[Ksummit-2010-discuss] checkpoint-restart: naked patch

Alexey Dobriyan adobriyan at gmail.com
Fri Nov 19 08:55:55 PST 2010


On Fri, Nov 19, 2010 at 6:50 PM, Tejun Heo <tj at kernel.org> wrote:
> On 11/19/2010 05:38 PM, Alexey Dobriyan wrote:
>> On Fri, Nov 19, 2010 at 6:32 PM, Tejun Heo <tj at kernel.org> wrote:
>>> On 11/19/2010 05:27 PM, Alexey Dobriyan wrote:
>>>> On Fri, Nov 19, 2010 at 6:19 PM, Tejun Heo <tj at kernel.org> wrote:
>>>>>> The paragon of absurdity is struct task_struct::did_exec .
>>>>>
>>>>> Yeah, then go and figure how to do that in a way which would be useful
>>>>> for other purposes too instead of trying to shove the whole
>>>>> checkpointer inside the kernel.  It sure would be harder but hey
>>>>> that's the way it is.
>>>>
>>>> System call for one bit? This is ridiculous.
>>>
>>> Why not just a flag in proc entry?  It's a frigging single bit.
>>
>> Because /proc/*/did_exec useless to anyone but C/R (even for reading!).
>
> I don't think you'll need a full file.  Just shove it in status or
> somewhere.  Your argument is completely absurd.  So, because exporting
> single bit is so horrible to everyone else, you want to shove the
> whole frigging checkpointer inside the kernel?
>
>> Because code is much simpler:
>>
>>     tsk->did_exec = !!tsk_img->did_exec;
>> +
>>     __u8 did_exec;
>
> Sigh, yeah, except for the horror show to create tsk_img.

task_struct image work is common for both userspace C/R and in-kernel.
You _have_ to define it.
Simpler code is only first line.

> Your "paragon of absurdity" is did_exec which is only ever used
> to decide whether setpgid() should fail with -EACCES, seriously?
> Here's a thought.  Ignore it for now and concentrate on more
> relevant problems.

You're so newjerseyly now.


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