Re: [Xen-devel] [PATCH] sched_credit: Remove cpu argument to __runq_insert()

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 30.10.15 at 16:09, <write.harmandeep@xxxxxxxxx> wrote:
> __runq_insert() takes two arguments, cpu and svc. However,
> the cpu argument is redundant because we can get all the
> information we need about cpu from svc.

While true and looking like an improvement at the source level, ...

> --- a/xen/common/sched_credit.c
> +++ b/xen/common/sched_credit.c
> @@ -252,13 +252,12 @@ __runq_elem(struct list_head *elem)
>  }
>  
>  static inline void
> -__runq_insert(unsigned int cpu, struct csched_vcpu *svc)
> +__runq_insert(struct csched_vcpu *svc)
>  {
> -    const struct list_head * const runq = RUNQ(cpu);
> +    const struct list_head * const runq = RUNQ(svc->vcpu->processor);

... this being an inline function the change will likely make the
compiler produce worse code, if only ...

>      struct list_head *iter;
>  
>      BUG_ON( __vcpu_on_runq(svc) );
> -    BUG_ON( cpu != svc->vcpu->processor );

... this was an ASSERT() instead of a BUG_ON() (which it looks like
it should be).

Jan


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