1#include <stdlib.h>
  2#include <string.h>
  3#include <malloc.h>
  4#include <pthread.h>
  5#include <unistd.h>
  6#include <assert.h>
  7
  8#include <linux/mempool.h>
  9#include <linux/poison.h>
 10#include <linux/slab.h>
 11#include <linux/radix-tree.h>
 12#include <urcu/uatomic.h>
 13
 14int nr_allocated;
 15int preempt_count;
 16
 17struct kmem_cache {
 18	pthread_mutex_t lock;
 19	int size;
 20	int nr_objs;
 21	void *objs;
 22	void (*ctor)(void *);
 23};
 24
 25void *mempool_alloc(mempool_t *pool, int gfp_mask)
 26{
 27	return pool->alloc(gfp_mask, pool->data);
 28}
 29
 30void mempool_free(void *element, mempool_t *pool)
 31{
 32	pool->free(element, pool->data);
 33}
 34
 35mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
 36			mempool_free_t *free_fn, void *pool_data)
 37{
 38	mempool_t *ret = malloc(sizeof(*ret));
 39
 40	ret->alloc = alloc_fn;
 41	ret->free = free_fn;
 42	ret->data = pool_data;
 43	return ret;
 44}
 45
 46void *kmem_cache_alloc(struct kmem_cache *cachep, int flags)
 47{
 48	struct radix_tree_node *node;
 49
 50	if (flags & __GFP_NOWARN)
 51		return NULL;
 52
 53	pthread_mutex_lock(&cachep->lock);
 54	if (cachep->nr_objs) {
 55		cachep->nr_objs--;
 56		node = cachep->objs;
 57		cachep->objs = node->private_data;
 58		pthread_mutex_unlock(&cachep->lock);
 59		node->private_data = NULL;
 60	} else {
 61		pthread_mutex_unlock(&cachep->lock);
 62		node = malloc(cachep->size);
 63		if (cachep->ctor)
 64			cachep->ctor(node);
 65	}
 66
 67	uatomic_inc(&nr_allocated);
 68	return node;
 69}
 70
 71void kmem_cache_free(struct kmem_cache *cachep, void *objp)
 72{
 73	assert(objp);
 74	uatomic_dec(&nr_allocated);
 75	pthread_mutex_lock(&cachep->lock);
 76	if (cachep->nr_objs > 10) {
 77		memset(objp, POISON_FREE, cachep->size);
 78		free(objp);
 79	} else {
 80		struct radix_tree_node *node = objp;
 81		cachep->nr_objs++;
 82		node->private_data = cachep->objs;
 83		cachep->objs = node;
 84	}
 85	pthread_mutex_unlock(&cachep->lock);
 86}
 87
 88void *kmalloc(size_t size, gfp_t gfp)
 89{
 90	void *ret = malloc(size);
 91	uatomic_inc(&nr_allocated);
 92	return ret;
 93}
 94
 95void kfree(void *p)
 96{
 97	if (!p)
 98		return;
 99	uatomic_dec(&nr_allocated);
100	free(p);
101}
102
103struct kmem_cache *
104kmem_cache_create(const char *name, size_t size, size_t offset,
105	unsigned long flags, void (*ctor)(void *))
106{
107	struct kmem_cache *ret = malloc(sizeof(*ret));
108
109	pthread_mutex_init(&ret->lock, NULL);
110	ret->size = size;
111	ret->nr_objs = 0;
112	ret->objs = NULL;
113	ret->ctor = ctor;
114	return ret;
115}