/* Change the size of a block allocated by `mmalloc'.
Copyright 1990, 1991 Free Software Foundation
- Written May 1989 by Mike Haertel. */
+ Written May 1989 by Mike Haertel. */
/* Copyright (c) 2010. The SimGrid Team.
* All rights reserved. */
int type;
size_t block, blocks, oldlimit;
- /* Only keep real realloc and hidden malloc and free to the relevant functions */
+ /* Only keep real realloc, and reroute hidden malloc and free to the relevant functions */
if (size == 0) {
- fprintf(stderr,"free from realloc...");
mfree(mdp, ptr);
- fprintf(stderr,"done\n");
return mmalloc(mdp, 0);
} else if (ptr == NULL) {
return mmalloc(mdp, size);
if ((char *) ptr < (char *) mdp->heapbase || BLOCK(ptr) > mdp->heapsize) {
printf
- ("FIXME. Ouch, this pointer is not mine, refusing to proceed (another solution would be to malloc it instead of reallocing it, see source code)\n");
+ ("FIXME. Ouch, this pointer is not mine, refusing to proceed (another solution would be to malloc it instead of reallocing it, see source code)\n");
result = mmalloc(mdp, size);
abort();
return result;
}
+ size_t requested_size = size; // The amount of memory requested by user, for real
+
+ /* Work even if the user was stupid enough to ask a ridicullously small block (even 0-length),
+ * ie return a valid block that can be realloced and freed.
+ * glibc malloc does not use this trick but return a constant pointer, but we need to enlist the free fragments later on.
+ */
+ if (size < SMALLEST_POSSIBLE_MALLOC)
+ size = SMALLEST_POSSIBLE_MALLOC;
+
block = BLOCK(ptr);
type = mdp->heapinfo[block].type;
- if (type<0)
- THROWF(arg_error,0,"Asked realloc a fragment comming from a *free* block. I'm puzzled.");
switch (type) {
+ case -1:
+ fprintf(stderr, "Asked realloc a fragment coming from a *free* block. I'm puzzled.\n");
+ abort();
+ break;
+
case 0:
/* Maybe reallocate a large block to a small fragment. */
result = mmalloc(mdp, size);
if (result != NULL) { // useless (mmalloc never returns NULL), but harmless
- memcpy(result, ptr, size);
+ memcpy(result, ptr, requested_size);
mfree(mdp, ptr);
return (result);
}
}
- /* The new size is a large allocation as well;
- see if we can hold it in place. */
+ /* Full blocks -> Full blocks; see if we can hold it in place. */
blocks = BLOCKIFY(size);
if (blocks < mdp->heapinfo[block].busy_block.size) {
- int it;
+ int it;
/* The new size is smaller; return excess memory to the free list. */
//printf("(%s) return excess memory...",xbt_thread_self_name());
- for (it= block+blocks; it< mdp->heapinfo[block].busy_block.size ; it++)
- mdp->heapinfo[it].type = 0;
+ for (it= block+blocks; it< mdp->heapinfo[block].busy_block.size ; it++)
+ mdp->heapinfo[it].type = 0; // FIXME that should be useless, type should already be 0 here
+
mdp->heapinfo[block + blocks].busy_block.size
- = mdp->heapinfo[block].busy_block.size - blocks;
+ = mdp->heapinfo[block].busy_block.size - blocks;
+ mfree(mdp, ADDRESS(block + blocks));
+
mdp->heapinfo[block].busy_block.size = blocks;
- mdp->heapinfo[block].busy_block.busy_size = size;
+ mdp->heapinfo[block].busy_block.busy_size = requested_size;
- mfree(mdp, ADDRESS(block + blocks));
result = ptr;
} else if (blocks == mdp->heapinfo[block].busy_block.size) {
- /* No size change necessary. */
+
+ /* No block size change necessary; only update the requested size */
result = ptr;
+ mdp->heapinfo[block].busy_block.busy_size = requested_size;
+
} else {
/* Won't fit, so allocate a new region that will.
- Free the old region first in case there is sufficient
- adjacent free space to grow without moving. */
+ Free the old region first in case there is sufficient adjacent free space to grow without moving.
+ This trick mandates using a specific version of mmalloc that does not memset the memory to 0 after
+ action for obvious reasons. */
blocks = mdp->heapinfo[block].busy_block.size;
/* Prevent free from actually returning memory to the system. */
oldlimit = mdp->heaplimit;
mdp->heaplimit = 0;
mfree(mdp, ptr);
mdp->heaplimit = oldlimit;
- result = mmalloc(mdp, size);
- if (result == NULL) {
- mmalloc(mdp, blocks * BLOCKSIZE);
- return (NULL);
- }
+
+ result = mmalloc_no_memset(mdp, requested_size);
+ //fprintf(stderr,"remalloc(%zu)~>%p\n",requested_size,result);
+
if (ptr != result)
memmove(result, ptr, blocks * BLOCKSIZE);
+ /* FIXME: we should memset the end of the recently area */
}
break;
- default:
- /* Old size is a fragment; type is logarithm
- to base two of the fragment size. */
+ default: /* Fragment -> ??; type=logarithm to base two of the fragment size. */
+
if (size > (size_t) (1 << (type - 1)) && size <= (size_t) (1 << type)) {
/* The new size is the same kind of fragment. */
//printf("(%s) new size is same kind of fragment...",xbt_thread_self_name());
+
result = ptr;
- } else {
+ int frag_nb = RESIDUAL(result, BLOCKSIZE) >> type;
+ mdp->heapinfo[block].busy_frag.frag_size[frag_nb] = requested_size;
+
+ } else { /* fragment -> Either other fragment, or block */
/* The new size is different; allocate a new space,
and copy the lesser of the new size and the old. */
//printf("(%s) new size is different...",xbt_thread_self_name());
- result = mmalloc(mdp, size);
- if (result == NULL)
- return (NULL);
+ result = mmalloc(mdp, requested_size);
- memcpy(result, ptr, MIN(size, (size_t) 1 << type));
+ memcpy(result, ptr, MIN(requested_size, (size_t) 1 << type));
mfree(mdp, ptr);
}
break;
