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Subject: Re: [PATCH v3 03/10] sched/topology: Provide cfs_overload_cpus bitmap
To:     Steven Sistare <steven.sistare@oracle.com>, mingo@redhat.com,
        peterz@infradead.org
Cc:     subhra.mazumdar@oracle.com, dhaval.giani@oracle.com,
        daniel.m.jordan@oracle.com, pavel.tatashin@microsoft.com,
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        riel@redhat.com, jbacik@fb.com, juri.lelli@redhat.com,
        vincent.guittot@linaro.org, quentin.perret@arm.com,
        linux-kernel@vger.kernel.org
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From:   Valentin Schneider <valentin.schneider@arm.com>
Message-ID: <7111ee5a-b408-1fa1-e9fa-42aad4d6ff4d@arm.com>
Date:   Tue, 20 Nov 2018 12:52:18 +0000
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On 19/11/2018 17:32, Steven Sistare wrote:
> On 11/9/2018 12:38 PM, Valentin Schneider wrote:
>> Hi Steve,
>>
>> On 09/11/2018 12:50, Steve Sistare wrote:
>> [...]
>>> @@ -482,6 +484,10 @@ static void update_top_cache_domain(int cpu)
>>>  	dirty_sched_domain_sysctl(cpu);
>>>  	destroy_sched_domains(tmp);
>>>  
>>> +	sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
>>> +	cfs_overload_cpus = (sd ? sd->shared->cfs_overload_cpus : NULL);
>>> +	rcu_assign_pointer(rq->cfs_overload_cpus, cfs_overload_cpus);
>>> +
>>
>> Why not do this in update_top_cache_domain() where we also look for the
>> highest SD_SHARE_PKG_RESOURCES and setup shortcut pointers?
> 
> My snippet needs rq which is currently referenced in cpu_attach_domain() but
> not in update_top_cache_domain().  I could just as easily do it in 
> update_top_cache_domain().  Either way is fine with me.
> 

I think having this in update_top_cache_domain() makes more sense - it's
where all the domain shortcuts are set, and we already play with LLC there.

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