Re: [RFC PATCH 1/2] cpumask: Implement cpumask_next_andnot

[Mathieu Desnoyers]

On 2024-09-03 15:28, Yury Norov wrote:
> On Tue, Sep 03, 2024 at 03:06:49PM -0400, Mathieu Desnoyers wrote:
> > Allow finding the next bit within two input cpumasks which is
> > respectively one and zero.
> >
> > Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
> > Cc: Yury Norov <yury.norov@xxxxxxxxx>
> > Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
>
> Acked-by: Yury Norov <yury.norov@xxxxxxxxx>

Thanks for the ack. However based on our discussion in the other
leg of this thread, I can simply use

+       for_each_cpu_andnot(cpu, cpumask, mm_allowed)
+               nr_set += !cpumask_test_and_set_cpu(cpu, mm_allowed);

which is already present in the API. I will drop this patch from
my series.

Thanks,

Mathieu

> > ---
> >   include/linux/cpumask.h | 17 +++++++++++++++++
> >   1 file changed, 17 insertions(+)
> >
> > diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
> > index 23686bed441d..5da1c66cfa65 100644
> > --- a/include/linux/cpumask.h
> > +++ b/include/linux/cpumask.h
> > @@ -246,6 +246,23 @@ static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp)
> >   	return find_next_zero_bit(cpumask_bits(srcp), small_cpumask_bits, n+1);
> >   }
> >   
> > +/**
> > + * cpumask_next_andnot - return the next cpu from *srcp1 & ~*srcp2
> > + * @n: the cpu prior to the place to search (ie. return will be > @n)
> > + * @src1p: the first input
> > + * @src2p: the second input
> > + *
> > + * Returns >= nr_cpu_ids if no cpus match in both.
> > + */
> > +static __always_inline
> > +unsigned int cpumask_next_andnot(int n, const struct cpumask *srcp1, const struct cpumask *srcp2)
> > +{
> > +	/* -1 is a legal arg here. */
> > +	if (n != -1)
> > +		cpumask_check(n);
> > +	return find_next_andnot_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), small_cpumask_bits, n+1);
> > +}
> > +
> >   #if NR_CPUS == 1
> >   /* Uniprocessor: there is only one valid CPU */
> >   static inline unsigned int cpumask_local_spread(unsigned int i, int node)
> > --
> > 2.39.2

--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com