+static inline int calculate_order(int size)
+{
+ int order;
+ int min_objects;
+ int fraction;
+
+ /*
+ * Attempt to find best configuration for a slab. This
+ * works by first attempting to generate a layout with
+ * the best configuration and backing off gradually.
+ *
+ * First we reduce the acceptable waste in a slab. Then
+ * we reduce the minimum objects required in a slab.
+ */
+ min_objects = slub_min_objects;
+ while (min_objects > 1) {
+ fraction = 8;
+ while (fraction >= 4) {
+ order = slab_order(size, min_objects,
+ slub_max_order, fraction);
+ if (order <= slub_max_order)
+ return order;
+ fraction /= 2;
+ }
+ min_objects /= 2;
+ }
+
+ /*
+ * We were unable to place multiple objects in a slab. Now
+ * lets see if we can place a single object there.
+ */
+ order = slab_order(size, 1, slub_max_order, 1);
+ if (order <= slub_max_order)
+ return order;
+
+ /*
+ * Doh this slab cannot be placed using slub_max_order.
+ */
+ order = slab_order(size, 1, MAX_ORDER, 1);
+ if (order <= MAX_ORDER)
+ return order;
+ return -ENOSYS;
+}
+
+/*
+ * Figure out what the alignment of the objects will be.
+ */
+static unsigned long calculate_alignment(unsigned long flags,
+ unsigned long align, unsigned long size)
+{
+ /*
+ * If the user wants hardware cache aligned objects then
+ * follow that suggestion if the object is sufficiently
+ * large.
+ *
+ * The hardware cache alignment cannot override the
+ * specified alignment though. If that is greater
+ * then use it.
+ */
+ if ((flags & SLAB_HWCACHE_ALIGN) &&
+ size > cache_line_size() / 2)
+ return max_t(unsigned long, align, cache_line_size());
+
+ if (align < ARCH_SLAB_MINALIGN)
+ return ARCH_SLAB_MINALIGN;
+
+ return ALIGN(align, sizeof(void *));
+}
+
+static void init_kmem_cache_cpu(struct kmem_cache *s,
+ struct kmem_cache_cpu *c)
+{
+ c->page = NULL;
+ c->freelist = NULL;
+ c->node = 0;
+ c->offset = s->offset / sizeof(void *);
+ c->objsize = s->objsize;
+}
+
+static void init_kmem_cache_node(struct kmem_cache_node *n)
+{
+ n->nr_partial = 0;
+ atomic_long_set(&n->nr_slabs, 0);
+ spin_lock_init(&n->list_lock);
+ INIT_LIST_HEAD(&n->partial);
+#ifdef CONFIG_SLUB_DEBUG
+ INIT_LIST_HEAD(&n->full);
+#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;
+}
+