mm/vmscan: Convert to hotplug state machine

Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20161103145021.28528-8-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 76fda22..b8404d3 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3556,24 +3556,21 @@ unsigned long shrink_all_memory(unsigned long nr_to_reclaim)
    not required for correctness.  So if the last cpu in a node goes
    away, we get changed to run anywhere: as the first one comes back,
    restore their cpu bindings. */
-static int cpu_callback(struct notifier_block *nfb, unsigned long action,
-                       void *hcpu)
+static int kswapd_cpu_online(unsigned int cpu)
 {
        int nid;
 
-       if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN) {
-               for_each_node_state(nid, N_MEMORY) {
-                       pg_data_t *pgdat = NODE_DATA(nid);
-                       const struct cpumask *mask;
+       for_each_node_state(nid, N_MEMORY) {
+               pg_data_t *pgdat = NODE_DATA(nid);
+               const struct cpumask *mask;
 
-                       mask = cpumask_of_node(pgdat->node_id);
+               mask = cpumask_of_node(pgdat->node_id);
 
-                       if (cpumask_any_and(cpu_online_mask, mask) < nr_cpu_ids)
-                               /* One of our CPUs online: restore mask */
-                               set_cpus_allowed_ptr(pgdat->kswapd, mask);
-               }
+               if (cpumask_any_and(cpu_online_mask, mask) < nr_cpu_ids)
+                       /* One of our CPUs online: restore mask */
+                       set_cpus_allowed_ptr(pgdat->kswapd, mask);
        }
-       return NOTIFY_OK;
+       return 0;
 }
 
 /*
@@ -3615,12 +3612,15 @@ void kswapd_stop(int nid)
 
 static int __init kswapd_init(void)
 {
-       int nid;
+       int nid, ret;
 
        swap_setup();
        for_each_node_state(nid, N_MEMORY)
                kswapd_run(nid);
-       hotcpu_notifier(cpu_callback, 0);
+       ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+                                       "mm/vmscan:online", kswapd_cpu_online,
+                                       NULL);
+       WARN_ON(ret < 0);
        return 0;
 }