Re: [PATCH mm-new v4 1/6] mm: khugepaged: add trace_mm_khugepaged_scan event

[Lance Yang <lance.yang@linux.dev>]

On 2026/1/11 20:19, Vernon Yang wrote:
> Add mm_khugepaged_scan event to track the total time for full scan
> and the total number of pages scanned of khugepaged.
> 
> Signed-off-by: Vernon Yang <yanglincheng@kylinos.cn>
> Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
> Reviewed-by: Barry Song <baohua@kernel.org>
> ---
>   include/trace/events/huge_memory.h | 24 ++++++++++++++++++++++++
>   mm/khugepaged.c                    |  2 ++
>   2 files changed, 26 insertions(+)
> 
> diff --git a/include/trace/events/huge_memory.h b/include/trace/events/huge_memory.h
> index 4e41bff31888..3d1069c3f0c5 100644
> --- a/include/trace/events/huge_memory.h
> +++ b/include/trace/events/huge_memory.h
> @@ -237,5 +237,29 @@ TRACE_EVENT(mm_khugepaged_collapse_file,
>   		__print_symbolic(__entry->result, SCAN_STATUS))
>   );
>   
> +TRACE_EVENT(mm_khugepaged_scan,
> +
> +	TP_PROTO(struct mm_struct *mm, int progress, bool full_scan_finished),
> +
> +	TP_ARGS(mm, progress, full_scan_finished),
> +
> +	TP_STRUCT__entry(
> +		__field(struct mm_struct *, mm)
> +		__field(int, progress)

Nit: progress should be unsigned int here, not int :)

Otherwise, LGTM.

Reviewed-by: Lance Yang <lance.yang@linux.dev>

> +		__field(bool, full_scan_finished)
> +	),
> +
> +	TP_fast_assign(
> +		__entry->mm = mm;
> +		__entry->progress = progress;
> +		__entry->full_scan_finished = full_scan_finished;
> +	),
> +
> +	TP_printk("mm=%p, progress=%d, full_scan_finished=%d",
> +		__entry->mm,
> +		__entry->progress,
> +		__entry->full_scan_finished)
> +);
> +
>   #endif /* __HUGE_MEMORY_H */
>   #include <trace/define_trace.h>
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index 9f790ec34400..2e570f83778c 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -2545,6 +2545,8 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, enum scan_result
>   		collect_mm_slot(slot);
>   	}
>   
> +	trace_mm_khugepaged_scan(mm, progress, khugepaged_scan.mm_slot == NULL);
> +
>   	return progress;
>   }
>