[PATCH v3] khugepaged: Pass folio instead of head page to trace events

[PATCH v3] khugepaged: Pass folio instead of head page to trace events

[nifan.cxl]

From: Fan Ni <fan.ni@samsung.com>

The trace functions trace_mm_collapse_huge_page_isolate() and
trace_mm_khugepaged_scan_pmd() each have a single user, which
always passes in the head page of a folio.
Refactor both functions to take a folio directly.

Signed-off-by: Fan Ni <fan.ni@samsung.com>
Reviewed-by: Nico Pache <npache@redhat.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Yang Shi <yang@os.amperecomputing.com>
Acked-by: David Hildenbrand <david@redhat.com>
---
v3:
1) No functional change compared to v2;
2) Picked up tags;
3) Squashed the two patches in v2 into one based on Yang Shi and
David Hildenbrand's feedback;
4) Reword the commit log to reflect the squash.

v2:
https://lore.kernel.org/linux-mm/20250418183920.273154-1-nifan.cxl@gmail.com/
---
 include/trace/events/huge_memory.h | 12 ++++++------
 mm/khugepaged.c                    |  6 +++---
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/include/trace/events/huge_memory.h b/include/trace/events/huge_memory.h
index 9d5c00b0285c..2305df6cb485 100644
--- a/include/trace/events/huge_memory.h
+++ b/include/trace/events/huge_memory.h
@@ -55,10 +55,10 @@ SCAN_STATUS
 
 TRACE_EVENT(mm_khugepaged_scan_pmd,
 
-	TP_PROTO(struct mm_struct *mm, struct page *page, bool writable,
+	TP_PROTO(struct mm_struct *mm, struct folio *folio, bool writable,
 		 int referenced, int none_or_zero, int status, int unmapped),
 
-	TP_ARGS(mm, page, writable, referenced, none_or_zero, status, unmapped),
+	TP_ARGS(mm, folio, writable, referenced, none_or_zero, status, unmapped),
 
 	TP_STRUCT__entry(
 		__field(struct mm_struct *, mm)
@@ -72,7 +72,7 @@ TRACE_EVENT(mm_khugepaged_scan_pmd,
 
 	TP_fast_assign(
 		__entry->mm = mm;
-		__entry->pfn = page ? page_to_pfn(page) : -1;
+		__entry->pfn = folio ? folio_pfn(folio) : -1;
 		__entry->writable = writable;
 		__entry->referenced = referenced;
 		__entry->none_or_zero = none_or_zero;
@@ -116,10 +116,10 @@ TRACE_EVENT(mm_collapse_huge_page,
 
 TRACE_EVENT(mm_collapse_huge_page_isolate,
 
-	TP_PROTO(struct page *page, int none_or_zero,
+	TP_PROTO(struct folio *folio, int none_or_zero,
 		 int referenced, bool  writable, int status),
 
-	TP_ARGS(page, none_or_zero, referenced, writable, status),
+	TP_ARGS(folio, none_or_zero, referenced, writable, status),
 
 	TP_STRUCT__entry(
 		__field(unsigned long, pfn)
@@ -130,7 +130,7 @@ TRACE_EVENT(mm_collapse_huge_page_isolate,
 	),
 
 	TP_fast_assign(
-		__entry->pfn = page ? page_to_pfn(page) : -1;
+		__entry->pfn = folio ? folio_pfn(folio) : -1;
 		__entry->none_or_zero = none_or_zero;
 		__entry->referenced = referenced;
 		__entry->writable = writable;
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 5cf204ab6af0..b04b6a770afe 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -696,13 +696,13 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
 		result = SCAN_LACK_REFERENCED_PAGE;
 	} else {
 		result = SCAN_SUCCEED;
-		trace_mm_collapse_huge_page_isolate(&folio->page, none_or_zero,
+		trace_mm_collapse_huge_page_isolate(folio, none_or_zero,
 						    referenced, writable, result);
 		return result;
 	}
 out:
 	release_pte_pages(pte, _pte, compound_pagelist);
-	trace_mm_collapse_huge_page_isolate(&folio->page, none_or_zero,
+	trace_mm_collapse_huge_page_isolate(folio, none_or_zero,
 					    referenced, writable, result);
 	return result;
 }
@@ -1435,7 +1435,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
 		*mmap_locked = false;
 	}
 out:
-	trace_mm_khugepaged_scan_pmd(mm, &folio->page, writable, referenced,
+	trace_mm_khugepaged_scan_pmd(mm, folio, writable, referenced,
 				     none_or_zero, result, unmapped);
 	return result;
 }
-- 
2.47.2

Re: [PATCH v3] khugepaged: Pass folio instead of head page to trace events

[Matthew Wilcox]

On Thu, Apr 24, 2025 at 05:16:51PM -0700, nifan.cxl@gmail.com wrote:
> From: Fan Ni <fan.ni@samsung.com>
> 
> The trace functions trace_mm_collapse_huge_page_isolate() and
> trace_mm_khugepaged_scan_pmd() each have a single user, which
> always passes in the head page of a folio.
> Refactor both functions to take a folio directly.
> 
> Signed-off-by: Fan Ni <fan.ni@samsung.com>
> Reviewed-by: Nico Pache <npache@redhat.com>
> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> Reviewed-by: Yang Shi <yang@os.amperecomputing.com>
> Acked-by: David Hildenbrand <david@redhat.com>

Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>