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Message-ID: <72170546-fad0-0b96-e075-b755c3a48bec@gmail.com>
Date:   Mon, 18 Jul 2022 14:42:52 +0300
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Subject: Re: [PATCH net-next 1/2] sched/topology: Expose
 sched_numa_find_closest
Content-Language: en-US
To:     Peter Zijlstra <peterz@infradead.org>,
        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
References: <20220717052301.19067-1-tariqt@nvidia.com>
 <20220717052301.19067-2-tariqt@nvidia.com>
 <YtUzu4d9F+V621tw@worktop.programming.kicks-ass.net>
From:   Tariq Toukan <ttoukan.linux@gmail.com>
In-Reply-To: <YtUzu4d9F+V621tw@worktop.programming.kicks-ass.net>
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On 7/18/2022 1:19 PM, Peter Zijlstra wrote:
> 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.

I'll fix.

> 
> 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?

Yes, it's good enough, at least as a first phase and basic functionality.
Later we might introduce whatever enhancements we find necessary.


Thanks,
Tariq