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

[Keir Fraser <keir.fraser@eu.citrix.com>]

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@dornerworks.com> 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@eu.citrix.com]
>> Sent: Wednesday, June 16, 2010 12:32 PM
>> To: Kathy Hadley; George Dunlap
>> Cc: xen-devel@lists.xensource.com; 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@dornerworks.com>
>> 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@eu.citrix.com]
>>>> Sent: Wednesday, June 16, 2010 12:20 PM
>>>> To: George Dunlap; Kathy Hadley
>>>> Cc: xen-devel@lists.xensource.com; 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@eu.citrix.com>
>>>> 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
>>>> 
>>> 
>> 
>