svn commit: r222060 - in user/avg/xcpu/sys: kern sys

[mdf at FreeBSD.org]

On Thu, May 26, 2011 at 9:05 AM, Andriy Gapon <avg at freebsd.org> wrote:
> on 26/05/2011 18:46 mdf at FreeBSD.org said the following:
>> A per-thread flag is needed as long as other CPUs can be running or
>> even just the scheduler on the remaining CPU.  So I would thing that
>> flag needs to be checked until the system has been massaged to the
>> state you describe above.
>
> I am not sure that I understand your reasoning if you mean that the flag needs to
> be checked in TD_IS_INPANIC.  That is, right now there is no TD_IS_INPANIC and
> things work after panic to a certain degree.  I do not intend to improve that
> degree and just want to keep an option to revert to the current state of matters.
> When TD_IS_INPANIC is introduced and stop_cpus_on_panic==1, then there will be
> only one thread left running after panic, that will be the thread that called
> panic, checking TDF_INPANIC just doesn't add anything.

Won't the scheduler still run even if other CPUs are halted?  Is there
any intent to prevent switching to another thread?  (I suppose this
could be achieved by setting td_critnest++ and wouldn't require a
flag).

It's possible I misunderstood your email so my response may have been
non-sensical.

Thanks,
matthew