Subject: Re: [RFC][PATCH 2/2] first callers of process_deny_checkpoint()
From: Greg Kurz <gkurz@fr.ibm.com>
To: "Serge E. Hallyn" <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>, linux-kernel@vger.kernel.org,
       containers@lists.linux-foundation.org, Ingo Molnar <mingo@elte.hu>,
       arnd@arndb.de, Dave Hansen <dave@linux.vnet.ibm.com>
In-Reply-To: <20081010140430.GA14640@us.ibm.com>
References: <20081009190405.13A253CB@kernel>
	 <20081009190406.1B257119@kernel> <48EF2BAB.1010009@fr.ibm.com>
	 <20081010140430.GA14640@us.ibm.com>
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Date: Fri, 10 Oct 2008 18:45:32 +0200
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On Fri, 2008-10-10 at 09:04 -0500, Serge E. Hallyn wrote:
> Remember a part of Ingo's motivation is to push c/r developers to
> address the lacking features that users use most, earlier.  So the
> warnings and subsequent email complaints are what we're after.  Hence a
> single 'checkpointable or not' flag.
> 
> Given the single flag, how do you know at sys_mq_unlink() whether the
> process also has an opensocket?
> 
> Rather than make this tracking facility more complicated and intrusive,
> if people complain that they couldn't checkpoint bc of a warning about
> aio, then we implement aio c/r!  We don't just try and reduce the amount
> of time that you can't checkpoint bc of lack of aio c/r support  :)
> 
> -serge

Serge,

It's exactly what I meant before, the tracking facility would be awfully
complicated. It cannot be done that way.
But there's also something awkward with the flag thing : can you provide
right now an exhaustive list of all the places where you must raise it ?

I'd rather do some heavy checking at checkpoint time.

Greg.


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