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-rw-r--r--kernel/sched/fair.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 7a02a2082e9..3e18f611a5a 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