sched/numa: Do not migrate memory immediately after switching node

[~andy/linux] / mm / mempolicy.c

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index aff1f1ed3dc544b8f336c4ddb8f112dbc7128699..196d8da2b657f84a662d3caa6dbd85f670e09d60 100644 (file)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2378,6 +2378,18 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
                last_nidpid = page_nidpid_xchg_last(page, this_nidpid);
                if (!nidpid_pid_unset(last_nidpid) && nidpid_to_nid(last_nidpid) != polnid)
                        goto out;
+
+#ifdef CONFIG_NUMA_BALANCING
+               /*
+                * If the scheduler has just moved us away from our
+                * preferred node, do not bother migrating pages yet.
+                * This way a short and temporary process migration will
+                * not cause excessive memory migration.
+                */
+               if (polnid != current->numa_preferred_nid &&
+                               !current->numa_migrate_seq)
+                       goto out;
+#endif
        }
 
        if (curnid != polnid)