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-rw-r--r--kernel/sched/core.c2
-rw-r--r--kernel/sched/fair.c18
-rw-r--r--mm/mempolicy.c12
3 files changed, 29 insertions, 3 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 66b878e..9060a7f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1631,7 +1631,7 @@ static void __sched_fork(struct task_struct *p)
p->node_stamp = 0ULL;
p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0;
- p->numa_migrate_seq = 0;
+ p->numa_migrate_seq = 1;
p->numa_scan_period = sysctl_numa_balancing_scan_delay;
p->numa_preferred_nid = -1;
p->numa_work.next = &p->numa_work;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index b1de7c5..61ec0d4 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -884,7 +884,7 @@ static unsigned int task_scan_max(struct task_struct *p)
* the preferred node but still allow the scheduler to move the task again if
* the nodes CPUs are overloaded.
*/
-unsigned int sysctl_numa_balancing_settle_count __read_mostly = 3;
+unsigned int sysctl_numa_balancing_settle_count __read_mostly = 4;
static inline int task_faults_idx(int nid, int priv)
{
@@ -980,7 +980,7 @@ static void task_numa_placement(struct task_struct *p)
/* Update the preferred nid and migrate task if possible */
p->numa_preferred_nid = max_nid;
- p->numa_migrate_seq = 0;
+ p->numa_migrate_seq = 1;
migrate_task_to(p, preferred_cpu);
}
}
@@ -4121,6 +4121,20 @@ static void move_task(struct task_struct *p, struct lb_env *env)
set_task_cpu(p, env->dst_cpu);
activate_task(env->dst_rq, p, 0);
check_preempt_curr(env->dst_rq, p, 0);
+#ifdef CONFIG_NUMA_BALANCING
+ if (p->numa_preferred_nid != -1) {
+ int src_nid = cpu_to_node(env->src_cpu);
+ int dst_nid = cpu_to_node(env->dst_cpu);
+
+ /*
+ * If the load balancer has moved the task then limit
+ * migrations from taking place in the short term in
+ * case this is a short-lived migration.
+ */
+ if (src_nid != dst_nid && dst_nid != p->numa_preferred_nid)
+ p->numa_migrate_seq = 0;
+ }
+#endif
}
/*
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index aff1f1e..196d8da 100644
--- 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)