mm: sched: numa: Control enabling and disabling of NUMA balancing
This patch adds Kconfig options and kernel parameters to allow the
enabling and disabling of automatic NUMA balancing. The existance
of such a switch was and is very important when debugging problems
related to transparent hugepages and we should have the same for
automatic NUMA placement.
Signed-off-by: Mel Gorman <mgorman@suse.de>
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index fd20e28..046308e 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2521,6 +2521,50 @@
mutex_unlock(&p->mutex);
}
+#ifdef CONFIG_NUMA_BALANCING
+static bool __initdata numabalancing_override;
+
+static void __init check_numabalancing_enable(void)
+{
+ bool numabalancing_default = false;
+
+ if (IS_ENABLED(CONFIG_NUMA_BALANCING_DEFAULT_ENABLED))
+ numabalancing_default = true;
+
+ if (nr_node_ids > 1 && !numabalancing_override) {
+ printk(KERN_INFO "Enabling automatic NUMA balancing. "
+ "Configure with numa_balancing= or sysctl");
+ set_numabalancing_state(numabalancing_default);
+ }
+}
+
+static int __init setup_numabalancing(char *str)
+{
+ int ret = 0;
+ if (!str)
+ goto out;
+ numabalancing_override = true;
+
+ if (!strcmp(str, "enable")) {
+ set_numabalancing_state(true);
+ ret = 1;
+ } else if (!strcmp(str, "disable")) {
+ set_numabalancing_state(false);
+ ret = 1;
+ }
+out:
+ if (!ret)
+ printk(KERN_WARNING "Unable to parse numa_balancing=\n");
+
+ return ret;
+}
+__setup("numa_balancing=", setup_numabalancing);
+#else
+static inline void __init check_numabalancing_enable(void)
+{
+}
+#endif /* CONFIG_NUMA_BALANCING */
+
/* assumes fs == KERNEL_DS */
void __init numa_policy_init(void)
{
@@ -2571,6 +2615,8 @@
if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes))
printk("numa_policy_init: interleaving failed\n");
+
+ check_numabalancing_enable();
}
/* Reset policy of current process to default */