RE: [Xen-devel] [PATCH 1/1] Xen ARINC 653 Scheduler (updated to add support for CPU pools)

["Kathy Hadley" <Kathy.Hadley@xxxxxxxxxxxxxxx>]

That sounds reasonable to me.

Kathy

> -----Original Message-----
> From: Keir Fraser [mailto:keir.fraser@xxxxxxxxxxxxx]
> Sent: Wednesday, June 16, 2010 12:50 PM
> To: Kathy Hadley; George Dunlap
> Cc: xen-devel@xxxxxxxxxxxxxxxxxxx; Juergen Gross
> Subject: Re: [Xen-devel] [PATCH 1/1] Xen ARINC 653 Scheduler (updated
> to add support for CPU pools)
> 
> Oh, I see. Well, the cause is that the
> common/schedule.c:sched_adjust_global() is broken. But, what should it
> actually do, given that multiple schedulers of same or differing types
> may
> exist in a system now? Perhaps the sysctl should take a cpupool id, to
> uniquely identify the scheduler instance to be adjusted?
> 
>  -- Keir
> 
> On 16/06/2010 17:40, "Kathy Hadley" <Kathy.Hadley@xxxxxxxxxxxxxxx>
> wrote:
> 
> > Keir, George, et. al.,
> >   I definitely saw two "ops" values.  When the .init function was
> called, ops
> > = 0xFF213DC0; I then used xmalloc() to allocate memory for the
> scheduler data
> > structure and set ops->sched_data equal to the address of that memory
> block
> > (similar to what is done in csched_init in sched_credit.c).  When the
> > .adjust_global function was called, ops = 0xFF2112D0 and ops-
> >sched_data was
> > not equal to the address of the memory block allocated in the .init
> function
> > (it was equal to the value set when "sched_arinc653_def" was
> declared).
> >
> >   Regards,
> > Kathy
> >
> >> -----Original Message-----
> >> From: Keir Fraser [mailto:keir.fraser@xxxxxxxxxxxxx]
> >> Sent: Wednesday, June 16, 2010 12:32 PM
> >> To: Kathy Hadley; George Dunlap
> >> Cc: xen-devel@xxxxxxxxxxxxxxxxxxx; Juergen Gross
> >> Subject: Re: [Xen-devel] [PATCH 1/1] Xen ARINC 653 Scheduler
> (updated
> >> to add support for CPU pools)
> >>
> >> On 16/06/2010 17:25, "Kathy Hadley" <Kathy.Hadley@xxxxxxxxxxxxxxx>
> >> wrote:
> >>
> >>> Keir,
> >>>   I only saw the .init function called once.  I downloaded xen-
> >> unstable on May
> >>> 27.  Were your updates after that?
> >>
> >> My changes were done before May 27, and that ties in with you seeing
> >> .init
> >> called only once. That being the case, you should not see multiple
> >> different
> >> ops structures ('struct scheduler' instances). The only ops struct
> that
> >> should exist in the system in this case should be the one statically
> >> defined
> >> near the top of common/schedule.c.
> >>
> >>  -- Keir
> >>
> >>>   Thanks,
> >>> Kathy Hadley
> >>>
> >>>
> >>>> -----Original Message-----
> >>>> From: Keir Fraser [mailto:keir.fraser@xxxxxxxxxxxxx]
> >>>> Sent: Wednesday, June 16, 2010 12:20 PM
> >>>> To: George Dunlap; Kathy Hadley
> >>>> Cc: xen-devel@xxxxxxxxxxxxxxxxxxx; Juergen Gross
> >>>> Subject: Re: [Xen-devel] [PATCH 1/1] Xen ARINC 653 Scheduler
> >> (updated
> >>>> to add support for CPU pools)
> >>>>
> >>>> On 16/06/2010 17:14, "George Dunlap" <George.Dunlap@xxxxxxxxxxxxx>
> >>>> wrote:
> >>>>
> >>>>>>  I actually tried the xmalloc() method first.  I found that when
> >> the
> >>>>>> .adjust_global function was called, the address of the "ops"
> data
> >>>> structure
> >>>>>> passed to that function was different from the address of the
> >> "ops"
> >>>> data
> >>>>>> structure when the .init function was called.  I wanted to use
> >>>> .adjust_global
> >>>>>> to modify the data structure that was created when the .init
> >>>> function was
> >>>>>> called, but I could not figure out a way to get the address of
> the
> >>>> second
> >>>>>> data structure.  Suggestions?
> >>>>>
> >>>>> It's been a month or two since I trawled through the cpupools
> code;
> >>>>> but I seem to recall that .init is called twice -- once for the
> >>>>> "default pool" (cpupool0), and once for an actually in-use pool.
> >>>>> (Juergen, can you correct me if I'm wrong?)  Is it possible that
> >>>>> that's the difference in the pointers that you're seeing?
> >>>>
> >>>> Oh yes, that was the old behaviour. I took a hatchet to the
> >>>> scheduler/cpupool interfaces a few weeks ago and now we should
> only
> >>>> initialise the scheduler once, unless extra cpupools are manually
> >>>> created.
> >>>> The fact that Kathy is seeing two different ops structures
> probably
> >>>> indicates that her xen-unstable tree is very out of date. Which
> may
> >>>> also
> >>>> mean that the patch will not apply to current tip.
> >>>>
> >>>>  -- Keir
> >>>>
> >>>
> >>
> >
> 


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