1 /* Memory allocator `malloc'. */
3 /* Copyright (c) 2010-2014. The SimGrid Team.
4 * All rights reserved. */
6 /* This program is free software; you can redistribute it and/or modify it
7 * under the terms of the license (GNU LGPL) which comes with this package. */
9 /* Copyright 1990, 1991, 1992 Free Software Foundation
11 Written May 1989 by Mike Haertel.
12 Heavily modified Mar 1992 by Fred Fish for mmap'd version. */
14 #include <string.h> /* Prototypes for memcpy, memmove, memset, etc */
16 #include "mmprivate.h"
18 /* Prototypes for local functions */
20 static void initialize(xbt_mheap_t mdp);
21 static void *register_morecore(xbt_mheap_t mdp, size_t size);
22 static void *align(xbt_mheap_t mdp, size_t size);
24 /* Allocation aligned on block boundary.
26 * It never returns NULL, but dies verbosely on error.
28 static void *align(struct mdesc *mdp, size_t size)
31 unsigned long int adj;
33 result = mmorecore(mdp, size);
35 /* if this reservation does not fill up the last block of our resa,
36 * complete the reservation by also asking for the full latest block.
38 * Also, the returned block is aligned to the end of block (but I've
39 * no fucking idea of why, actually -- http://abstrusegoose.com/432 --
40 * but not doing so seems to lead to issues).
42 adj = RESIDUAL(result, BLOCKSIZE);
44 adj = BLOCKSIZE - adj;
46 result = (char *) result + adj;
51 /* Finish the initialization of the mheap. If we want to inline it
52 * properly, we need to make the align function publicly visible, too */
53 static void initialize(xbt_mheap_t mdp)
56 malloc_info mi; /* to compute the offset of the swag hook */
58 mdp->heapsize = HEAP / BLOCKSIZE;
59 mdp->heapinfo = (malloc_info *)
60 align(mdp, mdp->heapsize * sizeof(malloc_info));
62 memset((void *) mdp->heapinfo, 0, mdp->heapsize * sizeof(malloc_info));
63 mdp->heapinfo[0].type=-1;
64 mdp->heapinfo[0].free_block.size = 0;
65 mdp->heapinfo[0].free_block.next = mdp->heapinfo[0].free_block.prev = 0;
67 mdp->heapbase = (void *) mdp->heapinfo;
68 mdp->flags |= MMALLOC_INITIALIZED;
70 for (i=0;i<BLOCKLOG;i++) {
71 xbt_swag_init(&(mdp->fraghead[i]),
72 xbt_swag_offset(mi, freehook));
76 #define update_hook(a,offset) do { if (a) { a = ((char*)a +(offset));} }while(0)
78 /* Get neatly aligned memory from the low level layers, and register it
79 * into the heap info table as necessary. */
80 static void *register_morecore(struct mdesc *mdp, size_t size)
84 malloc_info *newinfo, *oldinfo;
87 result = align(mdp, size); // Never returns NULL
89 /* Check if we need to grow the info table (in a multiplicative manner) */
90 if ((size_t) BLOCK((char *) result + size) > mdp->heapsize) {
93 newsize = mdp->heapsize;
94 while ((size_t) BLOCK((char *) result + size) > newsize)
97 /* Copy old info into new location */
98 oldinfo = mdp->heapinfo;
99 newinfo = (malloc_info *) align(mdp, newsize * sizeof(malloc_info));
100 memset(newinfo, 0, newsize * sizeof(malloc_info));
101 memcpy(newinfo, oldinfo, mdp->heapsize * sizeof(malloc_info));
103 /* 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 */
104 size_t offset=((char*)newinfo)-((char*)oldinfo);
106 for (i=1/*first element of heapinfo describes the mdesc area*/;
109 update_hook(newinfo[i].freehook.next,offset);
110 update_hook(newinfo[i].freehook.prev,offset);
112 // also update the starting points of the swag
113 for (i=0;i<BLOCKLOG;i++) {
114 update_hook(mdp->fraghead[i].head,offset);
115 update_hook(mdp->fraghead[i].tail,offset);
117 mdp->heapinfo = newinfo;
119 /* mark the space previously occupied by the block info as free by first marking it
120 * as occupied in the regular way, and then freing it */
121 for (it=0; it<BLOCKIFY(mdp->heapsize * sizeof(malloc_info)); it++){
122 newinfo[BLOCK(oldinfo)+it].type = 0;
123 newinfo[BLOCK(oldinfo)+it].busy_block.ignore = 0;
126 newinfo[BLOCK(oldinfo)].busy_block.size = BLOCKIFY(mdp->heapsize * sizeof(malloc_info));
127 newinfo[BLOCK(oldinfo)].busy_block.busy_size = size;
128 mfree(mdp, (void *) oldinfo);
129 mdp->heapsize = newsize;
132 mdp->heaplimit = BLOCK((char *) result + size);
137 /* Allocate memory from the heap. */
138 void *mmalloc(xbt_mheap_t mdp, size_t size) {
139 void *res= mmalloc_no_memset(mdp,size);
140 if (mdp->options & XBT_MHEAP_OPTION_MEMSET) {
145 /* Spliting mmalloc this way is mandated by a trick in mrealloc, that gives
146 back the memory of big blocks to the system before reallocating them: we don't
147 want to loose the beginning of the area when this happens */
148 void *mmalloc_no_memset(xbt_mheap_t mdp, size_t size)
151 size_t block, blocks, lastblocks, start;
156 size_t requested_size = size; // The amount of memory requested by user, for real
158 /* Work even if the user was stupid enough to ask a ridicullously small block (even 0-length),
159 * ie return a valid block that can be realloced and freed.
160 * glibc malloc does not use this trick but return a constant pointer, but we need to enlist the free fragments later on.
162 if (size < SMALLEST_POSSIBLE_MALLOC)
163 size = SMALLEST_POSSIBLE_MALLOC;
165 // printf("(%s) Mallocing %d bytes on %p (default: %p)...",xbt_thread_self_name(),size,mdp,__mmalloc_default_mdp);fflush(stdout);
167 if (!(mdp->flags & MMALLOC_INITIALIZED))
170 mmalloc_paranoia(mdp);
172 /* Determine the allocation policy based on the request size. */
173 if (size <= BLOCKSIZE / 2) {
174 /* Small allocation to receive a fragment of a block.
175 Determine the logarithm to base two of the fragment size. */
178 while ((size /= 2) != 0) {
182 /* Look in the fragment lists for a free fragment of the desired size. */
183 if (xbt_swag_size(&mdp->fraghead[log])>0) {
184 /* There are free fragments of this size; Get one of them and prepare to return it.
185 Update the block's nfree and if no other free fragment, get out of the swag. */
187 /* search a fragment that I could return as a result */
188 malloc_info *candidate_info = xbt_swag_getFirst(&mdp->fraghead[log]);
189 size_t candidate_block = (candidate_info - &(mdp->heapinfo[0]));
190 size_t candidate_frag;
191 for (candidate_frag=0;candidate_frag<(size_t) (BLOCKSIZE >> log);candidate_frag++)
192 if (candidate_info->busy_frag.frag_size[candidate_frag] == -1)
194 xbt_assert(candidate_frag < (size_t) (BLOCKSIZE >> log),
195 "Block %zu was registered as containing free fragments of type %zu, but I can't find any",candidate_block,log);
197 result = (void*) (((char*)ADDRESS(candidate_block)) + (candidate_frag << log));
199 /* Remove this fragment from the list of free guys */
200 candidate_info->busy_frag.nfree--;
201 if (candidate_info->busy_frag.nfree == 0) {
202 xbt_swag_remove(candidate_info,&mdp->fraghead[log]);
205 /* Update our metadata about this fragment */
206 candidate_info->busy_frag.frag_size[candidate_frag] = requested_size;
207 candidate_info->busy_frag.ignore[candidate_frag] = 0;
208 //xbt_backtrace_no_malloc(candidate_info->busy_frag.bt[candidate_frag],XBT_BACKTRACE_SIZE);
209 //xbt_libunwind_backtrace(candidate_info->busy_frag.bt[candidate_frag],XBT_BACKTRACE_SIZE);
211 /* Update the statistics. */
212 mdp -> heapstats.chunks_used++;
213 mdp -> heapstats.bytes_used += 1 << log;
214 mdp -> heapstats.chunks_free--;
215 mdp -> heapstats.bytes_free -= 1 << log;
218 /* No free fragments of the desired size, so get a new block
219 and break it into fragments, returning the first. */
221 result = mmalloc(mdp, BLOCKSIZE); // does not return NULL
222 block = BLOCK(result);
224 mdp->heapinfo[block].type = log;
225 /* Link all fragments but the first as free, and add the block to the swag of blocks containing free frags */
226 for (i = 1; i < (size_t) (BLOCKSIZE >> log); ++i) {
227 mdp->heapinfo[block].busy_frag.frag_size[i] = -1;
228 mdp->heapinfo[block].busy_frag.ignore[i] = 0;
230 mdp->heapinfo[block].busy_frag.nfree = i - 1;
231 mdp->heapinfo[block].freehook.prev = NULL;
232 mdp->heapinfo[block].freehook.next = NULL;
234 xbt_swag_insert(&mdp->heapinfo[block], &(mdp->fraghead[log]));
236 /* mark the fragment returned as busy */
237 mdp->heapinfo[block].busy_frag.frag_size[0] = requested_size;
238 mdp->heapinfo[block].busy_frag.ignore[0] = 0;
239 //xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_frag.bt[0],XBT_BACKTRACE_SIZE);
240 //xbt_libunwind_backtrace(mdp->heapinfo[block].busy_frag.bt[0],XBT_BACKTRACE_SIZE);
243 mdp -> heapstats.chunks_free += (BLOCKSIZE >> log) - 1;
244 mdp -> heapstats.bytes_free += BLOCKSIZE - (1 << log);
245 mdp -> heapstats.bytes_used -= BLOCKSIZE - (1 << log);
248 /* Large allocation to receive one or more blocks.
249 Search the free list in a circle starting at the last place visited.
250 If we loop completely around without finding a large enough
251 space we will have to get more memory from the system. */
252 blocks = BLOCKIFY(size);
253 start = block = MALLOC_SEARCH_START;
254 while (mdp->heapinfo[block].free_block.size < blocks) {
255 if (mdp->heapinfo[block].type >=0) { // Don't trust xbt_die and friends in malloc-level library, you fool!
256 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);
260 block = mdp->heapinfo[block].free_block.next;
261 if (block == start) {
262 /* Need to get more from the system. Check to see if
263 the new core will be contiguous with the final free
264 block; if so we don't need to get as much. */
265 block = mdp->heapinfo[0].free_block.prev;
266 lastblocks = mdp->heapinfo[block].free_block.size;
267 if (mdp->heaplimit != 0 &&
268 block + lastblocks == mdp->heaplimit &&
269 mmorecore(mdp, 0) == ADDRESS(block + lastblocks) &&
270 (register_morecore(mdp, (blocks - lastblocks) * BLOCKSIZE)) != NULL) {
271 /* Which block we are extending (the `final free
272 block' referred to above) might have changed, if
273 it got combined with a freed info table. */
274 block = mdp->heapinfo[0].free_block.prev;
276 mdp->heapinfo[block].free_block.size += (blocks - lastblocks);
279 result = register_morecore(mdp, blocks * BLOCKSIZE);
281 block = BLOCK(result);
282 for (it=0;it<blocks;it++){
283 mdp->heapinfo[block+it].type = 0;
284 mdp->heapinfo[block+it].busy_block.busy_size = 0;
285 mdp->heapinfo[block+it].busy_block.ignore = 0;
287 mdp->heapinfo[block].busy_block.size = blocks;
288 mdp->heapinfo[block].busy_block.busy_size = requested_size;
289 //mdp->heapinfo[block].busy_block.bt_size=xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
290 //mdp->heapinfo[block].busy_block.bt_size = xbt_libunwind_backtrace(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
291 mdp -> heapstats.chunks_used++;
292 mdp -> heapstats.bytes_used += blocks * BLOCKSIZE;
296 /* Need large block(s), but found some in the existing heap */
299 /* At this point we have found a suitable free list entry.
300 Figure out how to remove what we need from the list. */
301 result = ADDRESS(block);
302 if (mdp->heapinfo[block].free_block.size > blocks) {
303 /* The block we found has a bit left over,
304 so relink the tail end back into the free list. */
305 mdp->heapinfo[block + blocks].free_block.size
306 = mdp->heapinfo[block].free_block.size - blocks;
307 mdp->heapinfo[block + blocks].free_block.next
308 = mdp->heapinfo[block].free_block.next;
309 mdp->heapinfo[block + blocks].free_block.prev
310 = mdp->heapinfo[block].free_block.prev;
311 mdp->heapinfo[mdp->heapinfo[block].free_block.prev].free_block.next
312 = mdp->heapinfo[mdp->heapinfo[block].free_block.next].free_block.prev
313 = mdp->heapindex = block + blocks;
315 /* The block exactly matches our requirements,
316 so just remove it from the list. */
317 mdp->heapinfo[mdp->heapinfo[block].free_block.next].free_block.prev
318 = mdp->heapinfo[block].free_block.prev;
319 mdp->heapinfo[mdp->heapinfo[block].free_block.prev].free_block.next
320 = mdp->heapindex = mdp->heapinfo[block].free_block.next;
323 for (it=0;it<blocks;it++){
324 mdp->heapinfo[block+it].type = 0;
325 mdp->heapinfo[block+it].busy_block.busy_size = 0;
326 mdp->heapinfo[block+it].busy_block.ignore = 0;
328 mdp->heapinfo[block].busy_block.size = blocks;
329 mdp->heapinfo[block].busy_block.busy_size = requested_size;
330 //mdp->heapinfo[block].busy_block.bt_size = xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
331 //mdp->heapinfo[block].busy_block.bt_size = xbt_libunwind_backtrace(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
333 mdp -> heapstats.chunks_used++;
334 mdp -> heapstats.bytes_used += blocks * BLOCKSIZE;
335 mdp -> heapstats.bytes_free -= blocks * BLOCKSIZE;
338 //printf("(%s) Done mallocing. Result is %p\n",xbt_thread_self_name(),result);fflush(stdout);