Re: [PATCH 1/3] kernel/sched: introduce vcpu preempted check interface

[xinhui]

On 2016å06æ27æ 22:05, Boqun Feng wrote:
> On Mon, Jun 27, 2016 at 01:41:28PM -0400, Pan Xinhui wrote:
> > this supports to fix lock holder preempted issue which run as a guest
> >
> > for kernel users, we could use bool vcpu_is_preempted(int cpu) to detech
> > if one vcpu is preempted or not.
> >
> > The default implementation is a macrodefined by false. So compiler can
> > wrap it out if arch dose not support such vcpu pteempted check.
> >
> > archs can implement it by define arch_vcpu_is_preempted().
> >
> > Signed-off-by: Pan Xinhui <xinhui.pan@xxxxxxxxxxxxxxxxxx>
> > ---
> >   include/linux/sched.h | 9 +++++++++
> >   1 file changed, 9 insertions(+)
> >
> > diff --git a/include/linux/sched.h b/include/linux/sched.h
> > index 6e42ada..dc0a9c3 100644
> > --- a/include/linux/sched.h
> > +++ b/include/linux/sched.h
> > @@ -3293,6 +3293,15 @@ static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
> >
> >   #endif /* CONFIG_SMP */
> >
> > +#ifdef arch_vcpu_is_preempted
> > +static inline bool vcpu_is_preempted(int cpu)
> > +{
> > +	return arch_vcpu_is_preempted(cpu);
> > +}
> > +#else
> > +#define vcpu_is_preempted(cpu)	false
> > +#endif
> > +
>
> I think you are missing Peter's comment here. We can
>
> #ifndef vcpu_is_preempted
> #define vcpu_is_preempted(cpu)	fasle
> #endif
>
> And different archs implement their own versions of vcpu_is_preempted(),
> IOW, no need for an arch_vcpu_is_preempted().
yes, right.
just vcpu_is_preempted, no arch_vcpu_is_preempted..
thanks

> Regards,
> Boqun
>
> >   extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
> >   extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
> >
> > --
> > 2.4.11