1 files changed, 154 insertions, 14 deletions

diff --git a/mm/slub.c b/mm/slub.c
index ea9fd72..6d4346ba 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -269,7 +269,11 @@ static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
 
 static inline struct kmem_cache_cpu *get_cpu_slab(struct kmem_cache *s, int cpu)
 {
-	return &s->cpu_slab[cpu];
+#ifdef CONFIG_SMP
+	return s->cpu_slab[cpu];
+#else
+	return &s->cpu_slab;
+#endif
 }
 
 static inline int check_valid_pointer(struct kmem_cache *s,
@@ -1858,16 +1862,6 @@ static void init_kmem_cache_cpu(struct kmem_cache *s,
 	c->node = 0;
 }
 
-static inline int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
-{
-	int cpu;
-
-	for_each_possible_cpu(cpu)
-		init_kmem_cache_cpu(s, get_cpu_slab(s, cpu));
-
-	return 1;
-}
-
 static void init_kmem_cache_node(struct kmem_cache_node *n)
 {
 	n->nr_partial = 0;
@@ -1879,6 +1873,131 @@ static void init_kmem_cache_node(struct kmem_cache_node *n)
 #endif
 }
 
+#ifdef CONFIG_SMP
+/*
+ * Per cpu array for per cpu structures.
+ *
+ * The per cpu array places all kmem_cache_cpu structures from one processor
+ * close together meaning that it becomes possible that multiple per cpu
+ * structures are contained in one cacheline. This may be particularly
+ * beneficial for the kmalloc caches.
+ *
+ * A desktop system typically has around 60-80 slabs. With 100 here we are
+ * likely able to get per cpu structures for all caches from the array defined
+ * here. We must be able to cover all kmalloc caches during bootstrap.
+ *
+ * If the per cpu array is exhausted then fall back to kmalloc
+ * of individual cachelines. No sharing is possible then.
+ */
+#define NR_KMEM_CACHE_CPU 100
+
+static DEFINE_PER_CPU(struct kmem_cache_cpu,
+				kmem_cache_cpu)[NR_KMEM_CACHE_CPU];
+
+static DEFINE_PER_CPU(struct kmem_cache_cpu *, kmem_cache_cpu_free);
+static cpumask_t kmem_cach_cpu_free_init_once = CPU_MASK_NONE;
+
+static struct kmem_cache_cpu *alloc_kmem_cache_cpu(struct kmem_cache *s,
+							int cpu, gfp_t flags)
+{
+	struct kmem_cache_cpu *c = per_cpu(kmem_cache_cpu_free, cpu);
+
+	if (c)
+		per_cpu(kmem_cache_cpu_free, cpu) =
+				(void *)c->freelist;
+	else {
+		/* Table overflow: So allocate ourselves */
+		c = kmalloc_node(
+			ALIGN(sizeof(struct kmem_cache_cpu), cache_line_size()),
+			flags, cpu_to_node(cpu));
+		if (!c)
+			return NULL;
+	}
+
+	init_kmem_cache_cpu(s, c);
+	return c;
+}
+
+static void free_kmem_cache_cpu(struct kmem_cache_cpu *c, int cpu)
+{
+	if (c < per_cpu(kmem_cache_cpu, cpu) ||
+			c > per_cpu(kmem_cache_cpu, cpu) + NR_KMEM_CACHE_CPU) {
+		kfree(c);
+		return;
+	}
+	c->freelist = (void *)per_cpu(kmem_cache_cpu_free, cpu);
+	per_cpu(kmem_cache_cpu_free, cpu) = c;
+}
+
+static void free_kmem_cache_cpus(struct kmem_cache *s)
+{
+	int cpu;
+
+	for_each_online_cpu(cpu) {
+		struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
+
+		if (c) {
+			s->cpu_slab[cpu] = NULL;
+			free_kmem_cache_cpu(c, cpu);
+		}
+	}
+}
+
+static int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
+{
+	int cpu;
+
+	for_each_online_cpu(cpu) {
+		struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
+
+		if (c)
+			continue;
+
+		c = alloc_kmem_cache_cpu(s, cpu, flags);
+		if (!c) {
+			free_kmem_cache_cpus(s);
+			return 0;
+		}
+		s->cpu_slab[cpu] = c;
+	}
+	return 1;
+}
+
+/*
+ * Initialize the per cpu array.
+ */
+static void init_alloc_cpu_cpu(int cpu)
+{
+	int i;
+
+	if (cpu_isset(cpu, kmem_cach_cpu_free_init_once))
+		return;
+
+	for (i = NR_KMEM_CACHE_CPU - 1; i >= 0; i--)
+		free_kmem_cache_cpu(&per_cpu(kmem_cache_cpu, cpu)[i], cpu);
+
+	cpu_set(cpu, kmem_cach_cpu_free_init_once);
+}
+
+static void __init init_alloc_cpu(void)
+{
+	int cpu;
+
+	for_each_online_cpu(cpu)
+		init_alloc_cpu_cpu(cpu);
+  }
+
+#else
+static inline void free_kmem_cache_cpus(struct kmem_cache *s) {}
+static inline void init_alloc_cpu(void) {}
+
+static inline int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
+{
+	init_kmem_cache_cpu(s, &s->cpu_slab);
+	return 1;
+}
+#endif
+
 #ifdef CONFIG_NUMA
 /*
  * No kmalloc_node yet so do it by hand. We know that this is the first
@@ -1886,7 +2005,8 @@ static void init_kmem_cache_node(struct kmem_cache_node *n)
  * possible.
  *
  * Note that this function only works on the kmalloc_node_cache
- * when allocating for the kmalloc_node_cache.
+ * when allocating for the kmalloc_node_cache. This is used for bootstrapping
+ * memory on a fresh node that has no slab structures yet.
  */
 static struct kmem_cache_node *early_kmem_cache_node_alloc(gfp_t gfpflags,
 							   int node)
@@ -2115,6 +2235,7 @@ static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags,
 
 	if (alloc_kmem_cache_cpus(s, gfpflags & ~SLUB_DMA))
 		return 1;
+	free_kmem_cache_nodes(s);
 error:
 	if (flags & SLAB_PANIC)
 		panic("Cannot create slab %s size=%lu realsize=%u "
@@ -2197,6 +2318,7 @@ static inline int kmem_cache_close(struct kmem_cache *s)
 	flush_all(s);
 
 	/* Attempt to free all objects */
+	free_kmem_cache_cpus(s);
 	for_each_node_state(node, N_NORMAL_MEMORY) {
 		struct kmem_cache_node *n = get_node(s, node);
 
@@ -2584,6 +2706,8 @@ void __init kmem_cache_init(void)
 	int i;
 	int caches = 0;
 
+	init_alloc_cpu();
+
 #ifdef CONFIG_NUMA
 	/*
 	 * Must first have the slab cache available for the allocations of the
@@ -2644,10 +2768,12 @@ void __init kmem_cache_init(void)
 
 #ifdef CONFIG_SMP
 	register_cpu_notifier(&slab_notifier);
+	kmem_size = offsetof(struct kmem_cache, cpu_slab) +
+				nr_cpu_ids * sizeof(struct kmem_cache_cpu *);
+#else
+	kmem_size = sizeof(struct kmem_cache);
 #endif
 
-	kmem_size = offsetof(struct kmem_cache, cpu_slab) +
-				nr_cpu_ids * sizeof(struct kmem_cache_cpu);
 
 	printk(KERN_INFO "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
 		" CPUs=%d, Nodes=%d\n",
@@ -2774,15 +2900,29 @@ static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb,
 	unsigned long flags;
 
 	switch (action) {
+	case CPU_UP_PREPARE:
+	case CPU_UP_PREPARE_FROZEN:
+		init_alloc_cpu_cpu(cpu);
+		down_read(&slub_lock);
+		list_for_each_entry(s, &slab_caches, list)
+			s->cpu_slab[cpu] = alloc_kmem_cache_cpu(s, cpu,
+							GFP_KERNEL);
+		up_read(&slub_lock);
+		break;
+
 	case CPU_UP_CANCELED:
 	case CPU_UP_CANCELED_FROZEN:
 	case CPU_DEAD:
 	case CPU_DEAD_FROZEN:
 		down_read(&slub_lock);
 		list_for_each_entry(s, &slab_caches, list) {
+			struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
+
 			local_irq_save(flags);
 			__flush_cpu_slab(s, cpu);
 			local_irq_restore(flags);
+			free_kmem_cache_cpu(c, cpu);
+			s->cpu_slab[cpu] = NULL;
 		}
 		up_read(&slub_lock);
 		break;