1 files changed, 18 insertions, 0 deletions

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 7a02a2082e95..3e18f611a5aa 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -861,6 +861,24 @@ void task_numa_work(struct callback_head *work)
                 return;
 
         /*
+         * We do not care about task placement until a task runs on a node
+         * other than the first one used by the address space. This is
+         * largely because migrations are driven by what CPU the task
+         * is running on. If it's never scheduled on another node, it'll
+         * not migrate so why bother trapping the fault.
+         */
+        if (mm->first_nid == NUMA_PTE_SCAN_INIT)
+                mm->first_nid = numa_node_id();
+        if (mm->first_nid != NUMA_PTE_SCAN_ACTIVE) {
+                /* Are we running on a new node yet? */
+                if (numa_node_id() == mm->first_nid &&
+                    !sched_feat_numa(NUMA_FORCE))
+                        return;
+
+                mm->first_nid = NUMA_PTE_SCAN_ACTIVE;
+        }
+
+        /*
          * Reset the scan period if enough time has gone by. Objective is that
          * scanning will be reduced if pages are properly placed. As tasks
          * can enter different phases this needs to be re-examined. Lacking