Re: [PATCH v2 2/2] x86/hyperv: remove on-stack cpumask from hv_send_ipi_mask_allbutself

[Wei Liu]

On Sat, Sep 11, 2021 at 03:09:50PM +0000, Michael Kelley wrote:
> From: Wei Liu <wei.liu@xxxxxxxxxx> Sent: Friday, September 10, 2021 11:57 AM
[...]
> > -static bool __send_ipi_mask(const struct cpumask *mask, int vector)
> > +static bool __send_ipi_mask(const struct cpumask *mask, int vector,
> > +		bool exclude_self)
> >  {
> > -	int cur_cpu, vcpu;
> > +	int cur_cpu, vcpu, this_cpu = smp_processor_id();
> >  	struct hv_send_ipi ipi_arg;
> >  	u64 status;
> > +	unsigned int weight;
> > 
> >  	trace_hyperv_send_ipi_mask(mask, vector);
> > 
> > -	if (cpumask_empty(mask))
> > +	weight = cpumask_weight(mask);
> > +
> > +	/*
> > +	 * Do nothing if
> > +	 *   1. the mask is empty
> > +	 *   2. the mask only contains self when exclude_self is true
> > +	 */
> > +	if (weight == 0 ||
> > +	    (exclude_self && weight == 1 && cpumask_first(mask) == this_cpu))
> 
> Nit:  cpumask_test_cpu(this_cpu, mask) would seem to be a better fit for this
> use case than cpumask_first().  But either works.

I will adjust the code when I commit this patch.

Wei.