regional.c revision 269257 
1/*
2 * regional.c -- region based memory allocator.
3 *
4 * Copyright (c) 2001-2006, NLnet Labs. All rights reserved.
5 *
6 * Copyright (c) 2007, NLnet Labs. All rights reserved.
7 *
8 * This software is open source.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 *
14 * Redistributions of source code must retain the above copyright notice,
15 * this list of conditions and the following disclaimer.
16 *
17 * Redistributions in binary form must reproduce the above copyright notice,
18 * this list of conditions and the following disclaimer in the documentation
19 * and/or other materials provided with the distribution.
20 *
21 * Neither the name of the NLNET LABS nor the names of its contributors may
22 * be used to endorse or promote products derived from this software without
23 * specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
29 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
31 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
32 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
33 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
34 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
35 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 */
37
38/**
39 * \file
40 * Regional allocator. Allocates small portions of of larger chunks.
41 */
42
43#include "config.h"
44#include "util/log.h"
45#include "util/regional.h"
46
47#ifdef ALIGNMENT
48#  undef ALIGNMENT
49#endif
50/** increase size until it fits alignment of s bytes */
51#define ALIGN_UP(x, s)     (((x) + s - 1) & (~(s - 1)))
52/** what size to align on; make sure a char* fits in it. */
53#define ALIGNMENT          (sizeof(uint64_t))
54
55/** Default reasonable size for chunks */
56#define REGIONAL_CHUNK_SIZE         8192
57#ifdef UNBOUND_ALLOC_NONREGIONAL
58/** All objects allocated outside of chunks, for debug */
59#define REGIONAL_LARGE_OBJECT_SIZE  0
60#else
61/** Default size for large objects - allocated outside of chunks. */
62#define REGIONAL_LARGE_OBJECT_SIZE  2048
63#endif
64
65struct regional*
66regional_create(void)
67{
68	return regional_create_custom(REGIONAL_CHUNK_SIZE);
69}
70
71/** init regional struct with first block */
72static void
73regional_init(struct regional* r)
74{
75	size_t a = ALIGN_UP(sizeof(struct regional), ALIGNMENT);
76	r->data = (char*)r + a;
77	r->available = r->first_size - a;
78	r->next = NULL;
79	r->large_list = NULL;
80	r->total_large = 0;
81}
82
83struct regional*
84regional_create_custom(size_t size)
85{
86	struct regional* r = (struct regional*)malloc(size);
87	log_assert(sizeof(struct regional) <= size);
88	if(!r) return NULL;
89	r->first_size = size;
90	regional_init(r);
91	return r;
92}
93
94void
95regional_free_all(struct regional *r)
96{
97	char* p = r->next, *np;
98	while(p) {
99		np = *(char**)p;
100		free(p);
101		p = np;
102	}
103	p = r->large_list;
104	while(p) {
105		np = *(char**)p;
106		free(p);
107		p = np;
108	}
109	regional_init(r);
110}
111
112void
113regional_destroy(struct regional *r)
114{
115	if(!r) return;
116	regional_free_all(r);
117	free(r);
118}
119
120void *
121regional_alloc(struct regional *r, size_t size)
122{
123	size_t a = ALIGN_UP(size, ALIGNMENT);
124	void *s;
125	/* large objects */
126	if(a > REGIONAL_LARGE_OBJECT_SIZE) {
127		s = malloc(ALIGNMENT + size);
128		if(!s) return NULL;
129		r->total_large += ALIGNMENT+size;
130		*(char**)s = r->large_list;
131		r->large_list = (char*)s;
132		return (char*)s+ALIGNMENT;
133	}
134	/* create a new chunk */
135	if(a > r->available) {
136		s = malloc(REGIONAL_CHUNK_SIZE);
137		if(!s) return NULL;
138		*(char**)s = r->next;
139		r->next = (char*)s;
140		r->data = (char*)s + ALIGNMENT;
141		r->available = REGIONAL_CHUNK_SIZE - ALIGNMENT;
142	}
143	/* put in this chunk */
144	r->available -= a;
145	s = r->data;
146	r->data += a;
147	return s;
148}
149
150void *
151regional_alloc_init(struct regional* r, const void *init, size_t size)
152{
153	void *s = regional_alloc(r, size);
154	if(!s) return NULL;
155	memcpy(s, init, size);
156	return s;
157}
158
159void *
160regional_alloc_zero(struct regional *r, size_t size)
161{
162	void *s = regional_alloc(r, size);
163	if(!s) return NULL;
164	memset(s, 0, size);
165	return s;
166}
167
168char *
169regional_strdup(struct regional *r, const char *string)
170{
171	return (char*)regional_alloc_init(r, string, strlen(string)+1);
172}
173
174/**
175 * reasonably slow, but stats and get_mem are not supposed to be fast
176 * count the number of chunks in use
177 */
178static size_t
179count_chunks(struct regional* r)
180{
181	size_t c = 1;
182	char* p = r->next;
183	while(p) {
184		c++;
185		p = *(char**)p;
186	}
187	return c;
188}
189
190/**
191 * also reasonably slow, counts the number of large objects
192 */
193static size_t
194count_large(struct regional* r)
195{
196	size_t c = 0;
197	char* p = r->large_list;
198	while(p) {
199		c++;
200		p = *(char**)p;
201	}
202	return c;
203}
204
205void
206regional_log_stats(struct regional *r)
207{
208	/* some basic assertions put here (non time critical code) */
209	log_assert(ALIGNMENT >= sizeof(char*));
210	log_assert(REGIONAL_CHUNK_SIZE > ALIGNMENT);
211	log_assert(REGIONAL_CHUNK_SIZE-ALIGNMENT > REGIONAL_LARGE_OBJECT_SIZE);
212	log_assert(REGIONAL_CHUNK_SIZE >= sizeof(struct regional));
213	/* debug print */
214	log_info("regional %u chunks, %u large",
215		(unsigned)count_chunks(r), (unsigned)count_large(r));
216}
217
218size_t
219regional_get_mem(struct regional* r)
220{
221	return r->first_size + (count_chunks(r)-1)*REGIONAL_CHUNK_SIZE
222		+ r->total_large;
223}
224