X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/276b2d9b83a3e3afcd449fb53a2dd8d662070036..08d324beef1e0fa723013987a98ed7740d2f8343:/src/xbt/mmalloc/mrealloc.c diff --git a/src/xbt/mmalloc/mrealloc.c b/src/xbt/mmalloc/mrealloc.c index 9d20e03b48..23d0a1c202 100644 --- a/src/xbt/mmalloc/mrealloc.c +++ b/src/xbt/mmalloc/mrealloc.c @@ -1,6 +1,6 @@ /* 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. */ @@ -26,93 +26,114 @@ void *mrealloc(xbt_mheap_t mdp, void *ptr, size_t size) int type; size_t block, blocks, oldlimit; + /* Only keep real realloc, and reroute hidden malloc and free to the relevant functions */ if (size == 0) { mfree(mdp, ptr); - return (mmalloc(mdp, 0)); + return mmalloc(mdp, 0); } else if (ptr == NULL) { - return (mmalloc(mdp, size)); + return mmalloc(mdp, size); } - //printf("(%s)realloc %p to %d...",xbt_thread_self_name(),ptr,(int)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].busy.type; + type = mdp->heapinfo[block].type; + 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. */ - if (size <= BLOCKSIZE / 2) { - //printf("(%s) alloc large block...",xbt_thread_self_name()); + + if (size <= BLOCKSIZE / 2) { // Full block -> Fragment; no need to optimize for time + result = mmalloc(mdp, size); - if (result != NULL) { - memcpy(result, ptr, size); + if (result != NULL) { // useless (mmalloc never returns NULL), but harmless + 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.info.block.size) { + if (blocks < mdp->heapinfo[block].busy_block.size) { + int it; /* The new size is smaller; return excess memory to the free list. */ //printf("(%s) return excess memory...",xbt_thread_self_name()); - mdp->heapinfo[block + blocks].busy.type = 0; - mdp->heapinfo[block + blocks].busy.info.block.size - = mdp->heapinfo[block].busy.info.block.size - blocks; - mdp->heapinfo[block].busy.info.block.size = blocks; - mdp->heapinfo[block].busy.info.block.busy_size = size; + 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; mfree(mdp, ADDRESS(block + blocks)); + + mdp->heapinfo[block].busy_block.size = blocks; + mdp->heapinfo[block].busy_block.busy_size = requested_size; + result = ptr; - } else if (blocks == mdp->heapinfo[block].busy.info.block.size) { - /* No size change necessary. */ + } else if (blocks == mdp->heapinfo[block].busy_block.size) { + + /* 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. */ - blocks = mdp->heapinfo[block].busy.info.block.size; + 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(mdp, requested_size); if (ptr != result) memmove(result, ptr, blocks * BLOCKSIZE); } 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;