1 /* Memory allocator `malloc'. */
3 /* Copyright (c) 2010-2015. 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 /** Initialise heapinfo about the heapinfo pages :)
54 static void initialize_heapinfo_heapinfo(xbt_mheap_t mdp)
56 // Update heapinfo about the heapinfo pages (!):
57 xbt_assert((uintptr_t) mdp->heapinfo % BLOCKSIZE == 0);
58 int block = BLOCK(mdp->heapinfo);
59 size_t nblocks = mdp->heapsize * sizeof(malloc_info) / BLOCKSIZE;
61 for (size_t j=0; j!=nblocks; ++j) {
62 mdp->heapinfo[block+j].type = MMALLOC_TYPE_FREE;
63 mdp->heapinfo[block+j].free_block.size = 0;
64 mdp->heapinfo[block+j].free_block.next = 0;
65 mdp->heapinfo[block+j].free_block.prev = 0;
67 mdp->heapinfo[block].free_block.size = nblocks;
70 /* Finish the initialization of the mheap. If we want to inline it
71 * properly, we need to make the align function publicly visible, too */
72 static void initialize(xbt_mheap_t mdp)
75 malloc_info mi; /* to compute the offset of the swag hook */
77 // Update mdp meta-data:
78 mdp->heapsize = HEAP / BLOCKSIZE;
79 mdp->heapinfo = (malloc_info *)
80 align(mdp, mdp->heapsize * sizeof(malloc_info));
81 mdp->heapbase = (void *) mdp->heapinfo;
82 mdp->flags |= MMALLOC_INITIALIZED;
84 // Update root heapinfo:
85 memset((void *) mdp->heapinfo, 0, mdp->heapsize * sizeof(malloc_info));
86 mdp->heapinfo[0].type = MMALLOC_TYPE_FREE;
87 mdp->heapinfo[0].free_block.size = 0;
88 mdp->heapinfo[0].free_block.next = mdp->heapinfo[0].free_block.prev = 0;
91 initialize_heapinfo_heapinfo(mdp);
93 for (i=0;i<BLOCKLOG;i++) {
94 xbt_swag_init(&(mdp->fraghead[i]),
95 xbt_swag_offset(mi, freehook));
99 #define update_hook(a,offset) do { if (a) { a = ((char*)a +(offset));} }while(0)
101 /* Get neatly aligned memory from the low level layers, and register it
102 * into the heap info table as necessary. */
103 static void *register_morecore(struct mdesc *mdp, size_t size)
105 void* result = align(mdp, size); // Never returns NULL
107 /* Check if we need to grow the info table (in a multiplicative manner) */
108 if ((size_t) BLOCK((char *) result + size) > mdp->heapsize) {
111 size_t newsize = mdp->heapsize;
112 while ((size_t) BLOCK((char *) result + size) > newsize)
115 /* Copy old info into new location */
116 malloc_info* oldinfo = mdp->heapinfo;
117 malloc_info* newinfo = (malloc_info*)align(mdp, newsize * sizeof(malloc_info));
118 memcpy(newinfo, oldinfo, mdp->heapsize * sizeof(malloc_info));
120 /* Initialise the new blockinfo : */
121 memset((char*) newinfo + mdp->heapsize * sizeof(malloc_info), 0,
122 (newsize - mdp->heapsize)* sizeof(malloc_info));
124 /* 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 */
125 size_t offset=((char*)newinfo)-((char*)oldinfo);
127 for (int i = 1 /*first element of heapinfo describes the mdesc area*/; i < mdp->heaplimit; i++) {
128 update_hook(newinfo[i].freehook.next,offset);
129 update_hook(newinfo[i].freehook.prev,offset);
131 // also update the starting points of the swag
132 for (int i = 0; i < BLOCKLOG; i++) {
133 update_hook(mdp->fraghead[i].head,offset);
134 update_hook(mdp->fraghead[i].tail,offset);
136 mdp->heapinfo = newinfo;
138 /* mark the space previously occupied by the block info as free by first marking it
139 * as occupied in the regular way, and then freing it */
140 for (it=0; it<BLOCKIFY(mdp->heapsize * sizeof(malloc_info)); it++){
141 newinfo[BLOCK(oldinfo)+it].type = MMALLOC_TYPE_UNFRAGMENTED;
142 newinfo[BLOCK(oldinfo)+it].busy_block.ignore = 0;
145 newinfo[BLOCK(oldinfo)].busy_block.size = BLOCKIFY(mdp->heapsize * sizeof(malloc_info));
146 newinfo[BLOCK(oldinfo)].busy_block.busy_size = size;
147 mfree(mdp, (void *) oldinfo);
148 mdp->heapsize = newsize;
150 initialize_heapinfo_heapinfo(mdp);
153 mdp->heaplimit = BLOCK((char *) result + size);
158 /* Allocate memory from the heap. */
159 void *mmalloc(xbt_mheap_t mdp, size_t size) {
160 void *res= mmalloc_no_memset(mdp,size);
161 if (mdp->options & XBT_MHEAP_OPTION_MEMSET) {
166 /* Spliting mmalloc this way is mandated by a trick in mrealloc, that gives
167 back the memory of big blocks to the system before reallocating them: we don't
168 want to loose the beginning of the area when this happens */
169 void *mmalloc_no_memset(xbt_mheap_t mdp, size_t size)
180 size_t requested_size = size; // The amount of memory requested by user, for real
182 /* Work even if the user was stupid enough to ask a ridiculously small block (even 0-length),
183 * ie return a valid block that can be realloced and freed.
184 * glibc malloc does not use this trick but return a constant pointer, but we need to enlist the free fragments later on.
186 if (size < SMALLEST_POSSIBLE_MALLOC)
187 size = SMALLEST_POSSIBLE_MALLOC;
189 // printf("(%s) Mallocing %d bytes on %p (default: %p)...",xbt_thread_self_name(),size,mdp,__mmalloc_default_mdp);fflush(stdout);
191 if (!(mdp->flags & MMALLOC_INITIALIZED))
194 mmalloc_paranoia(mdp);
196 /* Determine the allocation policy based on the request size. */
197 if (size <= BLOCKSIZE / 2) {
198 /* Small allocation to receive a fragment of a block.
199 Determine the logarithm to base two of the fragment size. */
202 while ((size /= 2) != 0) {
206 /* Look in the fragment lists for a free fragment of the desired size. */
207 if (xbt_swag_size(&mdp->fraghead[log])>0) {
208 /* There are free fragments of this size; Get one of them and prepare to return it.
209 Update the block's nfree and if no other free fragment, get out of the swag. */
211 /* search a fragment that I could return as a result */
212 malloc_info *candidate_info = xbt_swag_getFirst(&mdp->fraghead[log]);
213 size_t candidate_block = (candidate_info - &(mdp->heapinfo[0]));
214 size_t candidate_frag;
215 for (candidate_frag=0;candidate_frag<(size_t) (BLOCKSIZE >> log);candidate_frag++)
216 if (candidate_info->busy_frag.frag_size[candidate_frag] == -1)
218 xbt_assert(candidate_frag < (size_t) (BLOCKSIZE >> log),
219 "Block %zu was registered as containing free fragments of type %zu, but I can't find any",candidate_block,log);
221 result = (void*) (((char*)ADDRESS(candidate_block)) + (candidate_frag << log));
223 /* Remove this fragment from the list of free guys */
224 candidate_info->busy_frag.nfree--;
225 if (candidate_info->busy_frag.nfree == 0) {
226 xbt_swag_remove(candidate_info,&mdp->fraghead[log]);
229 /* Update our metadata about this fragment */
230 candidate_info->busy_frag.frag_size[candidate_frag] = requested_size;
231 candidate_info->busy_frag.ignore[candidate_frag] = 0;
232 //xbt_backtrace_no_malloc(candidate_info->busy_frag.bt[candidate_frag],XBT_BACKTRACE_SIZE);
233 //xbt_libunwind_backtrace(candidate_info->busy_frag.bt[candidate_frag],XBT_BACKTRACE_SIZE);
235 /* Update the statistics. */
236 mdp -> heapstats.chunks_used++;
237 mdp -> heapstats.bytes_used += 1 << log;
238 mdp -> heapstats.chunks_free--;
239 mdp -> heapstats.bytes_free -= 1 << log;
242 /* No free fragments of the desired size, so get a new block
243 and break it into fragments, returning the first. */
245 result = mmalloc(mdp, BLOCKSIZE); // does not return NULL
246 block = BLOCK(result);
248 mdp->heapinfo[block].type = log;
249 /* Link all fragments but the first as free, and add the block to the swag of blocks containing free frags */
250 for (i = 1; i < (size_t) (BLOCKSIZE >> log); ++i) {
251 mdp->heapinfo[block].busy_frag.frag_size[i] = -1;
252 mdp->heapinfo[block].busy_frag.ignore[i] = 0;
254 mdp->heapinfo[block].busy_frag.nfree = i - 1;
255 mdp->heapinfo[block].freehook.prev = NULL;
256 mdp->heapinfo[block].freehook.next = NULL;
258 xbt_swag_insert(&mdp->heapinfo[block], &(mdp->fraghead[log]));
260 /* mark the fragment returned as busy */
261 mdp->heapinfo[block].busy_frag.frag_size[0] = requested_size;
262 mdp->heapinfo[block].busy_frag.ignore[0] = 0;
263 //xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_frag.bt[0],XBT_BACKTRACE_SIZE);
264 //xbt_libunwind_backtrace(mdp->heapinfo[block].busy_frag.bt[0],XBT_BACKTRACE_SIZE);
267 mdp -> heapstats.chunks_free += (BLOCKSIZE >> log) - 1;
268 mdp -> heapstats.bytes_free += BLOCKSIZE - (1 << log);
269 mdp -> heapstats.bytes_used -= BLOCKSIZE - (1 << log);
272 /* Large allocation to receive one or more blocks.
273 Search the free list in a circle starting at the last place visited.
274 If we loop completely around without finding a large enough
275 space we will have to get more memory from the system. */
276 blocks = BLOCKIFY(size);
277 start = block = MALLOC_SEARCH_START;
278 while (mdp->heapinfo[block].free_block.size < blocks) {
279 if (mdp->heapinfo[block].type >=0) { // Don't trust xbt_die and friends in malloc-level library, you fool!
280 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);
284 block = mdp->heapinfo[block].free_block.next;
285 if (block == start) {
286 /* Need to get more from the system. Check to see if
287 the new core will be contiguous with the final free
288 block; if so we don't need to get as much. */
289 block = mdp->heapinfo[0].free_block.prev;
290 lastblocks = mdp->heapinfo[block].free_block.size;
291 if (mdp->heaplimit != 0 &&
292 block + lastblocks == mdp->heaplimit &&
293 mmorecore(mdp, 0) == ADDRESS(block + lastblocks) &&
294 (register_morecore(mdp, (blocks - lastblocks) * BLOCKSIZE)) != NULL) {
295 /* Which block we are extending (the `final free
296 block' referred to above) might have changed, if
297 it got combined with a freed info table. */
298 block = mdp->heapinfo[0].free_block.prev;
300 mdp->heapinfo[block].free_block.size += (blocks - lastblocks);
303 result = register_morecore(mdp, blocks * BLOCKSIZE);
305 block = BLOCK(result);
306 for (it=0;it<blocks;it++){
307 mdp->heapinfo[block+it].type = MMALLOC_TYPE_UNFRAGMENTED;
308 mdp->heapinfo[block+it].busy_block.busy_size = 0;
309 mdp->heapinfo[block+it].busy_block.ignore = 0;
310 mdp->heapinfo[block+it].busy_block.size = 0;
312 mdp->heapinfo[block].busy_block.size = blocks;
313 mdp->heapinfo[block].busy_block.busy_size = requested_size;
314 //mdp->heapinfo[block].busy_block.bt_size=xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
315 //mdp->heapinfo[block].busy_block.bt_size = xbt_libunwind_backtrace(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
316 mdp -> heapstats.chunks_used++;
317 mdp -> heapstats.bytes_used += blocks * BLOCKSIZE;
321 /* Need large block(s), but found some in the existing heap */
324 /* At this point we have found a suitable free list entry.
325 Figure out how to remove what we need from the list. */
326 result = ADDRESS(block);
327 if (mdp->heapinfo[block].free_block.size > blocks) {
328 /* The block we found has a bit left over,
329 so relink the tail end back into the free list. */
330 mdp->heapinfo[block + blocks].free_block.size
331 = mdp->heapinfo[block].free_block.size - blocks;
332 mdp->heapinfo[block + blocks].free_block.next
333 = mdp->heapinfo[block].free_block.next;
334 mdp->heapinfo[block + blocks].free_block.prev
335 = mdp->heapinfo[block].free_block.prev;
336 mdp->heapinfo[mdp->heapinfo[block].free_block.prev].free_block.next
337 = mdp->heapinfo[mdp->heapinfo[block].free_block.next].free_block.prev
338 = mdp->heapindex = block + blocks;
340 /* The block exactly matches our requirements,
341 so just remove it from the list. */
342 mdp->heapinfo[mdp->heapinfo[block].free_block.next].free_block.prev
343 = mdp->heapinfo[block].free_block.prev;
344 mdp->heapinfo[mdp->heapinfo[block].free_block.prev].free_block.next
345 = mdp->heapindex = mdp->heapinfo[block].free_block.next;
348 for (it=0;it<blocks;it++){
349 mdp->heapinfo[block+it].type = MMALLOC_TYPE_UNFRAGMENTED;
350 mdp->heapinfo[block+it].busy_block.busy_size = 0;
351 mdp->heapinfo[block+it].busy_block.ignore = 0;
352 mdp->heapinfo[block+it].busy_block.size = 0;
354 mdp->heapinfo[block].busy_block.size = blocks;
355 mdp->heapinfo[block].busy_block.busy_size = requested_size;
356 //mdp->heapinfo[block].busy_block.bt_size = xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
357 //mdp->heapinfo[block].busy_block.bt_size = xbt_libunwind_backtrace(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
359 mdp -> heapstats.chunks_used++;
360 mdp -> heapstats.bytes_used += blocks * BLOCKSIZE;
361 mdp -> heapstats.bytes_free -= blocks * BLOCKSIZE;
364 //printf("(%s) Done mallocing. Result is %p\n",xbt_thread_self_name(),result);fflush(stdout);