[PATCH 1/8] mm/khugepaged: refactor per-scan state clearing into collapse_control_init_scan()

[Nico Pache <npache@redhat.com>]

Extract the repeated clearing of node_load, alloc_nmask, and
mthp_present_ptes into a helper to reduce duplication in
collapse_scan_pmd() and collapse_scan_file(). Althought file scans do not
current use the bitmap, they will in the future, and clearing it now is
harmless.

Signed-off-by: Nico Pache <npache@redhat.com>
---
 mm/khugepaged.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 617bca76db49..b3985b854e77 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -628,6 +628,17 @@ void __khugepaged_exit(struct mm_struct *mm)
 	}
 }
 
+/*
+ * collapse_control_init_scan() - initialize/reset collapse_control variables
+ * that require being cleared once per-scan.
+ */
+static void collapse_control_init_scan(struct collapse_control *cc)
+{
+	memset(cc->node_load, 0, sizeof(cc->node_load));
+	nodes_clear(cc->alloc_nmask);
+	bitmap_zero(cc->mthp_present_ptes, MAX_PTRS_PER_PTE);
+}
+
 static void release_pte_folio(struct folio *folio)
 {
 	node_stat_mod_folio(folio,
@@ -1616,9 +1627,7 @@ static enum scan_result collapse_scan_pmd(struct mm_struct *mm,
 		goto out;
 	}
 
-	bitmap_zero(cc->mthp_present_ptes, MAX_PTRS_PER_PTE);
-	memset(cc->node_load, 0, sizeof(cc->node_load));
-	nodes_clear(cc->alloc_nmask);
+	collapse_control_init_scan(cc);
 
 	enabled_orders = collapse_possible_orders(vma, vma->vm_flags, tva_flags);
 
@@ -2686,8 +2695,7 @@ static enum scan_result collapse_scan_file(struct mm_struct *mm,
 
 	present = 0;
 	swap = 0;
-	memset(cc->node_load, 0, sizeof(cc->node_load));
-	nodes_clear(cc->alloc_nmask);
+	collapse_control_init_scan(cc);
 	rcu_read_lock();
 	xas_for_each(&xas, folio, start + HPAGE_PMD_NR - 1) {
 		if (xas_retry(&xas, folio))
-- 
2.54.0