave Hansen
2008-08-08 12:15 ` Arnd Bergmann
2008-08-08 20:33 ` Oren Laadan
2008-08-08 9:25 ` [RFC][PATCH 0/4] kernel-based checkpoint restart Arnd Bergmann
2008-08-08 18:06 ` Dave Hansen
2008-08-08 18:18 ` Arnd Bergmann
2008-08-08 19:44 ` Oren Laadan
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