[PATCH 07/14] mm/ksm: reuse the zero page pointer for merge tracing

[Longlong Xia]

From: Longlong Xia <xialonglong@xxxxxxxxxx>

Cache ZERO_PAGE() in try_to_merge_with_zero_page() for use by both the
merge attempt and its tracepoint.

No functional change intended.

Assisted-by: Zcode:GLM-5.3
Signed-off-by: Longlong Xia <xialonglong@xxxxxxxxxx>

---
 mm/ksm.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/mm/ksm.c b/mm/ksm.c
index 78040ed99ccf..7fc9dac5d67c 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1580,15 +1580,14 @@ static int try_to_merge_with_zero_page(struct ksm_rmap_item *rmap_item,
 	 */
 	if (ksm_use_zero_pages && (rmap_item->oldchecksum == zero_checksum)) {
 		struct vm_area_struct *vma;
+		struct page *zero_page = ZERO_PAGE(rmap_item->address);
 
 		mmap_read_lock(mm);
 		vma = find_mergeable_vma(mm, rmap_item->address);
 		if (vma) {
-			err = try_to_merge_one_page(vma, page,
-					ZERO_PAGE(rmap_item->address));
-			trace_ksm_merge_one_page(
-				page_to_pfn(ZERO_PAGE(rmap_item->address)),
-				rmap_item, mm, err);
+			err = try_to_merge_one_page(vma, page, zero_page);
+			trace_ksm_merge_one_page(page_to_pfn(zero_page),
+						 rmap_item, mm, err);
 		} else {
 			/*
 			 * If the vma is out of date, we do not need to
-- 
2.43.0