Re: [PATCH v3 1/4] sched/fair: add SD_CLUSTER in comments

kuiliang Shi
2024-02-07T02:37:03Z

On 2/7/24 5:24 AM, Ricardo Neri wrote:
> On Tue, Feb 06, 2024 at 04:56:02PM +0800, kuiliang Shi wrote:
>>
>>
>> On 2/6/24 10:46 AM, Ricardo Neri wrote:
>>> On Fri, Feb 02, 2024 at 03:27:32PM +0100, Valentin Schneider wrote:
>>>>
>>>> Subject nit: the prefix should be sched/topology
>>>>
>>>> On 01/02/24 19:54, alexs@kernel.org wrote:
>>>>> From: Alex Shi <alexs@kernel.org>
>>>>>
>>>>> The description of SD_CLUSTER is missing. Add it.
>>>>>
>>>>> Signed-off-by: Alex Shi <alexs@kernel.org>
>>>>> To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
>>>>> To: Valentin Schneider <vschneid@redhat.com>
>>>>> To: Vincent Guittot <vincent.guittot@linaro.org>
>>>>> To: Juri Lelli <juri.lelli@redhat.com>
>>>>> To: Peter Zijlstra <peterz@infradead.org>
>>>>> To: Ingo Molnar <mingo@redhat.com>
>>>>> ---
>>>>> kernel/sched/topology.c | 1 +
>>>>> 1 file changed, 1 insertion(+)
>>>>>
>>>>> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
>>>>> index 10d1391e7416..8b45f16a1890 100644
>>>>> --- a/kernel/sched/topology.c
>>>>> +++ b/kernel/sched/topology.c
>>>>> @@ -1554,6 +1554,7 @@ static struct cpumask ***sched_domains_numa_masks;
>>>>> * function:
>>>>> *
>>>>> * SD_SHARE_CPUCAPACITY - describes SMT topologies
>>>>> + * SD_CLUSTER - describes CPU Cluster topologies
>>>>
>>>> So I know this is the naming we've gone for the "Cluster" naming, but this
>>>> comment isn't really explaining anything.
>>>>
>>>> include/linux/sched/sd_flags.h has a bit more info already:
>>>> * Domain members share CPU cluster (LLC tags or L2 cache)
>>>
>>> I also thought of this, but I didn't want to suggest to repeat in topolog.c
>>> what is described in sd_flags.h.
>>>
>>> Maybe it is better to remove the descriptions of all flags here and instead
>>> direct the reader to sd_flags.h?
>>
>> yes, good idea for getting their meaning directly from the header file.
>> So is it fine for next sending?
>
> Some tweaks below.
>
>>
>> sched/fair: remove duplicate comments for SD_ flags
>
> sched/topology: Remove duplicate descriptions from TOPOLOGY_SD_FLAGS
>>
>> Originally, it missed SD_CLUSTER flag description, but comparing to copy
>> the flags meaning from sd_flags.h, reader is better to get info from
>> there.
>
> These flags are already documented in include/linux/sched/sd_flags.h.
>
> Keep the comment on SD_ASYM_PACKING as it is a special case.
>>
>> Keep SD_ASYM_PACKING unchange for a point from another way.
>>
>> Signed-off-by: Alex Shi <alexs@kernel.org>
>> To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
>> To: Valentin Schneider <vschneid@redhat.com>
>> To: Vincent Guittot <vincent.guittot@linaro.org>
>> To: Juri Lelli <juri.lelli@redhat.com>
>> To: Peter Zijlstra <peterz@infradead.org>
>> To: Ingo Molnar <mingo@redhat.com>
>>
>> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
>> index 10d1391e7416..96a24bf954ad 100644
>> --- a/kernel/sched/topology.c
>> +++ b/kernel/sched/topology.c
>> @@ -1551,11 +1551,7 @@ static struct cpumask ***sched_domains_numa_masks;
>> *
>> * These flags are purely descriptive of the topology and do not prescribe
>> * behaviour. Behaviour is artificial and mapped in the below sd_init()
>> - * function:
>> - *
>> - * SD_SHARE_CPUCAPACITY - describes SMT topologies
>> - * SD_SHARE_PKG_RESOURCES - describes shared caches
>> - * SD_NUMA - describes NUMA topologies
>
> Maybe only remove the descriptions but keep the enumeration?
>
>> + * function, for details in include/linux/sched/sd_flags.h:
>
> function. For details, see include/linux/sched/sd_flags.h.
>

Thanks for comments. will update in next version.
>