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 void 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.
25 * It never returns NULL, but dies verbosely on error.
27 static void *align(struct mdesc *mdp, size_t size)
30 unsigned long int adj;
32 result = mmorecore(mdp, size);
34 /* if this reservation does not fill up the last block of our resa,
35 * complete the reservation by also asking for the full lastest block.
37 * Also, the returned block is aligned to the end of block (but I've
38 * no fucking idea of why, actually -- http://abstrusegoose.com/432 --
39 * but not doing so seems to lead to issues).
41 adj = RESIDUAL(result, BLOCKSIZE);
43 adj = BLOCKSIZE - adj;
45 result = (char *) result + adj;
50 /* Finish the initialization of the mheap. If we want to inline it
51 * properly, we need to make the align function publicly visible, too */
52 static void initialize(xbt_mheap_t mdp)
54 mdp->heapsize = HEAP / BLOCKSIZE;
55 mdp->heapinfo = (malloc_info *)
56 align(mdp, mdp->heapsize * sizeof(malloc_info));
58 memset((void *) mdp->heapinfo, 0, mdp->heapsize * sizeof(malloc_info));
59 mdp->heapinfo[0].type=-1;
60 mdp->heapinfo[0].free_block.size = 0;
61 mdp->heapinfo[0].free_block.next = mdp->heapinfo[0].free_block.prev = 0;
63 mdp->heapbase = (void *) mdp->heapinfo;
64 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); // Never returns NULL
77 /* Check if we need to grow the info table (in a multiplicative manner) */
78 if ((size_t) BLOCK((char *) result + size) > mdp->heapsize) {
81 newsize = mdp->heapsize;
82 while ((size_t) BLOCK((char *) result + size) > newsize)
85 /* Copy old info into new location */
86 oldinfo = mdp->heapinfo;
87 newinfo = (malloc_info *) align(mdp, newsize * sizeof(malloc_info));
88 memset(newinfo, 0, newsize * sizeof(malloc_info));
89 memcpy(newinfo, oldinfo, mdp->heapsize * sizeof(malloc_info));
90 mdp->heapinfo = newinfo;
92 /* mark the space previously occupied by the block info as free by first marking it
93 * as occupied in the regular way, and then freing it */
94 for (it=0; it<BLOCKIFY(mdp->heapsize * sizeof(malloc_info)); it++)
95 newinfo[BLOCK(oldinfo)+it].type = 0;
97 newinfo[BLOCK(oldinfo)].busy_block.size = BLOCKIFY(mdp->heapsize * sizeof(malloc_info));
98 newinfo[BLOCK(oldinfo)].busy_block.busy_size = size;
99 newinfo[BLOCK(oldinfo)].busy_block.bt_size = 0;// FIXME setup the backtrace
100 mfree(mdp, (void *) oldinfo);
101 mdp->heapsize = newsize;
104 mdp->heaplimit = BLOCK((char *) result + size);
108 /* Allocate memory from the heap. */
109 void *mmalloc(xbt_mheap_t mdp, size_t size) {
110 void *res= mmalloc_no_memset(mdp,size);
114 /* Spliting mmalloc this way is mandated by a trick in mrealloc, that gives
115 back the memory of big blocks to the system before reallocating them: we don't
116 want to loose the beginning of the area when this happens */
117 void *mmalloc_no_memset(xbt_mheap_t mdp, size_t size)
120 size_t block, blocks, lastblocks, start;
126 size_t requested_size = size; // The amount of memory requested by user, for real
128 /* Work even if the user was stupid enough to ask a ridicullously small block (even 0-length),
129 * ie return a valid block that can be realloced and freed.
130 * glibc malloc does not use this trick but return a constant pointer, but we need to enlist the free fragments later on.
132 if (size < SMALLEST_POSSIBLE_MALLOC)
133 size = SMALLEST_POSSIBLE_MALLOC;
135 // printf("(%s) Mallocing %d bytes on %p (default: %p)...",xbt_thread_self_name(),size,mdp,__mmalloc_default_mdp);fflush(stdout);
137 if (!(mdp->flags & MMALLOC_INITIALIZED))
140 /* Determine the allocation policy based on the request size. */
141 if (size <= BLOCKSIZE / 2) {
142 /* Small allocation to receive a fragment of a block.
143 Determine the logarithm to base two of the fragment size. */
146 while ((size /= 2) != 0) {
150 /* Look in the fragment lists for a
151 free fragment of the desired size. */
152 next = mdp->fraghead[log].next;
154 /* There are free fragments of this size.
155 Pop a fragment out of the fragment list and return it.
156 Update the block's nfree and first counters. */
158 result = (void *) next;
159 block = BLOCK(result);
161 frag_nb = RESIDUAL(result, BLOCKSIZE) >> log;
162 mdp->heapinfo[block].busy_frag.frag_size[frag_nb] = requested_size;
163 xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_frag.bt[frag_nb],XBT_BACKTRACE_SIZE);
165 next->prev->next = next->next;
166 if (next->next != NULL) {
167 next->next->prev = next->prev;
169 if (--mdp->heapinfo[block].busy_frag.nfree != 0) {
170 mdp->heapinfo[block].busy_frag.first =
171 RESIDUAL(next->next, BLOCKSIZE) >> log;
174 /* Update the statistics. */
175 mdp -> heapstats.chunks_used++;
176 mdp -> heapstats.bytes_used += 1 << log;
177 mdp -> heapstats.chunks_free--;
178 mdp -> heapstats.bytes_free -= 1 << log;
181 /* No free fragments of the desired size, so get a new block
182 and break it into fragments, returning the first. */
183 //printf("(%s) No free fragment...",xbt_thread_self_name());
185 result = mmalloc(mdp, BLOCKSIZE); // does not return NULL
187 /* Link all fragments but the first into the free list, and mark their requested size to -1. */
188 block = BLOCK(result);
189 for (i = 1; i < (size_t) (BLOCKSIZE >> log); ++i) {
190 mdp->heapinfo[block].busy_frag.frag_size[i] = -1;
191 next = (struct list *) ((char *) result + (i << log));
192 next->next = mdp->fraghead[log].next;
193 next->prev = &mdp->fraghead[log];
194 next->prev->next = next;
195 if (next->next != NULL) {
196 next->next->prev = next;
199 mdp->heapinfo[block].busy_frag.frag_size[0] = requested_size;
200 xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_frag.bt[0],XBT_BACKTRACE_SIZE);
202 /* Initialize the nfree and first counters for this block. */
203 mdp->heapinfo[block].type = log;
204 mdp->heapinfo[block].busy_frag.nfree = i - 1;
205 mdp->heapinfo[block].busy_frag.first = i - 1;
207 mdp -> heapstats.chunks_free += (BLOCKSIZE >> log) - 1;
208 mdp -> heapstats.bytes_free += BLOCKSIZE - (1 << log);
209 mdp -> heapstats.bytes_used -= BLOCKSIZE - (1 << log);
212 /* Large allocation to receive one or more blocks.
213 Search the free list in a circle starting at the last place visited.
214 If we loop completely around without finding a large enough
215 space we will have to get more memory from the system. */
216 blocks = BLOCKIFY(size);
217 start = block = MALLOC_SEARCH_START;
218 while (mdp->heapinfo[block].free_block.size < blocks) {
219 if (mdp->heapinfo[block].type >=0) { // Don't trust xbt_die and friends in malloc-level library, you fool!
220 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);
224 block = mdp->heapinfo[block].free_block.next;
225 if (block == start) {
226 /* Need to get more from the system. Check to see if
227 the new core will be contiguous with the final free
228 block; if so we don't need to get as much. */
229 block = mdp->heapinfo[0].free_block.prev;
230 lastblocks = mdp->heapinfo[block].free_block.size;
231 if (mdp->heaplimit != 0 &&
232 block + lastblocks == mdp->heaplimit &&
233 mmorecore(mdp, 0) == ADDRESS(block + lastblocks) &&
234 (register_morecore(mdp, (blocks - lastblocks) * BLOCKSIZE)) != NULL) {
235 /* Which block we are extending (the `final free
236 block' referred to above) might have changed, if
237 it got combined with a freed info table. */
238 block = mdp->heapinfo[0].free_block.prev;
240 mdp->heapinfo[block].free_block.size += (blocks - lastblocks);
243 result = register_morecore(mdp, blocks * BLOCKSIZE);
245 block = BLOCK(result);
246 for (it=0;it<blocks;it++){
247 mdp->heapinfo[block+it].type = 0;
249 mdp->heapinfo[block].busy_block.size = blocks;
250 mdp->heapinfo[block].busy_block.busy_size = requested_size;
251 mdp->heapinfo[block].busy_block.bt_size=xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
252 mdp -> heapstats.chunks_used++;
253 mdp -> heapstats.bytes_used += blocks * BLOCKSIZE;
256 /* Need large block(s), but found some in the existing heap */
259 /* At this point we have found a suitable free list entry.
260 Figure out how to remove what we need from the list. */
261 result = ADDRESS(block);
262 if (mdp->heapinfo[block].free_block.size > blocks) {
263 /* The block we found has a bit left over,
264 so relink the tail end back into the free list. */
265 mdp->heapinfo[block + blocks].free_block.size
266 = mdp->heapinfo[block].free_block.size - blocks;
267 mdp->heapinfo[block + blocks].free_block.next
268 = mdp->heapinfo[block].free_block.next;
269 mdp->heapinfo[block + blocks].free_block.prev
270 = mdp->heapinfo[block].free_block.prev;
271 mdp->heapinfo[mdp->heapinfo[block].free_block.prev].free_block.next
272 = mdp->heapinfo[mdp->heapinfo[block].free_block.next].free_block.prev
273 = mdp->heapindex = block + blocks;
275 /* The block exactly matches our requirements,
276 so just remove it from the list. */
277 mdp->heapinfo[mdp->heapinfo[block].free_block.next].free_block.prev
278 = mdp->heapinfo[block].free_block.prev;
279 mdp->heapinfo[mdp->heapinfo[block].free_block.prev].free_block.next
280 = mdp->heapindex = mdp->heapinfo[block].free_block.next;
283 for (it=0;it<blocks;it++){
284 mdp->heapinfo[block+it].type = 0;
286 mdp->heapinfo[block].busy_block.size = blocks;
287 mdp->heapinfo[block].busy_block.busy_size = requested_size;
288 //mdp->heapinfo[block].busy_block.bt_size = 0;
289 mdp->heapinfo[block].busy_block.bt_size = xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
291 mdp -> heapstats.chunks_used++;
292 mdp -> heapstats.bytes_used += blocks * BLOCKSIZE;
293 mdp -> heapstats.bytes_free -= blocks * BLOCKSIZE;
296 //printf("(%s) Done mallocing. Result is %p\n",xbt_thread_self_name(),result);fflush(stdout);