// SPDX-License-Identifier: GPL-2.0 #include <stdlib.h> #include <string.h> #include <malloc.h> #include <pthread.h> #include <unistd.h> #include <assert.h> #include <linux/gfp.h> #include <linux/poison.h> #include <linux/slab.h> #include <linux/radix-tree.h> #include <urcu/uatomic.h> int nr_allocated; int preempt_count; int kmalloc_verbose; int test_verbose; struct kmem_cache { pthread_mutex_t lock; int size; int nr_objs; void *objs; void (*ctor)(void *); }; void *kmem_cache_alloc(struct kmem_cache *cachep, int flags) { struct radix_tree_node *node; if (!(flags & __GFP_DIRECT_RECLAIM)) return NULL; pthread_mutex_lock(&cachep->lock); if (cachep->nr_objs) { cachep->nr_objs--; node = cachep->objs; cachep->objs = node->parent; pthread_mutex_unlock(&cachep->lock); node->parent = NULL; } else { pthread_mutex_unlock(&cachep->lock); node = malloc(cachep->size); if (cachep->ctor) cachep->ctor(node); } uatomic_inc(&nr_allocated); if (kmalloc_verbose) printf("Allocating %p from slab\n", node); return node; } void kmem_cache_free(struct kmem_cache *cachep, void *objp) { assert(objp); uatomic_dec(&nr_allocated); if (kmalloc_verbose) printf("Freeing %p to slab\n", objp); pthread_mutex_lock(&cachep->lock); if (cachep->nr_objs > 10) { memset(objp, POISON_FREE, cachep->size); free(objp); } else { struct radix_tree_node *node = objp; cachep->nr_objs++; node->parent = cachep->objs; cachep->objs = node; } pthread_mutex_unlock(&cachep->lock); } void *kmalloc(size_t size, gfp_t gfp) { void *ret; if (!(gfp & __GFP_DIRECT_RECLAIM)) return NULL; ret = malloc(size); uatomic_inc(&nr_allocated); if (kmalloc_verbose) printf("Allocating %p from malloc\n", ret); if (gfp & __GFP_ZERO) memset(ret, 0, size); return ret; } void kfree(void *p) { if (!p) return; uatomic_dec(&nr_allocated); if (kmalloc_verbose) printf("Freeing %p to malloc\n", p); free(p); } struct kmem_cache * kmem_cache_create(const char *name, size_t size, size_t offset, unsigned long flags, void (*ctor)(void *)) { struct kmem_cache *ret = malloc(sizeof(*ret)); pthread_mutex_init(&ret->lock, NULL); ret->size = size; ret->nr_objs = 0; ret->objs = NULL; ret->ctor = ctor; return ret; }