Re: [PATCH mm-new v8 1/4] mm: khugepaged: add trace_mm_khugepaged_scan event

Lorenzo Stoakes (Oracle)
2026-03-25T14:06:24Z

On Sat, Feb 21, 2026 at 05:39:15PM +0800, Vernon Yang wrote:
> From: Vernon Yang <yanglincheng@kylinos.cn>
>
> 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>
> Reviewed-by: Lance Yang <lance.yang@linux.dev>
> Reviewed-by: Dev Jain <dev.jain@arm.com>

LGTM, so:

Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>

> ---
> include/trace/events/huge_memory.h | 25 +++++++++++++++++++++++++
> mm/khugepaged.c | 2 ++
> 2 files changed, 27 insertions(+)
>
> diff --git a/include/trace/events/huge_memory.h b/include/trace/events/huge_memory.h
> index 4e41bff31888..384e29f6bef0 100644
> --- a/include/trace/events/huge_memory.h
> +++ b/include/trace/events/huge_memory.h
> @@ -237,5 +237,30 @@ TRACE_EVENT(mm_khugepaged_collapse_file,
> __print_symbolic(__entry->result, SCAN_STATUS))
> );
>
> +TRACE_EVENT(mm_khugepaged_scan,
> +
> + TP_PROTO(struct mm_struct *mm, unsigned int progress,
> + bool full_scan_finished),
> +
> + TP_ARGS(mm, progress, full_scan_finished),
> +
> + TP_STRUCT__entry(
> + __field(struct mm_struct *, mm)
> + __field(unsigned int, progress)
> + __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=%u, 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 c0f893bebcff..e2f6b68a0011 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -2527,6 +2527,8 @@ 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;
> }
>
> --
> 2.51.0
>