On 06/17/2011 07:03 PM, Jan Kiszka wrote:
> On 2011-06-17 18:53, Gilles Chanteperdrix wrote:
>> On 06/17/2011 04:38 PM, GIT version control wrote:
>>> Module: xenomai-jki
>>> Branch: for-upstream
>>> Commit: 7203b1a66ca0825d5bcda1c3abab9ca048177914
>>> Author: Jan Kiszka <jan.kis...@siemens.com>
>>> Date: Fri Jun 17 09:46:19 2011 +0200
>>> nucleus: Fix interrupt handler tails
>>> Our current interrupt handlers assume that they leave over the same task
>>> and CPU they entered. But commit f6af9b831c broke this assumption:
>>> xnpod_schedule invoked from the handler tail can now actually trigger a
>>> domain migration, and that can also include a CPU migration. This causes
>>> subtle corruptions as invalid xnstat_exectime_t objects may be restored
>>> and - even worse - we may improperly flush XNHTICK of the old CPU,
>>> leaving Linux timer-wise dead there (as happened to us).
>>> Fix this by moving XNHTICK replay and exectime accounting before the
>>> scheduling point. Note that this introduces a tiny imprecision in the
>> I am not sure I understand why moving the XNHTICK replay is needed: if
>> we switch to secondary mode, the HTICK is handled by xnpod_schedule
>> anyway, or am I missing something?
> The replay can work on an invalid sched (after CPU migration in
> secondary mode). We could reload the sched, but just moving the replay
> is simpler.
But does it not remove the purpose of this delayed replay?
Note that if you want to reload the sched, you also have to shut
interrupts off, because upon return from xnpod_schedule after migration,
interrupts are on.
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