linux-kernel - Re: [PATCH 23/30] cpumask: Implement cpumask_{first,next}

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Message-ID: <ZVzlIAUrxGUFsoyt@yury-ThinkPad>
Date:   Tue, 21 Nov 2023 09:13:04 -0800
From:   Yury Norov <yury.norov@...il.com>
To:     Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Boqun Feng <boqun.feng@...il.com>,
        "H . Peter Anvin" <hpa@...or.com>, Paul Turner <pjt@...gle.com>,
        linux-api@...r.kernel.org, Christian Brauner <brauner@...nel.org>,
        Florian Weimer <fw@...eb.enyo.de>, David.Laight@...lab.com,
        carlos@...hat.com, Peter Oskolkov <posk@...k.io>,
        Alexander Mikhalitsyn <alexander@...alicyn.com>,
        Chris Kennelly <ckennelly@...gle.com>
Subject: Re: [PATCH 23/30] cpumask: Implement
 cpumask_{first,next}_{not,}andnot

On Tue, Nov 22, 2022 at 03:39:25PM -0500, Mathieu Desnoyers wrote:
> Allow finding the first or next bit within two input cpumasks which is
> either:
> 
> - both zero and zero,
> - respectively one and zero.
> 
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
> ---
>  include/linux/cpumask.h | 60 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 60 insertions(+)
> 
> diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
> index c2aa0aa26b45..271bccc0a6d7 100644
> --- a/include/linux/cpumask.h
> +++ b/include/linux/cpumask.h
> @@ -153,6 +153,32 @@ unsigned int cpumask_first_and(const struct cpumask *srcp1, const struct cpumask
>  	return find_first_and_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), nr_cpumask_bits);
>  }
>  
> +/**
> + * cpumask_first_andnot - return the first cpu from *srcp1 & ~*srcp2
> + * @src1p: the first input
> + * @src2p: the second input
> + *
> + * Returns >= nr_cpu_ids if no cpus match in both.
> + */
> +static inline
> +unsigned int cpumask_first_andnot(const struct cpumask *srcp1, const struct cpumask *srcp2)
> +{
> +	return find_first_andnot_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), nr_cpumask_bits);
> +}
> +
> +/**
> + * cpumask_first_notandnot - return the first cpu from ~*srcp1 & ~*srcp2
> + * @src1p: the first input
> + * @src2p: the second input
> + *
> + * Returns >= nr_cpu_ids if no cpus match in both.
> + */
> +static inline
> +unsigned int cpumask_first_notandnot(const struct cpumask *srcp1, const struct cpumask *srcp2)

cpumask_first_zero_or

> +{
> +	return find_first_notandnot_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), nr_cpumask_bits);
> +}

Can you be consistent - either add cpumask_check for all new
functions, or don't.

> +
>  /**
>   * cpumask_last - get the last CPU in a cpumask
>   * @srcp:	- the cpumask pointer
> @@ -195,6 +221,40 @@ static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp)
>  	return find_next_zero_bit(cpumask_bits(srcp), nr_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 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), nr_cpumask_bits, n+1);
> +}
> +
> +/**
> + * cpumask_next_notandnot - 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 inline
> +unsigned int cpumask_next_notandnot(int n, const struct cpumask *srcp1, const struct cpumask *srcp2)

same here: cpumask_next_zero_or()

Thanks,
        Yury

> +{
> +	/* -1 is a legal arg here. */
> +	if (n != -1)
> +		cpumask_check(n);
> +	return find_next_notandnot_bit(cpumask_bits(srcp1), cpumask_bits(srcp2), nr_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)
> -- 
> 2.25.1
>