From: "Serge E. Hallyn" <serue@us.ibm.com>
To: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>,
containers <containers@lists.linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Oren Laadan <orenl@cs.columbia.edu>,
Alexey Dobriyan <adobriyan@gmail.com>,
hch@infradead.org
Subject: Re: [RFC][PATCH 8/8] check files for checkpointability
Date: Mon, 2 Mar 2009 07:37:54 -0600 [thread overview]
Message-ID: <20090302133754.GA8033@us.ibm.com> (raw)
In-Reply-To: <20090227203435.98735E54@kernel>
Quoting Dave Hansen (dave@linux.vnet.ibm.com):
>
> Introduce a files_struct counter to indicate whether a particular
> file_struct has ever contained a file which can not be
> checkpointed. This flag is a one-way trip; once it is set, it may
> not be unset.
>
> We assume at allocation that a new files_struct is clean and may
> be checkpointed. However, as soon as it has had its files filled
> from its parent's, we check it for real in __scan_files_for_cr().
> At that point, we mark it if it contained any uncheckpointable
> files.
>
> We also check each 'struct file' when it is installed in a fd
> slot. This way, if anyone open()s or managed to dup() an
> unsuppored file, we can catch it.
>
> Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
So on a practical note, Ingo's scheme appears to be paying off. In
order for any program's files_struct to be checkpointable right now,
it must be statically compiled, else ld.so (I assume) looks up
/proc/$$/status. So since proc is not checkpointable, the result
is irreversibly non-checkpointable.
So... does it make sense to mark proc as checkpointable? Do we
reasonably assume that the same procfile will be available at
restart?
-serge
next prev parent reply other threads:[~2009-03-02 13:44 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-27 20:34 [RFC][PATCH 1/8] kill '_data' in cr_hdr_fd_data name Dave Hansen
2009-02-27 20:34 ` [RFC][PATCH 2/8] breakout fdinfo sprintf() into its own function Dave Hansen
2009-02-27 20:56 ` Vegard Nossum
2009-02-27 21:23 ` Dave Hansen
2009-02-27 20:34 ` [RFC][PATCH 3/8] create fs flags to mark c/r supported fs's Dave Hansen
2009-02-27 21:16 ` Alexey Dobriyan
2009-02-27 21:20 ` Dave Hansen
2009-02-27 20:34 ` [RFC][PATCH 4/8] file c/r: expose functions to query fs support Dave Hansen
2009-02-27 21:14 ` Sukadev Bhattiprolu
2009-02-27 21:24 ` Dave Hansen
2009-02-27 21:32 ` Dave Hansen
2009-02-28 1:33 ` Sukadev Bhattiprolu
2009-02-27 20:34 ` [RFC][PATCH 5/8] add f_op for checkpointability Dave Hansen
2009-02-28 2:14 ` Sukadev Bhattiprolu
2009-02-28 2:51 ` Dave Hansen
2009-02-28 20:53 ` Christoph Hellwig
2009-02-28 21:37 ` Dave Hansen
2009-03-01 15:19 ` Serge E. Hallyn
2009-03-02 17:05 ` Dave Hansen
2009-03-03 13:15 ` Christoph Hellwig
2009-03-20 21:13 ` Dave Hansen
2009-03-20 21:30 ` Oren Laadan
2009-02-27 20:34 ` [RFC][PATCH 6/8] mark /dev/null and zero as checkpointable Dave Hansen
2009-02-27 20:34 ` [RFC][PATCH 7/8] add c/r info to fdinfo Dave Hansen
2009-02-27 20:34 ` [RFC][PATCH 8/8] check files for checkpointability Dave Hansen
2009-02-28 2:57 ` Sukadev Bhattiprolu
2009-03-01 17:00 ` Serge E. Hallyn
2009-03-04 23:41 ` Dave Hansen
2009-03-01 19:43 ` Serge E. Hallyn
2009-03-02 13:37 ` Serge E. Hallyn [this message]
2009-03-02 15:56 ` Dave Hansen
2009-03-02 15:59 ` Nathan Lynch
2009-03-02 16:27 ` Dave Hansen
2009-03-02 17:22 ` Nathan Lynch
2009-03-02 17:30 ` Dave Hansen
2009-03-02 17:44 ` Serge E. Hallyn
2009-03-02 17:58 ` Dave Hansen
2009-03-02 18:13 ` Dave Hansen
2009-03-02 18:35 ` Serge E. Hallyn
2009-03-05 8:20 ` Cedric Le Goater
2009-03-02 16:28 ` Serge E. Hallyn
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