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

kuiliang Shi
2024-02-04T11:57:24Z

On 2/2/24 10:27 PM, 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 had to go through a bit of git history to remember what the CLUSTER thing
> was about, how about this:
>
> * SD_CLUSTER - describes shared shared caches, cache tags or busses

Double "shared", so could we use:
* SD_CLUSTER - describes shared caches, cache tags or busses?

> * SD_SHARE_PKG_RESOURCES - describes shared LLC cache
>
> And looking at this it would make sense to:
> rename SD_CLUSTER into SD_SHARE_PKG_RESOURCES
> rename SD_SHARE_PKG_RESOURCES into SD_SHARE_LLC
> but that's another topic...

Uh, naming is a hard things. :)

Thanks
Alex
>
>> * SD_SHARE_PKG_RESOURCES - describes shared caches
>> * SD_NUMA - describes NUMA topologies
>> *
>> --
>> 2.43.0
>