slub: Convert to hotplug state machine

Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: linux-mm@kvack.org
Cc: rt@linutronix.de
Cc: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20160818125731.27256-5-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 22 insertions, 44 deletions

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index c2cf14953abc..82ee32107dff 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -15,6 +15,7 @@ enum cpuhp_state {
         CPUHP_X86_HPET_DEAD,
         CPUHP_X86_APB_DEAD,
         CPUHP_VIRT_NET_DEAD,
+        CPUHP_SLUB_DEAD,
         CPUHP_WORKQUEUE_PREP,
         CPUHP_POWER_NUMA_PREPARE,
         CPUHP_HRTIMERS_PREPARE,
diff --git a/mm/slub.c b/mm/slub.c
index 9adae58462f8..2b3e740609e9 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -194,10 +194,6 @@ static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
 #define __OBJECT_POISON         0x80000000UL /* Poison object */
 #define __CMPXCHG_DOUBLE        0x40000000UL /* Use cmpxchg_double */
 
-#ifdef CONFIG_SMP
-static struct notifier_block slab_notifier;
-#endif
-
 /*
  * Tracking user of a slab.
  */
@@ -2305,6 +2301,25 @@ static void flush_all(struct kmem_cache *s)
 }
 
 /*
+ * Use the cpu notifier to insure that the cpu slabs are flushed when
+ * necessary.
+ */
+static int slub_cpu_dead(unsigned int cpu)
+{
+        struct kmem_cache *s;
+        unsigned long flags;
+
+        mutex_lock(&slab_mutex);
+        list_for_each_entry(s, &slab_caches, list) {
+                local_irq_save(flags);
+                __flush_cpu_slab(s, cpu);
+                local_irq_restore(flags);
+        }
+        mutex_unlock(&slab_mutex);
+        return 0;
+}
+
+/*
  * Check if the objects in a per cpu structure fit numa
  * locality expectations.
  */
@@ -4144,9 +4159,8 @@ void __init kmem_cache_init(void)
         /* Setup random freelists for each cache */
         init_freelist_randomization();
 
-#ifdef CONFIG_SMP
-        register_cpu_notifier(&slab_notifier);
-#endif
+        cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
+                                  slub_cpu_dead);
 
         pr_info("SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d, CPUs=%d, Nodes=%d\n",
                 cache_line_size(),
@@ -4210,43 +4224,6 @@ int __kmem_cache_create(struct kmem_cache *s, unsigned long flags)
         return err;
 }
 
-#ifdef CONFIG_SMP
-/*
- * Use the cpu notifier to insure that the cpu slabs are flushed when
- * necessary.
- */
-static int slab_cpuup_callback(struct notifier_block *nfb,
-                unsigned long action, void *hcpu)
-{
-        long cpu = (long)hcpu;
-        struct kmem_cache *s;
-        unsigned long flags;
-
-        switch (action) {
-        case CPU_UP_CANCELED:
-        case CPU_UP_CANCELED_FROZEN:
-        case CPU_DEAD:
-        case CPU_DEAD_FROZEN:
-                mutex_lock(&slab_mutex);
-                list_for_each_entry(s, &slab_caches, list) {
-                        local_irq_save(flags);
-                        __flush_cpu_slab(s, cpu);
-                        local_irq_restore(flags);
-                }
-                mutex_unlock(&slab_mutex);
-                break;
-        default:
-                break;
-        }
-        return NOTIFY_OK;
-}
-
-static struct notifier_block slab_notifier = {
-        .notifier_call = slab_cpuup_callback
-};
-
-#endif
-
 void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
 {
         struct kmem_cache *s;