Re: om2.6 What's currently showable ?

On Mon, Jul 24, 2006 at 03:49:21PM +0200, Florian Delizy wrote:
> Well actually, that's the case ... If I choose to use the 2.6 kernel, 
> (which I did), we have to have something *working* in a production 
> environement, and I have to demonstrate it ... on a 2.6. As I had been 
> told already, it seems that oM2.6 is able to migrate processes, unless 
> some bad syscalls happens ... Which bad syscalls ? For instance, a 
> program using a shared library would have a mmap on it, would that fail 
> on oM2.6 ?

Mmap is very complex syscall and very wide:
- Anonymous private mmap is working already very well (that is the simplest)
- File private mmap use to work, with the rinode thingie. not sure that's
  still the case now .. not tested for a while as well.
- Anonymous shared mmap are not suppose to work yet, and should send
  back the process to the deputy. untested.
- File shared mmap are not suppose to work either. untested

all shared mmaping can be made to work though. with some
read only mapping to catch write fault, and have handler to propagate
stuff.. the performance now is another thing ..

> This choice is quite important to me, and moreover, I can only help 
> continuing to develop oM if I can proove the feasability with oM2.6

OM on 2.6 is definitely feasible. A experienced developer full time on
it should complete it in few weeks I guess.

> I am not sure that would be enough ... though ... I guess that programs 
> that we have to migrate are something like, using a shared lib, now the 
> question is how would taht be done ... (I don't know yet). A simple 
> scenario, if several programs are using a single shared lib, and all 
> programs are spread over different cluster nodes, would that work ?

yes it definitively works. a shared lib is anyway a private mapping (or
a shared mapping over non-writable stuff, which is the same as private).

-- 
Vincent Hanquez

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