Re: [PATCH RFC v3] mm: memory-tiering: Fix PGPROMOTE_CANDIDATE counting

[Huang, Ying]

"Zhijian Li (Fujitsu)" <lizhijian@xxxxxxxxxxx> writes:

> On 22/07/2025 22:16, Ruan Shiyang wrote:
>> From: Li Zhijian<lizhijian@xxxxxxxxxxx>
>> 
>
> I believe you are the actual author of this patch, so please change to yourself :)
>
>
>> Cc: Juri Lelli<juri.lelli@xxxxxxxxxx>
>> Cc: Vincent Guittot<vincent.guittot@xxxxxxxxxx>
>> Cc: Dietmar Eggemann<dietmar.eggemann@xxxxxxx>
>> Cc: Steven Rostedt<rostedt@xxxxxxxxxxx>
>> Cc: Ben Segall<bsegall@xxxxxxxxxx>
>> Cc: Mel Gorman<mgorman@xxxxxxx>
>> Cc: Valentin Schneider<vschneid@xxxxxxxxxx>
>> Reported-by: Yasunori Gotou (Fujitsu)<y-goto@xxxxxxxxxxx>
>> Signed-off-by: Li Zhijian<lizhijian@xxxxxxxxxxx>
>> Signed-off-by: Ruan Shiyang<ruansy.fnst@xxxxxxxxxxx>
>> ---
>>   include/linux/mmzone.h | 2 ++
>>   kernel/sched/fair.c    | 6 ++++--
>>   mm/vmstat.c            | 1 +
>>   3 files changed, 7 insertions(+), 2 deletions(-)
>> 
>> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
>> index 283913d42d7b..6216e2eecf3b 100644
>> --- a/include/linux/mmzone.h
>> +++ b/include/linux/mmzone.h
>> @@ -231,6 +231,8 @@ enum node_stat_item {
>>   #ifdef CONFIG_NUMA_BALANCING
>>   	PGPROMOTE_SUCCESS,	/* promote successfully */
>>   	PGPROMOTE_CANDIDATE,	/* candidate pages to promote */
>
> Additionally, I think the current comment for PGPROMOTE_CANDIDATE is inaccurate. If possible, I'd like to refine it along with this patch.
> For example:
> 	/*
> 	 * Candidate pages for promotion based on hint fault latency. This counter
> 	 * is used to control the promotion rate and adjust the hotness threshold.
> 	 */
> What are your thoughts, @Ying?

This looks good to me, Thanks!

---
Best Regards,
Huang, Ying

>
>
>> +	PGPROMOTE_CANDIDATE_NOLIMIT,	/* candidate pages without considering
>> +					 * hot threshold */
>
> Similarly, the comment for PGPROMOTE_CANDIDATE_NOLIMIT can also be made more precise.
>
>
> Thanks
> Zhijian
>
>>   #endif