Re: manual page migration, revisited...

[Ray Bryant <raybry@sgi.com>]

Nigel Cunningham wrote:
> Hi.
> 
> On Sat, 2004-11-06 at 09:50, Ray Bryant wrote:
> 
>>Marcelo and Takahashi-san (and anyone else who would like to comment),
>>
>>This is a little off topic, but this is as good of thread as any to start this 
>>discussion on.  Feel free to peel this off as a separate discussion thread 
>>asap if you like.
>>
>>We have a requirement (for a potential customer) to do the following kind of
>>thing:
>>
>>(1)  Suspend and swap out a running process so that the node where the process
>>      is running can be reassigned to a higher priority job.
>>
>>(2)  Resume and swap back in those suspended jobs, restoring the original
>>      memory layout on the original nodes, or
>>
>>(3)  Resume and swap back in those suspended jobs on a new set of nodes, with
>>      as similar topological layout as possible.  (It's also possible we may
>>      want to just move the jobs directly from one set of nodes to another
>>      without swapping them out first.
> 
> 
> You may not even need any kernel patches to accomplish this. Bernard
> Blackham wrote some code called cryopid: http://cryopid.berlios.de/. I
> haven't tried it myself, but it sounds like it might be at least part of
> what you're after.
> 
> Regards,
> 
> Nigel
Nigel,

I think that having the resumed processes show up with a different pid than 
they had before is show-stopper.  In a multiprocess parallel program, we have
no idea whether the program itself has saved way pid's and is using them to
send signals or whatnot.  So I don't think there is a user space-only solution
that will solve this problem for us, but it an interesting alternative to
the kernel-only solutions I've been contemplating.  There is probably some
intermediate ground there which holds the real solution.

-- 
Best Regards,
Ray
-----------------------------------------------
                   Ray Bryant
512-453-9679 (work)         512-507-7807 (cell)
raybry@sgi.com             raybry@austin.rr.com
The box said: "Requires Windows 98 or better",
            so I installed Linux.
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