1 /*
2 * Copyright 2010 Marek Olšák <maraeo@gmail.com>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * on the rights to use, copy, modify, merge, publish, distribute, sub
8 * license, and/or sell copies of the Software, and to permit persons to whom
9 * the Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
19 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
20 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
21 * USE OR OTHER DEALINGS IN THE SOFTWARE. */
22
23 #include "util/u_slab.h"
24
25 #include "util/u_math.h"
26 #include "util/u_memory.h"
27 #include "util/u_simple_list.h"
28
29 #include <stdio.h>
30
31 #define UTIL_SLAB_MAGIC 0xcafe4321
32
33 /* The block is either allocated memory or free space. */
34 struct util_slab_block {
35 /* The header. */
36 /* The first next free block. */
37 struct util_slab_block *next_free;
38
39 intptr_t magic;
40
41 /* Memory after the last member is dedicated to the block itself.
42 * The allocated size is always larger than this structure. */
43 };
44
45 static struct util_slab_block *
util_slab_get_block(struct util_slab_mempool * pool,struct util_slab_page * page,unsigned index)46 util_slab_get_block(struct util_slab_mempool *pool,
47 struct util_slab_page *page, unsigned index)
48 {
49 return (struct util_slab_block*)
50 ((uint8_t*)page + sizeof(struct util_slab_page) +
51 (pool->block_size * index));
52 }
53
util_slab_add_new_page(struct util_slab_mempool * pool)54 static void util_slab_add_new_page(struct util_slab_mempool *pool)
55 {
56 struct util_slab_page *page;
57 struct util_slab_block *block;
58 int i;
59
60 page = MALLOC(pool->page_size);
61 insert_at_tail(&pool->list, page);
62
63 /* Mark all blocks as free. */
64 for (i = 0; i < pool->num_blocks-1; i++) {
65 block = util_slab_get_block(pool, page, i);
66 block->next_free = util_slab_get_block(pool, page, i+1);
67 block->magic = UTIL_SLAB_MAGIC;
68 }
69
70 block = util_slab_get_block(pool, page, pool->num_blocks-1);
71 block->next_free = pool->first_free;
72 block->magic = UTIL_SLAB_MAGIC;
73 pool->first_free = util_slab_get_block(pool, page, 0);
74 pool->num_pages++;
75
76 #if 0
77 fprintf(stderr, "New page! Num of pages: %i\n", pool->num_pages);
78 #endif
79 }
80
util_slab_alloc_st(struct util_slab_mempool * pool)81 static void *util_slab_alloc_st(struct util_slab_mempool *pool)
82 {
83 struct util_slab_block *block;
84
85 if (!pool->first_free)
86 util_slab_add_new_page(pool);
87
88 block = pool->first_free;
89 assert(block->magic == UTIL_SLAB_MAGIC);
90 pool->first_free = block->next_free;
91
92 return (uint8_t*)block + sizeof(struct util_slab_block);
93 }
94
util_slab_free_st(struct util_slab_mempool * pool,void * ptr)95 static void util_slab_free_st(struct util_slab_mempool *pool, void *ptr)
96 {
97 struct util_slab_block *block =
98 (struct util_slab_block*)
99 ((uint8_t*)ptr - sizeof(struct util_slab_block));
100
101 assert(block->magic == UTIL_SLAB_MAGIC);
102 block->next_free = pool->first_free;
103 pool->first_free = block;
104 }
105
util_slab_alloc_mt(struct util_slab_mempool * pool)106 static void *util_slab_alloc_mt(struct util_slab_mempool *pool)
107 {
108 void *mem;
109
110 pipe_mutex_lock(pool->mutex);
111 mem = util_slab_alloc_st(pool);
112 pipe_mutex_unlock(pool->mutex);
113 return mem;
114 }
115
util_slab_free_mt(struct util_slab_mempool * pool,void * ptr)116 static void util_slab_free_mt(struct util_slab_mempool *pool, void *ptr)
117 {
118 pipe_mutex_lock(pool->mutex);
119 util_slab_free_st(pool, ptr);
120 pipe_mutex_unlock(pool->mutex);
121 }
122
util_slab_set_thread_safety(struct util_slab_mempool * pool,enum util_slab_threading threading)123 void util_slab_set_thread_safety(struct util_slab_mempool *pool,
124 enum util_slab_threading threading)
125 {
126 pool->threading = threading;
127
128 if (threading) {
129 pool->alloc = util_slab_alloc_mt;
130 pool->free = util_slab_free_mt;
131 } else {
132 pool->alloc = util_slab_alloc_st;
133 pool->free = util_slab_free_st;
134 }
135 }
136
util_slab_create(struct util_slab_mempool * pool,unsigned item_size,unsigned num_blocks,enum util_slab_threading threading)137 void util_slab_create(struct util_slab_mempool *pool,
138 unsigned item_size,
139 unsigned num_blocks,
140 enum util_slab_threading threading)
141 {
142 item_size = align(item_size, sizeof(intptr_t));
143
144 pool->num_pages = 0;
145 pool->num_blocks = num_blocks;
146 pool->block_size = sizeof(struct util_slab_block) + item_size;
147 pool->block_size = align(pool->block_size, sizeof(intptr_t));
148 pool->page_size = sizeof(struct util_slab_page) +
149 num_blocks * pool->block_size;
150 pool->first_free = NULL;
151
152 make_empty_list(&pool->list);
153
154 pipe_mutex_init(pool->mutex);
155
156 util_slab_set_thread_safety(pool, threading);
157 }
158
util_slab_destroy(struct util_slab_mempool * pool)159 void util_slab_destroy(struct util_slab_mempool *pool)
160 {
161 struct util_slab_page *page, *temp;
162
163 if (pool->list.next) {
164 foreach_s(page, temp, &pool->list) {
165 remove_from_list(page);
166 FREE(page);
167 }
168 }
169
170 pipe_mutex_destroy(pool->mutex);
171 }
172