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) 2010-2013. 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 latest 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)
55 malloc_info mi; /* to compute the offset of the swag hook */
57 mdp->heapsize = HEAP / BLOCKSIZE;
58 mdp->heapinfo = (malloc_info *)
59 align(mdp, mdp->heapsize * sizeof(malloc_info));
61 memset((void *) mdp->heapinfo, 0, mdp->heapsize * sizeof(malloc_info));
62 mdp->heapinfo[0].type=-1;
63 mdp->heapinfo[0].free_block.size = 0;
64 mdp->heapinfo[0].free_block.next = mdp->heapinfo[0].free_block.prev = 0;
66 mdp->heapbase = (void *) mdp->heapinfo;
67 mdp->flags |= MMALLOC_INITIALIZED;
69 for (i=0;i<BLOCKLOG;i++) {
70 xbt_swag_init(&(mdp->fraghead[i]),
71 xbt_swag_offset(mi, freehook));
75 #define update_hook(a,offset) do { if (a) { a = ((char*)a +(offset));} }while(0)
77 /* Get neatly aligned memory from the low level layers, and register it
78 * into the heap info table as necessary. */
79 static void *register_morecore(struct mdesc *mdp, size_t size)
83 malloc_info *newinfo, *oldinfo;
86 result = align(mdp, size); // Never returns NULL
88 /* Check if we need to grow the info table (in a multiplicative manner) */
89 if ((size_t) BLOCK((char *) result + size) > mdp->heapsize) {
92 newsize = mdp->heapsize;
93 while ((size_t) BLOCK((char *) result + size) > newsize)
96 /* Copy old info into new location */
97 oldinfo = mdp->heapinfo;
98 newinfo = (malloc_info *) align(mdp, newsize * sizeof(malloc_info));
99 memset(newinfo, 0, newsize * sizeof(malloc_info));
100 memcpy(newinfo, oldinfo, mdp->heapsize * sizeof(malloc_info));
102 /* Update the swag of busy blocks containing free fragments by applying the offset to all swag_hooks. Yeah. My hand is right in the fan and I still type */
103 size_t offset=((char*)newinfo)-((char*)oldinfo);
105 for (i=1/*first element of heapinfo describes the mdesc area*/;
108 update_hook(newinfo[i].freehook.next,offset);
109 update_hook(newinfo[i].freehook.prev,offset);
111 // also update the starting points of the swag
112 for (i=0;i<BLOCKLOG;i++) {
113 update_hook(mdp->fraghead[i].head,offset);
114 update_hook(mdp->fraghead[i].tail,offset);
116 mdp->heapinfo = newinfo;
118 /* mark the space previously occupied by the block info as free by first marking it
119 * as occupied in the regular way, and then freing it */
120 for (it=0; it<BLOCKIFY(mdp->heapsize * sizeof(malloc_info)); it++){
121 newinfo[BLOCK(oldinfo)+it].type = 0;
122 newinfo[BLOCK(oldinfo)+it].busy_block.ignore = 0;
125 newinfo[BLOCK(oldinfo)].busy_block.size = BLOCKIFY(mdp->heapsize * sizeof(malloc_info));
126 newinfo[BLOCK(oldinfo)].busy_block.busy_size = size;
127 mfree(mdp, (void *) oldinfo);
128 mdp->heapsize = newsize;
131 mdp->heaplimit = BLOCK((char *) result + size);
136 /* Allocate memory from the heap. */
137 void *mmalloc(xbt_mheap_t mdp, size_t size) {
138 void *res= mmalloc_no_memset(mdp,size);
139 // fprintf(stderr,"malloc(%zu)~>%p\n",size,res);
143 /* Spliting mmalloc this way is mandated by a trick in mrealloc, that gives
144 back the memory of big blocks to the system before reallocating them: we don't
145 want to loose the beginning of the area when this happens */
146 void *mmalloc_no_memset(xbt_mheap_t mdp, size_t size)
149 size_t block, blocks, lastblocks, start;
154 size_t requested_size = size; // The amount of memory requested by user, for real
156 /* Work even if the user was stupid enough to ask a ridicullously small block (even 0-length),
157 * ie return a valid block that can be realloced and freed.
158 * glibc malloc does not use this trick but return a constant pointer, but we need to enlist the free fragments later on.
160 if (size < SMALLEST_POSSIBLE_MALLOC)
161 size = SMALLEST_POSSIBLE_MALLOC;
163 // printf("(%s) Mallocing %d bytes on %p (default: %p)...",xbt_thread_self_name(),size,mdp,__mmalloc_default_mdp);fflush(stdout);
165 if (!(mdp->flags & MMALLOC_INITIALIZED))
168 mmalloc_paranoia(mdp);
170 /* Determine the allocation policy based on the request size. */
171 if (size <= BLOCKSIZE / 2) {
172 /* Small allocation to receive a fragment of a block.
173 Determine the logarithm to base two of the fragment size. */
176 while ((size /= 2) != 0) {
180 /* Look in the fragment lists for a free fragment of the desired size. */
181 if (xbt_swag_size(&mdp->fraghead[log])>0) {
182 /* There are free fragments of this size; Get one of them and prepare to return it.
183 Update the block's nfree and if no other free fragment, get out of the swag. */
185 /* search a fragment that I could return as a result */
186 malloc_info *candidate_info = xbt_swag_getFirst(&mdp->fraghead[log]);
187 size_t candidate_block = (candidate_info - &(mdp->heapinfo[0]));
188 size_t candidate_frag;
189 for (candidate_frag=0;candidate_frag<(size_t) (BLOCKSIZE >> log);candidate_frag++)
190 if (candidate_info->busy_frag.frag_size[candidate_frag] == -1)
192 xbt_assert(candidate_frag < (size_t) (BLOCKSIZE >> log),
193 "Block %zu was registered as containing free fragments of type %zu, but I can't find any",candidate_block,log);
195 result = (void*) (((char*)ADDRESS(candidate_block)) + (candidate_frag << log));
197 /* Remove this fragment from the list of free guys */
198 candidate_info->busy_frag.nfree--;
199 if (candidate_info->busy_frag.nfree == 0) {
200 xbt_swag_remove(candidate_info,&mdp->fraghead[log]);
203 /* Update our metadata about this fragment */
204 candidate_info->busy_frag.frag_size[candidate_frag] = requested_size;
205 candidate_info->busy_frag.ignore[candidate_frag] = 0;
206 //xbt_backtrace_no_malloc(candidate_info->busy_frag.bt[candidate_frag],XBT_BACKTRACE_SIZE);
207 //xbt_libunwind_backtrace(candidate_info->busy_frag.bt[candidate_frag],XBT_BACKTRACE_SIZE);
209 /* Update the statistics. */
210 mdp -> heapstats.chunks_used++;
211 mdp -> heapstats.bytes_used += 1 << log;
212 mdp -> heapstats.chunks_free--;
213 mdp -> heapstats.bytes_free -= 1 << log;
216 /* No free fragments of the desired size, so get a new block
217 and break it into fragments, returning the first. */
219 result = mmalloc(mdp, BLOCKSIZE); // does not return NULL
220 block = BLOCK(result);
222 mdp->heapinfo[block].type = log;
223 /* Link all fragments but the first as free, and add the block to the swag of blocks containing free frags */
224 for (i = 1; i < (size_t) (BLOCKSIZE >> log); ++i) {
225 mdp->heapinfo[block].busy_frag.frag_size[i] = -1;
226 mdp->heapinfo[block].busy_frag.ignore[i] = 0;
228 mdp->heapinfo[block].busy_frag.nfree = i - 1;
229 mdp->heapinfo[block].freehook.prev = NULL;
230 mdp->heapinfo[block].freehook.next = NULL;
232 xbt_swag_insert(&mdp->heapinfo[block], &(mdp->fraghead[log]));
234 /* mark the fragment returned as busy */
235 mdp->heapinfo[block].busy_frag.frag_size[0] = requested_size;
236 mdp->heapinfo[block].busy_frag.ignore[0] = 0;
237 //xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_frag.bt[0],XBT_BACKTRACE_SIZE);
238 //xbt_libunwind_backtrace(mdp->heapinfo[block].busy_frag.bt[0],XBT_BACKTRACE_SIZE);
241 mdp -> heapstats.chunks_free += (BLOCKSIZE >> log) - 1;
242 mdp -> heapstats.bytes_free += BLOCKSIZE - (1 << log);
243 mdp -> heapstats.bytes_used -= BLOCKSIZE - (1 << log);
246 /* Large allocation to receive one or more blocks.
247 Search the free list in a circle starting at the last place visited.
248 If we loop completely around without finding a large enough
249 space we will have to get more memory from the system. */
250 blocks = BLOCKIFY(size);
251 start = block = MALLOC_SEARCH_START;
252 while (mdp->heapinfo[block].free_block.size < blocks) {
253 if (mdp->heapinfo[block].type >=0) { // Don't trust xbt_die and friends in malloc-level library, you fool!
254 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);
258 block = mdp->heapinfo[block].free_block.next;
259 if (block == start) {
260 /* Need to get more from the system. Check to see if
261 the new core will be contiguous with the final free
262 block; if so we don't need to get as much. */
263 block = mdp->heapinfo[0].free_block.prev;
264 lastblocks = mdp->heapinfo[block].free_block.size;
265 if (mdp->heaplimit != 0 &&
266 block + lastblocks == mdp->heaplimit &&
267 mmorecore(mdp, 0) == ADDRESS(block + lastblocks) &&
268 (register_morecore(mdp, (blocks - lastblocks) * BLOCKSIZE)) != NULL) {
269 /* Which block we are extending (the `final free
270 block' referred to above) might have changed, if
271 it got combined with a freed info table. */
272 block = mdp->heapinfo[0].free_block.prev;
274 mdp->heapinfo[block].free_block.size += (blocks - lastblocks);
277 result = register_morecore(mdp, blocks * BLOCKSIZE);
279 block = BLOCK(result);
280 for (it=0;it<blocks;it++){
281 mdp->heapinfo[block+it].type = 0;
282 mdp->heapinfo[block+it].busy_block.busy_size = 0;
283 mdp->heapinfo[block+it].busy_block.ignore = 0;
285 mdp->heapinfo[block].busy_block.size = blocks;
286 mdp->heapinfo[block].busy_block.busy_size = requested_size;
287 //mdp->heapinfo[block].busy_block.bt_size=xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
288 //mdp->heapinfo[block].busy_block.bt_size = xbt_libunwind_backtrace(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
289 mdp -> heapstats.chunks_used++;
290 mdp -> heapstats.bytes_used += blocks * BLOCKSIZE;
294 /* Need large block(s), but found some in the existing heap */
297 /* At this point we have found a suitable free list entry.
298 Figure out how to remove what we need from the list. */
299 result = ADDRESS(block);
300 if (mdp->heapinfo[block].free_block.size > blocks) {
301 /* The block we found has a bit left over,
302 so relink the tail end back into the free list. */
303 mdp->heapinfo[block + blocks].free_block.size
304 = mdp->heapinfo[block].free_block.size - blocks;
305 mdp->heapinfo[block + blocks].free_block.next
306 = mdp->heapinfo[block].free_block.next;
307 mdp->heapinfo[block + blocks].free_block.prev
308 = mdp->heapinfo[block].free_block.prev;
309 mdp->heapinfo[mdp->heapinfo[block].free_block.prev].free_block.next
310 = mdp->heapinfo[mdp->heapinfo[block].free_block.next].free_block.prev
311 = mdp->heapindex = block + blocks;
313 /* The block exactly matches our requirements,
314 so just remove it from the list. */
315 mdp->heapinfo[mdp->heapinfo[block].free_block.next].free_block.prev
316 = mdp->heapinfo[block].free_block.prev;
317 mdp->heapinfo[mdp->heapinfo[block].free_block.prev].free_block.next
318 = mdp->heapindex = mdp->heapinfo[block].free_block.next;
321 for (it=0;it<blocks;it++){
322 mdp->heapinfo[block+it].type = 0;
323 mdp->heapinfo[block+it].busy_block.busy_size = 0;
324 mdp->heapinfo[block+it].busy_block.ignore = 0;
326 mdp->heapinfo[block].busy_block.size = blocks;
327 mdp->heapinfo[block].busy_block.busy_size = requested_size;
328 //mdp->heapinfo[block].busy_block.bt_size = xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
329 //mdp->heapinfo[block].busy_block.bt_size = xbt_libunwind_backtrace(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
331 mdp -> heapstats.chunks_used++;
332 mdp -> heapstats.bytes_used += blocks * BLOCKSIZE;
333 mdp -> heapstats.bytes_free -= blocks * BLOCKSIZE;
336 //printf("(%s) Done mallocing. Result is %p\n",xbt_thread_self_name(),result);fflush(stdout);