slab: Convert to hotplug state machine
Install the callbacks via the state machine.
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>
Link: http://lkml.kernel.org/r/20160823125319.abeapfjapf2kfezp@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/mm/slab.c b/mm/slab.c
index b672710..090fb26 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -886,6 +886,7 @@
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 @@
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 @@
return ret;
}
+#ifdef CONFIG_SMP
+
static void cpuup_canceled(long cpu)
{
struct kmem_cache *cachep;
@@ -1075,65 +1079,54 @@
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 */
-#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);
+ mutex_lock(&slab_mutex);
+ err = cpuup_prepare(cpu);
+ mutex_unlock(&slab_mutex);
+ return err;
}
-static struct notifier_block cpucache_notifier = {
- &cpuup_callback, NULL, 0
-};
+/*
+ * 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
+
+static int slab_online_cpu(unsigned int cpu)
+{
+ start_cpu_timer(cpu);
+ return 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 @@
/* 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 @@
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;