Re: [PATCH v3 01/10] cpumask: add cpumask_any_and_but()

Yury Norov
2024-04-03T16:31:52Z

On Wed, Apr 03, 2024 at 11:59:41PM +0800, Dawei Li wrote:
> From: Mark Rutland <mark.rutland@arm.com>
>
> In some cases, it's useful to be able to select a random cpu from the
> intersection of two masks, excluding a particular CPU.
>
> For example, in some systems an uncore PMU is shared by a subset of
> CPUs, and management of this PMU is assigned to some arbitrary CPU in
> this set. Whenever the management CPU is hotplugged out, we wish to
> migrate responsibility to another arbitrary CPU which is both in this
> set and online.
>
> Today we can use cpumask_any_and() to select an arbitrary CPU in the
> intersection of two masks. We can also use cpumask_any_but() to select
> any arbitrary cpu in a mask excluding, a particular CPU.
>
> To do both, we either need to use a temporary cpumask, which is
> wasteful, or use some lower-level cpumask helpers, which can be unclear.
>
> This patch adds a new cpumask_any_and_but() to cater for these cases.
>
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Rusty Russell <rusty@rustcorp.com.au>
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Dawei Li <dawei.li@shingroup.cn>

Thank you,

Acked-by: Yury Norov <yury.norov@gmail.com>