1 /* Memory allocator `malloc'. */
3 /* Copyright (c) 2010-2017. The SimGrid Team. All rights reserved. */
5 /* This program is free software; you can redistribute it and/or modify it
6 * under the terms of the license (GNU LGPL) which comes with this package. */
8 /* Copyright 1990, 1991, 1992 Free Software Foundation
10 Written May 1989 by Mike Haertel.
11 Heavily modified Mar 1992 by Fred Fish for mmap'd version. */
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 /** Initialise heapinfo about the heapinfo pages :)
53 static void initialize_heapinfo_heapinfo(xbt_mheap_t mdp)
55 // Update heapinfo about the heapinfo pages (!):
56 xbt_assert((uintptr_t) mdp->heapinfo % BLOCKSIZE == 0);
57 int block = BLOCK(mdp->heapinfo);
58 size_t nblocks = mdp->heapsize * sizeof(malloc_info) / BLOCKSIZE;
60 for (size_t j=0; j!=nblocks; ++j) {
61 mdp->heapinfo[block+j].type = MMALLOC_TYPE_FREE;
62 mdp->heapinfo[block+j].free_block.size = 0;
63 mdp->heapinfo[block+j].free_block.next = 0;
64 mdp->heapinfo[block+j].free_block.prev = 0;
66 mdp->heapinfo[block].free_block.size = nblocks;
69 /* Finish the initialization of the mheap. If we want to inline it
70 * properly, we need to make the align function publicly visible, too */
71 static void initialize(xbt_mheap_t mdp)
74 malloc_info mi; /* to compute the offset of the swag hook */
76 // Update mdp meta-data:
77 mdp->heapsize = HEAP / BLOCKSIZE;
78 mdp->heapinfo = (malloc_info *)
79 align(mdp, mdp->heapsize * sizeof(malloc_info));
80 mdp->heapbase = (void *) mdp->heapinfo;
81 mdp->flags |= MMALLOC_INITIALIZED;
83 // Update root heapinfo:
84 memset((void *) mdp->heapinfo, 0, mdp->heapsize * sizeof(malloc_info));
85 mdp->heapinfo[0].type = MMALLOC_TYPE_FREE;
86 mdp->heapinfo[0].free_block.size = 0;
87 mdp->heapinfo[0].free_block.next = mdp->heapinfo[0].free_block.prev = 0;
90 initialize_heapinfo_heapinfo(mdp);
92 for (i=0;i<BLOCKLOG;i++) {
93 xbt_swag_init(&(mdp->fraghead[i]),
94 xbt_swag_offset(mi, freehook));
98 static inline void update_hook(void **a, size_t offset)
101 *a = (char*)*a + offset;
104 /* Get neatly aligned memory from the low level layers, and register it
105 * into the heap info table as necessary. */
106 static void *register_morecore(struct mdesc *mdp, size_t size)
108 void* result = align(mdp, size); // Never returns NULL
110 /* Check if we need to grow the info table (in a multiplicative manner) */
111 if ((size_t) BLOCK((char *) result + size) > mdp->heapsize) {
114 size_t newsize = mdp->heapsize;
115 while ((size_t) BLOCK((char *) result + size) > newsize)
118 /* Copy old info into new location */
119 malloc_info* oldinfo = mdp->heapinfo;
120 malloc_info* newinfo = (malloc_info*)align(mdp, newsize * sizeof(malloc_info));
121 memcpy(newinfo, oldinfo, mdp->heapsize * sizeof(malloc_info));
123 /* Initialise the new blockinfo : */
124 memset((char*) newinfo + mdp->heapsize * sizeof(malloc_info), 0,
125 (newsize - mdp->heapsize)* sizeof(malloc_info));
127 /* 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 */
128 size_t offset=((char*)newinfo)-((char*)oldinfo);
130 for (int i = 1 /*first element of heapinfo describes the mdesc area*/; i < mdp->heaplimit; i++) {
131 update_hook(&newinfo[i].freehook.next, offset);
132 update_hook(&newinfo[i].freehook.prev, offset);
134 // also update the starting points of the swag
135 for (int i = 0; i < BLOCKLOG; i++) {
136 update_hook(&mdp->fraghead[i].head, offset);
137 update_hook(&mdp->fraghead[i].tail, offset);
139 mdp->heapinfo = newinfo;
141 /* mark the space previously occupied by the block info as free by first marking it
142 * as occupied in the regular way, and then freing it */
143 for (it=0; it<BLOCKIFY(mdp->heapsize * sizeof(malloc_info)); it++){
144 newinfo[BLOCK(oldinfo)+it].type = MMALLOC_TYPE_UNFRAGMENTED;
145 newinfo[BLOCK(oldinfo)+it].busy_block.ignore = 0;
148 newinfo[BLOCK(oldinfo)].busy_block.size = BLOCKIFY(mdp->heapsize * sizeof(malloc_info));
149 newinfo[BLOCK(oldinfo)].busy_block.busy_size = size;
150 mfree(mdp, (void *) oldinfo);
151 mdp->heapsize = newsize;
153 initialize_heapinfo_heapinfo(mdp);
156 mdp->heaplimit = BLOCK((char *) result + size);
160 /* Allocate memory from the heap. */
161 void *mmalloc(xbt_mheap_t mdp, size_t size) {
162 void *res= mmalloc_no_memset(mdp,size);
163 if (mdp->options & XBT_MHEAP_OPTION_MEMSET) {
168 /* Spliting mmalloc this way is mandated by a trick in mrealloc, that gives
169 back the memory of big blocks to the system before reallocating them: we don't
170 want to loose the beginning of the area when this happens */
171 void *mmalloc_no_memset(xbt_mheap_t mdp, size_t size)
176 size_t requested_size = size; // The amount of memory requested by user, for real
178 /* Work even if the user was stupid enough to ask a ridiculously small block (even 0-length),
179 * ie return a valid block that can be realloced and freed.
180 * glibc malloc does not use this trick but return a constant pointer, but we need to enlist the free fragments later on.
182 if (size < SMALLEST_POSSIBLE_MALLOC)
183 size = SMALLEST_POSSIBLE_MALLOC;
185 // printf("(%s) Mallocing %d bytes on %p (default: %p)...",xbt_thread_self_name(),size,mdp,__mmalloc_default_mdp);fflush(stdout);
187 if (!(mdp->flags & MMALLOC_INITIALIZED))
190 mmalloc_paranoia(mdp);
192 /* Determine the allocation policy based on the request size. */
193 if (size <= BLOCKSIZE / 2) {
194 /* Small allocation to receive a fragment of a block.
195 Determine the logarithm to base two of the fragment size. */
198 while ((size /= 2) != 0) {
202 /* Look in the fragment lists for a free fragment of the desired size. */
203 if (xbt_swag_size(&mdp->fraghead[log])>0) {
204 /* There are free fragments of this size; Get one of them and prepare to return it.
205 Update the block's nfree and if no other free fragment, get out of the swag. */
207 /* search a fragment that I could return as a result */
208 malloc_info *candidate_info = xbt_swag_getFirst(&mdp->fraghead[log]);
209 size_t candidate_block = (candidate_info - &(mdp->heapinfo[0]));
210 size_t candidate_frag;
211 for (candidate_frag=0;candidate_frag<(size_t) (BLOCKSIZE >> log);candidate_frag++)
212 if (candidate_info->busy_frag.frag_size[candidate_frag] == -1)
214 xbt_assert(candidate_frag < (size_t) (BLOCKSIZE >> log),
215 "Block %zu was registered as containing free fragments of type %zu, but I can't find any",candidate_block,log);
217 result = (void*) (((char*)ADDRESS(candidate_block)) + (candidate_frag << log));
219 /* Remove this fragment from the list of free guys */
220 candidate_info->busy_frag.nfree--;
221 if (candidate_info->busy_frag.nfree == 0) {
222 xbt_swag_remove(candidate_info,&mdp->fraghead[log]);
225 /* Update our metadata about this fragment */
226 candidate_info->busy_frag.frag_size[candidate_frag] = requested_size;
227 candidate_info->busy_frag.ignore[candidate_frag] = 0;
228 //xbt_backtrace_no_malloc(candidate_info->busy_frag.bt[candidate_frag],XBT_BACKTRACE_SIZE);
229 //xbt_libunwind_backtrace(candidate_info->busy_frag.bt[candidate_frag],XBT_BACKTRACE_SIZE);
231 /* Update the statistics. */
232 mdp -> heapstats.chunks_used++;
233 mdp -> heapstats.bytes_used += 1 << log;
234 mdp -> heapstats.chunks_free--;
235 mdp -> heapstats.bytes_free -= 1 << log;
238 /* No free fragments of the desired size, so get a new block
239 and break it into fragments, returning the first. */
241 result = mmalloc(mdp, BLOCKSIZE); // does not return NULL
242 block = BLOCK(result);
244 mdp->heapinfo[block].type = log;
245 /* Link all fragments but the first as free, and add the block to the swag of blocks containing free frags */
247 for (i = 1; i < (size_t) (BLOCKSIZE >> log); ++i) {
248 mdp->heapinfo[block].busy_frag.frag_size[i] = -1;
249 mdp->heapinfo[block].busy_frag.ignore[i] = 0;
251 mdp->heapinfo[block].busy_frag.nfree = i - 1;
252 mdp->heapinfo[block].freehook.prev = NULL;
253 mdp->heapinfo[block].freehook.next = NULL;
255 xbt_swag_insert(&mdp->heapinfo[block], &(mdp->fraghead[log]));
257 /* mark the fragment returned as busy */
258 mdp->heapinfo[block].busy_frag.frag_size[0] = requested_size;
259 mdp->heapinfo[block].busy_frag.ignore[0] = 0;
260 //xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_frag.bt[0],XBT_BACKTRACE_SIZE);
261 //xbt_libunwind_backtrace(mdp->heapinfo[block].busy_frag.bt[0],XBT_BACKTRACE_SIZE);
264 mdp -> heapstats.chunks_free += (BLOCKSIZE >> log) - 1;
265 mdp -> heapstats.bytes_free += BLOCKSIZE - (1 << log);
266 mdp -> heapstats.bytes_used -= BLOCKSIZE - (1 << log);
269 /* Large allocation to receive one or more blocks.
270 Search the free list in a circle starting at the last place visited.
271 If we loop completely around without finding a large enough
272 space we will have to get more memory from the system. */
273 size_t blocks = BLOCKIFY(size);
274 size_t start = MALLOC_SEARCH_START;
275 block = MALLOC_SEARCH_START;
276 while (mdp->heapinfo[block].free_block.size < blocks) {
277 if (mdp->heapinfo[block].type >=0) { // Don't trust xbt_die and friends in malloc-level library, you fool!
278 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);
282 block = mdp->heapinfo[block].free_block.next;
283 if (block == start) {
284 /* Need to get more from the system. Check to see if
285 the new core will be contiguous with the final free
286 block; if so we don't need to get as much. */
287 block = mdp->heapinfo[0].free_block.prev;
288 size_t lastblocks = mdp->heapinfo[block].free_block.size;
289 if (mdp->heaplimit != 0 &&
290 block + lastblocks == mdp->heaplimit &&
291 mmorecore(mdp, 0) == ADDRESS(block + lastblocks) &&
292 (register_morecore(mdp, (blocks - lastblocks) * BLOCKSIZE)) != NULL) {
293 /* Which block we are extending (the `final free
294 block' referred to above) might have changed, if
295 it got combined with a freed info table. */
296 block = mdp->heapinfo[0].free_block.prev;
298 mdp->heapinfo[block].free_block.size += (blocks - lastblocks);
301 result = register_morecore(mdp, blocks * BLOCKSIZE);
303 block = BLOCK(result);
304 for (int it = 0; it < blocks; it++) {
305 mdp->heapinfo[block + it].type = MMALLOC_TYPE_UNFRAGMENTED;
306 mdp->heapinfo[block + it].busy_block.busy_size = 0;
307 mdp->heapinfo[block + it].busy_block.ignore = 0;
308 mdp->heapinfo[block + it].busy_block.size = 0;
310 mdp->heapinfo[block].busy_block.size = blocks;
311 mdp->heapinfo[block].busy_block.busy_size = requested_size;
312 //mdp->heapinfo[block].busy_block.bt_size=xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
313 //mdp->heapinfo[block].busy_block.bt_size = xbt_libunwind_backtrace(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
314 mdp -> heapstats.chunks_used++;
315 mdp -> heapstats.bytes_used += blocks * BLOCKSIZE;
319 /* Need large block(s), but found some in the existing heap */
322 /* At this point we have found a suitable free list entry.
323 Figure out how to remove what we need from the list. */
324 result = ADDRESS(block);
325 if (mdp->heapinfo[block].free_block.size > blocks) {
326 /* The block we found has a bit left over,
327 so relink the tail end back into the free list. */
328 mdp->heapinfo[block + blocks].free_block.size
329 = mdp->heapinfo[block].free_block.size - blocks;
330 mdp->heapinfo[block + blocks].free_block.next
331 = mdp->heapinfo[block].free_block.next;
332 mdp->heapinfo[block + blocks].free_block.prev
333 = mdp->heapinfo[block].free_block.prev;
334 mdp->heapinfo[mdp->heapinfo[block].free_block.prev].free_block.next
335 = mdp->heapinfo[mdp->heapinfo[block].free_block.next].free_block.prev
336 = mdp->heapindex = block + blocks;
338 /* The block exactly matches our requirements,
339 so just remove it from the list. */
340 mdp->heapinfo[mdp->heapinfo[block].free_block.next].free_block.prev
341 = mdp->heapinfo[block].free_block.prev;
342 mdp->heapinfo[mdp->heapinfo[block].free_block.prev].free_block.next
343 = mdp->heapindex = mdp->heapinfo[block].free_block.next;
346 for (int it = 0; it < blocks; it++) {
347 mdp->heapinfo[block+it].type = MMALLOC_TYPE_UNFRAGMENTED;
348 mdp->heapinfo[block+it].busy_block.busy_size = 0;
349 mdp->heapinfo[block+it].busy_block.ignore = 0;
350 mdp->heapinfo[block+it].busy_block.size = 0;
352 mdp->heapinfo[block].busy_block.size = blocks;
353 mdp->heapinfo[block].busy_block.busy_size = requested_size;
354 //mdp->heapinfo[block].busy_block.bt_size = xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
355 //mdp->heapinfo[block].busy_block.bt_size = xbt_libunwind_backtrace(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
357 mdp -> heapstats.chunks_used++;
358 mdp -> heapstats.bytes_used += blocks * BLOCKSIZE;
359 mdp -> heapstats.bytes_free -= blocks * BLOCKSIZE;
362 //printf("(%s) Done mallocing. Result is %p\n",xbt_thread_self_name(),result);fflush(stdout);