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Date:   Mon, 18 Jul 2022 12:19:39 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Tariq Toukan <tariqt@nvidia.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Saeed Mahameed <saeedm@nvidia.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Ingo Molnar <mingo@redhat.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        Gal Pressman <gal@nvidia.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 1/2] sched/topology: Expose
 sched_numa_find_closest
Message-ID: <YtUzu4d9F+V621tw@worktop.programming.kicks-ass.net>
References: <20220717052301.19067-1-tariqt@nvidia.com>
 <20220717052301.19067-2-tariqt@nvidia.com>
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On Sun, Jul 17, 2022 at 08:23:00AM +0300, Tariq Toukan wrote:
> This logic can help device drivers prefer some remote cpus
> over others, according to the NUMA distance metrics.
> 
> Reviewed-by: Gal Pressman <gal@nvidia.com>
> Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
> ---
>  include/linux/sched/topology.h | 2 ++
>  kernel/sched/topology.c        | 1 +
>  2 files changed, 3 insertions(+)
> 
> diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
> index 56cffe42abbc..d467c30bdbb9 100644
> --- a/include/linux/sched/topology.h
> +++ b/include/linux/sched/topology.h
> @@ -61,6 +61,8 @@ static inline int cpu_numa_flags(void)
>  {
>  	return SD_NUMA;
>  }
> +
> +int sched_numa_find_closest(const struct cpumask *cpus, int cpu);
>  #endif
>  
>  extern int arch_asym_cpu_priority(int cpu);
> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
> index 05b6c2ad90b9..688334ac4980 100644
> --- a/kernel/sched/topology.c
> +++ b/kernel/sched/topology.c
> @@ -2066,6 +2066,7 @@ int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
>  
>  	return found;
>  }
> +EXPORT_SYMBOL(sched_numa_find_closest);

EXPORT_SYMBOL_GPL() if anything.

Also, this thing will be subject to sched_domains, that means that if
someone uses cpusets or other means to partition the machine, that
effects the result.

Is that what you want?