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

Vernon Yang
2026-02-21T09:39:54Z

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>
---
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