[PATCH 03/27] mm: numa: Account for THP numa hinting faults on the correct node

[Mel Gorman]

THP NUMA hinting fault on pages that are not migrated are being
accounted for incorrectly. Currently the fault will be counted as if the
task was running on a node local to the page which is not necessarily
true.

Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
---
 mm/huge_memory.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 45ef9dc..e52c131 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1293,7 +1293,7 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	struct page *page;
 	unsigned long haddr = addr & HPAGE_PMD_MASK;
 	int target_nid;
-	int current_nid = -1;
+	int src_nid = -1;
 	bool migrated;
 
 	spin_lock(&mm->page_table_lock);
@@ -1302,9 +1302,9 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 
 	page = pmd_page(pmd);
 	get_page(page);
-	current_nid = page_to_nid(page);
+	src_nid = numa_node_id();
 	count_vm_numa_event(NUMA_HINT_FAULTS);
-	if (current_nid == numa_node_id())
+	if (src_nid == page_to_nid(page))
 		count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
 
 	target_nid = mpol_misplaced(page, vma, haddr);
@@ -1346,8 +1346,8 @@ clear_pmdnuma:
 	update_mmu_cache_pmd(vma, addr, pmdp);
 out_unlock:
 	spin_unlock(&mm->page_table_lock);
-	if (current_nid != -1)
-		task_numa_fault(current_nid, HPAGE_PMD_NR, false);
+	if (src_nid != -1)
+		task_numa_fault(src_nid, HPAGE_PMD_NR, false);
 	return 0;
 }
 
-- 
1.8.1.4

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