1 /* Memory allocator `malloc'.
2 Copyright 1990, 1991, 1992 Free Software Foundation
4 Written May 1989 by Mike Haertel.
5 Heavily modified Mar 1992 by Fred Fish for mmap'd version. */
7 /* Copyright (c) 2010. The SimGrid Team.
8 * All rights reserved. */
10 /* This program is free software; you can redistribute it and/or modify it
11 * under the terms of the license (GNU LGPL) which comes with this package. */
13 #include <string.h> /* Prototypes for memcpy, memmove, memset, etc */
15 #include "mmprivate.h"
17 /* Prototypes for local functions */
19 static int initialize(xbt_mheap_t mdp);
20 static void *register_morecore(xbt_mheap_t mdp, size_t size);
21 static void *align(xbt_mheap_t mdp, size_t size);
23 /* Allocation aligned on block boundary */
24 static void *align(struct mdesc *mdp, size_t size)
27 unsigned long int adj;
29 result = mmorecore(mdp, size);
31 /* if this reservation does not fill up the last block of our resa,
32 * complete the reservation by also asking for the full lastest block.
34 * Also, the returned block is aligned to the end of block (but I've
35 * no fucking idea of why, actually -- http://abstrusegoose.com/432 --
36 * but not doing so seems to lead to issues).
38 adj = RESIDUAL(result, BLOCKSIZE);
40 adj = BLOCKSIZE - adj;
42 result = (char *) result + adj;
47 /* Finish the initialization of the mheap. If we want to inline it
48 * properly, we need to make the align function publicly visible, too */
49 static int initialize(xbt_mheap_t mdp)
51 mdp->heapsize = HEAP / BLOCKSIZE;
52 mdp->heapinfo = (malloc_info *)
53 align(mdp, mdp->heapsize * sizeof(malloc_info));
54 if (mdp->heapinfo == NULL) {
57 memset((void *) mdp->heapinfo, 0, mdp->heapsize * sizeof(malloc_info));
58 mdp->heapinfo[0].type=-1;
59 mdp->heapinfo[0].free_block.size = 0;
60 mdp->heapinfo[0].free_block.next = mdp->heapinfo[0].free_block.prev = 0;
62 mdp->heapbase = (void *) mdp->heapinfo;
63 mdp->flags |= MMALLOC_INITIALIZED;
67 /* Get neatly aligned memory from the low level layers, and register it
68 * into the heap info table as necessary. */
69 static void *register_morecore(struct mdesc *mdp, size_t size)
72 malloc_info *newinfo, *oldinfo;
75 result = align(mdp, size);
80 /* Check if we need to grow the info table (in a multiplicative manner) */
81 if ((size_t) BLOCK((char *) result + size) > mdp->heapsize) {
84 newsize = mdp->heapsize;
85 while ((size_t) BLOCK((char *) result + size) > newsize)
88 /* Copy old info into new location */
89 oldinfo = mdp->heapinfo;
90 newinfo = (malloc_info *) align(mdp, newsize * sizeof(malloc_info));
91 memset(newinfo, 0, newsize * sizeof(malloc_info));
92 memcpy(newinfo, oldinfo, mdp->heapsize * sizeof(malloc_info));
93 mdp->heapinfo = newinfo;
95 /* mark the space previously occupied by the block info as free by first marking it
96 * as occupied in the regular way, and then freing it */
97 for (it=0; it<BLOCKIFY(mdp->heapsize * sizeof(malloc_info)); it++)
98 newinfo[BLOCK(oldinfo)+it].type = 0;
100 newinfo[BLOCK(oldinfo)].busy_block.size = BLOCKIFY(mdp->heapsize * sizeof(malloc_info));
101 newinfo[BLOCK(oldinfo)].busy_block.busy_size = size;
102 mfree(mdp, (void *) oldinfo);
103 mdp->heapsize = newsize;
106 mdp->heaplimit = BLOCK((char *) result + size);
110 /* Allocate memory from the heap. */
112 void *mmalloc(xbt_mheap_t mdp, size_t size)
115 size_t block, blocks, lastblocks, start;
121 /* Work even if the user was stupid enough to ask a 0-byte block, ie return a valid block that can be realloced or freed
122 * glibc malloc does not use this trick but return a constant pointer, but my hack is quicker to implement ;)
127 // printf("(%s) Mallocing %d bytes on %p (default: %p)...",xbt_thread_self_name(),size,mdp,__mmalloc_default_mdp);fflush(stdout);
129 if (!(mdp->flags & MMALLOC_INITIALIZED)) {
130 if (!initialize(mdp)) {
135 if (size < sizeof(struct list)) {
136 size = sizeof(struct list);
139 /* Determine the allocation policy based on the request size. */
140 if (size <= BLOCKSIZE / 2) {
141 /* Small allocation to receive a fragment of a block.
142 Determine the logarithm to base two of the fragment size. */
145 while ((size /= 2) != 0) {
149 /* Look in the fragment lists for a
150 free fragment of the desired size. */
151 next = mdp->fraghead[log].next;
153 /* There are free fragments of this size.
154 Pop a fragment out of the fragment list and return it.
155 Update the block's nfree and first counters. */
156 result = (void *) next;
157 next->prev->next = next->next;
158 if (next->next != NULL) {
159 next->next->prev = next->prev;
161 block = BLOCK(result);
162 if (--mdp->heapinfo[block].busy_frag.nfree != 0) {
163 mdp->heapinfo[block].busy_frag.first =
164 RESIDUAL(next->next, BLOCKSIZE) >> log;
168 /* No free fragments of the desired size, so get a new block
169 and break it into fragments, returning the first. */
170 //printf("(%s) No free fragment...",xbt_thread_self_name());
171 result = mmalloc(mdp, BLOCKSIZE);
172 //printf("(%s) Fragment: %p...",xbt_thread_self_name(),result);
173 if (result == NULL) {
177 /* Link all fragments but the first into the free list. */
178 for (i = 1; i < (size_t) (BLOCKSIZE >> log); ++i) {
179 next = (struct list *) ((char *) result + (i << log));
180 next->next = mdp->fraghead[log].next;
181 next->prev = &mdp->fraghead[log];
182 next->prev->next = next;
183 if (next->next != NULL) {
184 next->next->prev = next;
188 /* Initialize the nfree and first counters for this block. */
189 block = BLOCK(result);
190 mdp->heapinfo[block].type = log;
191 mdp->heapinfo[block].busy_frag.nfree = i - 1;
192 mdp->heapinfo[block].busy_frag.first = i - 1;
195 /* Large allocation to receive one or more blocks.
196 Search the free list in a circle starting at the last place visited.
197 If we loop completely around without finding a large enough
198 space we will have to get more memory from the system. */
199 blocks = BLOCKIFY(size);
200 start = block = MALLOC_SEARCH_START;
201 while (mdp->heapinfo[block].free_block.size < blocks) {
202 if (mdp->heapinfo[block].type >=0) {
203 fprintf(stderr,"Internal error: found a free block not marked as such (block=%lu type=%lu). Please report this bug.\n",(unsigned long)block,(unsigned long)mdp->heapinfo[block].type);
207 block = mdp->heapinfo[block].free_block.next;
208 if (block == start) {
209 /* Need to get more from the system. Check to see if
210 the new core will be contiguous with the final free
211 block; if so we don't need to get as much. */
212 block = mdp->heapinfo[0].free_block.prev;
213 lastblocks = mdp->heapinfo[block].free_block.size;
214 if (mdp->heaplimit != 0 &&
215 block + lastblocks == mdp->heaplimit &&
216 mmorecore(mdp, 0) == ADDRESS(block + lastblocks) &&
217 (register_morecore(mdp, (blocks - lastblocks) * BLOCKSIZE)) != NULL) {
218 /* Which block we are extending (the `final free
219 block' referred to above) might have changed, if
220 it got combined with a freed info table. */
221 block = mdp->heapinfo[0].free_block.prev;
223 mdp->heapinfo[block].free_block.size += (blocks - lastblocks);
226 result = register_morecore(mdp, blocks * BLOCKSIZE);
227 if (result == NULL) {
230 block = BLOCK(result);
231 for (it=0;it<blocks;it++)
232 mdp->heapinfo[block+it].type = 0;
233 mdp->heapinfo[block].busy_block.size = blocks;
234 mdp->heapinfo[block].busy_block.busy_size = size;
239 /* At this point we have found a suitable free list entry.
240 Figure out how to remove what we need from the list. */
241 result = ADDRESS(block);
242 if (mdp->heapinfo[block].free_block.size > blocks) {
243 /* The block we found has a bit left over,
244 so relink the tail end back into the free list. */
245 mdp->heapinfo[block + blocks].free_block.size
246 = mdp->heapinfo[block].free_block.size - blocks;
247 mdp->heapinfo[block + blocks].free_block.next
248 = mdp->heapinfo[block].free_block.next;
249 mdp->heapinfo[block + blocks].free_block.prev
250 = mdp->heapinfo[block].free_block.prev;
251 mdp->heapinfo[mdp->heapinfo[block].free_block.prev].free_block.next
252 = mdp->heapinfo[mdp->heapinfo[block].free_block.next].free_block.prev
253 = mdp->heapindex = block + blocks;
255 /* The block exactly matches our requirements,
256 so just remove it from the list. */
257 mdp->heapinfo[mdp->heapinfo[block].free_block.next].free_block.prev
258 = mdp->heapinfo[block].free_block.prev;
259 mdp->heapinfo[mdp->heapinfo[block].free_block.prev].free_block.next
260 = mdp->heapindex = mdp->heapinfo[block].free_block.next;
263 for (it=0;it<blocks;it++)
264 mdp->heapinfo[block+it].type = 0;
265 mdp->heapinfo[block].busy_block.size = blocks;
266 mdp->heapinfo[block].busy_block.busy_size = size;
268 //printf("(%s) Done mallocing. Result is %p\n",xbt_thread_self_name(),result);fflush(stdout);