linux-kernel - [PATCH] mm/memory.c: Add return NUMA_NO_NODE in numa_migrate_check() when folio_nid() and numa_node

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Message-ID: <20250109064632.898260-1-donettom@linux.ibm.com>
Date: Thu,  9 Jan 2025 00:46:32 -0600
From: Donet Tom <donettom@...ux.ibm.com>
To: Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Cc: Ritesh Harjani <ritesh.list@...il.com>,
        Baolin Wang <baolin.wang@...ux.alibaba.com>,
        "Aneesh Kumar K . V" <aneesh.kumar@...nel.org>,
        Matthew Wilcox <willy@...radead.org>, Zi Yan <ziy@...dia.com>,
        David Hildenbrand <david@...hat.com>,
        Muchun Song <muchun.song@...ux.dev>
Subject: [PATCH] mm/memory.c: Add return NUMA_NO_NODE in numa_migrate_check() when folio_nid() and numa_node_id() are the same.

If the folio_nid() and numa_node_id() are the same, it indicates
that the folio is already on the same node as the process. In
this case, there's no need to migrate the pages.

This patch adds return NUMA_NO_NODE in numa_migrate_check() when
the folio_nid() and numa_node_id() match, preventing the function
from executing the remaining code unnecessarily.

Signed-off-by: Donet Tom <donettom@...ux.ibm.com>
---
 mm/memory.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/memory.c b/mm/memory.c
index 398c031be9ba..dfd89ff7f639 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5509,6 +5509,7 @@ int numa_migrate_check(struct folio *folio, struct vm_fault *vmf,
 	if (folio_nid(folio) == numa_node_id()) {
 		count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
 		*flags |= TNF_FAULT_LOCAL;
+		return NUMA_NO_NODE;
 	}
 
 	return mpol_misplaced(folio, vmf, addr);
-- 
2.43.5