Re: [discuss] Re: 2.6.19-rc5: known regressions (v3)

[Andrew Morton]

On Thu, 16 Nov 2006 11:55:46 +0100
Mikael Pettersson <mikpe@xxxxxxxx> wrote:

> Andrew Morton writes:
>  > Surely the appropriate behaviour is to allow oprofile to steal the NMI and
>  > to then put the NMI back to doing the watchdog thing after oprofile has
>  > finished with it.
> 
> Which is _exactly_ what pre-2.6.19-rc1 kernels did. I implemented
> the in-kernel API allowing real performance counter drivers like
> oprofile (and perfctr) to claim the HW from the NMI watchdog,
> do their work, and then release it which resumed the watchdog.

OK.  But from Andi's comments it seems that the NMI watchdog was failing to
resume its operation.

> Note that oprofile (and perfctr) didn't do anything behind the
> NMI watchdog's back. They went via the API. Nothing dodgy going on.
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