1 files changed, 51 insertions, 63 deletions

diff --git a/mm/slab.c b/mm/slab.c
index b67271024135..090fb26b3a39 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -886,6 +886,7 @@ static int init_cache_node(struct kmem_cache *cachep, int node, gfp_t gfp)
         return 0;
 }
 
+#if (defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)) || defined(CONFIG_SMP)
 /*
  * Allocates and initializes node for a node on each slab cache, used for
  * either memory or cpu hotplug.  If memory is being hot-added, the kmem_cache_node
@@ -908,6 +909,7 @@ static int init_cache_node_node(int node)
 
         return 0;
 }
+#endif
 
 static int setup_kmem_cache_node(struct kmem_cache *cachep,
                                 int node, gfp_t gfp, bool force_change)
@@ -975,6 +977,8 @@ fail:
         return ret;
 }
 
+#ifdef CONFIG_SMP
+
 static void cpuup_canceled(long cpu)
 {
         struct kmem_cache *cachep;
@@ -1075,65 +1079,54 @@ bad:
         return -ENOMEM;
 }
 
-static int cpuup_callback(struct notifier_block *nfb,
-                                    unsigned long action, void *hcpu)
+int slab_prepare_cpu(unsigned int cpu)
 {
-        long cpu = (long)hcpu;
-        int err = 0;
+        int err;
 
-        switch (action) {
-        case CPU_UP_PREPARE:
-        case CPU_UP_PREPARE_FROZEN:
-                mutex_lock(&slab_mutex);
-                err = cpuup_prepare(cpu);
-                mutex_unlock(&slab_mutex);
-                break;
-        case CPU_ONLINE:
-        case CPU_ONLINE_FROZEN:
-                start_cpu_timer(cpu);
-                break;
-#ifdef CONFIG_HOTPLUG_CPU
-        case CPU_DOWN_PREPARE:
-        case CPU_DOWN_PREPARE_FROZEN:
-                /*
-                 * Shutdown cache reaper. Note that the slab_mutex is
-                 * held so that if cache_reap() is invoked it cannot do
-                 * anything expensive but will only modify reap_work
-                 * and reschedule the timer.
-                */
-                cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu));
-                /* Now the cache_reaper is guaranteed to be not running. */
-                per_cpu(slab_reap_work, cpu).work.func = NULL;
-                break;
-        case CPU_DOWN_FAILED:
-        case CPU_DOWN_FAILED_FROZEN:
-                start_cpu_timer(cpu);
-                break;
-        case CPU_DEAD:
-        case CPU_DEAD_FROZEN:
-                /*
-                 * Even if all the cpus of a node are down, we don't free the
-                 * kmem_cache_node of any cache. This to avoid a race between
-                 * cpu_down, and a kmalloc allocation from another cpu for
-                 * memory from the node of the cpu going down.  The node
-                 * structure is usually allocated from kmem_cache_create() and
-                 * gets destroyed at kmem_cache_destroy().
-                 */
-                /* fall through */
+        mutex_lock(&slab_mutex);
+        err = cpuup_prepare(cpu);
+        mutex_unlock(&slab_mutex);
+        return err;
+}
+
+/*
+ * This is called for a failed online attempt and for a successful
+ * offline.
+ *
+ * Even if all the cpus of a node are down, we don't free the
+ * kmem_list3 of any cache. This to avoid a race between cpu_down, and
+ * a kmalloc allocation from another cpu for memory from the node of
+ * the cpu going down.  The list3 structure is usually allocated from
+ * kmem_cache_create() and gets destroyed at kmem_cache_destroy().
+ */
+int slab_dead_cpu(unsigned int cpu)
+{
+        mutex_lock(&slab_mutex);
+        cpuup_canceled(cpu);
+        mutex_unlock(&slab_mutex);
+        return 0;
+}
 #endif
-        case CPU_UP_CANCELED:
-        case CPU_UP_CANCELED_FROZEN:
-                mutex_lock(&slab_mutex);
-                cpuup_canceled(cpu);
-                mutex_unlock(&slab_mutex);
-                break;
-        }
-        return notifier_from_errno(err);
+
+static int slab_online_cpu(unsigned int cpu)
+{
+        start_cpu_timer(cpu);
+        return 0;
 }
 
-static struct notifier_block cpucache_notifier = {
-        &cpuup_callback, NULL, 0
-};
+static int slab_offline_cpu(unsigned int cpu)
+{
+        /*
+         * Shutdown cache reaper. Note that the slab_mutex is held so
+         * that if cache_reap() is invoked it cannot do anything
+         * expensive but will only modify reap_work and reschedule the
+         * timer.
+         */
+        cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu));
+        /* Now the cache_reaper is guaranteed to be not running. */
+        per_cpu(slab_reap_work, cpu).work.func = NULL;
+        return 0;
+}
 
 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
 /*
@@ -1336,12 +1329,6 @@ void __init kmem_cache_init_late(void)
         /* Done! */
         slab_state = FULL;
 
-        /*
-         * Register a cpu startup notifier callback that initializes
-         * cpu_cache_get for all new cpus
-         */
-        register_cpu_notifier(&cpucache_notifier);
-
 #ifdef CONFIG_NUMA
         /*
          * Register a memory hotplug callback that initializes and frees
@@ -1358,13 +1345,14 @@ void __init kmem_cache_init_late(void)
 
 static int __init cpucache_init(void)
 {
-        int cpu;
+        int ret;
 
         /*
          * Register the timers that return unneeded pages to the page allocator
          */
-        for_each_online_cpu(cpu)
-                start_cpu_timer(cpu);
+        ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "SLAB online",
+                                slab_online_cpu, slab_offline_cpu);
+        WARN_ON(ret < 0);
 
         /* Done! */
         slab_state = FULL;