tools/testing: Add support for prefilled slab sheafs

Add the prefilled sheaf structs to the slab header and the associated
functions to the testing/shared/linux.c file.

Signed-off-by: Liam R. Howlett <[e-mail]>
Reviewed-by: Suren Baghdasaryan <[e-mail]>
Signed-off-by: Vlastimil Babka <[e-mail]>

tools/include/linux/slab.h

···
 	void (*ctor)(void *);
 };
 
+struct slab_sheaf {
+	union {
+		struct list_head barn_list;
+		/* only used for prefilled sheafs */
+		unsigned int capacity;
+	};
+	struct kmem_cache *cache;
+	unsigned int size;
+	int node; /* only used for rcu_sheaf */
+	void *objects[];
+};
+
 static inline void *kzalloc(size_t size, gfp_t gfp)
 {
 	return kmalloc(size, gfp | __GFP_ZERO);
···
 void kmem_cache_free_bulk(struct kmem_cache *cachep, size_t size, void **list);
 int kmem_cache_alloc_bulk(struct kmem_cache *cachep, gfp_t gfp, size_t size,
 			  void **list);
+struct slab_sheaf *
+kmem_cache_prefill_sheaf(struct kmem_cache *s, gfp_t gfp, unsigned int size);
+
+void *
+kmem_cache_alloc_from_sheaf(struct kmem_cache *s, gfp_t gfp,
+		struct slab_sheaf *sheaf);
+
+void kmem_cache_return_sheaf(struct kmem_cache *s, gfp_t gfp,
+		struct slab_sheaf *sheaf);
+int kmem_cache_refill_sheaf(struct kmem_cache *s, gfp_t gfp,
+		struct slab_sheaf **sheafp, unsigned int size);
+
+static inline unsigned int kmem_cache_sheaf_size(struct slab_sheaf *sheaf)
+{
+	return sheaf->size;
+}
 
 #endif		/* _TOOLS_SLAB_H */

tools/testing/shared/linux.c

···
 	if (kmalloc_verbose)
 		pr_debug("Bulk free %p[0-%zu]\n", list, size - 1);
 
+	if (cachep->exec_callback) {
+		if (cachep->callback)
+			cachep->callback(cachep->private);
+		cachep->exec_callback = false;
+	}
+
 	pthread_mutex_lock(&cachep->lock);
 	for (int i = 0; i < size; i++)
 		kmem_cache_free_locked(cachep, list[i]);
···
 	ret->private = NULL;
 
 	return ret;
+}
+
+struct slab_sheaf *
+kmem_cache_prefill_sheaf(struct kmem_cache *s, gfp_t gfp, unsigned int size)
+{
+	struct slab_sheaf *sheaf;
+	unsigned int capacity;
+
+	if (s->exec_callback) {
+		if (s->callback)
+			s->callback(s->private);
+		s->exec_callback = false;
+	}
+
+	capacity = max(size, s->sheaf_capacity);
+
+	sheaf = calloc(1, sizeof(*sheaf) + sizeof(void *) * capacity);
+	if (!sheaf)
+		return NULL;
+
+	sheaf->cache = s;
+	sheaf->capacity = capacity;
+	sheaf->size = kmem_cache_alloc_bulk(s, gfp, size, sheaf->objects);
+	if (!sheaf->size) {
+		free(sheaf);
+		return NULL;
+	}
+
+	return sheaf;
+}
+
+int kmem_cache_refill_sheaf(struct kmem_cache *s, gfp_t gfp,
+		 struct slab_sheaf **sheafp, unsigned int size)
+{
+	struct slab_sheaf *sheaf = *sheafp;
+	int refill;
+
+	if (sheaf->size >= size)
+		return 0;
+
+	if (size > sheaf->capacity) {
+		sheaf = kmem_cache_prefill_sheaf(s, gfp, size);
+		if (!sheaf)
+			return -ENOMEM;
+
+		kmem_cache_return_sheaf(s, gfp, *sheafp);
+		*sheafp = sheaf;
+		return 0;
+	}
+
+	refill = kmem_cache_alloc_bulk(s, gfp, size - sheaf->size,
+				       &sheaf->objects[sheaf->size]);
+	if (!refill)
+		return -ENOMEM;
+
+	sheaf->size += refill;
+	return 0;
+}
+
+void kmem_cache_return_sheaf(struct kmem_cache *s, gfp_t gfp,
+		 struct slab_sheaf *sheaf)
+{
+	if (sheaf->size)
+		kmem_cache_free_bulk(s, sheaf->size, &sheaf->objects[0]);
+
+	free(sheaf);
+}
+
+void *
+kmem_cache_alloc_from_sheaf(struct kmem_cache *s, gfp_t gfp,
+		struct slab_sheaf *sheaf)
+{
+	void *obj;
+
+	if (sheaf->size == 0) {
+		printf("Nothing left in sheaf!\n");
+		return NULL;
+	}
+
+	obj = sheaf->objects[--sheaf->size];
+	sheaf->objects[sheaf->size] = NULL;
+
+	return obj;
 }
 
 /*