Re: [PATCH v2 1/1] s390/spinlock: Provide vcpu_is_preempted

From: Heiko Carstens
Date: Wed Oct 19 2016 - 12:19:01 EST


On Wed, Oct 19, 2016 at 08:56:36AM +0200, Christian Borntraeger wrote:
> On 09/29/2016 05:51 PM, Christian Borntraeger wrote:
> > this implements the s390 backend for commit
> > "kernel/sched: introduce vcpu preempted check interface"
> > by reworking the existing smp_vcpu_scheduled into
> > arch_vcpu_is_preempted. We can then also get rid of the
> > local cpu_is_preempted function by moving the
> > CIF_ENABLED_WAIT test into arch_vcpu_is_preempted.
> >
> > Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
>
>
> Martin, Peter,
>
> I think we could go with the patch as is. In other words not providing
> arch_vcpu_is_preempted for !CONFIG_SMP.
>
> This will result in compile errors if code does spinning or yielding for
> non-SMP kernels - which does not make sense to me, so this might actually
> be a nice indicator.
> If you prefer the !CONFIG_SMP implementation let me know and I will respin.

...but I do prefer an implementation for !CONFIG_SMP. I'm tired of fixing
silly compile errors that only happen on s390.