| /* Copyright 2013-2014 IBM Corp. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or |
| * implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| /* This file provides some functions to manage a pool of pre-allocated |
| * objects. It also provides a method to reserve a pre-defined number |
| * of objects for higher priorty requests. The allocations follow the |
| * following rules: |
| * |
| * 1. An allocation will succeed at any priority if there is more than |
| * the reserved number of objects free. |
| * 2. Only high priority allocations will succeed when there are less |
| * than the reserved number of objects free. |
| * 3. When an allocation is freed it is always added to the high priority |
| * pool if there are less than the reserved number of allocations |
| * available. |
| */ |
| |
| #include <pool.h> |
| #include <string.h> |
| #include <stdlib.h> |
| #include <ccan/list/list.h> |
| |
| void* pool_get(struct pool *pool, enum pool_priority priority) |
| { |
| void *obj; |
| |
| if (!pool->free_count || |
| ((pool->free_count <= pool->reserved) && priority == POOL_NORMAL)) |
| return NULL; |
| |
| pool->free_count--; |
| obj = (void *) list_pop_(&pool->free_list, 0); |
| assert(obj); |
| memset(obj, 0, pool->obj_size); |
| return obj; |
| } |
| |
| void pool_free_object(struct pool *pool, void *obj) |
| { |
| pool->free_count++; |
| list_add_tail(&pool->free_list, |
| (struct list_node *) (obj)); |
| } |
| |
| int pool_init(struct pool *pool, size_t obj_size, int count, int reserved) |
| { |
| int i; |
| |
| if (obj_size < sizeof(struct list_node)) |
| obj_size = sizeof(struct list_node); |
| |
| assert(count >= reserved); |
| pool->buf = malloc(obj_size*count); |
| if (!pool->buf) |
| return -1; |
| |
| pool->obj_size = obj_size; |
| pool->free_count = count; |
| pool->reserved = reserved; |
| list_head_init(&pool->free_list); |
| |
| for(i = 0; i < count; i++) |
| list_add_tail(&pool->free_list, |
| (struct list_node *) (pool->buf + obj_size*i)); |
| |
| return 0; |
| } |