[PATCH 7.2 v16 08/13] mm/khugepaged: improve tracepoints for mTHP orders

Nico Pache
2026-04-19T19:01:12Z

Add the order to the mm_collapse_huge_page<_swapin,_isolate> tracepoints to
give better insight into what order is being operated at for.

Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Nico Pache <npache@redhat.com>
---
include/trace/events/huge_memory.h | 34 +++++++++++++++++++-----------
mm/khugepaged.c | 9 ++++----
2 files changed, 27 insertions(+), 16 deletions(-)

diff --git a/include/trace/events/huge_memory.h b/include/trace/events/huge_memory.h
index bcdc57eea270..291fae364c62 100644
--- a/include/trace/events/huge_memory.h
+++ b/include/trace/events/huge_memory.h
@@ -89,40 +89,44 @@ TRACE_EVENT(mm_khugepaged_scan_pmd,

TRACE_EVENT(mm_collapse_huge_page,

- TP_PROTO(struct mm_struct *mm, int isolated, int status),
+ TP_PROTO(struct mm_struct *mm, int isolated, int status, unsigned int order),

- TP_ARGS(mm, isolated, status),
+ TP_ARGS(mm, isolated, status, order),

TP_STRUCT__entry(
__field(struct mm_struct *, mm)
__field(int, isolated)
__field(int, status)
+ __field(unsigned int, order)
),

TP_fast_assign(
__entry->mm = mm;
__entry->isolated = isolated;
__entry->status = status;
+ __entry->order = order;
),

- TP_printk("mm=%p, isolated=%d, status=%s",
+ TP_printk("mm=%p, isolated=%d, status=%s, order=%u",
__entry->mm,
__entry->isolated,
- __print_symbolic(__entry->status, SCAN_STATUS))
+ __print_symbolic(__entry->status, SCAN_STATUS),
+ __entry->order)
);

TRACE_EVENT(mm_collapse_huge_page_isolate,

TP_PROTO(struct folio *folio, int none_or_zero,
- int referenced, int status),
+ int referenced, int status, unsigned int order),

- TP_ARGS(folio, none_or_zero, referenced, status),
+ TP_ARGS(folio, none_or_zero, referenced, status, order),

TP_STRUCT__entry(
__field(unsigned long, pfn)
__field(int, none_or_zero)
__field(int, referenced)
__field(int, status)
+ __field(unsigned int, order)
),

TP_fast_assign(
@@ -130,26 +134,30 @@ TRACE_EVENT(mm_collapse_huge_page_isolate,
__entry->none_or_zero = none_or_zero;
__entry->referenced = referenced;
__entry->status = status;
+ __entry->order = order;
),

- TP_printk("scan_pfn=0x%lx, none_or_zero=%d, referenced=%d, status=%s",
+ TP_printk("scan_pfn=0x%lx, none_or_zero=%d, referenced=%d, status=%s, order=%u",
__entry->pfn,
__entry->none_or_zero,
__entry->referenced,
- __print_symbolic(__entry->status, SCAN_STATUS))
+ __print_symbolic(__entry->status, SCAN_STATUS),
+ __entry->order)
);

TRACE_EVENT(mm_collapse_huge_page_swapin,

- TP_PROTO(struct mm_struct *mm, int swapped_in, int referenced, int ret),
+ TP_PROTO(struct mm_struct *mm, int swapped_in, int referenced, int ret,
+ unsigned int order),

- TP_ARGS(mm, swapped_in, referenced, ret),
+ TP_ARGS(mm, swapped_in, referenced, ret, order),

TP_STRUCT__entry(
__field(struct mm_struct *, mm)
__field(int, swapped_in)
__field(int, referenced)
__field(int, ret)
+ __field(unsigned int, order)
),

TP_fast_assign(
@@ -157,13 +165,15 @@ TRACE_EVENT(mm_collapse_huge_page_swapin,
__entry->swapped_in = swapped_in;
__entry->referenced = referenced;
__entry->ret = ret;
+ __entry->order = order;
),

- TP_printk("mm=%p, swapped_in=%d, referenced=%d, ret=%d",
+ TP_printk("mm=%p, swapped_in=%d, referenced=%d, ret=%d, order=%u",
__entry->mm,
__entry->swapped_in,
__entry->referenced,
- __entry->ret)
+ __entry->ret,
+ __entry->order)
);

TRACE_EVENT(mm_khugepaged_scan_file,
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 0a1c7cc20c0e..a4f1c570b69b 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -780,13 +780,13 @@ static enum scan_result __collapse_huge_page_isolate(struct vm_area_struct *vma,
} else {
result = SCAN_SUCCEED;
trace_mm_collapse_huge_page_isolate(folio, none_or_zero,
- referenced, result);
+ referenced, result, order);
return result;
}
out:
release_pte_pages(pte, _pte, compound_pagelist);
trace_mm_collapse_huge_page_isolate(folio, none_or_zero,
- referenced, result);
+ referenced, result, order);
return result;
}

@@ -1180,7 +1180,8 @@ static enum scan_result __collapse_huge_page_swapin(struct mm_struct *mm,

result = SCAN_SUCCEED;
out:
- trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, result);
+ trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, result,
+ order);
return result;
}

@@ -1376,7 +1377,7 @@ static enum scan_result collapse_huge_page(struct mm_struct *mm, unsigned long s
out_nolock:
if (folio)
folio_put(folio);
- trace_mm_collapse_huge_page(mm, result == SCAN_SUCCEED, result);
+ trace_mm_collapse_huge_page(mm, result == SCAN_SUCCEED, result, order);
return result;
}

--
2.53.0